Mike Massimino served as a NASA Astronaut from 1996 until 2014 and flew in space twice: STS-109 on space shuttle Columbia in March 2002 and STS-125 on space shuttle Atlantis in May 2009 - the final two Hubble Space Telescope servicing missions. Mike became the first human to tweet from space, was the last human to work inside of Hubble, and set a team record with his crewmates for the most cumulative spacewalking time in a single space shuttle mission.