NASA astronauts prepare for spacewalk just weeks after Russian satellite strike creates debris field
Dr Thomas Marshburn and Kayla Barron are scheduled to begin their spacewalk at 7:10 a.m. ET, and it is expected to last for about six and a half hours.
The astronauts will replace an S-band Subassembly Antenna using a spare that has been mounted outside the space station. According to NASA, S-band radio frequencies are used to transmit low-speed data and voice over 220 miles from the space station to flight controllers on the ground.
After operating for 21 years, the antenna recently stopped sending signals to Earth using NASA’s Data Relay and Tracking Satellite System. Vincent LaCourt, NASA’s spacewalk flight director, said mission managers discovered the problem in September.
“That moment allowed us to put Tom and Kayla in a neutral buoyancy lab or a large pool, where we practiced spacewalking and practiced our precise spacewalking,” says LaCourt. we.
In general, the loss of this antenna has little effect on the operation of the space station. However, maintaining antennas like this allows for redundancy of communications. The backup installation, which has existed outside the station since 2010, will allow that backup system to continue. The station has other low-speed S-band systems and a high-speed KU-band system that relays video back and forth.
During the spacewalk, Marshburn will be at the end of the Canadaarm2 robotic arm, which European Space Agency astronaut Matthias Maurer will control from within the space station.
Marshburn will wear a red-striped space suit as crew member 1 and Barron will wear an unmarked suit as crew member 2. This is the first spacewalk of the crew. Barron and was Marshburn’s fifth outing.
Marshburn, Barron and Maurer arrived at the space station with NASA astronaut Raja Chari in their SpaceX Crew Dragon capsule on Nov.
Tuesday’s spacewalk was the 245th conducted to assemble, maintain and upgrade the space station, which has served as the center of continuous low-Earth orbit for humans for 21 years.
Concerns about debris
NASA Administrator Bill Nelson said in a statement that he was “outraged by this irresponsible and destabilizing act. Given the long and long history of human flight, it is unthinkable. imagined that Russia would endanger not only the American astronauts and their international partners on the ISS, but also their astronauts, whose actions were reckless and dangerous, threatening the entire station. China’s universe.”
Dana Weigel, deputy director of NASA’s International Space Station Program, said: “Although the debris field was very concentrated at first, it dispersed over time. The spacewalk planning team ran models and predictions to understand the environment the astronauts would be in during their spacewalk.
It increased the risk for space walkers by 7%, “not a huge increase and that’s what we see with normal atmospheric oscillations and normal debris loads.” move over,” Weigel said. “What it really tells us is that EVA (peripheral activity) is always inherently risky.”
This risk involves any debris that has the potential to enter the spacesuits or the space station itself. The pieces that can penetrate the spacesuit are much smaller than anything they can track, Weigel said.
“It means penetration but it doesn’t mean it’s a disaster,” says Weigel. “There’s a certain penetration size that can help. Having an emergency oxygen pack on the suit feeds it for a while. When we talk about EVA risk, it’s usually around 1 in 2,700, so that’s considered the risk of having some size of penetration during EVA’s six and a half hours.”
Weigel says that some previous spacewalks have been more risky this time around.
“Unfortunately, when you have a debris event like this and you get a lot of really small pieces scattered around, it becomes part of the average environment,” says Weigel. “At some point, there isn’t a particular orientation aspect to the debris. So there’s no difference they’ll make on a spacewalk.”
The event messed up the mission list for the spacewalk itself, and several “starting” missions were scrapped, including routing cables and removing bolts on spare nitrogen tanks, LaCourt said. . Given the time, however, astronauts will be inclined to do a few things that could prevent future spaceflight scheduling.
Overall, the team says they’re cautious with their decisions because some of these were made weeks before all the assessment data from the new debris were available. Given the high risk and increased uncertainty due to new debris, “we don’t want to keep the crew away any longer for items that we don’t consider important,” Weigel said.
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