SpaceX

[Sigmetnow]

—- Today in space news

  Eric Berger
@SciGuySpace 3/30/21, 10:39 AM
Insane day in space:
• SpaceShip III reveal by Virgin Galactic
• SN 11 flies and then rains down debris on launch site
• SpaceX reveals cupola capability on Crew Dragon
• Full crew of @inspiration4x announced, including @DrSianProctor

https://twitter.com/sciguyspace/status/1376907058516271108

So...:

Eric Berger
@SciGuySpace 3/30/21
In the arc of space tourism, is it more consequential today to have the all-private Inspiration4 orbital crew announcement; or Virgin Galactic’s reveal of a lighter, more robust SpaceShip III?
 https://twitter.com/sciguyspace/status/1376929310443966468
Poll at the link.
 
Eric Berger:
Orbital spaceflight is clearly more important long term. However, if Virgin Galactic is successful—and yes that’s a big IF—it has the potential to expose many more people to the overview effect more quickly.
 
Chris B - NSF:
Crew Dragon paid respect to Shuttle. Virgin Galactic airbrushed it out of their "history of flight" decal.
And for that reason............
 
Eric Berger:
Yeah. what's up with that?!?

—- Because Canadarm vs. Cargo Dragon

NASA
@NASA 3/29/21, 4:45 PM
On April 5, NASA’s @SpaceX Crew-1 astronauts suit up to relocate their Crew Dragon “Resilience” spacecraft on the @Space_Station — marking another 1st for commercial spaceflight! Get the details: go.nasa.gov/3ryqOZ8

Time: Coverage starts at 6am ET
Video : nasa.gov/live 

  https://twitter.com/nasa/status/1376636723392872452
 

This excellent image from @RaffaeleDiPalma shows why Crew-1 Dragon needs to be relocated from the forward port of Harmony to the top port - so that Crew-2 Dragon can dock to the forward port, which will leave the top port clear when Crew-1 departs. (1/2)
 
This in turn will allow the SpaceX-22 Cargo Dragon to dock at the top port, which is necessary as the space station's robot arm can't reach into the Trunk to extract cargo if Cargo Dragon docks to the forward port. (2/2)

https://twitter.com/space_pete/status/1376661988345049090
⬇️ Image below.

[Sigmetnow]

—- Starship
SpaceX:
Shortly after the landing burn started, SN11 experienced a rapid unscheduled disassembly. Teams will continue to review data and work toward our next flight test.
https://www.spacex.com/vehicles/starship/index.html

< FWIW RUD at landing burn ignition altitude was roughly 1300’+/- which would explain the large debris field.

Chris B - NSF:
Worth noting that Falcon 9's didn't nail the landing for a while. Now look at them. SpaceX even created a fun video about it!
➡️https://www.youtube.com/watch?v=bvim4rsNHkQ
I dare say SpaceX will be able to create a Starship version of this in the near future, once they are also nailing landings.

https://twitter.com/nasaspaceflight/status/1377032333677756421
(Elon Musk liked this tweet.)

—-

Mary:
Both aft flaps on Starship SN15 are going to be installed today!!
https://twitter.com/bocachicagal/status/1377282348144820229

Starship SN15 is headed for the high bay.
https://twitter.com/bocachicagal/status/1377355812071428102 

Photo at each link.

Brady Kenniston
@TheFavoritist 3/30/21, 8:16 PM
The "Mystery Structure" has a nosecone lifted inside its cage, potentially to be used as a test rig. Meanwhile BN1 will be scrapped and Starship SN11 launches but fails during the landing maneuver.
➡️youtu.be/gBNk97u3ENo   

https://twitter.com/thefavoritist/status/1377052172270108672
My current WAG: it’s a support structure for moveable platforms that can be raised and lowered like those for window washers, to be used by people installing heat shield tiles or other exterior work.  Quicker, safer and more efficient access than fixed platforms, or moving crane lifts around. We’ll see.

—- Inspiration4 Livestream 
Meet The First All-Civilian Space Crew
➡️https://www.youtube.com/watch?v=4bkx2ENyAAs
  45 min press conference. Just after minutes 18 & 28, Benji Reed talks about the glass dome “cupola”. Min 38, they talk about the moment they were notified of their selection. Chris was actually referred by a friend who was selected for the Generosity pillar but who couldn’t go for personal reasons.

SpaceX to upgrade Dragon with the most immersive window ever launched into space 
By Eric Ralph March 31, 2021

In a live March 30th event celebrating the final crew selection, SpaceX director Benji Reed stated that NASA has been closely involved with with development of Dragon’s dome window. Most notably, he strongly implied that flight-proven Crew Dragons would be able to swap between dome and docking hardware with enough ease that a Dragon flown with a dome on a SpaceX tourist mission could still be modified to support NASA astronaut launches, thus ensuring commonality within the Dragon ‘fleet’ SpaceX is building.

https://www.teslarati.com/spacex-crew-dragon-glass-dome-upgrade-inspiration4/

Musk has been thinking about big space windows on Starship for quite some time. He recently reposted this render:

Elon Musk
@elonmusk 3/20/21, 5:21 AM
Music in zero gravity

https://twitter.com/wholemarsblog/status/1373223075207073795
⬇️ Image below. (I’m still trying to figure out how she moves away from there after she finishes her set. Also how she prevents that dress from totally enveloping her while she plays. )

—- More about space windows today:

Axiom Space
@Axiom_Space 3/31/21, 12:17 PM
The windows of the Axiom Earth Observatory cupola will be the largest ever constructed for space. Seen here, our window frame being rinsed prior to a chemical coating that will ensure corrosion protection. This milestone sets up the remainder of the window test program.
  —-
Of several module subsystem test programs underway now, this will one day translate to eight windows encircling astronauts aboard the future Axiom Station as they overlook the planet in 360-degree freedom.
The first commercial destination in low-Earth orbit is on the way. 

https://twitter.com/axiom_space/status/1377294066203918337
Vid clip of window ‘treatment’ at the link.


—- Crew-2 launch 

Kathy Lueders
@KathyLueders 3/31/21, 12:02 PM
We’re inviting you to take part in virtual activities and events leading up to the @SpaceX Crew-2 mission to the @Space_Station, targeted no earlier than 6:11 am ET on April 22! Live coverage and countdown commentary will begin at 2 am ET on @NASA TV. go.nasa.gov/3wdAtb1 

https://twitter.com/kathylueders/status/1377290087147393028

NASA Invites Public to Share Excitement of Agency’s SpaceX Crew-2 Mission
https://www.nasa.gov/feature/nasa-invites-public-to-share-excitement-of-agency-s-spacex-crew-2-mission

—- SpaceX on a roll

Eric Berger
@SciGuySpace 3/31/21, 2:56 PM
With the @inspiration4x mission launching this fall, it now seems likely that barring a serious incident Crew Dragon will fly five astronaut missions before humans board Starliner (Demo-2, Crews 1,2,3, Insp4). First Starliner crewed mission is likely NET 4Q of this year.

https://twitter.com/sciguyspace/status/1377333907759095813
 
—- And, Starliner OFT-2 slips again 

Eric Berger
@SciGuySpace 3/31/21, 6:20 PM
There's no official confirmation of this yet, but another launch slip of Boeing's Orbital Flight 2 mission is coming. @SpaceflightNow has already moved the mission to "Late July" and a source tells me the same. May be due to avionics, but I'm not certain. 

https://twitter.com/sciguyspace/status/1377385340361662467

[Sigmetnow]

—- Emotional rescue

Everyday Astronaut
@Erdayastronaut 3/31/21
I can’t believe it... we recovered EVERYTHING! No damage to ANY of our gear by inches, just dirty! The only thing that went wrong was our dish guide wire got hit and it moved our remote connection so we lost footage. Going through the footage now with @considercosmos and wow

https://twitter.com/erdayastronaut/status/1377420977894612992
Photo at the link.

—- Starship: Orbital Launch Tower
SpaceX has begun building a Starship 'launch tower' that could be the tallest structure in South Texas once complete
https://twitter.com/teslarati/status/1377689166369206276
⬇️ Photo below.

SpaceX’s Starship booster-catching ‘launch tower’ begins to take shape in Texas
By Eric Ralph April 1, 2021

Aerial photos show that SpaceX has rapidly begun building the first of two planned skyscraper-sized Starship ‘launch towers’ in South Texas – towers that could one day catch the Super Heavy boosters out of the air with huge arms. ... 

https://www.teslarati.com/spacex-starship-booster-catching-launch-tower-progress/
⬇️ Photo below.

—- Cheese-it

Elon Musk
@elonmusk 4/1/21, 6:25 AM
SpaceX is going to put a literal Dogecoin on the literal moon
 
< I know it’s April Fool’s but I don’t for a second question that he means this
 
Elon Musk:
After all, SpaceX’s first payload to orbit & back was a wheel of cheese …

https://twitter.com/elonmusk/status/1377596011774808069
< If FH's was a Roadster, what is Starships first payload to orbit gonna be?

The West Wing:  Leo's Cheese Speech
➡️ https://www.youtube.com/watch?v=Vm9HZq53rqU&feature=youtu.be

—-
Two steps forward: Virgin Galactic’s new ship and Dragon’s diverse crew 
"You have to start somewhere."
Eric Berger - 4/1/2021

Two developments this week show how US companies are making slow but steady progress toward ushering in an era of space tourism.

On Tuesday, Virgin Galactic released images of its next-generation suborbital space plane. A few hours later, the two final crew members of an all-private mission aboard a SpaceX Crew Dragon spacecraft were publicly named. None of this is happening as quickly as we might hope, but we are slowly moving toward the day when more and more "regular" people could go into space. ... 

https://arstechnica.com/science/2021/04/finally-were-seeing-some-small-but-real-steps-toward-space-tourism/

I feel bad for the astronauts who have worked for years, even decades, in the NASA astronaut corps, hoping to be one of the very few chosen to go to space — only to have (talented but non-NASA) civilians beat them there.  Particularly for the ones selected for the Starliner, who have seen their dreams pushed further and further back. (Although I appreciate the karma of Chris Ferguson retiring from NASA after three space shuttle missions, going to work for Boeing as director of Crew and Mission Operations for Boeing's Commercial Crew Program, getting himself assigned in 2018 to the first crewed Starliner flight, then stepping down in 2020 “for personal reasons” after it became clear that particular bird would not fly crew any time soon.)

[Sigmetnow]

—- Starship SN15
  Photo at these links:

Mary
@BocaChicaGal 4/2/21, 8:58 AM
This morning Starship SN15’s nosecone is heading into the high bay. It appears that SpaceX is not wasting any time in preparing SN15 to roll to the launch site ASAP.
https://twitter.com/bocachicagal/status/1377968691783041033

Mary
@BocaChicaGal 4/2/21, 5:25 PM
Starship SN15’s nosecone is being stacked in the high bay. #WenHop
https://twitter.com/bocachicagal/status/1378096321282904069 

Video

Brady Kenniston
@TheFavoritist 4/2/21, 9:40 PM
Starship SN15's nosecone was lifted onto its tank section. SN15 is an upgraded version of the previous Starship prototypes that implements some major changes according to Elon.
Video from Mary (@BocaChicaGal) and the NSF Robotic Camera Team
➡️youtu.be/Kqn9Y0qeNuo.

https://twitter.com/thefavoritist/status/1378160433958375426


—-Crew-2 Launch in three weeks? No sweat; let’s Launch some Starlinks first, from the other pad.
April 7: Falcon 9 • Starlink V1.0-L23
Launch time: 1634 GMT (12:34 p.m. EDT)
Launch site: SLC-40, Cape Canaveral Space Force Station, Florida
A SpaceX Falcon 9 rocket will launch the 24th batch of approximately 60 satellites for SpaceX’s Starlink broadband network, a mission designated Starlink V1.0-L23.

— Notice to Mariners: Starlink launch

Raul
@Raul74Cz 4/2/21, 7:11 AM
LHAs map for #Starlink v1.0-L23 mission from SLC-40 NET 07 Apr 16:34 UTC, altern. 08-15 Apr based on issued NOTMAR. Booster landing ~615km downrange, fairing recovery ~667km downrange. Double S2 burn launch profile with S2 reentry south of Australia again. bit.do/LHA13 

https://twitter.com/raul74cz/status/1377941669761458180
⬇️ Maps below. Second shows the usual reentry area for a Falcon 9 upper stage (and many other rockets).


—-SpaceX COPVs are tough little birds which have a history of traveling independently  
A COPV from the Falcon 9 second stage which reentered over the Pacific Northwest has been discovered in eastern Washington.

GRANT COUNTY, Wash. - A portion of the SpaceX rocket that re-entered Earth's atmosphere last week in a dazzling light show has been discovered in Eastern Washington, officials said.

Kyle Foreman of the Grant County Sheriff's Office says the debris was a composite overwrapped pressure vessel that would have contained pressurized helium. ...

https://nbc16.com/news/local/debris-from-spacex-rocket-located-recovered-in-wash-state

—-Bill Nelson, NASA Admin.

Eric Berger
@SciGuySpace 4/2/21, 9:02 AM
This Via Satellite interview with Bill Nelson, in 2018, offers a pretty good preview of what to expect from the incoming administrator. This answer was especially interesting:

https://twitter.com/sciguyspace/status/1377969582460272641
⬇️ Text image below.

From the Archive: 2018 Interview with Sen. Bill Nelson 
FCC Chairman Wants to Cultivate Innovation in Space
https://www.satellitetoday.com/government-military/2021/04/01/from-the-archive-2018-interview-with-sen-bill-nelson/

—- Europa Clipper

NASA_SLS
@NASA_SLS 4/2/21, 2:25 PM
NASA's Europa Clipper has passed its critical design review. The spacecraft will swoop around Jupiter's moon Europa to investigate the habitability of the ocean world.
DETAILS >> go.nasa.gov/2PsO51v   

https://twitter.com/nasa_sls/status/1378050852800376832

Michael Baylor:
Do they still think that they are launching it? 

https://twitter.com/nextspaceflight/status/1378052221053542408
The replies to both tweets are pretty funny, if you are aware that launching EC on a commercial rocket (probably Falcon Heavy), rather than SLS, was approved back in February:

NASA to use commercial launch vehicle for Europa Clipper 

WASHINGTON — NASA is no longer considering launching the Europa Clipper mission on the Space Launch System, deciding instead to launch the spacecraft on a commercial rocket it will procure in the next year.
During a Feb. 10 presentation at a meeting of NASA’s Outer Planets Assessment Group (OPAG), leaders of the Europa Clipper project said the agency recently decided to consider only commercial launch vehicles for the mission, and no longer support a launch of the spacecraft on the SLS. ...

https://www.copernical.com/news-public/item/22079-2021-02-11-05-57-28

[gerontocrat]

They are sending a huge coffin into space.
Saves using valuable land for the dead?

[Sigmetnow]

They are sending a huge coffin into space.
Saves using valuable land for the dead?

Visual reminder to boaters thinking it might be fun to get up close to a booster landing: Not a good idea.

[Sigmetnow]

—- Starship

TankWatchers
@WatchersTank 4/2/21, 7:37 AM
MYSTERIOUS NOSECONE IN STARBASE
What do you think will be the purpose of this nosecone?
Yesterday SpaceX also attached 2 white bars where usually the flaps are installed.
@BocaChicaGal for @NASASpaceflight 

https://twitter.com/watcherstank/status/1377948230944747520
⬇️ Photo below.
 
We can now see that the “mystery structure” surrounds a Starship forward section that is considerably smaller in diameter than the normal Starship barrel.
The Starship User Guide says the ship’s payload fairing outer diameter is 9 meters, and the payload bay is 8 meters....
So perhaps we are seeing a prototype payload bay and its support structures — a normal-size nosecone can likely be sleeved over it.  This is no dummy mass simulator; interesting bits are visible incorporated into the lower right of the new section.   Lots of sensors, no doubt!

