MicroCATS in space

Scientists at

, which is operated by Battelle for the US Department of Energy, are developing lightweight, compact microchemical and thermal systems for NASA applications.

These microchemical and thermal systems, also known as MicroCATS, configure such things as microchannel absorbers, reactors, separators and heat exchangers to produce the propellant from resources found on Mars and the moon. In addition, the system will also be designed to regenerate breathable air for life support. The NASA contract is valued at $13.7 million over four years.

"Further development of the microchannel architecture makes this all feasible," says Kriston Brooks, PNNL principal investigator. "Our ultimate goal is then to use the same microtechnology principles on a larger scale to provide propellant for a manned mission to Mars in the 2030 timeframe."

PNNL's mission supports the US President's new vision for space exploration. President Bush pledged to return to the moon by 2020 in preparation for future human exploration of Mars and other distant destinations in his January 2004 address at NASA headquarters.

"The contract is four times larger than any PNNL has previously had with NASA," says Martin Kress, Battelle's NASA relationship manager. "We hope this technology system ushers in an entirely new approach for lunar and Martian exploration and habitation," Kress added.

The compact microtechnology processing station, referred to as ISPP, the In Situ Propellant Production system, will collect carbon dioxide from the Martian atmosphere and have it react with hydrogen gas to produce methane fuel and oxygen forming the propellant for the return voyage.

"Additionally, by collecting and reconditioning exhaled air, the system will produce pure oxygen for crew members; a problem that nearly doomed the Apollo 13 mission," noted Brooks. Both methane and oxygen can also be used to generate electrical power for vital life support systems making this capability central to a manned outer space infrastructure.

"Since the system uses modular banks of identical microchannel components, there is a built-in redundancy achieving enhanced safety and reliability," stated Brooks. "We anticipate increased system efficiency as well as improved economic benefits when the research is complete."

Microchannel technology generally has at least one dimension that is 200 microns or less in size. Due to improved heat and mass transfer rates, the microtechnology process can be intensified, resulting in significant size reductions over conventional hardware. At these small scales, hydrodynamic, surface, and interfacial forces dominate, allowing the devices to operate independent of gravity.

"We also hope to demonstrate the concept of making use of resources found both on the moon and Mars, not only for propellant and breathing air, but ultimately to build a community in space," says Brooks. "For instance, silica, iron and titanium retrieved from soil on the moon could be used to produce photovoltaics capable of generating electricity, and producing metals for building construction and other manufacturing processes."

Brooks admits that these capabilities are still conceptual, but says that by demonstrating the next generation of microchannel technology for ISPP, researchers may be able to advance these capabilities as well.