(CAPE CANAVERAL, Fla.) — Spacewalking astronauts made urgent repairs at the International Space Station on Tuesday, three days after a critical relay box abruptly failed.
The 250-mile-high (400-kilometer-high) replacement job fell to commander Peggy Whitson, the world’s most experienced female astronaut. She now ties the record for most spacewalks by an American — 10.
Even though a second relay box managed the data load just fine after Saturday’s breakdown, NASA scrambled to put together a spacewalk in order to restore backup capability. The system is vital for operating the station’s solar panels, radiators and robotic equipment.
The failed data-relay unit — recently refurbished with upgraded software — was just installed in March. Hauling out a spare, Whitson photographed the faulty device to help engineers figure out what went wrong. Then she quickly removed it and bolted down the spare, an identical 50-pound (22-kilogram) box measuring 14 by 8 by 13 inches (35-20-33 centimeters) — officially known as an MDM or multiplexer-demultiplexer. But when Whitson discovered some metal flecks on some of the bolt holes, she had to pull the spare box back out.