—- Back in space again
Given the recent discussion here of the adverse health effects of long-duration spaceflight, I note that their extensive prior space experience has not prevented these astronauts from being cleared to launch again this month to the ISS for a 6-month stay:

Busy month of crew rotations on tap at International Space Station
April 1, 2021 Stephen Clark

Novitskiy, 49, will launch on his third expedition to the space station after spending 340 days in orbit on his two previous missions. Vande Hei, 54, is a retired U.S. Army colonel who logged 168 days in orbit on a space station mission in 2017 and 2018.

NASA astronaut Shane Kimbrough, a 53-year-old former Army helicopter pilot, is commander of the Crew-2 mission. He is a veteran of two previous space missions, including a flight on the space shuttle Endeavour in 2008 and a long-duration expedition on the space station in 2016 and 2017.

Japanese astronaut Akihiko Hoshide and French-born European Space Agency astronaut Thomas Pesquet will also fly on the Crew-2 mission. Hoshide, 52, is an aerospace engineer with decades of experience in Japan’s space program. This is his third spaceflight, after a mission on the space shuttle Discovery in 2008 and then spent four months on the space station in 2012.

Pesquet is a 43-year-old former Air France airline pilot with one previous trip to the space station under his belt. He lived and worked on the space station in 2016 and 2017, flying to the complex on the same Soyuz mission as Russian cosmonaut Oleg Novitskiy, who will arrive at the station two weeks before the Crew-2 mission docks later this month. 

https://spaceflightnow.com/2021/04/01/busy-month-of-crew-rotations-on-tap-at-international-space-station/

—- NASA deep space biology study
Yeast growth study, to be launched as a cubesat with Artemis I
The 1st long-duration biology experiment in deep space completed its assembly and tests — bringing it one step closer to launching on our @NASAArtemis I mission around the Moon! Get more details on BioSentinel’s groundbreaking mission here:
NASA’s BioSentinel Team Prepares CubeSat For Deep Space Flight 
https://www.nasa.gov/feature/ames/nasa-s-biosentinel-team-prepares-cubesat-for-deep-space-flight

[Tor Bejnar]

How are astronauts protected from radiation in a spacecraft?

A few mm of aluminium blocks most of the radiation you would encounter in low Earth orbit. In the ISS, 95% of the radiation is blocked. This is enough for low Earth orbit: these orbits are inside the Van Allen Belts, so they are protected from the worst radiation. If we want to go beyond LEO for longer periods, more protection is needed.

[interstitial]

Polyethylene (PE) makes better shielding for space craft then aluminum. If I remember correctly it takes 1 m of H2O to shield. I have no idea how much PE that would be.
For a mars mission: Radiation is highly variable in space and randomly astronauts would need to enter a shielded chamber for anywhere  from a few minutes to a few weeks with little warning. The psychological stress from not just spending time in a confined space for several years but then randomly being confined to an even smaller space, probably a bunk, with little room to move around in is no small factor. Their are few analogues. A nuclear submarine with tours of less than a year come to mind. A nuclear submarine would be palatial in comparison with recreation spaces and multiple decks. All the plans I have seen appear to be about the size of a normal apartment. All of that space would be communal. For 6-8 people. For 5-6 years. While there would be no shortage of volunteers I don't think I have met anyone who would survive that trip sane. I know I would not.

[Sigmetnow]

—- Monday ISS parking spot swap

NASA
@NASA 4/4/21, 5:52 PM
Coming up: the first-ever port relocation for a @Commercial_Crew spacecraft on the @Space_Station. With four astronauts aboard, the @SpaceX Crew Dragon Resilience will undock, then redock at the Harmony module's space-facing port.
➡️ Watch at 6am ET: go.nasa.gov/31Ju1ur 

https://twitter.com/nasa/status/1378827722273783809

—- Wednesday Starlink launch
April 7: Falcon 9 • Starlink V1.0-L23
Launch time: 1634 GMT (12:34 p.m. EDT)
Launch site: SLC-40, Cape Canaveral Space Force Station, Florida
A SpaceX Falcon 9 rocket will launch the 24th batch of approximately 60 satellites for SpaceX’s Starlink broadband network, a mission designated Starlink V1.0-L23.
https://spaceflightnow.com/launch-schedule/

—- Starship

SPadre
@SpacePadreIsle 4/3/21, 4:23 PM
Large things that help make Starships be rolling down Starbase street Monday

https://twitter.com/spacepadreisle/status/1378443080559423491
Image at the link: Road closure 8am-12pm “intermittent”

[Update: fully stacked] SpaceX speeds up work on Starship with “hundreds of improvements”
By Eric Ralph  April 2, 2021
https://www.teslarati.com/spacex-speeds-up-starship-sn15-work-hundreds-upgrades/


A technical problem during engine startup is believed to have led to the loss of Starship SN11, not any use of the Flight Termination System (FTS). Still awaiting specific details from Elon.

—-
Starship SN15 prepares to rollout as Raptor testing ups a gear 
written by Chris BerginApril 4, 2021

“Next major technology rev is at SN20. Those ships will be orbit-capable with heat shield & stage separation system. Ascent success probability is high. However, SN20+ vehicles will probably need many flight attempts to survive Mach 25 entry heating & land intact.”
...
“BN1 is a manufacturing pathfinder, so will be scrapped. We learned a lot, but have already changed design to BN2,” Elon noted, with the design change likely to be related to the position of the LOX and CH4 tanks in the stack.
...
“Goal is to get BN2 with engines on orbital pad before end of April. It might even be orbit-capable if we are lucky,” Elon added, with “orbit-capable” a highly surprising statement given his initial note about the first test of a Super Heavy originally being a 150-meter hop.
...
The Raptor Vacuum (RVac), with its huge nozzle, will be the engine that will provide the bulk of Starship’s propulsive power in space.
So far, testing this engine has been progressing, with Elon recently noting, “Going well. Lot of work for an extra 20 secs of Isp!”
Elon had previously cited the advantage of vertical testing for Raptors as one reason the Tripod was converted to hosting the Starship engine. “Testing Raptor in vertical configuration (on the giant tripod) should allow us to simplify some aspects of the engine design.”
Soon, McGregor will have two additional vertical test stands for Raptor, with the construction of a new stand ongoing at the Texas site. ...

https://www.nasaspaceflight.com/2021/04/starship-sn15-rollout-raptor-testing/

—- Starlink
Elon Musk’s Starlink could make Earth visible to alien civilizations: paper 
https://www.teslarati.com/elon-musk-starlink-aliens-detection-study/
April 3, 2021


—- Future Russian & Japanese rockets look a lot like Falcon 9 & Starship

Katya Pavlushchenko
@katlinegrey 4/4/21, 3:48 AM
The conceptual design of the #AmurSPG rocket will be ready in September 2021, said Alexander Bloshenko, the executive director of Roscosmos. The methane-fueled rocket will take to LEO 12 t of payload in expendable version, and 10,5 t in reusable version. tass.ru/kosmos/11063605
[Infographics, in Russian — rocket looks like a Falcon 9!]

Elon Musk:
This a good path, but I recommend aiming for full reusability
 
< More like the Falcon Nein..
Elon Musk:
Haha Falcon? Nein!
https://twitter.com/elonmusk/status/1378836915420602372

   —-
< What do you think about JAXA's fully reusable space plane? It has similar design ambitions as Starship.
{Infographics in Japanese. Vaguely Starship-ish.]

Elon Musk:
I recommend propulsive landing, as that is extensible to planets, moons & asteroids. Wings & runways are limited to Earth.
https://twitter.com/elonmusk/status/1378836600881352706   

< How many times can a Falcon 9 booster be reused (re-flown and landed), what's the max. limit that SpaceX is targeting?
 
Elon Musk:
For practical purposes, there is no limit. It will just get increasingly difficult to service.

https://twitter.com/elonmusk/status/1378836183745191936

[Sigmetnow]

All the plans I have seen appear to be about the size of a normal apartment.

A single Starship has a payload volume approximately the same size as the entire pressurized volume of the International Space Station, or bigger than a 6-bedroom house.  Astronauts fare quite well psychologically in that space for 6 months or more.  And there will be multiple Starships on each Mars sortie.  Perhaps they will dock to each other and double (or more) the space available during a trip.  Dangerous radiation storms usually do not last longer than a few hours or days; cargo Starships could provide additional shielding for temporary human sheltering.

Early cargo Starships will remain on the surface, making additional work space available while larger habitats are constructed, no doubt including protection using layers of Martian soil — perhaps tunnels dug by electric Boring Company machines.

[Sigmetnow]

Happening now:
Dragon ISS Port Relocation
Compilation of a thread detailing the steps for the maneuver, written by Anthony Vareha , NASA Flight Director:

Good morning/ evening. Just waking up for the #Crew1 port relocate shift. In a previous tweet I explained why (sometimes capsules need specific parking), now let's talk the actual event tonight.

The whole @Space_Station crew will wake up on time at 0600 UTC as on any day. Amidst the normal breakfast routine, @Astro_illini will put away his sleeping station as the ship returns from "bedroom" to "spaceship". Control panel displays will be activated and configured.

The crew will pull ISS emergency equipment out of Dragon - it doesn't necessarily need to make the ride and can be put back at the end of the day. Dragon has its own free- flight emergency equipment.

Shannon and @Astro_Soichi will put on their @SpaceX suits in #ISS while @Astro_illini and @AstroVicGlover finalize cabin prep - just a bit easier to do it in different rooms. Then we close the hatch with all 4 inside and start to depressurize the docking tube ("vestibule")
 ...

https://threadreaderapp.com/thread/1378905528387129348.html

< Thanks for the thread! Why the need for all 4 to suit up/be inside?
<< If they can't re-dock, and end up having to return to earth, all four have to be together. Otherwise, someone is stuck on the ISS w/out a lifeboat, and that's a cardinal sin.
< Side question, in case of an emergency evacuation, do the astronauts must use the same vehicle as the one they came in ? How would they connect their non-SpaceX suits to dragon ? (can they ?)
<< Short answer is yes. That's the reason when they isolate sections or modules the crew must isolate in the module their ride home is docked to.   

https://twitter.com/enterprise_flt/status/1378905528387129348

Watch live at https://www.nasa.gov/nasalive

—-
Edit:

William Harwood
@cbs_spacenews 4/5/21, 7:21 AM
ISS/Crew-1: Hard mate confirmed; the Crew-1 Dragon "Resilience" is now firmly locked into place at IDA-3; hatches will be opened in about 2 hours, after extensive leak checks and vestibule pressurization 

https://twitter.com/cbs_spacenews/status/1379031477011279872

[Sigmetnow]

—- Starship

< Elon how is the investigation into SN11’s RUD going?
Elon Musk:
Ascent phase, transition to horizontal & control during free fall were good.
A (relatively) small CH4 leak led to fire on engine 2 & fried part of avionics, causing hard start attempting landing burn in CH4 turbopump.
This is getting fixed 6 ways to Sunday.

https://twitter.com/elonmusk/status/1379022709737275393

Engine Fire Due To Fuel Leak Led To Prototype Rocket Explosion Explains Musk 
Apr 5, 2021 08:08 EDT
https://wccftech.com/engine-fire-due-to-fuel-leak-led-to-prototype-rocket-explosion-explains-musk/

—- Ground Service Equipment tank built by SpaceX is on the move

Mary
@BocaChicaGal 4/5/21, 3:50 PM
The GSE 1 tank is taking a stroll down highway 4 at the production site this afternoon.   

➡️ https://twitter.com/bocachicagal/status/1379159435046699025
Photo at the link.

—- Crews 1, 2 & 3. Also Cargo & Inspiration4!

SpaceX has a packed schedule for crew and cargo Dragon missions in the months ahead:
April 22 — Crew-2 launch
April 28 — Crew-1 return
June 3 — CRS-22 [Cargo] launch
Sept. 15 — Inspiration4 launch
Oct. 23 — Crew-3 launch
Oct. 31 — Crew-2 return 

https://twitter.com/thesheetztweetz/status/1379176348619567105

⬇️ Photo below.

If you look closely, you'll notice the members of #Crew2 aren't *just* holding up two fingers, but dirty fingers because they've marked their initials in the soot of their [reflown] #Falcon9 booster behind them.
Possible new crew tradition only applicable to #SpaceX crews??
  —
More: blogs.nasa.gov/commercialcrew/ 

https://twitter.com/alteredjamie/status/1379175415709843460

NASA, SpaceX Relocate Crew-1 Dragon; More Crewed Flight Preps Continue 
April 5, 2021
https://blogs.nasa.gov/commercialcrew/2021/04/05/nasa-spacex-relocate-crew-1-dragon-more-crewed-flight-preps-continue/
No mention of Starliner OFT-2....

—-

NASA Commercial Crew
@Commercial_Crew 4/5/21, 9:50 AM
Today marks the 10th anniversary of the public-private partnership that returned human spaceflight to the U.S. — the Commercial Crew Program!
Learn more about how we are enabling safe, reliable & cost-effective transportation to & from the @Space_Station: go.nasa.gov/2X27I0k   
https://twitter.com/commercial_crew/status/1379069013754515456
[Photos of SpaceX & ULA/Boeing hardware at the link.]

Jeff Foust
While NASA dates the start of the commercial crew program to April 2011, it made the first round of CCDev awards in February 2010. And, the earlier COTS cargo effort was run by the Commercial Crew and Cargo Program.
   —
Since “Commercial Crew and Cargo Program” created an… unfortunate acronym, NASA appended “Office” to the name to create the scifi-friendly C3PO. (Presumably Lucasfilm never complained.)
https://www.nasa.gov/offices/c3po/home/c3po_goal_objectives.html

https://twitter.com/commercial_crew/status/1379069013754515456

—-
NASA blames recent Hubble woes on aging hardware
https://spaceflightnow.com/2021/03/31/nasa-blames-recent-hubble-woes-on-aging-hardware/—-

—-
Sources report that the confirmation hearing for @SenBillNelson's nomination to become the next @NASA Administrator will be held on 28 April.
https://twitter.com/nasawatch/status/1379073780924973059

—-
Biden administration renews mandate for National Space Council
https://spaceflightnow.com/2021/03/30/biden-administrations-renews-mandate-for-national-space-council/

—-
No mention of satellites or Starlink.  But:
“Broadband Internet is the new electricity. It is necessary for Americans to do their jobs, to participate equally in school learning, health care, and to stay connected. Yet, by one definition, more than 30 million Americans live in areas where there is no broadband infrastructure that provides minimally acceptable speeds.”
Biden broadband plan will be hated by big ISPs, welcomed by Internet users 
Biden wants to end hidden fees and fund municipal and nonprofit networks.
Mar 31, 2021
https://arstechnica.com/tech-policy/2021/03/biden-broadband-plan-will-be-hated-by-big-isps-welcomed-by-internet-users/

[Sigmetnow]

—- Busy April launch schedule
Starlink and OneWeb add satellites to their constellations; Soyuz and Dragon crews launch to the ISS.
How many times will Delta Heavy scrub this launch?

April 7: Falcon 9 • Starlink V1.0-L23
Launch time: 1634 GMT (12:34 p.m. EDT)
Launch site: SLC-40, Cape Canaveral Space Force Station, Florida
A SpaceX Falcon 9 rocket will launch the 24th batch of approximately 60 satellites for SpaceX’s Starlink broadband network, a mission designated Starlink V1.0-L23.

April 9: Soyuz • ISS 64S
Launch time: 0742 GMT (3:42 a.m. EDT)
Launch site: Baikonur Cosmodrome, Kazakhstan
A Russian government Soyuz rocket will launch the crewed Soyuz MS-18 spacecraft to the International Space Station with members of the next Expedition crew. The capsule will remain at the station for about six months, providing an escape pod for the residents.

April 22: Falcon 9 • Crew 2
Launch time: 1011 GMT (6:11 a.m. EDT)
Launch site: LC-39A, Kennedy Space Center, Florida
A SpaceX Falcon 9 rocket will launch a Crew Dragon spacecraft on its second operational flight with astronauts on-board to the International Space Station. NASA astronauts Shane Kimbrough, Megan McArthur, Japanese astronaut Akihiko Hoshide, and European Space Agency astronaut Thomas Pesquet will launch on the Crew Dragon spacecraft. The Crew Dragon will return to a splashdown at sea. Delayed from March 30 and April 20

April 25: Soyuz • OneWeb 6
Launch time: TBD
Launch site: Vostochny Cosmodrome, Russia
A Russian Soyuz rocket will launch 36 satellites into orbit for OneWeb, which is developing a constellation of hundreds of satellites in low Earth orbit for low-latency broadband communications. The Soyuz-2.1b rocket will use a Fregat upper stage.

