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Astronauts to spacewalk despite risk of debris

2021-11-30T08:54:56.214Z


Two NASA astronauts will go on a spacewalk just two weeks after a Russian antisatellite test. Russia's missile test alarmed the International Space Station 3:30 (CNN) - Two newly arrived NASA astronauts will leave the International Space Station on Tuesday for a spacewalk to replace a malfunctioning communications antenna. Dr. Thomas Marshburn and Kayla Barron are scheduled to begin their spacewalk at 7:10 am ET, and it is expected to last around six and a half hours. Live coverage of t


Russia's missile test alarmed the International Space Station 3:30

(CNN) -

Two newly arrived NASA astronauts will leave the International Space Station on Tuesday for a spacewalk to replace a malfunctioning communications antenna.

Dr. Thomas Marshburn and Kayla Barron are scheduled to begin their spacewalk at 7:10 am ET, and it is expected to last around six and a half hours.

Live coverage of the spacewalk will air on NASA TV and the agency's website.

Marshburn is seen during his first spacewalk on July 20, 2009.

The astronauts will replace an S-band antenna subassembly using a spare that is already attached outside the space station.

S-band radio frequencies are used to transmit low-speed voice and data from the space station over 350 kilometers to flight controllers on the ground, according to NASA.

After being in operation for 21 years, the antenna recently stopped sending signals to Earth via NASA's data relay and tracking satellite system.

Mission managers discovered the problem in September, said Vincent LaCourt, NASA's spacewalk flight director.

Objective of the spacewalk

"That moment allowed us to have Tom and Kayla go to our neutral buoyancy lab, or large pool where we do spacewalking, and we practice our defined spacewalk," LaCourt said.

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In general, the loss of this antenna has a low impact on space station operations.

However, maintaining antennas like this allows for redundancy in communications.

The installation of the replacement, 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 high-speed KU band systems that transmit video back and forth.

During the spacewalk, Marshburn will be at the end of the Canadarm2 robotic arm, which will be controlled by European Space Agency astronaut Matthias Maurer from inside the space station.

Marshburn will wear the red striped spacesuit as a member of Extravehicular Crew 1 and Barron will wear the unmarked suit as a member of Extravehicular Crew 2. This is Barron's first spacewalk, and it is Marshburn's fifth outing.

Marshburn, Barron, and Maurer arrived at the space station along with NASA astronaut Raja Chari in their SpaceX Crew Dragon capsule on November 11.

Tuesday's spacewalk is the 245th conducted to assemble, maintain and upgrade the space station, which has served as a continuous low-Earth orbit center for humans for 21 years.

Debris concerns

The spacewalk comes just two weeks after debris was created in low Earth orbit by a Russian anti-satellite test that forced members of the International Space Station crew to get into their spacecraft for safety.

  • Space junk is a big problem.

    Russia's anti-satellite missile test just made it even worse

The US Space Command said Russia tested a direct ascent anti-satellite missile, or DA-ASAT, that struck a Russian satellite and created a low-Earth orbit debris field of 1,700 trackable orbital pieces that is also likely to generate hundreds of thousands of pieces of smaller orbital debris.

It will take months to catalog all the new debris created by the test.

NASA Administrator Bill Nelson said in a statement that he was "outraged by this irresponsible and destabilizing action. With its long history of manned spaceflight, it is unthinkable that Russia would endanger not only US and international astronauts associated in the ISS, but also its own cosmonauts. Their actions are reckless and dangerous, and they also threaten the Chinese space station. "

What is the risk

While the debris field was highly concentrated at first, it has dispersed over time, said Dana Weigel, deputy director of NASA's International Space Station Program.

The team that planned the spacewalk ran models and predictions to understand the environment the astronauts will be in during their spacewalk.

Wan Yaping, the first Chinese astronaut to do a spacewalk 0:45

It has increased the risk for spacewalkers by 7%, which "is not a huge increase and is within what we see with normal atmospheric fluctuations and the normal amount of moving debris," Weigel said.

"What it really tells us is that VAS (extravehicular activity) has always been risky."

This risk refers to any debris that can penetrate the spacesuits or the space station itself.

The pieces that spacesuits could penetrate are much smaller than anything they can track, Weigel said.

"It means breakthrough, but it doesn't mean it's catastrophic breakthrough," Weigel said.

"There is a certain penetration size that is bearable. There is an emergency oxygen packet in the suit that would feed it for a while. When we talk about the risk of EVA, it is usually around 1 in 2700, so the risk is considered. to have some size of a penetration in the course during the duration of the VAS of six and a half hours. "

Changes in spacewalk

Weigel said that some previous spacewalks have been at greater risk than this one.

"Unfortunately, when you have a debris event like this and you have a lot of really small pieces scattered around, it just becomes part of the average environment," Weigel said.

"At some point, there is no specific directional aspect to the debris. So there is nothing different that they will do on the spacewalk."

The event changed the to-do list for the spacewalk itself and some "breakthrough" tasks were eliminated, including routing cables and releasing bolts into a spare nitrogen tank, LaCourt said.

However, if there is time, the astronauts will take care of some things that could impede the scheduling of future spacewalks.

Overall, the team said they have been conservative with their decisions because some of them were made a couple of weeks ago before they had all the new debris assessment data.

Amid heightened risk and increased uncertainty from new debris, "we didn't want to leave the crew out any longer for items that we don't consider critical," Weigel said.

Space walk

Source: cnnespanol

All news articles on 2021-11-30

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