Over the next couple of weeks, the astronauts on board the International Space Station will get to stretch their legs during a series of strolls through the vacuum of space. The first of those three spacewalks gets underway this morning before 8AM ET, when NASA astronaut Shane Kimbrough and Thomas Pesquet of the European Space Agency are scheduled to exit the ISS. The pair are tasked with doing a number of repairs and upgrades to the outside of the orbiting lab over the course of a six-and-a-half hour walk.
The biggest focus of today’s spacewalk is helping to move around a piece of hardware that’s needed for NASA’s Commercial Crew Program. Through that initiative, private companies SpaceX and Boeing are developing vehicles to send astronauts to and from the ISS, and the first flights of those spacecraft could start as early as next year. When the vehicles arrive at the station, though, they’ll need a place to hook up. And that’s what today’s spacewalk will help with.
Specifically, the piece of hardware that needs moving around is a cone-shaped structure called a pressurized mating adapter, or a PMA. Currently, the ISS is home to three of these PMAs, which are built by Boeing. They’ve been used to either connect parts of the ISS together or to help spacecraft like the Space Shuttle hook up to the station. Now, two of the PMAs are going to allow the crewed vehicles built by SpaceX and Boeing to park at the ISS once they start carrying people into orbit. NASA is putting docking adapters on the ends of these PMAS, which will allow the spacecraft to automatically dock with the station and safely deliver their astronauts.
NASA astronauts already installed one docking adapter to a PMA in August, but the ultimate plan is to have two adapters once the Commercial Crew Program gets underway. Before another docking adapter can be installed, though, NASA wants to relocate the PMA it will sit on — called PMA-3. Right now, PMA-3 is attached to the Tranquility module, but NASA wants it to live on the “space-facing” side of the Harmony module. Today, NASA’s Kimbrough will disconnect some cables and electronic connections on PMA-3. Then on Sunday, operators on the ground will remotely operate the Canadian robotic arm and move PMA-3 to its new home on the Harmony module. During the second spacewalk, slated for next week, Kimbrough will reconnect those cables and connections on the PMA, fully hooking up the adapter to its new module.
Kimbrough is also doing a few additional tasks during his spacewalk today, such as upgrading a computer processor on the outside of the station and changing out light bulbs on a couple of cameras. Meanwhile, ESA’s Pesquet will be on a completely different side of the station trying to find the source of a small ammonia leak that NASA has been tracking for a while. Once he’s done with that, Pesquet will then grease up the end of one of the station’s robotic arms, which is in need of some lubrication.
NASA’s coverage of today’s spacewalk began at 6:30AM ET. So if you’re having a slow Friday, tune in to some astronauts doing incredibly complex busy work in one of the harshest environments imaginable.