Mike Massimino is a former NASA Astronaut, an New York Times bestselling author, a Columbia University engineering professor, and an advisor at The Intrepid Sea, Air and Space Museum. A veteran of two space shuttle missions and four spacewalks, Mike was the first person to tweet from space, holds the team record for the most spacewalking time on a single space shuttle mission, and successfully completed the most complicated spacewalk ever attempted to repair the Hubble Space Telescope.