Astronauts Reid Wiseman of NASA and Alexander Gerst of the European Space Agency completed the first of three Expedition 41 spacewalks on Tuesday, working outside the Quest airlock of the International Space Station for approximately six hours.

Deutsche Welle reports that Wiseman and Gerst, who became only the third German astronaut to venture into open space, completed the NASA-run extra-vehicular activity (EVA) with tasks involving cleanup, replacement, and installation on the exterior of the space station.

The astronauts relocated a failed cooling pump to External Stowage Platform-2 (ESP-2) outside the Quest airlock, stowed adjustable grapple bars on ESP-2, replaced a light on an External Television Camera Group outside the Destiny laboratory, and installed a Mobile Transporter Relay Assembly (MTRA) on the S0 truss above the laboratory. According to a statement from NASA: “The MTRA adds the capability to provide ‘keep-alive’ power to the Mobile Servicing System when the Mobile Transporter is moving between worksites.”

Wiseman will venture out again on Oct. 15 for another spacewalk, this time accompanied by NASA astronaut Barry Wilmore. The duo will attempt to replace some electronics that stopped working in May. “When you look out a little further as to how the EVAs stack up after the first of the year out into the spring, we’re really going to start this transformation of the space station,” said Kenny Todd, space station integration operations manager, during a news conference last week according to Space.com.

“We’re going to be doing the things we need to do on these EVAs to prep for moving some modules around. All that is in preparation for being able to support future [commercial] crewed vehicles coming to station,” said Todd. “We’re trying to get out in front of that… We’ll be prepping for moving modules, we’ll be installing a new docking adapter system. All of that will be happening throughout the next several months onboard the station.”

“Alex and I would just like to express our huge gratitude for getting us back into planned EVAs, safely outside, safely back in on a great EVA,” said Wiseman to mission control radio in Houston, TX, according to CBS News. “It’s a good day for NASA, it’s definitely a good day for the European Space Agency.”