April 26: Delta 4-Heavy • NROL-82
Launch time: TBD
Launch site: SLC-6, Vandenberg Air Force Base, California
A United Launch Alliance Delta 4-Heavy rocket will launch a classified spy satellite cargo for the U.S. National Reconnaissance Office. The largest of the Delta 4 family, the Heavy version features three Common Booster Cores mounted together to form a triple-body rocket. Delayed from September.

NET Late July: Atlas 5 • CST-100 Starliner Orbital Flight Test 2

https://spaceflightnow.com/launch-schedule/

—- Politics

Christian Davenport
@wapodavenport 4/5/21
In a letter to the White House in Feb. Rep. Eddie Bernice Johnson, Chair of the House Science Committee, urged the President to "defer" the award of the lunar lander, saying the "government should own it" instead of pursuing a commercial program.
  —
The HLS program, though, has widespread Congressional support. NASA is expected to make the award this month. And incoming NASA Administrator has told people he will push hard to get it funded. Doesn’t look like the letter will go very far—and no other members signed it.
https://twitter.com/wapodavenport/status/1379160705102921729
[Text image at the link. Why pay for something we don’t own?]
 
Eric Berger:
Sure, let's "own" another bloated space infrastructure program. It's worked out super well in the last decade!
< Someone really didn't learn, I guess:
“While not done yet, [Commercial Crew] is poised to save the Agency approximately $20B-$30B, and provide two, independent crew transportation systems,” NASA said.
https://www.cnbc.com/2020/05/13/nasa-estimates-having-spacex-and-boeing-build-spacecraft-for-astronauts-saved-up-to-30-billion.html
< What's the background on the "nine or more of every ten dollars" comment?  Surely most of the those nine dollars go to SLS.
< Given she is from the Dallas area, what PAC or lobbyist has her in their pocket?

[Sigmetnow]

—- Starlink
SpaceX
@SpaceX 4/6/21, 6:02 PM
Launch of 60 Starlink satellites is targeted for [Wednesday], April 7 at 12:34 p.m. EDT [1634 GMT] from SLC-40 in Florida → spacex.com/launches
 https://twitter.com/spacex/status/1379555200722038786

Michael Sheetz
@thesheetztweetz 4/6/21, 10:52 AM
SpaceX president Shotwell says the company has roughly 1,320 of its version 1.0 Starlink satellites in orbit right now.
We hope to have “full connectivity globally” after about 28 launches.
https://twitter.com/thesheetztweetz/status/1379447033900244993
[ L-28.  They’ve done 23 launches. ]
MS: The v1.0 satellites don't have "laser links" (also known as intersatellite links), but still planning to create a "mesh network" over the longer term.
< Bandwidth?
<< Each satellite has a max throughput of about 20Gbps download/upload to consumers; there are plans for the v2.0 satellites to have triple that capacity. 

—- Orbital launch tank moved to pad
GSE Tank & Crane Rolled Out to the Launch Pad | SpaceX Boca Chica
➡️https://www.youtube.com/watch?v=R_r7vDXJf0s
Sorry to end it on such a cliffhanger! Michael and I were keeping tabs on the GSE tank lift for hours but didn't happen. Needed to get this one up to hang with the fam.

—- Is it a rocket ship or a Ground Service Equipment tank?

Eric Ralph:
Just dawned on me that this is a much bigger deal than it might seem. For SpaceX to design and build its own custom bulk commodity storage tanks instead of buying what is arguably a fairly routine and cheap off-the-shelf technology, Starship production has to be DIRT CHEAP.
https://twitter.com/13ericralph31/status/1379233656737161219

Now we already now Musk's claims that Starship launches will be single digit millions but this move to build propellant storage tanks that are virtually identical to Starship tankage is practically incontrovertible proof that Starship production is almost unbelievably cheap.
This is mostly important for anyone skeptical of Starships build costs and how sustainable such a 'hardware-rich' R&D program is. It would be hard to argue that SpaceX is going out of its way to build custom storage tanks that are far more expensive than proven COTS [Commercial Off The Shelf] solutions.
As far as I know, a brand new COTS 100,000 gallon LOx or LNG storage tank probably costs a few million dollars. SpaceX would need around 30 such tanks for an initial pad capable of two back-to-back launches. Maybe $100M total, possibly less for such a large order.
< Was this purpose built from scratch or from reused Starship SN sections?
ER: Given that they're almost entirely the same rings and domes joined, welded, and mated in the same way on the same assembly lines, it's almost impossible to say and the distinction is minimal. SN12-14 parts may have been retasked but only because they're interchangeable.
 I mean there's a vague possibility that SpaceX just redirected unused rings already staged for SN12-SN14 but the point is that there are already three of these identical Starship-clone GSE tanks in work In a sense, they ARE slightly modified Starships.

SpaceX is building launch pad tanks out of Starship parts and that’s a big deal 
https://www.teslarati.com/spacex-starship-launch-pad-custom-storage-tanks/

  —-
April 6, 2021 Overview
What's Next for SpaceX in Boca Chica | NSF Explains 



—- SpaceX Sea Fleet says goodbye to the sisters

Gavin Cornwell
@SpaceXFleet 4/6/21, 5:57 PM
I fear the dreaded day is upon us.
Ms. Tree has just set her tracker destination for Louisiana. This may be the end of Ms. Tree and Ms. Chief's involvement in SpaceX operations.
Both ships have been stripped of all SpaceX equipment over the last month. Watching for a departure
 
MS. TREE WE LOVE YOU. THANK YOU FOR AN AMAZING FEW YEARS! 
https://twitter.com/spacexfleet/status/1379556825847242763
Ms. Tree is giving a water salute as she departs the SpaceX recovery fleet!
⬇️ Photo below

Gavin Cornwell
@SpaceXFleet 4/6/21, 6:40 PM
Ms. Tree. Ms. Chief.  Thank you for the amazing moments. We will miss you. ❤. Audio: ON
➡️ https://twitter.com/spacexfleet/status/1379564713361747972
Video tribute at the link.

Gavin Cornwell
@SpaceXFleet 4/6/21
I've put together a longer form piece to answer all your burning questions about what is going on with fairing recovery!

The state of SpaceX Fairing Recovery in 2021 
https://spacexfleet.com/the-state-of-spacex-fairing-recovery-in-2021/

[Sigmetnow]

—- Starlink launched this afternoon
The F9 booster that launched Bob & Doug on their Demo-2 mission just helped put 60 more Starlink satellites into orbit.  SpaceX made up for not having on-board video during ascent and separation by having an amazing rocket view of the touchdown on OCISLY.

Michael Sheetz
@thesheetztweetz 4/7/21, 12:44 PM
SpaceX lands another Falcon 9 booster, this one for its seventh time – with a great onboard view as it approached the droneship:
The company has recovered 79 orbital rocket boosters to date. 

➡️ https://twitter.com/thesheetztweetz/status/1379837543261343751
Neat Gif of the booster landing at the link.

SpaceX launches Starlink v1.0 L23 mission 
written by Lee Kanayama April 7, 2021

This time, B1058 was turned around in 27 days and 8 hours. This makes Starlink v1.0 L23 the second fastest turnaround for Falcon 9, just barely beat by B1060 on the Starlink v1.0 L18 mission at 27 days and 4 hours.
However, this launch gives B1058 the fastest average turnaround time at 52 days. These fast turnaround records help SpaceX rapidly reuse Falcon 9 boosters in support of Starlink and other missions. ... 

https://www.nasaspaceflight.com/2021/04/spacex-launch-starlink-l23/

—-

Eric Berger:
2021 orbital launches by U.S. companies:
SpaceX: 10
Rocket Lab: 2
Northrop Grumman: 1
Virgin Orbit: 1
 
Elon Musk:
Global payload to orbit is the key metric 

https://twitter.com/elonmusk/status/1379880518250983425

< Are you abandoning the idea of reusing fairings entirely or will they still be fished out of the water at least to attempt reuse?
Farewell Ms Tree & Ms Chief
      
Elon Musk:
They will be recovered from the water & reused
https://twitter.com/elonmusk/status/1379744947453054981

< Any news or pictures of the new A Shortfall Of Gravitas droneship?
Elon Musk:
Coming soon. Crazy number of launches this year!

< Elon teasing us with A Shortfall of Gravitas again. (Illusive new droneship)
It's something that has been on the cards since 2018 but is now very much imminent with the sighting of its Octagrabber robot being built at Cidco Rd.

—- Starship

[That old clip of F9 landing on drone ship.]
< If I saw this in a movie, I would think, "Neat in concept - but it'd never work." Absolutely genius engineering. SpaceX is *literally* turning science fiction to reality.
Elon Musk:
Starship booster, largest flying object ever designed, will be caught out of sky by launch tower. Big step forward, as reflight can be done in under an hour.
 https://twitter.com/elonmusk/status/1379874956343828485

< What about the Starship itself? Landing legs or catching with tower as well?
Elon Musk:
Ideal scenario imo is catching Starship in horizontal “glide” with no landing burn, although that is quite a challenge for the tower! Next best is catching with tower, with emergency pad landing mode on skirt (no legs).
 
< Ok but what about for mars where there is no tower
Elon Musk:
Needs legs for moon & Mars
https://twitter.com/elonmusk/status/1379880889383972865

Chris B - NSF
@NASASpaceflight 4/7/21, 5:10 PM
As Starship SN15 prepares to roll to the launch site, the Forward Dome of SN20 has been spotted, with this vehicle set to be an Orbital Class Starship.
Video and Pictures from Mary (@BocaChicaGal). Edited by Theo Ripper (@theoripper).
➡️youtu.be/FUoy_nsrtNg
https://twitter.com/nasaspaceflight/status/1379904500744527877

Mary
@BocaChicaGal 4/7/21, 4:45 PM
Intermittent highway 4 road closure has been scheduled for tomorrow Thursday, April 8 from 11 a.m. - 1:30 p.m. We’ll have to wait and see what is going to be transported. Boca Chica beach will remain open. 

[Sigmetnow]

Mary
@BocaChicaGal 4/8/21, 10:56 AM
Starship SN15 has rolled out of the high bay.
@NASASpaceflight 

https://twitter.com/bocachicagal/status/1380172626870603780
⬇️ Photo below.
 
Wen roll?
Edit:
NSF is live, and intends to stay live through the lift to the launch stand if it happens today.
LIVE: Starship SN15 Rollout
➡️youtu.be/b0tpApLtukc

⬇️ Screencap below.

[Sigmetnow]

—- Starship today
Just the world’s largest rocket being rolled down a back country road and lifted by a crane to the launch stand.

Cosmic Perspective
@considercosmos 4/8/21, 1:54 PM
Scifi views on the highway to Mars #Starship #sn15   

https://twitter.com/considercosmos/status/1380217606183944192
⬇️ Photo below.
⬇️ Also, note human for scale in the NSF screencap.

—- He’s serious!
469 feet = 143 meters

TankWatchers
@WatchersTank 4/8/21, 4:05 PM
SUPER HEAVY LAUNCH & CATCH TOWER!
A new FAA filling confirms that SpaceX is planning to build a Launch/Catch tower for Super Heavy Booster, the tower will be located at SpaceX's Boca Chica Launch site.
We can't wait to see what the future holds!
https://twitter.com/watcherstank/status/1380250360011440128
⬇️ Text image below.

Elon Musk:
Just one skyscraper catching another nbd haha

< how do you plan on doing that? by the gridfins?
Elon Musk:
Load points just below the grid fins
  —
Shock absorption is built into tower arms. Since tower is ground side, it can use a lot more mass to arrest booster downward momentum.
https://twitter.com/elonmusk/status/1380260058026532864

—-
SpaceX landed a rocket on a boat five years ago—it changed everything 
"We were like, well, we didn't really account for that."
Eric Berger - 4/8/2021

A Falcon 9 rocket that lands on a drone ship can lift about 5.5 tons to geostationary transfer orbit, compared to 3.5 tons for a rocket that lands back at the launch site. Had SpaceX not figured out how to land the Falcon 9 first stage on a drone ship, it would have eliminated about 40 percent of the rocket's lift capability, a huge penalty that would have negated the benefit of reusing rockets.

Nearly a decade ago, Jeff Bezos' Blue Origin patented the concept of landing a rocket on a barge for this very reason. (This forced SpaceX to go to court, and its challenge against the patent eventually succeeded.) But there is a big difference in knowing something and actually doing something. Since acquiring its patent, Blue Origin has yet to launch an orbital rocket, let alone land one. Bezos has retrofitted and named a platform ship, Jacklyn, but it is unlikely to catch a rocket before 2023 at the earliest.

By contrast, since its first successful landing on the drone ship Of Course I Still Love You, SpaceX has safely returned 56 more Falcon 9 rockets at sea. Ocean-based landings have proven a remarkably enabling technology. Of SpaceX's 10 orbital rocket launches in 2021, every one of them rode to orbit on a previously flown first stage. Some returned to space within four weeks of a previous launch. By landing its first Falcon 9 rocket at sea, SpaceX began a revolution in launch. No longer is reusing rockets a novelty—it's considered an essential part of the business.

"I’m really surprised when I see new launch vehicles in development now that aren’t reusable," Peter Beck, the founder of Rocket Lab, told me in December. ...   

https://arstechnica.com/science/2021/04/spacex-landed-a-rocket-on-a-boat-five-years-ago-it-changed-everything/

CRS-8 | First Stage Landing on Droneship
➡️https://www.youtube.com/watch?v=sYmQQn_ZSys
Brief clip.

—- SpaceX Sea Fleet

Julia:
The technicians often waved when they arrived home. They also enjoyed checking out the photos that were posted on social media of their arrival. The Sisters always were show stoppers coming back to port. #SpaceXFleet#caughtnomore
https://twitter.com/julia_bergeron/status/1380156069788446720
2 photos at the link.

< Does the crew go with the ship or are they SpaceX employees? Or were they contracted separately?
Julia:
 The ships crew stay with the ship and are Guise Offshore employees. The technicians are SpaceX employees who work on the various vessels. 

—- Inspiration4

Our crew has completed centrifuge training, known as high-G force training, to prepare them for high levels of acceleration and ensure they have the knowledge and skills to safely operate in a high-G environment.   

https://twitter.com/inspiration4x/status/1380213362320105472
Photo-gif at the link of each crew member in the trainer.

—- The new ULA Vulcan rocket is meant to replace the Russian-engine-powered Atlas V

< Will Vulcan ever be crew rated along with launch crew missions to like the iss or even lunar gateway?

ULA CEO Tory Bruno:
Up to our customer
 
Eric Berger:
This is a fascinating question. If Boeing were betting on a long-term future for Starliner, they definitely would want to human rate Vulcan. Otherwise, the plan would have to be flying Atlas V (and Russian engines) indefinitely. That seems untenable. 

https://twitter.com/sciguyspace/status/1380216488922058753

From 2019:
On the day of a key test, Russia trolls Boeing’s Starliner mission
https://arstechnica.com/science/2019/12/on-the-day-of-a-key-test-russia-trolls-boeings-starliner-mission/

[Sigmetnow]

—- ISS crew rotations underway
Soyuz MS-18 has just accomplished a super-fast 3-hour, two orbit rendezvous with the Station.  But one Russian and one American from the crew may now spend a record 353 days in orbit. 
Five days after the current crew of Soyuz 17 departs, Dragon Crew-2 will arrive.

Soyuz MS-18 launch marks 60 years of human spaceflight
The launch comes three days before the 60th anniversary of Yuri Gagarin’s groundbreaking orbital flight when he became the first member of the human race to reach space.
written by Justin Davenport, April 8, 2021

Soyuz MS-18 is scheduled to return to Earth on October 13 following more than 180 days in space. However, unlike the vast majority of Soyuz crew missions to the Station since 2003, Vande Hei and Dubrov will not return with the craft they launched on.

