The atmosphere of any manned spacecraft needs to be continuously monitored in order to safeguard the crew’s health. A rapid response by the astronauts to the release of harmful gaseous contaminants, accidental off-gassing of materials, or malfunctions of the air revitalisation system is essential. And the need for air monitoring grows with mission duration. The air quality aboard the International Space Station is an increasing concern, and ANITA has contributed to better information and much shorter response time for many contaminants. [Illustration: European Space Agency]

SINTEF’s project manager Atle Honne with a measurement set-up for ESA’s trace gas monitoring project. The grey canister contains a test gas mixture delivered from NASA which at that time was known only to NASA. Photo: SINTEF.

NASA astronaut Clayton Anderson with ANITA on the ISS at the time of system start-up in September 2007. ANITA is contained in the two EXPRESS rack inserts behind Clay’s right hand and lower arm. The control laptop computer is mounted on the blue box in the upper left-hand corner. Photo: NASA.

In a project for ESA (European Space Agency), SINTEF develops a FTIR (Fourier Transform Infra-Red) system for trace gas monitoring in co-operation with Kayser-Threde GmbH. The ongoing development for ESA is aiming for long duration missions like the ISS (International Space Station) and - in a longer perspective - a moon base, and possibly for missions to Mars.

The system applies off-the-shelf or modified FTIR hardware and specially developed analysis software. The software includes novel compensation methods for hardware imperfections and insufficiencies, allowing the successful simultaneous monitoring of over 30 frequently detected air contaminants in the presence of water vapour, carbon dioxide, and methane. In a blind sample test campaign for  NASA, an early version of ANITA was ranked first with substantial distance to the competitors.

The launch of the latest prototype of ANITA to the ISS (International Space Station) was performed in August 2007 by the Space Shuttle Endeavour flight STS-118. ANITA was installed for testing in the US lab Destiny in cooperation with NASA, and the system start-up took place in September. After an initial 10-day test phase, formally as a scientific experiment, the system was operated to gather information on the indoor air quality on the ISS.
 
ANITA’s standard operation in space was fully automatic with a time resolution of 6 minutes. In addition, a few non-local air samples were taken manually, using a hand pump and a sample bag, and fed to ANITA for automatic analysis. Thanks to ANITA’s successful operation, giving new and very valuable information on the gas status and air dynamics in the spacecraft air, the operation was prolonged until august 2008. Then, further operation was no longer possible, because of a long-planned relocation of the indoor infrastructure on the ISS.

The data from ANITA achieved several “firsts” on the ISS. A few gases were for the very first time measured in the air inside the ISS, or even sampled from the ISS. One of these gases was entirely unexpected to be present at measurable quantities. Many gases were for the first time measured onboard, i.e. without having to wait for air samples to be returned to ground for analysis. And even more gases were for the first time measured with high time resolution.

In a figure below, an example plot shows ANITA measurements on two accidental PFP (perfluoropropane) leakages on April 29 and May 23, 2008. Before ANITA, PFP was known to be in the air on the ISS because of its presence in Russian cooling systems, but it could never be measured. ANITA provided regular measurements as well as precise timing, size, and longer-term effects of any leakages. ANITA also revealed that the countermeasures supposed to clean the PFP from the air were entirely unsuccessful, so that, as a consequence of the ANITA measurement results, the attempted countermeasures were just turned off.

Other possible application areas for such systems and techniques include monitoring of indoor air and industrial processes.

For further information please contact Atle Honne.