NASA has indicated which companies it believes are closest to offering commercial options to carry American astronauts into space.
With the remaining Shuttle fleet about to retire, NASA has offered £166m ($270m) in funds to four firms to help them advance their designs for new orbiters.
Blue Origin, of Kent, Washington (a company set up by Amazon.com founder Jeff Bezos), has kept most of its space development activity under wraps, but has requested funds from NASA to help it advance plans for a cone-shaped crew vehicle.
SpaceX, of Hawthorne, California, garnered much publicity recently when it test launched a rocket called Falcon 9 and a capsule called Dragon.
Boeing’s Houston, Texas, team has a capsule design called CST-100 which could transport up to seven astronauts.
Sierra Nevada Corporation (SNC) of Louisville, Colorado, is developing a shuttle-like vehicle called the Dream Chaser that would launch on the nose of a rocket.
After the final Shuttle mission is flown later this year US crews will have to go to the ISS on Russian rockets, until these astronaut “taxi” services first launch (expected around the middle of this decade).
Full Story: BBC/Jonathan Amos