Instead, Roscosmos will launch Soyuz MS-19 no earlier than October 5 with Commander Anton Shkaplerov and two civilian spaceflight participants. Russian film director Klim Shipenko and a Russian actress, who is yet to be named, will film a movie called “The Challenge” and spend approximately a week aboard the ISS before returning to Earth aboard Soyuz MS-18 with Novitsky. 

Vande Hei and Dubrov will therefore have an extra long-duration mission that will last into early 2022 before they and Shkaplerov return to Earth on Soyuz MS-19, with that landing currently planned for March 28, 2022.

This planned timeline means Vande Hei and Dubrov will spend 353 days in orbit. For comparison, the “Year In Space” mission of Scott Kelly and Mikhail Kornienko lasted 340 days. ...

https://www.nasaspaceflight.com/2021/04/soyuz-ms18-launch-docking/


NASA astronaut, two cosmonauts set for launch to space station
April 8, 2021 William Harwood

NASA astronaut Mark Vande Hei and two Russian cosmonauts will ride a Soyuz ferry ship to the International Space Station early Friday, the first step in a record crew rotation requiring two launches and two landings with four different spacecraft in just three weeks.

https://spaceflightnow.com/2021/04/08/nasa-astronaut-two-cosmonauts-set-for-launch-to-space-station/

[vox_mundi]

OneWeb, SpaceX Satellites Dodged a Potential Collision In Orbit
https://www.theverge.com/2021/4/9/22374262/oneweb-spacex-satellites-dodged-potential-collision-orbit-space-force

Two satellites from the fast-growing constellations of OneWeb and SpaceX’s Starlink dodged a dangerously close approach with one another in orbit last weekend, representatives from the US Space Force and OneWeb said. It’s the first known collision avoidance event for the two rival companies as they race to expand their new broadband-beaming networks in space.

On March 30th, five days after OneWeb launched its latest batch of 36 satellites from Russia, the company received several “red alerts” from the US Space Force’s 18th Space Control Squadron warning of a possible collision with a Starlink satellite. Because OneWeb’s constellation operates in higher orbits around Earth, the company’s satellites must pass through SpaceX’s mesh of Starlink satellites, which orbit at an altitude of roughly 550 km.

One Space Force alert indicated a collision probability of 1.3 percent, with the two satellites coming as close as 190 feet — a dangerously close proximity for satellites in orbit. If satellites collide in orbit, it could cause a cascading disaster that could generate hundreds of pieces of debris and send them on crash courses with other satellites nearby.

Space Force’s urgent alerts sent OneWeb engineers scrambling to email SpaceX’s Starlink team to coordinate maneuvers that would put the two satellites at safer distances from one another.

SpaceX’s automated system for avoiding satellite collisions has sparked controversy, raising concerns from other satellite operators who say they have no way of knowing which way the system will move a Starlink satellite in the event of a close approach. “Coordination is the issue,” McLaughlin says. “It is not sufficient to say ‘I’ve got an automated system,’ because the other guy may not have, and won’t understand what yours is trying to do.”

... Satellite maneuvers in space are common, but worry in the industry is mounting as OneWeb, SpaceX, Amazon, and other companies race to toss more satellites into space. And this Starlink close call isn’t the first. In 2019, a European Space Agency satellite had to move out of the way of a Starlink satellite to avoid a potential collision. SpaceX didn’t move its satellite because of a computer bug that prevented proper communication with ESA, it said at the time.

https://www.theverge.com/2019/9/3/20847243/spacex-starlink-satellite-european-space-agency-aeolus-conjunction-space-debris

With more OneWeb satellite launches planned on a monthly basis, and with planned constellations from Amazon and Telesat in higher orbits than Starlink, the need to establish clear rules of the road in orbit is becoming more urgent than ever. SpaceX looms especially large, not just because of the size of its constellation but because of where it’s sending them. “OneWeb and others will have to transit through Starlink to reach their destinations, so SpaceX needs to ensure now that other satellite operators can do that safely,” says Caleb Henry, a satellite industry analyst at Quilty Analytics.

[Sigmetnow]

—- Starlink vs. Runaway collisions
Prof. Hugh Lewis

I am seeing some ill-informed takes on today's near-miss in orbit so would like to offer some trajectory corrections if I may. Firstly, the chance that a single collision would trigger a catastrophic 'chain reaction' that would sweep through LEO is tiny.
For every close pass involving catalogued objects in orbit we can estimate a collision probability, or Pc. The Pc is between 0 and 1. If it is 1 we can say that a collision is certain. If it is 0 then we can say that a miss is certain.

The event today may have had a Pc between 0.02 & 0.2. In any case, the Pc was relatively small (compared to a Pc of 1) so a miss was the most likely outcome. For a chain reaction to occur a long & sustained sequence of collisions would need to take place.
For each event in that chain the most likely outcome would be a miss. The probability that collision 1 occurs *and* triggers collision 2 in the chain is even smaller than the original Pc. So the chance that the events in the chain continue will get smaller and smaller.

That's not to say that some version of a chain cannot happen. In fact we sometimes see these chains in our computer simulations: a fragment from an earlier collision hitting another object and creating more fragments that go on to hit other objects.
But these chains do not continue because the probabilities decrease to extremely small values after just a few events. The longest chain I have seen in one of our simulations is 7 events (we found that one amongst 25,000 Monte Carlo runs)

In a paper I am presenting at the European Conference on #SpaceDebris (starting April 20th btw) we simulated the simultaneous collisional breakup of the top 50 statistically most concerning derelict objects in LEO to see what might happen.
Spoiler: no catastrophic collision 'chain reaction' occurred.

It's not all good news though. The space debris population is growing in the manner predicted by Kessler but just not in the way represented in the movie 'Gravity'. We still have a lot of work to do to solve this problem we have created.

Secondly, large constellations and particularly #Starlink seem like easy targets for criticism when referring to the so-called #KesslerSyndrome or collision chain reactions. But the reality is somewhat different thanks to the atmosphere.
At Starlink altitudes the atmospheric drag experienced by the satellites would cause them to decay & re-enter within a relatively short period of time (a few years) even if they were to fail. This is a highly effective debris mitigation measure.
Again, we have simulated this & found that even if 90% of all Starlink satellites were to fail, the long-term impact on the environment is virtually negligible because the atmosphere provides an effective intervention.

Of course collisions could (probably would) still occur but, for the most part, any fragments would decay out of the environment quite quickly.
The effect of the atmosphere is one of the key justifications given by SpaceX to the FCC for the change in altitude of the constellation
Based on Kessler's & Anz-Meador's stability model (presented at the 3rd European Conference on #SpaceDebris btw) the number of Starlink satellites proposed does not exceed the critical number of objects needed for a runaway population.

Sure, we need to do more work & Starlink is still a genuine cause for concern for many reasons, but not really because it is a potential 'trigger' for the #KesslerSyndrome. That's a view based on some flawed thinking & we can do better.
That's the end of this PSA. If you made it this far - thanks and well done!

https://threadreaderapp.com/thread/1380647894705930242.html

https://twitter.com/profhughlewis/status/1380647894705930242

[Sigmetnow]

—- Starship

Elon Musk
@elonmusk 4/10/21, 3:45 AM
The Starship launch tower that catches the giant rocket booster is basically Mechazilla
  —
Just needs some legs 

https://twitter.com/elonmusk/status/1380788934905503744

⬇️ Mechazilla image below.

—-
Crews added a new black cap to the blunt nosecone that currently resides in the mystery structure. It's unknown what the cap is for. Meanwhile, Starship SN15 freely sits on Pad A, untethered from Tankzilla.
Video & Photos from Mary (@BocaChicaGal)
➡️youtu.be/UiZhK3SfDN4
   
—-
/r/SpaceX Masterrace:
Chad Falcon 9 landing legs
⬇️ Meme below.


—- SpaceX YouTubers
Jackie Wattles:
I talked to some folks you may have heard of for a story about the insane amount of work that goes into those independent live streams on YouTube. (feat. @Erdayastronaut, @thejackbeyer and @LabPadre )

$200,000 streaming rigs and millions of views: inside the cottage industry popping up around SpaceX
By Jackie Wattles, CNN Business
Fri April 9, 2021
https://www.cnn.com/2021/04/09/tech/spacex-starship-livestream-youtube-scn/index.html

 
YouTuber records himself trespassing at SpaceX’s Starship facilities
‘Yes it was wrong, yes it was illegal’
https://www.theverge.com/2021/4/8/22372649/youtuber-trespassing-spacex-texas-starship-facilities

——-
—-

A Pixar-style intro for @SpaceX [Starship] before they start their live streams!
➡️ https://twitter.com/timbirks1/status/1380138845145038858
Video render at the link.  Credit: u/jmvbmw on Reddit.

Elon Musk:
Pretty much
https://twitter.com/elonmusk/status/1380775355502317568 

—- Dragon & Starliner space suits
I knew the Dragon suit was “one piece,” (helps with not losing gloves, shoes, etc. while donning and doffing suit in microgravity) but:  wow.

Eric Berger:
Pretty wild to watch @Astro_Soichi put on a SpaceX pressure suit in microgravity.
 

 
5 minutes, and all by himself.

—-
For comparison, here’s Everyday Astronaut’s experience with donning and wearing the Boeing Starliner space suit.


New Spacesuit Unveiled for Starliner Astronauts 
https://www.nasa.gov/feature/new-spacesuit-unveiled-for-starliner-astronauts

For both:
< The main issue is that the suit doesn't have a self-contained life support system. It must be connected to power, oxygen, and air conditioning to keep its occupant alive. A true EVA suit has all of that stuff. There are other differences as well.

—- Quotable

Elon Musk
@elonmusk 4/10/21, 3:15 AM
… going to moon very soon  

https://twitter.com/elonmusk/status/1380781539647053826

[Sigmetnow]

—- Then and Now

Renata Konkoly
@RenataKonkoly 4/8/21, 8:56 PM
5 years ago, on April 8, 2016 @SpaceX successfully landed a Falcon 9 booster on a drone ship (Of Course I Still Love You) for the first time.
@elonmusk and @HansKoenigsmann were glowing with pride and happiness at the post-launch press conference 
“SpaceX Dragon headed to ISS” Apr 8, 2016

 
youtu.be/Nz60GcmKOvc
 
https://twitter.com/renatakonkoly/status/1380323716245110784

Renata Konkoly:
OCISLY is the queen of landing platforms/zones, but of course we still love all of them

Total: 79 landings

OCISLY: 41
JRTI: 16
LZ-1: 16
LZ-2: 3 (Falcon Heavy side boosters)
LZ-4 in Vandenberg: 3

(Third pic: @Maxar)   

https://twitter.com/renatakonkoly/status/1380326048676610050
[ 4 pics of the ships and LZs at the link.]
 

—- NASA budget & Artemis

Eric Berger
@SciGuySpace 4/9/21, 11:08 AM
The initial FY 2022 budget request from the White House seeks a 6.3 percent increase in NASA's budget, to $24.7 billion. Biggest increases for Artemis, R&D, Earth science. Details to come.

https://www.whitehouse.gov/wp-content/uploads/2021/04/FY2022-Discretionary-Request.pdf
  —
This language, related to Artemis, is important. "This funding supports the development of capabilities for sustainable, long duration human exploration beyond Earth, and eventually to Mars." But no specifics on whether sustainable means lunar bases or repeated forays.   

https://twitter.com/sciguyspace/status/1380538224058241032

  —-
NEW: NASA will land the first woman and the *first person of color* on the Moon under the Artemis program

Eric Berger:
This, from NASA's press secretary, reflects the space agency's statement of President Biden's 2022 budget request:

Acting NASA Administrator Statement on Agency FY 2022 Discretionary Request
https://www.nasa.gov/press-release/acting-nasa-administrator-statement-on-agency-fy-2022-discretionary-request

NASA's Artemis program will land the first person of color on the moon
https://www.cnn.com/2021/04/09/world/nasa-artemis-person-of-color-crew-scn/index.html

[Sigmetnow]

—- B1058-7 and The Worm

ΔV Photos
Close-up shots of core B1058's unique NASA logos! They are symbols of this booster's historic maiden flight which launched astronauts Bob Behnken and Doug Hurley to the ISS.   

https://twitter.com/deltavphotos/status/1380988989818208264
Photos at the link
 
Gavin Cornwell:
Getting more and more toasted with each appearance

Elon Musk:
That rocket is a hardcore veteran of many missions

—- Starship
April 10, 2021.  So much site construction underway!

Crews prepare Starship SN15 for more tests, potentially occurring this upcoming week with cryo proof testing. Meanwhile, crews attach new lines to the blunt nosecone with the black cap.
Video from Mary (@BocaChicaGal) & NSF Robotic Camera Team
➡️https://www.youtube.com/watch?v=I-URdvY_XQk

—- 

TankWatchers
SPACEX WILL USE STARLINK FOR STARSHIP!
SpaceX has requested to operate a single Starlink terminal on the ground or during test flights (max 12.5km/8 minutes).
Also, a new white dish has been spotted on SN15.

https://twitter.com/watcherstank/status/1380844346224836611
Operation to begin NET April 20.
⬇️ Images below.

Like those previously authorized, the tests requested here are designed to demonstrate the ability to transmit to and receive information from a moving vehicle on the ground. Nothing about these experiments will change the operation of SpaceX spacecraft, which will continue to operate as authorized. As discussed below, these proposed operations will not adversely affect any other authorized spectrum user, including geostationary orbit (“GSO”) satellite systems.
SpaceX will analyze the data link performance and installation options for the mobile user terminals. In order to complete the link with its satellites, SpaceX will use gateway earth stations authorized by the Commission for communications with the Starlink system. Communications with the satellites will be limited to a minimum elevation of 25 degrees above the horizon at all times during testing.

—-
Possible SpaceX debris washes ashore in Oregon
It’s an unidentified floating object.
https://nypost.com/2021/04/10/possible-spacex-debris-washes-ashore-in-oregon/

—-
Ex-Bell Customer Trolls Company, Returns Equipment in SpaceX Starlink Box
https://www.iphoneincanada.ca/carriers/bell/ex-bell-customer-trolls-company-returns-equipment-in-spacex-starlink-box/

—-
Tom Cruise and Russia Want to Shoot Movies in Space, but These VR Filmmakers Got There First 
While the privatization of space has led to new interest from Hollywood, an ambitious 360 video project is already raising the bar.
https://www.indiewire.com/2021/04/space-explorers-felix-and-paul-tom-cruise-vr-film-1234629428/

[Sigmetnow]

—- SpaceX Sea Fleet

Chris B - NSF
@NASASpaceflight 4/12/21, 9:27 AM
Farewell water salute spin from Ms. Chief as SpaceX ends the use of fairing catchers (will now scoop the fairings from the surface of the Atlantic via soft touchdowns).
Via NSF Fleetcam...

https://twitter.com/nasaspaceflight/status/1381599817068085249
Fleetcam clip and pic at the link.

Marcus House video:
SpaceX's 'Wet' Fleet Gives Up On Catching Falling Fairings



—- Falcon Heavy history

Michael Seeley
@Mike_Seeley 4/11/21, 8:44 AM
2 yrs ago, the world's most powerful operational rocket took flight as the SpaceX Falcon Heavy rocket carried the ArabSat6a satellite to orbit.
8-mins after launch, the side boosters returned to LZ1 & LZ2. (Sonic booms galore!)
It was truly spectacular.

https://twitter.com/mike_seeley/status/1381226612595757056
➡️ 4 photos at the link. FH roll.  3 bright streaks off the pad.

—- Starship developments

Owe BL
#SpaceX Boca Chica construction site!
Yesterday a Strange Tip was added to the Mystic Nose Cone.
Just before that, a massive hydraulic element was installed and most likely connected to the tip.   Ideas?
@elonmusk please tell us something about it.

https://twitter.com/bl3d_eccentric/status/1380535668103905284
14 sec render: the new black cap and what’s inside. (Screencap below.)

