Simulating The Low Earth Orbit Environment

The Challenge

Atomic oxygen is the dominant species in Low Earth Orbit (LEO), that portion of the atmosphere where many satellites orbit the Earth. The orbital velocity of the spacecraft through the atmosphere acts to enhance the reaction of oxygen with spacecraft materials and the radiances formed as a result of their interaction.

The PSI Process

PSI developed a patented laboratory process that produces atomic oxygen at temperatures and velocities that simulate the EarthÕs atmospheric "wind" as it strikes spacecraft. This simulation facility has found wide application in accelerated spacecraft material testing and screening studies, and in quantifying interaction signatures. The PSI fast atom source (FASTª) was developed under a NASA SBIR program and is the only high flux wide area source of 8 km/s oxygen atoms available for space material testing.

The Result

Development of the fast atom source has led to a very significant commercial material testing program at PSI. We have also sold several systems worldwide with two presently operational in Europe, one in Japan, and two in the USA.

Early on we realized that the oxygen atom source could also be used as a research tool to study the optical signatures arising from collisions between energetic oxygen atoms and other target molecules. For over a decade, we have pursued the evaluation of the reaction cross sections for producing visible and infrared radiation in such interactions. Target molecules studied in the infrared include CO, N2, CO2, H2O, methane, methylamine and propane. We have also examined visible emissions in the interaction of 8 km/s oxygen atoms with gas phase and surface bound NO and the interaction of 8 km/s oxygen ions with N2 and H2O. This work has led to over a dozen journal publications establishing a unique database for such interactions.