Sierra Nevada Corp's "Dream Chaser" space plane, which resembles a miniature space shuttle, is one of four space taxis being developed by private industry with backing from the U.S. government.
For the unmanned test flight, it will be carried into the skies by WhiteKnightTwo, the carrier aircraft for the commercial suborbital passenger ship SpaceShipTwo, backed by Virgin Galactic, a U.S. company owned by Richard Branson's London-based Virgin Group.
The test flight was added after privately held Sierra Nevada got a $25.6-million boost to its existing $80 million contract with NASA.
The test flight will take place from either Edwards Air Force Base in California's Mojave Desert, or from the White Sands Missile Range in New Mexico, Ed Mango, manager of NASA's Commercial Crew Program, said at a community briefing at the Kennedy Space Center in Florida.
With the retirement of the space shuttles this summer, NASA is now dependent on Russia to fly astronauts to the space station, at a cost of more than $50 million per person.
The agency hopes to turn over crew transportation services to one or more commercial firms before the end of 2016, Mango said.
In addition to Sierra Nevada, NASA is funding spaceship development work at Boeing Co, Space Exploration Technologies, and Blue Origin, a start-up firm owned by Amazon founder Jeff Bezos.
"Having only one way to get crew to the station is a limitation," NASA astronaut Mike Fossum, who is currently living aboard the outpost, said during an in-flight interview last week.