For the past week, the toilet on the International Space Station has been having problems with the pump that separates fluids from air. While solid disposal has been working properly, the astronauts that are stationed on the ISS have had to find other solutions for urine collection.

The Saturday flight of Discovery will bring a new pump for the toilet. The spare part is Russian made, like the entire system, and has been shipped from Russia packed in a diplomatic pouch.

There have been worries that it wouldn’t be possible to ship the pump on this flight, because of the very advanced stage in which the process of arranging the luggage in the space shuttle is, but a solution has been finally found. Among other things that will have to wait for the next flight to reach the station will be a spare part for the oxygen generator and a microbe killing device that would have been used in the future in the European laboratory of the ISS.

Luggage load and balance is a very important issue for space shuttle flights. The Saturday flight will bring the Japanese lab Kibo to the space station. The lab is almost as big as a bus, and the shuttle’s robotic arm had to be taken out in order to make room for the 29,000 pounds scientific equipment.

The crew of this flight has only two members that have made spaceflights before, the commander Mark Kelly and Michael Fossum. The construction of the International Space Station will be completed after 10 more NASA missions.