Two NASA astronauts will step out into space on a mission to replace a faulty antenna system tomorrow (Dec. 2). The spacewalk was postponed after a space debris alert after accomodating for increased risk following a Russian anti-satellite test that created a debris cloud.
NASA astronauts Thomas Marshburn and Kayla Barron, who recently arrived at the International Space Station aboard SpaceX's Crew Dragon spacecraft as part of the company's Crew-3 mission, will complete a spacewalk together tomorrow. The pair is set to spend about six and a half hours replacing an antenna system on the orbiting lab.
You can watch Barron and Marshburn complete their spacewalk live right here at Space.com courtesy of NASA TV or directly at NASA's YouTube channel. The spacewalk is set to begin at 7:10 a.m. EDT (1210 GMT) with live coverage starting at 5:30 a.m. EDT (1030 GMT).
This is Barron's first spaceflight and it will also be her first spacewalk. Marshburn, however, is a veteran astronaut and has performed multiple spacewalks. During the space shuttle mission STS-127 in 2009, Marshburn took part in three spacewalks. During a later mission in 2013, after flying to the station aboard a Russian Soyuz capsule, Marshburn performed an unplanned spacewalk to address the possible source of an unexpected ammonia coolant leak.
For tomorrow's spacewalk, the pair will work together to replace an S-band Antenna Subassembly (SASA), an antenna system, with a spare version of the system that is stored on the space station's truss. The two astronauts will work at the P1, or Port 1, truss structure on the space station, where the antenna is located.
This replacement comes after the existing antenna recently stopped sending signals to Earth, which it had previously done through NASA's Tracking and Data Relay Satellite System. The antenna issue hasn't affected station operations much, according to a statement from NASA, but to ensure the station has full communications (and backup communications) available, the spacewalk will replace the system with a new one.
Essentially, the antenna system can "uplink from the ground to station," Dana Weigel, NASA's deputy manager of the International Space Station program, said during a pre-spacewalk news conference held Monday (Nov. 29), "but we can't get anything back through its downlink."
During the news conference, NASA personnel noted that the faulty system flew to space 21 years ago and has been working fine up until now. (The first crew arrived at the station 21 years ago, so the system has been there essentially since the very beginning.) The replacement flew to space in 2010, 11 years ago, and has not yet been used.
This spacewalk comes a couple of weeks after a Russian anti-satellite test against a defunct satellite created a debris cloud near the space station, causing the seven crew members on board to seek temporary shelter in their docked vehicles.
While the cloud of space debris created by the event has since dissipated, the event nevertheless has increased the risk that a small piece of debris could potentially puncture an astronaut's spacesuit, Weigel said.
According to Weigel, there is typically a one-in-2,700 chance of a piece of space debris puncturing a spacesuit and the Russian test has increased this risk by 7%.
Weigel added that the event caused the team planning the spacewalk to quickly make a decision as to what scheduled events during the spacewalk might need to change in response to the added space debris and increased risk.
"There's a few other things that we ended up taking off," Weigel told Space.com during the briefing. "We had to make a decision pretty early on in terms of what we were going to ask the crew to study and prepare to do — so before we really had an understanding of the free environment. We wanted to be conservative."