ISS astronauts to perform final spacewalk of Expedition 66

Date:
Wed, 23 Mar 2022 12:35:27 +0000

Description:
Expedition 66 astronauts Raja Chari and Matthias Maurer have ventured outside the International Space Station The post ISS astronauts to perform final spacewalk of Expedition 66 appeared first on NASASpaceFlight.com .

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Expedition 66 astronauts Raja Chari and Matthias Maurer have ventured outside the International Space Station on Wednesday, performing a spacewalk to carry out repairs and upgrades on the space station.

US EVA-80 marks the 248th spacewalk carried out at the International Space Station, including spacewalks carried out from the Russian Orbital Segment
and as part of Space Shuttle missions. It is expected to be the last
spacewalk before the departure of Soyuz MS-19 next Wednesday, which marks the handover from the current Expedition 66 to Expedition 67.



The spacewalk began at 12:32 UTC and is planned to last six and a half hours, a fairly typical duration for most ISS spacewalks.

The astronauts are tasked with carrying out a number of maintenance and upgrade tasks on the stations external hardware, including fitting hoses on a radiator module, installing a power and data cable on the European Space Agency (ESA) Columbus module, and replacing an external camera.

NASA astronaut Chari is designated EV-1 for Wednesdays spacewalk, identified by red stripes on his spacesuit. He is wearing Extravehicular Mobility Unit (EMU) 3004. In the EV-2 role, Maurer, a European Space Agency astronaut, is wearing EMU 3015 without the identification stripes.

The EMU spacesuits were developed during the Space Shuttle program. As
always, both astronauts suits will be equipped with Simplified Aid For EVA Rescue (SAFER) recovery aids, to provide an emergency maneuvering capability so they can return to the ISS in the unlikely event their tethers should break. Chari (left) and Maurer (right) carry out a spacesuit fit check with the aid of Thomas Marshburn (credit: NASA)

US EVA-80 is the fourth spacewalk of Expedition 66, following US EVAs 78 in December and 79 earlier this month. A Russian EVA was also performed from the Poisk module in January. With Expedition 66 due to hand over to Expedition 67 next Wednesday when Soyuz MS-19 returns to Earth, it is expected to be the last EVA of the current increment. See Also US EVA-80 Updates ISS Forum Section L2 ISS Section Click here to Join L2

Wednesdays spacewalk is the second of Raja Charis career, following US EVA-79 last Tuesday , and will be the first for Matthias Maurer. While Chari will spend most of the EVA riding the stations Canadarm2 robotic arm, Maurer will be required to translate across much of the US segment of the station.

Maurer stated in an ESA press release I really do have to do a complete tour of the space station. It is a motley mix and Im totally looking forward to
it. He will be the twelfth European Space Agency astronaut and the fourth German to conduct a spacewalk at the ISS, after Thomas Reiter, Hans Schlegel, and Alexander Gerst.

The astronauts will begin and end the spacewalk from the Quest airlock
module, which is used for all US EVAs carried out at the station. Raja Charis main focus will be on carrying out repairs to a Radiator Beam Valve Module (RBVM) , while Maurer will work on installing cables outside ESAs Columbus module .

The RBVMs help to route ammonia through the space stations radiators, providing cooling for onboard systems, including vital electronics.
Spacecraft must use radiators to help dissipate heat as in the vacuum of
space air circulation cannot be used to take heat away as it would on Earth. The RBVM jumpers were inspected on-orbit in 2017 before their refurbishment (credit: NASA)

There are six of these modules on the P1 and S1 truss elements. The RBVMs are vital items of cooling hardware, controlling the flow of ammonia to and from the radiator assemblies, which themselves extend from the space stations truss. The RBVMs can monitor pressure, temperature, and valve position, and can also vent ammonia during contingency situations. They also help to
control pressure in the External Active Thermal Control System (EATCS)
cooling loop.

A pair of ammonia line jumper hoses were removed from one of the RBVMs during a previous EVA after a small leak had been detected. These were returned to Earth for refurbishment, before being transported back to the ISS aboard a Dragon Cargo spacecraft. Chari will be reinstalling these jumpers onto the RBVM while mounted to a foot restraint on Canadarm2. He will also install two quick disconnects that will be used to provide power to a heater.

Meanwhile, Matthias Maurer will connect a power and data cable to the Bartolomeo external science platform , which was installed on the Columbus module last year.

Bartolomeo hosts experiments that need direct access to the vacuum of space, such as investigating how material samples are affected by long-duration exposure to space. Maurer will install the last connections needed to make
the platform fully -operational. He will also prepare the platform for experiments to be installed remotely using the stations robotic arm. The Bartolomeo facility (bottom right) attached to the Columbus module (credit: Airbus)

Another key objective for Wednesdays EVA will be to replace an external view camera on the P1 truss, a task for which Chari and Maurer will work together. Cameras are mounted at various points on the exterior of the ISS to document station activity and conditions. The new camera, to be installed on the
Camera Port 8 site, will have an improved two-way data rate to the ground.

After the camera installation, Chari will install T-handle tools on the port radiator grapple bar to aid astronauts on future EVAs. Later he and Maurer will complete the work on the RBVM by stringing a power cable to the module where Chari had installed jumpers earlier.

Other tasks scheduled for US EVA-80 include Maurer securing a loose
insulation blanket on the Japanese Kibo science module. He will also make his way to Truss P4, where he will release bolts connecting orbital replacement units on that truss.

Maurer will then re-torque the bolts at a lower setting. This will allow the Canadarm to more easily remove and replace these units as needed. He will
also adjust an electrical connector on the S0 Truss mounted to the Destiny module so that it can once again provide power to a component.

If the EVAs scheduled tasks are finished early, various get ahead tasks can
be performed by the astronauts as timing and consumables permit. If these tasks cannot be performed on this EVA they will be left for future
spacewalks.

(NASA astronaut Raja Chari works outside the ISS during US EVA-79 earlier this month. Credit: NASA)

The post ISS astronauts to perform final spacewalk of Expedition 66 appeared first on NASASpaceFlight.com .



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Link to news story:
https://www.nasaspaceflight.com/2022/03/us-eva-80/


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