The first spacewalk for the astronauts on the ISS consists of a tedious cleaning and lube job on Tuesday, in order to turn one of the international space station’s power-generating solar-panel wings toward the sun. The 10-foot-wide joint has been clogged with metal shavings from grinding parts for more than a year, limiting the amount of power the wind could produce. The spacewalkers will be Heide Stefanyshyn-Piper and Stephen Bowen and they will use a putty knife to scrape away the metal grit, wet wipes to clean and a grease gun to lubricate the area.

The spacewalk includes other jobs for the astronauts too. They must move an empty nitrogen tank into the docked space shuttle Endeavour’s cargo bay for a return to Earth and take an ammonia hose from the shuttle to store outside the station. Furthermore, they should lubricate another joint that is rotating just fine. This is the first of four spacewalks planned during Endeavour’s nearly two-week visit to the space station. Stefanyshyn-Piper and Bowen had to spend the night in a depressurized airlock, in order to purge nitrogen from their bodies and prevent decompression sickness, when nitrogen bubbles form in blood and tissue.

As for Endeavour’s heat shield that might have some problems similar to the Columbia ones, shuttle officials analyzed some images and concluded that there’s no need for an extra inspection. However, some analysis still has to be done before Endeavour can go home with its seven crew members. One of the main objectives of the mission was to safely open the hatch between the ISS and a cargo container that holds an extra toilet, refrigerator and kitchenette, exercise machine, sleeping compartments and a new system that recycles urine into drinking water. All of these have been transported in order to make the ISS suitable for six crew members from now on.