Guesses in the replies include a hydraulic solution to the header tank slosh problem, and my favorite: a test adapter allowing a quick attachment to integration crane, obviating the need to hoist humans up there to do it.  SpaceX has already automated the Port Canaveral crane’s Falcon 9 booster interstage lift connection:

Adam Bernstein
@ABernNYC 4/12/21, 11:36 AM
Getting ready to put the cap on B1058.   

https://twitter.com/abernnyc/status/1381632275658465280
Photo at the link.

——

Mary
@BocaChicaGal 4/11/21, 8:47 PM
Wow.....look at all the TPS tiles on this section of Starship.   

https://twitter.com/bocachicagal/status/1381408545703391232
⬇️ Photo below.

—-
New sections are added to the Nosecone Test Rig (Mystery Structure). Meanwhile, COPVs delivered to the production site, a new Super Heavy Aft Dome is on the sleeving stand, and SN15 prepares for more testing.
Video & Photos from Mary (@BocaChicaGal)

Nosecone Test Rig Gets Bigger | SpaceX Boca Chica


—-

Eric Berger
Application for Starship hops up to 20 km and “experimental” recovery methods. Sounds fun!
https://twitter.com/sciguyspace/status/1381639267911360512

FCC Space Licenses
@FccSpace 4/12/21, 11:04 AM
Applicant: Space Exploration Technologies Corp. (SpaceX)
Dates: 04/11/2021-10/11/2021
Purpose: Experimental med altitude hops and recovery tests of the Starship Prototype suborbita(...)
apps.fcc.gov/oetcf/els/repo…
https://twitter.com/fccspace/status/1381624394292867073 

[Sigmetnow]

—- Crew-2

Thomas Pesquet
@Thom_astro 4/12/21, 11:57 AM
L-10 and quarantine is starting, a standard procedure to avoid brining any disease to the @Space_Station. I will share some of the photos from #MissionAlpha training in the next few days as a #AlphaTrainingRecap, here's the first in a series of 12.
  —
#AlphaTrainingRecap: Like the Apollo missions, we will land at sea and be rescued. We practiced rescuing ourselves if things don't go entirely as planned... and yes we look like @PowerRangers in these training suits  

https://twitter.com/thom_astro/status/1381637498787536900
Photos at the link.

—-
There are currently TEN PEOPLE orbiting the Earth at about 28,000 km/h (17,500 mph).
How wild is that?!
https://twitter.com/kfacciol/status/1380910645764317188

—- Starlink
SpaceX Is Selling Starlink Dish At A Much Lower Price Than What It Costs To Make 
https://www.tesmanian.com/blogs/tesmanian-blog/starlink-dish

Elon Musk:
For now. Costs are decreasing rapidly.
https://twitter.com/elonmusk/status/1381273474400800773

—- New NASA Administrator
"Senator Nelson’s imprint on the space program has thus been to perpetuate a system that rewards legislators whose states and districts have existing space facilities and jobs to protect."

Eric Berger:
My concern about Nelson is this: Over recent administrations, both Obama and Trump, the White House provided a check on legacy aerospace and Congressional desires to lavish funding on big programs like SLS and Orion. Nelson seems unlikely to do so.   

https://twitter.com/sciguyspace/status/1381615951930609668
 
Bill Nelson Isn't the Best Choice for NASA Administrator
Biden’s nominee exemplifies the agency’s pork-barrel, male-dominated past
Lori Garver. April 12, 2021
https://www.scientificamerican.com/article/bill-nelson-isnt-the-best-choice-for-nasa-administrator/

—- First human spaceflight
Stunning projection of Yuri Gagarin on world’s tallest building @BurjKhalifa tonight to commemorate first human spaceflight #CosmonauticsDay #Dubai  @uaegov
➡️ https://twitter.com/sarwatnasir/status/1381652617739313154
30 sec vid

[Sigmetnow]

—- To the Moon!
Astrobotic selects Falcon Heavy to launch NASA’s VIPER lunar rover 

Astrobotic announced April 13 that it selected SpaceX’s Falcon Heavy for its Griffin Mission 1 lunar lander mission, which will deliver the Volatiles Investigating Polar Exploration Rover (VIPER) spacecraft to the south pole of the moon in late 2023. Astrobotic won a NASA competition through the Commercial Lunar Payload Services (CLPS) program last year to transport VIPER on its Griffin lunar lander.
...
VIPER is the biggest mission that is part of CLPS, a NASA initiative to purchase payload accommodations on commercial lunar landers. Astrobotic won a $199.5 million task order in June 2020 to deliver VIPER to the lunar surface on its Griffin lander.

Most of the landers flying CLPS missions selected to date will launch on SpaceX. Intuitive Machines, which won CLPS task orders for two lander missions, will launch each on Falcon 9 vehicles late this year and in 2022. Masten Space Systems selected SpaceX to provide launch services for its XL-1 lander mission, which won a CLPS award for a late 2022 mission.

Astrobotic will launch its first CLPS mission, a smaller lunar lander called Peregrine, on the inaugural launch of United Launch Alliance’s Vulcan Centaur currently scheduled for late this year. Firefly Aerospace, which won the most recent CLPS award in January, has not selected a launch provider yet for its Blue Ghost lander, but noted the lander is too large to launch on the company’s own Alpha rocket.

The Astrobotic contract adds to a growing backlog for the Falcon Heavy, which has not flown since the Space Test Program (STP) 2 mission in June 2019. The next Falcon Heavy launch is expected no earlier than July, carrying a classified payload for the U.S. Space Force. Another Falcon Heavy launch for the Space Force is scheduled for late this year. ...

https://spacenews.com/astrobotic-selects-falcon-heavy-to-launch-nasas-viper-lunar-rover/

—- Starship SN15

Michael Baylor
@nextspaceflight 4/12/21, 7:48 PM
The road is opened! Looks like a good cryogenic proof test. Perhaps @elonmusk can confirm, but if not, we will know for sure if they start moving Raptors to the pad.
youtube.com/watch?v=CfdFqc…

https://twitter.com/nextspaceflight/status/1381756205954043908
Webcast screengrab image at the link.

—- Fewer winning spaces this time?

Boca Bingo
@BingoBoca 4/11/21, 5:20 AM
SN15 Bingo! Where do you think it will land?
And yes, while there is a chance it will land off the pad, I'd figure with so many SN15 and Raptor upgrades it will most likely land on the pad.

Thanks a lot to @RGVaerialphotos for providing the picture! <3 

https://twitter.com/bingoboca/status/1381175337674014720
⬇️ Image below.

—-

Chris B - NSF
@NASASpaceflight 4/12/21, 3:56 PM
Mary (@BocaChicaGal) spots a Super Heavy Grid Fin at SpaceX Starbase!

https://twitter.com/nasaspaceflight/status/1381697756524339210
⬇️ Photo below.


—- F9 Re-use

SpaceX boosters coming back & landing on earth to be reused is the most sci-fi thing I've seen which exists in real-life
  —
This simultaneous landing of Falcon 9 boosters on Falcon Heavy was done 2 years ago today. SpaceX managed to land all 3 boosters on Falcon Heavy on this mission.

➡️ https://twitter.com/ppathole/status/1381305040346882048
15 sec: 2 boosters landing LZ 1&2.

—-

Adam Bernstein
@ABernNYC 4/12/21, 3:00 PM
Up and AWAY!

https://twitter.com/abernnyc/status/1381683737193222152
⬇️ Photo below: F9 booster on a crane.


—- Russia bluster?

Reuters Science News
Russian President Vladimir Putin marked the 60th anniversary of Yuri Gagarin's historic space flight on Monday with a pledge that Moscow would remain a key space and nuclear power.​ reuters.com/article/us-rus…   

https://twitter.com/reutersscience/status/1381728849403215874

Eric Berger
Until Putin starts paying his aerospace engineers more than a starving wage, and cleans up the rampant corruption in his space industry, this is just bluster.

https://twitter.com/sciguyspace/status/1381782648322932740

[Sigmetnow]

—- Starship

Eric Berger:
Slow scheduled disassembly.
 
Mary
@BocaChicaGal 4/13/21, 8:18 AM
The dismantling of BN1 has begun.

https://twitter.com/bocachicagal/status/1381944855333593098
⬇️ Photo below.

—-
Starship SN15 was filled with liquid nitrogen to test the strength of its tanks at flight temperatures and pressures. It is unknown if the test was successful.
➡️youtu.be/bWpyhXZNZAc

—-
Mary
@BocaChicaGal 4/13/21, 6:58 PM
Another section has been attached to the top of the nosecone testing rig.
https://twitter.com/bocachicagal/status/1382105856662192133
⬇️ Photo below.

[Sigmetnow]

—- Another moon mission for SpaceX!
SpaceX Falcon 9 Will Launch Japanese Lander Carrying UAE Rover To The Lunar Surface

The United Arab Emirates (UAE) Mohammed Bin Rashid Space Centre (MBRSC) signed a contract with Japan’s iSpace, Inc., to deliver the ‘Rashid’ rover to the lunar surface aboard iSpace’s lander. iSpace selected SpaceX as a launch provider to propel its lunar lander to the Moon atop a Falcon 9 rocket. The mission is currently scheduled for 2022, from NASA's Kennedy Space Center in Cape Canaveral, Florida. ...   

https://www.tesmanian.com/blogs/tesmanian-blog/f9-uae
⬇️ Image below.

—-
More on what yesterday’s Astrobotic mission win means
SpaceX Falcon Heavy beats out ULA Vulcan rocket for NASA Moon rover launch
By Eric Ralph April 14, 2021

SpaceX’s Falcon Heavy rocket appears to have edged out competitor United Launch Alliance’s (ULA) next-generation Vulcan Centaur launch vehicle to send a NASA rover and commercial lander to the Moon in 2023.

Back in August 2019, not long after NASA first began announcing significant contracts under its Commercial Lunar Payload Services (CLPS) program, startup Astrobotic announced that it contracted with ULA to launch its first small “Peregrine” lander and a dozen or so attached NASA payloads to the Moon in 2021. Rather than the extremely expensive but operational Atlas V rocket, the startup instead chose to manifest Peregrine on the first launch of Vulcan Centaur, a new ULA rocket meant to replace both Atlas V and Delta IV Heavy.

Less than two years later, Astrobotic has decided to purchase a dedicated launch from SpaceX – not ULA – for even larger “Griffin” lander that aims to deliver NASA’s ice-prospecting VIPER rover to the Moon and kick off the exploration of permanently-shadowed craters at its south pole.

...ULA’s Vulcan Centaur rocket, which secured a lunar lander contract for its launch debut only to lose a similar lunar lander launch contract from the same company – well within the range of Vulcan’s claimed capabilities – less than two years later. If SpaceX’s relatively expensive Falcon Heavy managed to beat early Vulcan launch pricing, there is virtually no chance whatsoever that Vulcan Centaur will ever be able to commercially compete with Falcon 9.

https://www.teslarati.com/spacex-falcon-heavy-beats-ula-vulcan-nasa-moon-rover/

—- History
The Future of Design

4 min: Elon demonstrates CAD software they designed to manipulate Merlin engine wire frame display using hand gestures, then as a full render. 3D glasses. Oculus Rift.  Redesign the item using hand gestures, rather than using computer commands.  Then 3D print it: lay down tiny particles of titanium or Inconel [nickel-chromium-based superalloy], then use lasers to melt each layer together.

—-
Six decades after Gagarin, nostalgia—and not much else—fuels Russia in space
"Looking at the Earth from afar, you realize it is too small for conflict."
Eric Berger - 4/12/2021
https://arstechnica.com/science/2021/04/six-decades-after-gagarin-nostalgia-and-not-much-else-fuels-russia-in-space/


—- Finance
Sierra Nevada Corporation to spin off space division 
Jeff Foust April 14, 2021
https://spacenews.com/sierra-nevada-corporation-to-spin-off-space-division/
Sierra Space projects current revenues to grow x10 in the next 5-10 years.
Eric Berger:
Part of Sierra Nevada may be preparing to go SPAC. Worth noting that the projected revenues are largely based on securing future NASA contracts for Dream Chaser and habitats. Certainly no guarantee of that.

—-
Elon Musk's SpaceX raises $1.16 billion in equity financing 
https://www.reuters.com/article/us-space-exploration-technologies-financ-idUSKBN2C11V9


—- F9 Reuse
Eric Berger:
Graphic from @edzapata showing clear trend lines in Falcon 9 reuse. Days between reuse going down, frequency of booster use going up. Big milestone later this month when humans launch on a used Falcon 9 for the first time.
zapatatalksnasa.com/2021/04/14/lau…
https://twitter.com/sciguyspace/status/1382307666400219136
⬇️ Graph below.

[Sigmetnow]

—- Human Space Flight 2021

Michael Sheetz
@thesheetztweetz 4/14/21
SpaceX's Crew Dragon "Endeavour" prepares to launch its second astronaut mission, Crew-2, and is mated to a reused Falcon 9 rocket booster, after finishing processing on April 12.
Launching in 8 days: 

https://twitter.com/thesheetztweetz/status/1382453735855636482
⬇️ Two photos below.

Gavin Cornwell
@SpaceXFleet 4/14/21, 3:57 PM
Speaking of sea trials, it appears GO Navigator is offshore this afternoon rehearsing Dragon recovery. 

https://twitter.com/spacexfleet/status/1382422849210695686
Marine track map at the link

Julia
@julia_bergeron 4/14/21, 7:26 AM
Sea trials offer a unique opportunity for the recovery technicians to remain onboard the ASDS while it is in operation. Just Read the Instructions is about to put the normally remote operated vessel to the test after being docked for generator work. #Fleetcam

https://twitter.com/julia_bergeron/status/1382294193104642048
Photos at link. Crew on deck!

—-

Inspiration4
@inspiration4x 4/14/21
Our crew is excited to continue mission training in the weeks ahead! Training will include orbital mechanics, operating in microgravity, zero gravity, emergency preparedness, spacesuit and spacecraft ingress and egress exercises and partial- and full-mission simulation.

https://twitter.com/inspiration4x/status/1382387405936685059
Classroom photo at the link.

—- Starliner
It now seems likely that Starliner will not launch crew until early 2022
The first hurdle for Starliner: Finding an open port on the space station
Eric Berger - 4/13/2021
https://arstechnica.com/science/2021/04/it-now-seems-likely-that-starliner-will-not-launch-crew-until-early-2022/

Eric Berger
@SciGuySpace 4/13/21, 6:33 PM
Updating these Starliner launch estimates based on what we know today, about 5.5 months later.
• Orbital flight test-2, July/August 2021
• Crew flight test, February 2022
• Post-certification mission: Later 2022
https://twitter.com/sciguyspace/status/1382099732575715328

   —-
We have the first flight in late July and the manned flight in early January. So all agreed.
https://twitter.com/shuttlealmanac/status/1382130766822318080 

⬇️ Timeline below. Not official, but based on available information. Click to embiggen.

—-

Eric Berger:
Which of the following will be the next mission to launch carrying at least one space tourist?
https://twitter.com/sciguyspace/status/1382440461801910278
Vote at the link: New Shepard, Virgin Galactic - Branson, Inspiration 4, or Soyuz MS-20

Chris B - NSF
@NASASpaceflight
 "#TeamSpace" says "All of them! At the same time! And equally as amazing! Polls are biased!"
      
Eric Berger:
I welcome them all too! We may double the total number of non-professional astronauts who have flown into space this year if NS gets cranking.
https://twitter.com/sciguyspace/status/1382445346329137155   

[Sigmetnow]

—- NASA Commercial Crew

With 1⃣ week until launch, @NASA and @SpaceX managers are gathered today for the Flight Readiness Review of the upcoming Crew-2 mission.

A media teleconference will follow no earlier than 6 p.m. ET to discuss the outcome: go.nasa.gov/3toiBIu
4/15/21, 12:45 PM 

https://twitter.com/commercial_crew/status/1382736951518720010

—- Starship
Marcus House video
SpaceX Starship testing is already underway. What's new with SN15? How is it different?   

Details on Starship and Raptor engine updates.

—-

Austin Barnard
@austinbarnard45 4/14/21, 11:09 AM
SpaceX crews are hard at work following two cryo tests, meaning Raptors could be installed within days! Progress on the orbital pad is in overdrive, with the launch tower taking shape and the first GSE tank in place. Meanwhile BN1 is being scrapped for BN2, which will fly!
[4 photos at the link.]

