A new oxygen generation system tested between July 11 and 14 aboard the International Space Station will allow the orbiting laboratory's crew size to increase in 2009.

The hardware is part of the station's environmental control and life support system and will be used to augment the Russian Elektron oxygen generator. With the increased capability to produce oxygen, the station can better support six crew members as they work and live aboard the outpost. The station currently supports a three-person crew.

During normal operations, the new system will generate about 12 pounds of oxygen per day, enough for six people. However, it can provide as much as 20 pounds of oxygen per day, enough for as many as 11 people. It is designed to replace oxygen consumed through breathing or lost during experiment use and airlock depressurization. During last week’s test, which started Wednesday and ended Saturday, the system generated approximately 10 pounds of oxygen.

"The successful activation and operation of this new system during its test run is an important step toward establishing a truly international space station," said Mike Suffredini, manager of the space station program. "With this system's oxygen-generating capacity, we can expand the station's crew, providing more opportunities for our partner countries and unlocking more possibilities for research that will open new pathways for future exploration."

The 1,800-pound, refrigerator-sized component was delivered on space shuttle Discovery's STS-121 mission in July 2006 and installed in the space station's Destiny laboratory. Since then, several elements of hardware and software have been added to the station to support the new system's operation. The last required part, a hydrogen vent valve, was installed during a spacewalk on space shuttle Atlantis' STS-117 mission in June.

Work performed by space station Expedition 15 Flight Engineer Clayton Anderson and software updates to U.S. computers earlier in July completed preparations for the system's activation and operation.

The new system produces oxygen by tapping into the station's water supply. Through the process of electrolysis, it splits the water into hydrogen and oxygen molecules. The oxygen is delivered into the crew cabin, while the hydrogen is vented overboard through the hydrogen vent valve. In the future, NASA engineers will recycle the hydrogen for water production from carbon dioxide.

Currently, oxygen on the station comes from four sources: the Russian-built Elektron system, Russian supply vehicles, storage tanks in the U.S. Quest airlock and solid fuel oxygen generators called candles.

The new oxygen generation system in the U.S. Destiny laboratory is one of two primary components in the station's regenerative environmental control and life support system. The other component, the water recovery system, is planned to be installed on the space station in 2008. Periodically, NASA will activate and operate the new oxygen generator to ensure the system remains ready for its integration with the water recovery system.

The two new systems were to be included in the space station's Node 3 module, targeted for launch in 2010. However, mission managers decided to launch them earlier as part of a strategy to increase the station's crew to six people in 2009.

The oxygen generation system was designed and tested at NASA's Marshall Space Flight Center in Huntsville, Ala., and Hamilton Sundstrand Space Systems International in Windsor Locks, Conn. The Boeing Co. of Chicago provided laboratory integration, including the development of mechanical equipment, electrical equipment and computer software.