Virgin Galactic SpaceShip2 Test Flight

MOJAVE, CA - APRIL 29: (EXCLUSIVE COVERAGE) (EDITORIAL USE ONLY, NO SUBJECT SPECIFIC TV BROADCAST DOCUMENTARIES OR BOOK USE) Sir Richard Branson "chest bumps" Scaled Composites engineer Jason DiVenere following a sucessful rocket motor burn on SpaceShipTwo's first powered flight on April 29, 2013 in Mojave, California. SpaceShipTwo is a private enterprise aircraft, designed to carry paying passengers into space. The spacecraft was dropped from the mothership at high altitude and fired it's engine for a approximate 16-second burn taking the craft through the sound barrier. The hybrid rocket motor is fueled by nitrous oxide and a rubber propellent combination. The motor can be "shut down" at any time for safety and flight requirement purposes. (Photo by Mark Greenberg/Virgin Galactic/Getty Images)