Elon Musk:
Aiming to launch next week

https://twitter.com/elonmusk/status/1382582177943015431

—-
Gwynne Shotwell

Despite a test campaign that has so far been filled with vehicle explosions, she remained optimistic that the vehicle will be ready to fly people within several years. “I believe we will be flying large numbers of people on Starship in five years,” she said, including point-to-point transportation between two locations on Earth, a concept SpaceX first discussed in 2017.

Asked by Dava Newman, an MIT professor and former NASA deputy administrator, if that meant SpaceX would be ready to send people to Mars by 2030 to 2035, Shotwell offered a more aggressive schedule. “We’re shooting for before 2030. It might end up taking that long, but I hope not,” Shotwell said.

That timeline, she said, was based on the experience she expected the company to build up flying people on point-to-point and lunar Starship missions. “You’re flying enough where you hopefully have enough knowledge of the system and knowledge of risk that you can definitely start the journey to Mars within the next five years.”
“I recognize,” she added, “we never make our timelines, so they’re aspirational. But you have to aim high.”

SpaceX adds to latest funding round 
Jeff Foust April 15, 2021
https://spacenews.com/spacex-adds-to-latest-funding-round/

—-

Mary
@BocaChicaGal 4/15/21, 12:44 PM
I love the new signs at SpaceX Boca Chica launch site.

https://twitter.com/bocachicagal/status/1382736574685843463
⬇️ Photo below.
Sometimes, exceedingly so!

—-

Lex Fridman:
252 million years ago, nearly all life on Earth came to an end. The Permian-Triassic extinction, aka The Great Dying, killed 90% of species on Earth. Cause is unknown. Theories include volcanoes and meteors.

We're lucky.

Elon Musk:
One of many reasons that we need to make life multiplanetary!   

https://twitter.com/elonmusk/status/1382724076330917893

[Sigmetnow]

—- SpaceX Crew-2 Flight Readiness Review
Article (details the Dragon’s hardware upgrades, the F9 “Lox exception” and other items):
NASA, SpaceX clear crew capsule for launch next week
April 15, 2021 Stephen Clark
https://spaceflightnow.com/2021/04/15/nasa-spacex-clear-crew-capsule-for-launch-next-week/

Audio only:
Crew-2 Flight Readiness Review Media Teleconference
➡️https://www.youtube.com/watch?v=TtXGK4yGwF4

My notes:
Kathy Lueders, head of NASA’s human exploration and operations mission directorate:  Wow, a very moving day. Great FRR, so soon after first launch. Now this will be our first time using preflown capsule and booster.

Teams working well despite COVID. Crew arrives KSC Friday, in full quarantine [as has always been normal for astronauts].

Launch Backup dates? What of the 5-day handover? April 22 and 23 dates are both good to go to ISS. Then 26 and 27. Want to maintain 5-day ISS handover spacing, so Crew-1 return date will be adjusted as needed.

Crew-2 will have our first ESA astronaut, second JAXA astro.
ESA: this is essential for Europe.  European robotic arm to launch this summer. For first time, 3 ESA astros in a row will fly, so we will have a continuous presence on the ISS for 1.5 years.

10 crew on board ISS now -- no problems. Crew-2 will be first time with 2 US crew vehicles on the ISS.
Have inspected the on-Station Dragon -- it's doing great after six months in space.

Inspiration4 - how will this impact ISS flights?  SpaceX: Returning vehicle will be refurbished for Inspiration4.  We’ll be sure we favor the right customers at the right time. Axiom tourist mission will likely be next year.

Plans to permit more flights?  Busy schedule now: June - cargo flight with critical Solar arrays.
Add additional docking adapters? Maybe after Axiom module is added.

Kathy Lueders:  Gerst is looking younger; I'm looking older.


—- NASA Deputy Admin
NASA Watch
@NASAWatch
Sources report that the nomination of Pam Melroy @Astro_Pam by the White House to be Deputy Administrator of @NASA will be announced [Friday].
4/15/21, 4:58 PM
https://twitter.com/nasawatch/status/1382800552753512462
< Okay. This nomination like. Question is: would her likely-to-be-boss listen to her input?

[Sigmetnow]

—- HLS!

  Eric Berger:
Two sources say NASA is likely to announce its down-select for Human Landing System contracts today. Space agency has not confirmed this. Blue Origin's "national team," Dynetics, and SpaceX are the three contenders.
4/16/21, 11:12 AM

https://twitter.com/sciguyspace/status/1383075736861306884
< Welp there goes my productivity for the day waiting for this

CBS This Morning
For the first time since the Apollo program, @NASA is shopping for a new lander to go back to the moon. The agency is expected to choose from among three designs for its @NASAArtemis program.
Mark Strassmann shows us the companies competing for their chance to make history.
4/16/21, 7:55 AM 

➡️ https://twitter.com/cbsthismorning/status/1383026229599739907
5 minute segment from the show. Including:
Human Landing System program manager Lisa Watson-Morgan:
"Well, because if you've always done what you did, you're always going to get what you got!" Watson-Morgan said. "I mean, you know, we have to try new things...We definitely, I mean, it would be un-American to not try something new, right?"
 
—- Starship
A helpful commenter notes that SpaceX's proposed launch tower in Boca Chica will be nearly half as tall as the Eiffel Tower.  — EB
Rocket Report: SpaceX to build huge launch tower, Branson sells Virgin stock 
Eric Berger - 4/16/2021

FAA approves large Starship launch tower. 
In a document published on its website, the Federal Aviation Administration said it has determined that SpaceX's plans to build a large launch tower for its Starship launch system poses no hazard to aviation. The document reveals that SpaceX intends to build a 479-foot tall launch tower at its Boca Chica launch site in South Texas.

A sizable structure ...   
The document states: "SpaceX is proposing a 469' tall launch tower with 10' lightning rod to lift its new rocket and booster on the launch mount, and to catch the super-heavy booster upon return from launch. The tower will be constructed out of structural steel trusses to allow the mechanical arms to lift vehicles." This is rather large. NASA's mobile launcher for the Space Launch System rocket stands 380 feet tall above the ground. (submitted by Ken the Bin)   

https://arstechnica.com/science/2021/04/rocket-report-spacex-to-build-huge-launch-tower-branson-sells-virgin-stock/

—-
As Starship SN15 prepares for Raptor installation and further testing, new sections of SN16 are lifted in the Mid Bay for stacking. Meanwhile, Raptor engine SN56 loaded in the van for the trip back to McGregor.
Video & Photos from Mary (@BocaChicaGal)
➡️youtu.be/3LzjeFEpjBM
4/15/21, 8:21 PM
https://twitter.com/thefavoritist/status/1382851698880823296

[Sigmetnow]

—- Crew-2 launch preparations

William Harwood
@cbs_spacenews
Crew-2: The Falcon 9 rocket and Crew Dragon ferry ship that will launch four astronauts to the ISS Thursday was hauled out of SpaceX's hangar at KSC pad 39 today in preparation for a planned first stage engine test firing Saturday pic.twitter.com/DvZP9XrX2L
4/16/21, 10:16 AM
https://twitter.com/cbs_spacenews/status/1383061790263799809 

⬇️ Photo below.

—- New marine warnings for Crew-2 launch

Emre Kelly:
Haven’t seen one of these “blast danger area” warnings before. Since it’s #Crew2 related, most likely static fire operations on Saturday.
https://twitter.com/emrekelly/status/1382782600658444293
Two marine warning charts at the link.

Mark Vlaun [USCG Captain, Port of Jacksonville, Canaveral, ...] @mvlaun :
It is. We’ve had a lot of fishing vessel activity out there lately, so you’ll see some USCG presence near the zone to keep everyone safe and help our partners prep for #crew2.

EK:  Thanks Mark!

Mark Vlaun:
Thank you! I appreciate it anytime you amplify the message on the limited access areas. It helps us make sure people can safely view the mission without scrubbing the mission they intend to view, or more importantly, putting themselves or others at risk!

Chris B - NSF
@NASASpaceflight
Let's get more to RT Emre's tweet then. That's a note not many will appreciate.   

—- Meanwhile, on the ISS

William Harwood
@cbs_spacenews
Soyuz MS-17/63S: Amid Crew-2 launch preps in Florida, outgoing ISS commander Sergey Ryzhikov, Sergey Kud-Sverchkov and NASA's Kate Rubins are gearing up to undock from the station at 9:34pm EDT (0134 UTC), setting up a landing on the steppe of Kazakstan at 12:56am Saturday
4/16/21, 10:20 AM

https://twitter.com/cbs_spacenews/status/1383062848239239168

—- Houston, Texas:  home of NASA's Johnson Space Center

Houston, we have a commander!
Shannon Walker of @NASA_Astronauts is set to be the first native Houstonian to command the @Space_Station. A member of the NASA’s @SpaceX Crew-1 mission, Walker was born, raised and completed her Ph.D. in Houston. 

https://twitter.com/nasa_johnson/status/1382131021139873796
 
Shannon Walker to Become First Native Houstonian to Command International Space Station 

Walker is a member of NASA’s SpaceX Crew-1 mission that flew to the space station on the Crew Dragon Resilience spacecraft, the first commercial human spacecraft system. She and her fellow Crew-1 astronauts joined Expedition 64 upon their arrival and are nearing completion of a six-month science mission that included science and research investigations.

Walker and the Expedition 64 crew worked on a number of experiments, including tissue chips that mimic the structure and function of human organs to understand the role of microgravity on human health and diseases and translate those findings to improve human health on Earth. Astronauts also grew radishes in different types of light and soils as part of ongoing efforts to produce food in space, and tested a new system to remove heat from spacesuits.

Command will officially transfer to her when the off-going commander, Roscosmos cosmonaut Sergey Ryzhikov, departs the station. Ryzhikov and fellow cosmonaut Sergey Kud-Sverchkov, along with NASA astronaut Kate Rubins, will begin the journey back to Earth in their Soyuz MS-17 spacecraft on April 16.
Walker is scheduled to join Michael Hopkins, Victor Glover and Soichi Noguchi aboard Resilience on Wednesday, April 28, and depart the station for return to Earth. 

https://www.nasa.gov/press-release/shannon-walker-to-become-first-native-houstonian-to-command-international-space

The Russian commander tweeted a nice explanation of his handoff ceremony for ISS command.
Translated:

Sergey Kud-Sverchkov:
Before leaving home, the commander of the expedition #МКС transfers command to his successor. This time it's Shannon Walker.
 The transfer of command takes place during a traditional official ceremony. The current commander gives the new commander a symbolic key from the station.
   —
Here it is, a metal key - a symbol of command. This is a reduced copy of the key for opening the passageways, one of which was opened by the first expedition 20 years ago.#МКС ...
 Now Shannon is in charge of the station and its crew! And we continue to prepare for the return home.
➡️ https://twitter.com/kudsverchkov/status/1383027544484626436
Photos at the tweets.

A Russian reply offers tips for that side of the station :
< Here's a key for you, Shannon, a handful of Podolsk soil and Admiral Ushakov's ring. Wipe the icons twice a week.
 If suddenly your head starts spinning, go over the cracks with the sealant over the tape.
 With God blessing! 

[Sigmetnow]

—- SpaceX wins sole HLS contract!!!

Christian Davenport
@wapodavenport
SpaceX bid $2.9 billion for the NASA lunar lander system--far below Blue Origin and Dynetics--and won the contract, according to a source selection document obtained by The Post. Story TK
4/16/21, 1:31 PM
https://twitter.com/wapodavenport/status/1383110799086997505
Eric Berger
Have heard the same. One big reason is that NASA could not afford more than one contract due to limited Congressional funding.

Eric Berger:
Here's the deal: A sole-source award to SpaceX for the Human Landing System is going to be hugely unpopular in Congress. But it means NASA is is serious about getting to the Moon with the funding they have. And if Congress adds budget, NASA can bring on an HLS competitor.
  —
In an ideal world there should be competition in the HLS program. It worked for commercial cargo, and it worked for crew. But NASA is getting a small fraction of what it needs for HLS while Congress is fully funding the rocket and spacecraft programs.
  —
Finally, that Bill Nelson confirmation hearing next week is going to be spicy.

4/16/21, 1:36 PM  https://twitter.com/sciguyspace/status/1383111960984649731
 
—

Michael Baylor:
Blue Origin tried to be the new old space with the National Team. It did not work. Hopefully, they vertically integrate in the future. New Glenn has huge potential, and they have hired incredible talent, but they need to stay vertically integrated. National Team was a bad idea. 
  —
The HLS selection has implications beyond Dynetics and the National Team landers. It means no HLS launches for Vulcan, New Glenn, or SLS. Starship can only be launched on Super Heavy.
  —
The actual cost for SpaceX developing a system capable of landing humans on the Moon is surely far higher than $2.3 billion. SpaceX will privately fund a lot of this, saving the taxpayers money.

4/16/21, 1:36 PM https://twitter.com/nextspaceflight/status/1383112039258750978

William Harwood
@cbs_spacenews
Crew-2: Speaking at the Crew-2 arrival event, Steve Jurczyk, acting NASA administrator, says the agency will make an "important announcement" about its Artemis lunar lander competition during a 4pm EDT (2000 UTC) teleconference

4/16/21, 1:28 PM. https://twitter.com/cbs_spacenews/status/1383109999480700930


—- Crew-2

  William Harwood
@cbs_spacenews
Crew-2: Meanwhile, a brief runway Q & A session with the Crew-2 astronauts has concluded; Falcon 9 first stage engine test firing Saturday at 6:11am; dress rehearsal countdown Sunday; launch at 6:11am Thursday; ISS docking around 5:30am Friday

  4/16/21, 1:29 PM.  https://twitter.com/cbs_spacenews/status/1383110394215075840

—-
SpaceX photo of the Crew-2 Dragon and Falcon 9.
https://twitter.com/spacex/status/1383084131987324928
Photo ⬇️, another at the link.

[Sigmetnow]

Friday April 16, 2021

Quite an exciting afternoon!
NASA announces SpaceX Starship to be the sole survivor of the Human Landing System down-selection.

NASA Picks SpaceX to Land Next Americans on Moon 
➡️ https://www.nasa.gov/press-release/as-artemis-moves-forward-nasa-picks-spacex-to-land-next-americans-on-moon

Elon Musk’s SpaceX wins contract to develop spacecraft to land astronauts on the moon
➡️ https://www.msn.com/en-us/news/technology/elon-musk-e2-80-99s-spacex-wins-contract-to-develop-spacecraft-to-land-astronauts-on-the-moon/ar-BB1fJccC

Although the news leaked early, the official announcement was rather strange, beginning as a presentation of the winners of a kids’ essay contest (which crashed the NASA server), then a short video announcing the HLS winner...
NASA Picks SpaceX for Artemis Human Lunar Lander Development
➡️https://www.youtube.com/watch?v=y-sA3R4MWjA

... which segued into a press Q&A teleconference which had no SpaceX representatives available to answer questions!
Human Landing System Announcement Media Teleconference
➡️https://www.youtube.com/watch?v=y6BqZrs0x4E

As a result, the NASA folks had to deal with questions like whether Starship will launch on SLS.

NASA is requiring a test flight to fully check out all systems with a landing on the lunar surface prior to the formal demonstration mission.  On-orbit refueling will also be demonstrated.

The initial HLS award is for a single uncrewed landing and a single crewed landing. Additional landings can be awarded to SpaceX or other companies through a new competition for recurring landings.

SpaceX's proposal includes a 2024 landing target, but NASA cautions that there risk with this schedule.  They envision the mission as Starship launching and getting successfully to the moon, at which point Orion would launch to meet up with it.  Still talking Near Rectilinear HALO orbit, and eventually Gateway.

SpaceX can pick the launch site for these HLS missions with Starship — it doesn’t have to be KSC.  SpaceX can also perform non-NASA flights with Starship that may not follow NASA’s rules.

Acting NASA Administrator Steve Jurczyk says NASA wants to fly the "next American astronauts on the moon as quickly and safely as possible."


Can Congress force them to change their mind on who won?
Steve Jurczyk, of NASA, on the choice of SpaceX for the Human Landing System: "We're moving forward. We don't anticipate revisiting this selection."

