The most recent mission to the International Space Station had maintenance as its main mission, with some new installations and experiments mixed in.

Installation of a new water rack, a device that recycles used water on the station to make it potable, and maintenance of the solar array were conducted during Space Shuttle Endeavor’s most recent flight, STS 126.

“We were a big maintenance flight,” said Mission Specialist Heidemarie Stefanshyn-Piper.

Moving the water rack was much easier in orbit than it was on the ground, said Stefanshyn-Piper. About nine hours were required to load the large piece of equipment on the ground, she estimates. In orbit, it took two astronauts about nine minutes to put it in place.

The main job of the water rack will be to process condensation and urine into potable water, Stefanshyn-Piper said.

“We would take yesterday’s coffee and turn it into today’s coffee,” she said.

Cleaning the Solar Alpha Rotary Joints was the most time-consuming of the jobs conducted during the mission. Stefanshyn-Piper said it was a learning experience with grease guns. The objective was to clean the SARJ of small particles that have accumulated in them over the past 10 years of service and to regrease critical areas.

Stefanshyn-Piper and another astronaut spent up to six hours at a time in four space walks cleaning and greasing one SARJ on the outside of the space station. She said it was slow, tedious work, and they learned that one air bubble in a grease bag can expand in the vacuum of space and explode the bag.

“A little bit of grease makes a big mess, I learned that,” Stefanshyn-Piper said.

They were able to lubricate and clean the array of the debris by using a rag with grease on it and have it working almost as good as the day it was installed.

Some science experiments were brought on board the Space Station, such as spiders and butterfly caterpillars, Stefanshyn-Piper said. The objective was to observe their behavior in weightless conditions, such as how spiders fare making webs in the absence of gravity. For the most part the spiders had no problem making their webs, but Commander Christopher Ferguson said it was evident when the spiders were having a bad day.

The mission also was the first time Mission Specialist Donald Pettit’s invention of the space cup was used. It consisted of a collapsible container that used surface tension to keep drinkable liquid in the container until the astronaut drank from it.

By the end of the mission, the Endeavor had delivered about 14,000 pounds of equipment and supplies to the space station and brought back to Earth about 4,000 pounds of waste. One of the things they brought back, an old tub of urine, ended up leaking after the mission was over, Ferguson said.