NASA will reveal Tuesday who will build the next spaceship to carry U.S. astronauts into orbit.

Officials will likely choose between SpaceX, Boeing Co. and Sierra Nevada Corp., three companies already receiving federal funding to design human-rated spacecraft.

Officials could select one or more of the companies to continue working on their commercial space taxis.

NASA Administrator Charlie Bolden will make the announcement during a 4 p.m. EDT (2000 GMT) briefing at the Kennedy Space Center in Florida. You can watch the event below.

NASA has spent nearly $2 billion to advance commercial crew spacecraft concepts, but the effort to develop a privately-run space line has run into delays which the space agency blames on inadequate budgets passed by Congress.

Companies received government funding in three rounds, with the next phase to include money for orbital test flights leading to the start of operational missions to the International Space Station by the end of 2017.

The commercial crew program is framed as a public-private partnership, with the bulk of the funding to design, develop and test the vehicles coming from NASA, plus private capital contributions.

NASA can stop using Russian Soyuz spacecraft to ferry astronauts to and from the space station once a U.S.-made commercial vehicle is ready.

The space agency foresees at least two commercial crew flights per year to rotate astronauts on the space station.

SpaceX has proposed a crew-capable Dragon space capsule for human flights launching on the Hawthorne, Calif.-based company's Falcon 9 rocket and returning to Earth for a touchdown on land with parachutes and braking rockets.

Boeing's CST-100 capsule is being designed to lift off on United Launch Alliance Atlas 5 rockets and come back to Earth under parachutes for an airbag-cushioned landing at White Sands, N.M.

The Dream Chaser space plane proposed by Sierra Nevada would take off on the Atlas 5 booster and glide home to landing at the Kennedy Space Center's space shuttle runway.

All of the vehicles can carry up to seven astronauts or a mix of fewer crew members and cargo.

Follow Stephen Clark on Twitter: @StephenClark1.