NASA was coy about their reasoning for choosing SpaceX and only SpaceX, but in the Source Selection document, NASA says it wanted "to preserve a competitive environment at this stage of the HLS Program." "NASA’s current fiscal year budget did not support even a single Option A award," and so SpaceX updated payments "that fits within NASA’s current budget."

"SpaceX’s plans to self-fund and assume financial risk for over half of the development and test activities as an investment in its architecture, which it plans to utilize for numerous commercial applications, presents outstanding benefits to NASA."

Dynetics technical approach was "marginal" ("of little merit") and their price was significantly higher than Blue Origin's, which was in turn significantly higher than SpaceX.  BO also put themselves out of the running by requesting up-front payments that were expressly forbidden in the contract.

NASA Source Selection Statement
➡️ https://www.nasa.gov/sites/default/files/atoms/files/option-a-source-selection-statement-final.pdf

SpaceX has the capability to bring lots of payload to lunar orbit, but Orion is not capable of returning that quantity to Earth.

"SpaceX’s quiescent lunar orbit operations capability will allow it to loiter for 100 days prior to rendezvous with the crew vehicle. "

"Here, I note that the SEP closely analyzed SpaceX’s proposal and was able to independently substantiate its claimed performance capabilities."

"I agree with the SEP’s assignment of a significant strength for SpaceX’s proposed capability to substantially exceed NASA’s threshold values or meet NASA’s goal values for numerous initial performance requirements."


Michael Baylor:
Today NASA formally acknowledged that a fully reusable Starship/Super Heavy launch system is possible.
This stamp of approval should send shockwaves through the launch industry. It is time to focus on competing with Starship, not Falcon 9.

⬇️ Below: SpaceX’s new render of Lunar Starship

[oren]

Good for NASA, good for SpaceX.
But silly me is looking at the image and wondering what happens when lunar dust starts flying in all directions during landing, and when the surface turns out to be not very flat. The lack of a concrete landing pad combined with the powered landing method and unstable form factor (very tall, short pointy legs) could present a challenge.
P.s. I am sure someone has already considered this... but I am still wondering.

[crandles]

Good for NASA, good for SpaceX.
But silly me is looking at the image and wondering what happens when lunar dust starts flying in all directions during landing, and when the surface turns out to be not very flat. The lack of a concrete landing pad combined with the powered landing method and unstable form factor (very tall, short pointy legs) could present a challenge.
P.s. I am sure someone has already considered this... but I am still wondering.

I think I have understood that Starship lands (on moon Mars and any other low gravity body) using hot gas thrusters high up on Starship so the thrust is far from ground level to reduce the throwing up dust problem. Vacuum conditions also reduce the dust problem I think: On Earth we are used to thrust hits atmosphere creating wind which affects all dust. In vacuum there are much fewer thrust molecules creating thrust than the sum of the thrust molecules plus the affected atmospheric molecules.

Uneven surface - perhaps less clear, but do remember when little fuel left in Starship, most of the weight is in engines which are very low and small amount of fuel left is also lower than assuming weight evenly distributed with height. So the centre of gravity is rather low given the shape of Starship. Thus you would need a very steep slope or very large boulder under one leg to make it topple over. Hopefully these can be avoided by different techniques - aim for a flat crater region rather than region with steep slopes. Avoid boulders with a bit of spare hot gas thruster to divert a little if needed.

[vox_mundi]

[Sigmetnow]

Good for NASA, good for SpaceX.
But silly me is looking at the image and wondering what happens when lunar dust starts flying in all directions during landing, and when the surface turns out to be not very flat. The lack of a concrete landing pad combined with the powered landing method and unstable form factor (very tall, short pointy legs) could present a challenge.
P.s. I am sure someone has already considered this... but I am still wondering.

Yes, SpaceX has plans for landing on unprepared surfaces — but exact details will evolve as prototypes are built and tested.  As Vox noted, Lunar Starship will use thrusters near the top to avoid kicking up dust on the surface.  The 1/6 lunar gravity means less thrust is needed than for earth landings.  Musk has also noted that the landing legs would be “self-leveling.”  Given that, plus cameras/radar/LiDAR and new navigation and imaging software to autonomously find a good spot, and Starship should have a good chance of sticking the landing.

Dust mitigation is, by the way, one element that NASA evaluated when considering the suitability of the proposed landers.

As to being very tall... who would have thought that water towers could fly?

Click to embiggen the sections of SpaceX’s render attached below.

[Sigmetnow]

—- Starship flight TFR posted for Tuesday, April 20.  Road closures scheduled for Mon, Tue, Wed. (Static fire expected.)

—-
Chris Davenport:
Bill Nelson confirmation hearing Wednesday. Crew-2 Thursday (bright and early). Ingenuity flight on Mars TK. SN-15 flight (and landing ? ) TK. I say bring it! You only live once. Let's go....

—- More on NASA’s HLS SpaceX selection
NASA selects SpaceX as its sole provider for a lunar lander 
"We looked at what’s the best value to the government."
Eric Berger - 4/16/2021
https://arstechnica.com/science/2021/04/nasa-selects-spacex-as-its-sole-provider-for-a-lunar-lander/

In case you’re just joining us, here’s a good overview:
NASA selects SpaceX to put astronauts back on the moon 
https://www.nationalgeographic.com/science/article/nasa-selects-spacex-to-build-the-lunar-lander-for-artemis-missions-to-the-moon

Notes:  SpaceX is financing over 50% of their HLS project, the contract is fixed price and any added budget will come out of SpaceX’s wallet.  Theirs was by far the cheapest proposal; in fact the government couldn't afford any of them, so SpaceX changed their funding schedule so NASA could pick them.

Eric Berger:
Looks like SpaceX can finally stop nicking knickers to pay for Starship.
https://twitter.com/sciguyspace/status/1383118535031889920
⬇️ Slide below from a very early Starship presentation. [ref: “South Park” show]

  Eric Berger:
In retrospect, today was a pretty easy decision for NASA. Who, among its human spaceflight contractors, has actually delivered over the last decade.
    And who has not?
What's remarkable is that they made this decision despite what is bound to be brutal blowback from Congress.

https://twitter.com/sciguyspace/status/1383203649959063553
4/16/21, 7:40 PM

HLS Contract: Sore Losers In Big Aerospace 
By Keith Cowing on April 16, 2021 8:56 PM.

Coalition for Deep Space Comment As NASA Continues Path to Return to Moon
"The Coalition for Deep Space Exploration (Coalition) applauds NASA for awarding a Human Landing System (HLS) contract for the Artemis program. Along with the Space Launch System, the Orion spacecraft, Exploration Ground Systems, and the Gateway, the HLS is a critical component for enabling the return of astronauts to the Moon for the first time since the Apollo era." 

Keith's note: If you read this Coalition for Deep Space Exploration statement carefully you will see that while they "applaud NASA" on the HLS contract thing they are so small that can't even mention or congratulate SpaceX. SpaceX is not a member of the Coalition but all of the Big Aerospace companies who lost out on this contract are members.

https://twitter.com/nasawatch/status/1383222822772744195

—-

Chris B - NSF
Chris Gebhardt (@ChrisG_NSF) asks about the Landing Demonstration Test flight.

https://twitter.com/nasaspaceflight/status/1383163156411912193
4/16/21, 4:59 PM
At the link: 2 min audio clip from the HLS announcement teleconference

—-
Elon Musk:
… going to moon very soon
https://twitter.com/elonmusk/status/1380781539647053826
4/10/21, 3:15 AM

Elon Musk:
Everything to the moon!
https://twitter.com/elonmusk/status/1383233200885882885
4/16/21, 9:37 PM

—-
Video:  Starship SN15's Raptor engines are at the launch site for installation on the vehicle, the GSE 3 tank's forward dome section was stacked, and Starship won the lunar HLS contract.
Video + Photos by Mary (@BocaChicaGal) for @NASASpaceflight.
➡️youtu.be/zxTWXU_CoLM
4/16/21, 9:41 PM

[oren]

the landing legs would be “self-leveling.”  Given that, plus cameras/radar/LiDAR and new navigation and imaging software to autonomously find a good spot, and Starship should have a good chance of sticking the landing.

Thanks.
I am left wondering how many moon landings would be required to prove this system, compared to how many are planned , given that a lot depends on the luck of the draw of the specific very local terrain for each landing.
Again, I am sure this has been taken into account.

[Sigmetnow]

the landing legs would be “self-leveling.”  Given that, plus cameras/radar/LiDAR and new navigation and imaging software to autonomously find a good spot, and Starship should have a good chance of sticking the landing.

Thanks.
I am left wondering how many moon landings would be required to prove this system, compared to how many are planned , given that a lot depends on the luck of the draw of the specific very local terrain for each landing.
Again, I am sure this has been taken into account.

Excellent question.  Musk has said there will be “maybe hundreds” of Starship flights before it will be certified for human flight.  As Gwynne Shotwell has said, they expect to have so much experience flying the rocket over the next few years that they are reasonably comfortable planning trips to the moon and Mars.

The difference this time is the rocket and spacecraft in question will be Rapidly Reusable, as opposed to Once and Done as in the past.  Starship will have many, many flights, and reliability will be calculated using real world experience, not just engineering data.

[Sigmetnow]

Speaking of rough landings, watch a Falcon 9 barely survive this one — fortunately, the moon’s lesser gravity will mean slower entry-descent-landing speeds than on earth! 

One of the more spicy Falcon 9 booster landings
This was from BulgariaSat-1 in 2017, and was the second flight of B1029.
Well done landing legs 

➡️ https://twitter.com/terminalcount/status/1382714871171710976

—- Crew-2
Today:
William Harwood:
Crew-2: The four Crew-2 astronauts have suited up, boarded SpaceX Teslas and headed to pad 39A to strap in atop their Falcon 9 and work through a dress rehearsal countdown; the simulation ends at 6:11am EDT (1011 UTC), the same time as their actual liftoff Thursday
https://twitter.com/cbs_spacenews/status/1383679701625933827
4/18/21, 3:12 AM

Yesterday:
SpaceX:
Static fire test of Falcon 9 complete – targeting Thursday, April 22 at 6:11 a.m. EDT for launch of Dragon’s second operational mission to the @Space_Station  spacex.com/launches

The Falcon 9 first stage previously launched the Crew-1 mission, and the Dragon spacecraft previously flew @AstroBehnken and @Astro_Doug to and from the @Space_Station during the Demo-2 mission
https://twitter.com/spacex/status/1383245015380418561
4/16/21, 10:24 PM
Launch and docking photos.

—- Also yesterday
NASA astronaut Kate Rubins returns safely to Earth after six months in space 
April 17, 2021 / 2:41 PM

NASA astronaut Kate Rubins, 42, safely returned to Earth on Saturday after living aboard the International Space Station for six months, according to NASA. Rubins, along with Russian cosmonauts Sergey Kud-Sverchkov and Sergey Ryzhikov, arrived southeast of the town Dzhezkazgan, Kazakhstan, in a parachute landing at 10:55 a.m. local time. 
The crew served as Expedition 63-64 and began their mission on October 14 last year. 

Rubins became the first person to ever sequence DNA in outer space on her first spaceflight, Expedition 48/49 in 2016. During her latest 185-day mission, Rubins conducted "hundreds of hours" of International Space Station research, including work on the Cardinal Heart experiment which studies the effects of gravity and cardiovascular cells at the cellular and tissue levels and could further knowledge of heart problems on Earth, NASA reported. Her research also included studying DNA sequencing and microbiology studies.

"Rubins collected hundreds of microbial samples at different locations within the space station for the 3DMM study to construct a 3D map of bacteria and bacterial products throughout the station," NASA reported. "By advancing understanding of the orbiting laboratory's microbiome, this work helps identify potential risks and supports developing countermeasures to mitigate those risks."

The International Space Station is a laboratory that orbits around Earth. The first piece of the station was launched in November 1998. 
Rubins will now return to her home in Houston, Texas. She is scheduled to speak about her mission in a news conference on Wednesday.   

https://www.cbsnews.com/news/nasa-astronaut-kate-rubins-earth-space/
⬇️ Photo below.

—-

Chris B - NSF
@NASASpaceflight
It's rather crowded on the Space Station!
https://twitter.com/nasaspaceflight/status/1382783151794184198
4/15/21, 3:49 PM
⬇️ Photo below
 
Axiom Space
@Axiom_Space
So, room needed for four to eight more?
https://twitter.com/axiom_space/status/1382811854242652161

—-
White House nominates Pam Melroy to be NASA deputy administrator 
https://spacenews.com/white-house-nominates-melroy-to-be-nasa-deputy-administrator/
USAF test pilot, space shuttle pilot; Lockheed Martin, FAA, DARPA.

[Sigmetnow]

—- Starship
New Starship SN16 Sections Lifted into the Mid Bay for Stacking | SpaceX Boca Chica
➡️https://youtu.be/3LzjeFEpjBM
That big Chick-fil-A sign, though.

SpaceX continues to work on the present and the future as Starship SN15 prepares for a flight test next week, while the Orbital Launch Site readies for Super Heavy.
➡️youtu.be/RD72zZxtcFM


Cool, the retro futurist look of the space capsule.
https://twitter.com/jmmuyl/status/1383359709076344840
⬇️ Image below.

—-
Elon Musk:
Make life multiplanetary! #Mars
https://twitter.com/elonmusk/status/1382858937792307202
4/15/21

Mars will not be an escape hatch for the rich, Mars is a inhospitable. A radioactive wasteland, the ground is poisonous and breathing is impossible. However, if we manage to develop the tech to survive on said wasteland. We can use the tech to help life here on Earth!
➡️ https://twitter.com/austinbarnard45/status/1383578979974598657
Clip from EM interview at the link.
Clip is from 2 years ago.  Full video:  ➡️youtu.be/Dfg1n7Lh62Q

Shackleton's ad inspired a great crew to overcome insurmountable odds. The prospect of humans overcoming hard things sounds like an excellent future to me.
https://twitter.com/heyblaineallen/status/1383655991120588800
⬇️ Shackleton’s newspaper ad

—-
Elon Musk:
If we make life multiplanetary, there may come a day when some plants & animals die out on Earth, but are still alive on Mars
 https://twitter.com/elonmusk/status/1383280704042127363
< Backup the biosphere!

—- SpaceX as a business
Dave Lee:
I had a fantastic discussion with [Eric Berger] @SciGuySpace about the critical role of @elonmusk at SpaceX and why winning the $2.9B NASA contract is a big deal.
https://twitter.com/heydave7/status/1383413764158935042
4/17/21

The Magic of SpaceX w/ Eric Berger author of Liftoff (Ep. 310) 
➡️https://www.youtube.com/watch?v=oF_oEvjm1XQ
Video is primarily about how SpaceX and Elon Musk operate.
HLS, Starship and Starlink discussion starts around minute 43.

[Sigmetnow]

—- Starship
Brownsville TFRs are cancelled. Static fire now NET Wednesday. But today’s road closure was put to good use:

Mary
@BocaChicaGal
The GSE 2 tank has arrived at the launch site at SpaceX Boca Chica.

https://twitter.com/bocachicagal/status/1384249705857617927
4/19/21, 4:57 PM
Photo at the link: GSE tank on the move.

—-
Today’s burning question:
How many tanker launches will be required to refuel a (Lunar) Starship? 

In a recent video, Scott Manley suggests “a half dozen or so.”
NASA Will Spend $2,941,394,557 On SpaceX's Massive Lunar Starship Lander!!!
➡️https://www.youtube.com/watch?v=GuSM_-Aw5HM

The NASA’s HLS Source Selection document praises Blue Origin for requiring “only” three launches for its ship, and dings SpaceX for requiring “a significant number of vehicle launches in rapid succession ... and numerous in-space cryogenic propellant transfer events” — but does note that SpaceX operations occur in “earth orbit,” [LEO?] where operational risks are more easily overcome, compared to Blue Origin’s and Dynetics’ docking and refueling operations which occur in lunar orbit.

I seem to recall reading Musk saying they think that Starship “might” be able to take off from the moon and return to LEO without further refueling... or they could “brute force it with tankers.” 

