During the past 10 years, Presidents George W. Bush and Obama have directed NASA to turn the job of transporting cargo and crew to the space station over to the private sector. As that process gathers pace, here is a list of the key players.
The Antares rocket, built by Orbital Sciences Corp., is set for a first test launch Wednesday evening, weather permitting. Its maker is, like SpaceX, under contract with NASA to ferry cargo to the International Space Station.
The space shuttle Endeavour landed in California on its way to its final resting place. On the way, it made a flyover in Tucson, Arizona where former Congresswoman Gabrielle Giffords and her husband Mark Kelly, Endeavour's retired commander, were watching.