Solar Storms May Have Hindered SOS During Historic 1928 “Red Tent” Polar Expeditionhttps://spectrum.ieee.org/tech-talk/tech-history/dawn-of-electronics/solar-storms-sos-red-tent-expeditionIn May 1928, a team of explorers returning from the North Pole via airship crashed on the frigid ice. Their attempts to use their portable radio transmitter to call for help failed; although they could hear broadcasts from Rome detailing attempts to rescue them, their calls could not reach a relatively nearby ship. Now, new research suggests that the communication problems may have been caused by radio “dead zones,” made worse by high solar activity that triggered massive solar storms.
... On 24 May 1928, after just over 20 hours of flight, the ‘Dirigible Italia,’ captained by Italian designer Umberto Nobile, circled the North Pole. Nobile had flown on a 1926 Norwegian expedition aboard an airship he had designed; that was the first vehicle to reach the North Pole. Two years later, he had returned to stake a claim for his native country.
https://en.m.wikipedia.org/wiki/Italia_(airship)
After a brief ceremony at the pole, with winds too strong to attempt a landing on the ice, the vehicle turned south to make the 360-kilometer return trip to the crew’s base on the Svalbard archipelago. But an unknown problem caused the airship to plunge to the Earth, slamming into the ice and shattering the cabin. The crash killed one of the explorers. The balloon, freed from the weight of the carriage, took to the air, carrying six more crew members away, never to be seen again. The nine survivors sheltered beneath a red tent that gave its name to the historical disaster.
Among the supplies left on the ice was the simple high-frequency radio transmitter intended to allow communications between the airship and explorers on the ground. The low-powered radio ran on batteries and had a transmission range of 30 to 50 meters.
As the shipwrecked crew settled into their uncomfortable new quarters, radio operator Giuseppe Biagi began sending SOS messages. At the 55th minute of each odd hour, the prearranged time for the Italia to contact the Italian Navy’s ship, Citta dei Milano, anchored in King’s Bay, he pled for help, then listened in vain for a response.
Amazingly, while the tiny antenna could not contact the ship, it could pick up radio broadcasts from Rome—with signals originating more than ten times farther away than the point where the navy ship was docked. The explorers listened as news of their disappearance and updates on the rescue operations were broadcast.
It took nine days for someone to finally hear their calls for help. On 3 June 1928, a Russian amateur radio enthusiast, Nicolaj Schmidt, picked up the SOS with his homemade radio receiver in a small village approximately 1900 km from the Red Tent. After nearly 50 days on the ice, the explorers were ultimately rescued, though 15 of the rescuers died in the attempt.
At 10:35 UT of 25 May 1928, the “Dirigible Italia” wrecked on the sea ice 400 km northeast of NyAlesund, Norway, its point of origin. Nine survivors took cover under a red tent, lending the incident its historical name.... Zolesi and his colleagues relied on a standard international model of the ionosphere to provide a monthly average picture of the northern pole. But their lack of knowledge about the Earth’s atmosphere nearly proved fatal to the team. The 8.9 MHZ frequency relied on by the explorers would have fallen in the radio dead zone for locations to the north of the 66° N line of latitude. Both the Red Tent and the Citta di Milano sat at nearly 80° N, while Arkhangelsk, the closest city to Schmidt, sits at 64.5°.
The researchers also studied sunspot drawings captured by the Mount Wilson Observatory in California between 25 and 31 May 1928. They revealed a significant increase in the number of sunspot groups. ... They found that the planet underwent periods of magnetic fluctuations in mid- to late May 1928, peaking on 28 May.
“The space weather conditions were affected by a significant geomagnetic storm during the early days after the shipwreck,” Zolesi says. “These conditions might have severely affected the radio communications of the survivors during the tragedy.”
The Shipwreck of the Airship “Dirigibile Italia” in the 1928 Polar Venture: A Retrospective Analysis of the Ionospheric and Geomagnetic Conditionshttps://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2020S2020SW002459
