Oxygen

by John B. Olson and Randall Ingermanson

Published 1 December 2001

The Fifth Man

by John B. Olson and Randy Ingermanson

Published 1 September 2002
In the sequel to 'Oxygen', the crew of Ares 10 lands safely on Mars, but when their work to discover microscopic life on the planet is sabotaged, they wonder if the perpetrator is human or alien.