The second spacewalk in the AMS series on 22 November has been dubbed the “nail-biter” and will see Luca and Drew exit the Station’s airlock at approximately 13:05 CET (12:05 GMT). This spacewalk is made up of four main stages: setup, preparing/accessing the worksite, tube cutting and clean-up.
In their first AMS spacewalk, Luca and Drew managed to complete just under two hours’ worth of tasks that were scheduled for spacewalk number two. As they have already broken the carbon fibre cover of the Vertical Support Beam (VSB) and jettisoned this, this task is no longer on the cards for this spacewalk. Instead, the pair will move ahead with cutting a 6mm tube to vent existing CO2 from the instrument’s cooling system and cutting tubes within the VSB that will be rerouted to the new pump components during the next spacewalks.
After exiting the airlock, Luca will begin once again by attaching himself to the Station’s 16-m long robotic arm as Drew ferries equipment by hand along the Station’s exterior to the AMS. Luca’s journey to AMS on the Canadarm2, which will be remotely operated by NASA’s Jessica Meir and Christina Koch inside the Space Station, is expected to take 35 minutes.
Once at the worksite, Luca and Drew will start to prepare the site and power cables and install a Mechanical Attach Device (MAD) to a beam on the AMS. Later in the series, they will attach the Upgraded Tracker Thermal Pump System (UTTPS) to this MAD support structure – this is the new pump/CO2 refill device that will be connected to the cut tubes.
Once the MAD has been installed, Luca will conduct what’s called a “depress cut”. Using a cutter tool he will cut the 6mm fill port tube and wait for around 10 minutes until Mission Control verify a pressure drop in the AMS system. He will then move onto the next stage – cutting six of eight tubes in two locations within the VSB.
This tube-cutting activity is what gave the second spacewalk its name.
To help them in this activity Luca and Drew have other special tools. One of these is a tube cutting guide marked with red and green lines that indicate which tubes should be cut.
Once the tubes have been cut, they need to be pushed back into the VSB. The pair will also need to take photos of the worksite and GoPro video showing the cut tube locations.
Multilayer insultation (MLI) will then be applied to close the VSB. Components will be wrapped up like a burrito and Luca must ensure all vital areas are covered.
The work that Luca and Drew need to perform in these AMS spacewalks is surgical in nature. The leading role of EV1 is like a surgeon, while EV2 could be compared to a scrub nurse and anaesthesiologist combined. Their task is made all the more difficult by their pressurised suits and gloves and because AMS was never designed for maintenance in orbit, one of the major risks is sharp edges.
Both Luca and Drew must be very cautious to ensure their gloves are not damaged in any way by AMS components or tools. They will check their gloves regularly throughout the spacewalk. Even a small hole in a pressurised spacesuit can cause a big problem, so they will need to remain vigilant throughout the full six and half hours.
The pair will also document their spacewalk and the tasks they carry out by taking photos and videos at every step of the way. This is important for support crews on the ground as they plan the next phase of operations.
Clean-up and return
Once the pair have completed their spacewalk tasks, and any ‘get-ahead’ tasks if time allows, they will proceed with clean-up. This includes carrying out an inventory of the crew lock bags they brought with them to make sure all tools and equipment is accounted for.
Once the duo and mission control are satisfied, our spacewalkers will make their way back to the airlock. As per the first spacewalk, Drew will return along the truss of the Station while Luca will be transported back on the robotic arm.
After his journey on the arm, Luca will recover his first safety line (he also has a second safety line attached to the robotic arm) and make his way back to the airlock.
Reentering the airlock will take around 20 minutes. First in are the crewlock bags containing tools and equipment, followed by Drew and then Luca who will close the thermal cover and then the hatch – marking the end of the spacewalk.
After around six and a half hours of highly concentrated work in open space, the pair will no doubt be relieved to be back inside where NASA astronauts Jessica Meir and Christina Koch will help them out of their suits and into the relative safety of the Space Station.
You can watch the entire second AMS spacewalk live on ESA Web TV from 12:30 CET (11:30 GMT) with commentary from NASA. As EV1, Luca will be wearing a white suit with red stripes, while Drew will be in an all-white spacesuit.
You can also follow the action on Twitter via @esaspaceflight where we’ll be tweeting throughout the spacewalk and ask any questions using the hashtag #SpacewalkForAMS.
Below is a rough timeline of events for the second spacewalk. Please note, all times are in GMT.
|Preparation starts for second spacewalk||07:00|
|Airlock depressurization starts||11:30|
|Live coverage starts||11:30|
|Exit the airlock||11:50|
|Luca starts ride on robotic arm||12:10|
|Work start on preparing power cable||12:45|
|Cutting tubes starts||14:15|
|Removing insulation material||16:45|
|Robotic arm takes Luca back to airlock||17:30|
|Return inside airlock||18:15|
|Hatch closure and repressurisation||18:45|