Last fall there was this exchange:

Chris B - NSF (@NASASpaceflight) 10/1/20, 7:57 PM
< is there any substantial difference between ring sections of Starship and Super Heavy? Safe to assume Super Heavy uses thicker steel rings to support higher loads, right?
Elon Musk: The ship rings are thicker than they need to be (for now), so same thickness works for booster & ship for hoop stress. Booster lower tank will have longitudinal stiffeners to prevent buckling.

< I remember u saying that the initial few iterations Superheavy will have 28 engines instead of 31, so regarding this engine upgrade, is it to accommodate/allow a heavier tank with more propellant?
< Correct me if wrong, this upgrade will allow each tanker flight to deliver ~300 tonnes of propellant to LEO while reserving ~30 tonnes of landing propellant ...
< And ultimately this upgrade will result into cutting the number of refuelling flights to 4 instead of 8 which would be a huge improvement!
Elon Musk:  Probably 5 or 6 with an optimized tanker, although filling up the ship in orbit isn’t required for Mars, so 4 is possible.

https://twitter.com/elonmusk/status/1311907493182926849
 
—- Amazon’s Project Kuiper internet satellites
Need for speed? Amazon’s FCC license requires it to launch at least 50 percent of its proposed 3,236 “Project Kuiper” satellite internet LEO constellation by July 2026.
Although Amazon’s Jeff Bezos owns Blue Origin, which is developing its New Glenn heavy lift rocket and a new “BE-4” engine (which ULA will use on its next-generation, cheaper Vulcan rocket) — these may be delayed.  Amazon announced today that it has contracted with ULA for nine Atlas V missions to launch its first satellites.

Amazon’s first Internet satellites will not launch on Blue Origin rockets 
Eric Berger - 4/19/2021
https://arstechnica.com/science/2021/04/amazons-first-internet-satellites-will-not-launch-on-blue-origin-rockets/

Amazon signs with ULA for rockets to launch Jeff Bezos’ Kuiper internet satellites 
Amazon emphasized that Project Kuiper "will need multiple launch vehicles and launch partners" to deploy the constellation on time....
https://www.cnbc.com/2021/04/19/amazon-signs-ula-rockets-to-launch-bezos-kuiper-internet-satellites.html
 
—- HLS Memes!
"Orion is the large bus to take astronauts to the moon so they don't need to ride in the cramped lander the whole time."
See:
https://www.reddit.com/r/SpaceXMasterrace/comments/mtlbje/orion_is_the_large_bus_to_take_astronaut_to_the/
A couple are shown below.

[Sigmetnow]

—- Crew-2 Launch Readiness Review

Eric Berger:
NASA's Steve Stich says the Crew-2 mission is "go for launch" on Thursday at at 6:11am ET (10:11 UTC).
  —
Stich said NASA and SpaceX have closed the "additional LOX" issue on the Falcon 9 rocket's first stage. [The weight of the additional LOx is small in comparison to the rest of the rocket; the F9’s Guidance, Navigation and Control can handle it easily, and vents can handle any boil-off].

Most closely watched item will now be the weather, with launch opportunities for Thursday and Friday on the table.
  —
The launch day forecast for Crew-2 is good for Thursday and appears to be even better for Friday. Note this does not include conditions for ascent weather, down range of the launch site, for potential abort situations.
  —
Benji Reed of SpaceX comments on the Human Landing System that NASA awarded his company Friday. "This is a huge honor, It's truly a great thing for us to be a part of the Artemis team." 

4/20/21, 8:13 AM
https://twitter.com/sciguyspace/status/1384480256103378944

⬇️ Crew-2 mission patch below.

—- Starship
Road closure for Wednesday is scheduled.

VIDEO: The 2nd GSE tank arrived at the orbital launch pad on Monday while teams continued to assemble the nosecone testing jig.
Video and Pictures from Mary (@BocaChicaGal). 4/20/21, 1:59 AM
Second GSE Tank Arrives at the Orbital Launch Pad | SpaceX Boca Chica
➡️https://www.youtube.com/watch?v=nAUZVEKpWk8

—-
SUPER HEAVY LAUNCH & CATCH TOWER!

Elon Musk:
Load points just below the grid fins
  —
Shock absorption is built into tower arms. Since tower is ground side, it can use a lot more mass to arrest booster downward momentum.
https://twitter.com/elonmusk/status/1380260058026532864

   —-
Catching super heavy, the perfect solution!
https://twitter.com/julius_burton/status/1345436609848684550
12 seconds render: Robot arms on a pole catch SH

Elon:
Nice.   

—- HLS
A review of what’s in the Source Selection document, and possible future developments for all three competitors.
New renders by Mack Crawford.
After NASA taps SpaceX’s Starship for first Artemis landings, agency looks to on-ramp future vehicles
written by Thomas Burghardt  April 20, 2021
https://www.nasaspaceflight.com/2021/04/nasa-starship-first-landings-on-ramp/

—- Starlink

Everyday Astronaut:
Will users always be locked into one location or in the future if a user has the standard Dishy McFlatface (not a new portable one), could you say put it on an RV or tiny home? Or maybe take one you have in Iowa and put it in a studio in Texas 
 
Elon Musk:
Yeah, should be fully mobile later this year, so you can move it anywhere or use it on an RV or truck in motion. We need a few more satellite launches to achieve compete coverage & some key software upgrades. 

https://twitter.com/elonmusk/status/1382842277719003136
 4/15/21, 7:44 PM

—-
In the latest FCC filing, Starlink agrees to competitors’ demands for orbit height and operational limits — with the condition that competitors’ satellites protect Starlink.
https://wccftech.com/starlink-blows-dish-away-accepts-competitors-demands/


—- ISS
With video.  Love the mice running around the walls of their cage!
Life aboard the international space station

"You indicated that there's really no up or down," Pogue said. "So, is there any reason that one of you couldn't turn head-down? The blood's not rushing to your head, Victor?"

"Not at all," laughed Glover. "Not at all. In fact, it doesn't seem weird to me until I look at Hopper and go, 'Why is Hopper upside-down?'" 

https://www.cbsnews.com/news/life-aboard-the-international-space-station/

—-
Russia to decide whether to quit the International Space Station
Russia's Annual ISS Complaints Begin - Again 
By Keith Cowing on April 20, 2021 11:43 AM.

"Russia's Deputy Prime Minister Yury Borisov said in recent days that Moscow was considering whether to leave the ISS programme from 2025 because of the station's age. Roscosmos said on Monday that a decision on quitting the ISS had not yet been made. "When we make a decision we will start negotiations with our partners on forms and conditions of cooperation beyond 2024," the space agency told AFP in a statement."

"We have 2024 as an agreed time limit with our partners on the work of the ISS. After that, decisions will be made based on the technical condition of the station's modules, which have mostly worn out their service life, as well as our plans to deploy a next-generation national orbital service station," Roscosmos said."

 Keith's note: It is springtime and right on schedule the Russians are once again making strange noises as a prelude to renegotiating something. It happens every year. They never have enough money to do the things that they threaten to do - or not do - or both. Of course, all of the problems they allude to seem to have to do with their hardware (and lack of Soyuz seat sales). So ... what are they going to do? Give their ISS hardware to the ISS partners? Sell it? Detach it and deorbit it? FYI there is a huge lien against the entire program to deorbit ISS once it has completed its task. Is Russia going to help pay for this? As for the new Russian space station - show me the money.   

http://nasawatch.com/archives/2021/04/russias-annual.html

And there’s poor ESA at the LRR this morning, celebrating the European robotic arm finally arriving at the ISS this summer with the long-delayed Russian Multipurpose Laboratory Module.

Matthew Bodner:
Still no official announcement of Russian withdrawal from ISS in 2025, but here’s the Roscosmos chief teasing construction of a module to be used as the core of a new Russian station in 2025. This module actually was commissioned for ISS in 2024.
  —
Rogozin later explained that Russia isn’t talking about de-orbiting its ISS modules in 2025, but rather a gradual withdrawal from the project over time.
But still no official anything, even though all signs indicate Russia really is tapping out.
  —
Maybe they’re saving the official announcement for Putin’s big speech tomorrow.
If I was the writer of this timeline thats how I’d do it. 

https://twitter.com/mattb0401/status/1384533094452109321
4/20/21, 11:43 AM

[Sigmetnow]

—- Crew-2 launch delayed
4/21/21, 7:34 AM

NASA Commercial Crew
@Commercial_Crew
Launch Update @NASA and @SpaceX now are targeting Friday, April 23 at 5:49 a.m. ET [9:49am UTC] for the launch of the Crew-2 mission to the @Space_Station due to unfavorable weather conditions along the flight path on Thursday.
Learn more: go.nasa.gov/3tC8IXO   

https://twitter.com/commercial_crew/status/1384832941172289536
Sunrise pad photo at the link.

Per the “Countdown Clock” briefing (held this morning outside in front of KSC’s giant countdown clock), Crew-1 is still targeted to return from the ISS on the 28th.
Also, NASA noted that the plan has always been to alternate Dragon and Starliner flights, so they don’t anticipate a run of Starliner flights to catch them up, after that craft begins flying crew.

NEXT LIVE EVENTS
(All times Eastern U.S. time. UTC-4.)
April 21, Wednesday
HAPPENING NOW:  10 a.m. – Hearing on the nomination of Sen. Bill Nelson to be NASA Administrator – Senate Committee on Commerce, Science and Transportation
3:15 p.m. – News Conference with ISS Expedition 64 Flight Engineer Kate Rubins of NASA

Nelson’s hearing is expected to be... “spicy,” given his previous SLS support over commercial crew, and now NASA’s selection of SpaceX for HLS.

[Sigmetnow]

—- Bill Nelson for NASA Admin - Senate Confirmation hearing
Eric Berger
@SciGuySpace
Bill Nelson's vision for NASA: " If you ask me what is my vision for the future of NASA, it is for us to continue exploring the heavens with humans and machines. There is a lot of excitement."
4/21/21, 10:40 AM
https://twitter.com/sciguyspace/status/1384879787487862801
 
Eric Berger:
Asked about the 2024 timetable for the Moon landing, Nelson's answer 100 percent backs up NASA's selection of a single awardee (SpaceX) for the first landing. Future missions will open up to competition, Nelson says.
  —
Nelson did not specifically mention SpaceX, but it seems notable that he fully supported the "NASA official making the determination." Basically, I detected no distance between Nelson and NASA's decision-making process, which is significant.

  —
"Mars is the goal of the 2030s," Bill Nelson says of NASA and human exploration.
  —
Nelson keeps saying Starliner will launch humans later this year, and the Space Launch System rocket will launch later this year. Neither is likely to happen.
 —
These Senators are very interested in competition in space all of a sudden. The good news for them is that Super Heavy is about to give the SLS rocket all the competition it could ever want.
  —
It's hilarious to see these Senators, again and again, saying they're going to hold NASA to its 2024 Moon landing date. They funded the lander that NASA needs at about one-quarter the level of funding the space agency said it needed.

Joe McKirdy:
Also, big note: He promised to pursue dissimilar redundancy with respects the HLS. This is BIG.
  —
Chairwoman Cantwell "A question for the record: .... clearly I think there needs to be redundancy and it has to be clear this process can't be redundancy later it has to be redundancy now."

[Sigmetnow]

OneWeb, SpaceX Satellites Dodged a Potential Collision In Orbit
https://www.theverge.com/2021/4/9/22374262/oneweb-spacex-satellites-dodged-potential-collision-orbit-space-force

Two satellites from the fast-growing constellations of OneWeb and SpaceX’s Starlink dodged a dangerously close approach with one another in orbit last weekend, representatives from the US Space Force and OneWeb said. ...

Not so much, it seems.
Turns out there never was a dangerously close approach between Starlink and OneWeb Satellites, and the stories from 2 weeks ago were quite misleading.

The issue involved a recently-launched OneWeb satellite that was navigating through the Starlink constellation.  There were several communications between OneWeb and SpaceX.  SpaceX’s avoidance system, which is more accurate and faster-reacting, suggested the risk of collision was below the threshold for needed action, and operators should watch and wait. OneWeb’s system is less accurate and slower-acting, so OneWeb decided to act anyway.  Because OneWeb decided to plan a maneuver, it asked SpaceX to turn off Starlink-1546’s autonomous conjunction avoidance system. SpaceX obliged this request and confirmed to OneWeb that the system had been turned off.
From the timeline:

1. OneWeb contacted SpaceX by email on 4/1/2021 at 18:26 UTC regarding a notice from the United States Space Force's 18th Space Control Squadron (“18 SPCS”), SpaceX responded within minutes and communicated to OneWeb that Starlink-1546 was/is maneuverable.

2. OneWeb asked SpaceX via email on 4/2/2021 12:20 UTC for more detail, and SpaceX responded minutes later to explain that:
• the maneuver threshold for Starlink satellites is 1e-5 and that maneuvers occur approximately 12 hours before the predicted closest approach of the satellites.
• Starlink-1546 was maneuverable and its autonomous collision avoidance system was functioning nominally.
• if a maneuver was needed, typically a single in-track burn would be conducted to reduce collision probability.

... 
5. OneWeb sent an email to SpaceX on 4/2/2021 at 22:50 UTC with the maneuver plan and the ephemerides they had screened by 18 SPCS.
• After the maneuver was planned, 18 SPCS provided its latest CDM that showed Pc below standard maneuver thresholds.
• All subsequent CDMs show continued lowering Pc. In other words, the probability of collision was already below any threshold that required a maneuver and kept dropping.

6. While all CDM Pc values remained below the maneuver threshold, OneWeb-0178 maneuvered on 4/3/2021
at 11:27 UTC.
• 18 SPCS reported actual miss distance as 1,120 m.
• LeoLabs reported actual miss distance as 1,072 m.
• Both 18 SPCS and LeoLabs reported final Pc below 1e-20—one in one hundred million million million—this was not a close call or a near miss.   

SpaceX’s letter to the FCC notes:

- OneWeb’s head lobbyist recently made demonstrably inaccurate statements to the media about recent coordinations of physical operations. Specifically, Mr. McLaughin of OneWeb told the Wall Street Journal that SpaceX switched off its AI-powered, autonomous collision avoidance system and “they couldn’t do anything to avoid a collision.” Rather, SpaceX and OneWeb were working together in good faith at the technical level. As part of these discussions, OneWeb itself requested that SpaceX turn off the system temporarily to allow their maneuver, as agreed by the parties, per the chronology, below.

-The recent technical coordination with OneWeb was not an exceptional event and the Starlink team has successfully conducted similar coordinations with other satellite owner/operators.
- Technical data indicates that this event was neither a “close call” and not “urgent” nor as reported in the press, presumably based on information provided by OneWeb.
- All operator-to-operator interactions between SpaceX and OneWeb to date have involved open, constructive technical discussions. 

And includes this background:

Background
• The 18 SPCS sends satellite operators alerts whenever satellites have conjunctions that have (i) a time of closest approach within 72 hours, (ii) a probability of collision greater than 1/10,000 (1e-4), and (iii) a miss distance less than 1 km.
• If the notice is for two maneuverable satellites, the satellites’ operators contact each other to coordinate potential collision avoidance maneuvers, i.e., maneuvers that reduce collision probability
• The first satellite operations coordination between SpaceX and OneWeb was over a year ago on March 12, 2020.
   - 18 SPCS provided notice of a conjunction between ONEWEB-0052 and Starlink-1057, and the parties held coordination discussions.
   - Based on these discussions, Starlink-1057 did an autonomous conjunction avoidance maneuver for this case.
• Between March 2020 and prior to the early April 2021 conjunction with OneWeb, Starlink satellites have conducted many autonomous maneuvers to reduce collision probabilities, with no issues. 

SpaceX’s filing:
https://licensing.fcc.gov/myibfs/download.do?attachment_key=6212177

[PDF] Turns out there never was a dangerously close approach between Starlink and Oneweb Satellites, and the stories from 2 weeks ago were quite misleading : SpaceXLounge
https://www.reddit.com/r/SpaceXLounge/comments/mv2vq7/pdf_turns_out_there_never_was_a_dangerously_close/