He joined NASA's Jet Propulsion Laboratory as a senior research engineer in 1996 and subsequently became a programme manager. He was selected as an astronaut in 1998. In 2007 he flew on space shuttle Atlantis (STS-117) logging 336 hours in space including over 14 EVA hours. In 2009 he served aboard space shuttle Discovery (STS-128) and has a cumulative total of over 668 hours in space and over 34 EVA hours. Olivas retired from NASA on 25 May 2010.