Several companies are working on rockets and spacecraft that could ferry supplies and astronauts to the International Space Station, now that the shuttle program is over.
A brief look at each:
* Alliant Techsystems Inc., or ATK, headquartered in Arlington, Va., with aerospace division in Magna, Utah. Developing Liberty launch system including rocket and passenger spacecraft. Test flights to begin in 2014, with possible first manned launch in 2015.
* Blue Origin in Kent, Wash. Run by Amazon founder Jeff Bezos.