NASA - which recently retired its shuttle fleet - wants to hire private "space taxis" that will transport U.S. astronauts to and from the International Space Station (ISS).
The space agency believes outsourcing low Earth orbit transportation will allow it to focus its energy and resources on deep space exploration.
As such, NASA's draft request for proposal (RFP) outlines an Integrated Design Contract (IDC) that will be awarded to multiple companies from July 2012-April 2014.
Corporations competing for the lucrative $1.61 billion contract will be expected to provide a complete end-to-end design, including spacecraft, launch vehicles, launch services, ground and mission operations and recovery.
"This IDC effort will bring us through the critical design phase to fully incorporate our human spaceflight safety requirements and NASA's International Space Station mission needs," explained NASA Commercial Crew Program Manager Ed Mango.
"We look forward to strong U.S. industry response."
NASA's space shuttle program was retired this past July after some three decades of spaceflight. The United States therefore remains dependent on Russia's Soyuz spacecraft to carry astronauts to and from the ISS - with Europe and Japan also providing unmanned cargo ships to haul supplies to orbiting station.
It should be noted that NASA has already clinched a deal with the privately owned Space X to fly 12 ISS delivery flights using its robotic Dragon space capsule and Falcon 9 rocket. The first flight is expected to launch by the end of 2011.
In addition, the space agency has also hired Orbital Sciences Corp. to fly 8 ISS cargo missions using its unmanned Cygnus spacecraft and Taurus 2 rockets. The first Cygnus mission to the space station could take places as early as February 2012.