NASA chose three aerospace companies to continue working over the next two years on commercial spaceships intended to carry astronauts to the International Space Station by 2016.

The space agency awarded Boeing’s [BA] Houston operation, Space X of Hawthorne, Calif., and Sierra Nevada Corp. of Louisville, Colo. so-called Commercial Crew Integrated Capability (CCiCap) contracts worth more than a combined $1.1 billion to design and develop the spacecraft that are intended to take the place of NASA’s now-retired space shuttle. The agency intends to pay private spacecraft providers to carry crew to low-Earth orbit in the privately owned vehicles.

“Today, we are announcing another critical step toward launching our astronauts from U.S. soil on space systems built by American companies,” NASA Administrator Charles Bolden said at the agency’s Kennedy Space Center last Friday. Since NASA retired the space shuttle last year it has arranged for Russia to carry astronauts to the space station, until commercial craft are ready.

The CCiCap contracts make up the third phase of NASA’s effort to help private companies develop spaceships to carry crew to low-Earth orbit. For the second phase, called Commercial Crew Development-2 (CCDev-2), the agency awarded contracts last year to the three companies tapped last Friday along with an unsuccessful bidder in the latest round: Blue Origin of Kent, Wash. (Defense Daily, April 20, 2011).

For this latest effort, the three selected firms will perform tests and mature integrated designs on their respective spacecraft between now and May 31, 2014, NASA said.

“This would then set the stage for a future activity that will launch crewed orbital demonstration missions to low Earth orbit by the middle of the decade,” the agency said.

NASA’s CCiCap initiative is separate from its other commercial-crew efforts to develop the Orion crew vehicle and Space Launch System heavy-lift rocket, which are intended to carry astronauts beyond low-Earth orbit.

NASA hopes that under CCiCap the new commercial spacecraft will carry away U.S. astronauts within five years.

Lawmakers who oversee NASA hailed last Friday’s contract announcement.

Sen. Bill Nelson (D-Fla.), chairman of the Senate Commerce Space and Science subcommittee, called the news “another sign of America’s resurgence in space.”

Sen. Kay Bailey Hutchison (R-Texas)–ranking member of the Senate Appropriations subcommittee that dictates NASA funding and the Senate Commerce Committee–said the CCiCap contract action is “consistent with the approach several of us in the Congress urged NASA to take, to ensure that the limited funds available are spent on developments that have a strong probability of success.”

“This is a step that should keep development of commercial crew capability on a schedule to launch as soon and as safely as possible while on a realistic budget,” she added.

The CCiCap contracts are worth $460 million for Boeing, $440 million for SpaceX, and $212.5 million for Sierra Nevada.

Boeing highlighted in a statement the work it already has done on its CST-100 spacecraft, launch services, and ground systems during the CCDev-2 and earlier Commercial Crew Development (CCDev) phases. The company said it “completed tests on engines, abort systems, propulsion, heat shield jettison, attitude control systems and landing to provide full data on functional elements of the spacecraft’s design.”

“This (CCiCap) award will enable us to build on the successes achieved in our Commercial Crew Development (CCDev) and CCDev-2 work for effective development through Critical Design Review, as we progress toward human rating and certification,” John Mulholland, vice president and program manager of Boeing Commercial Programs, said.

SpaceX is adapting its Dragon cargo capsule for manned missions, and Sierra Nevada is developing a Dream Chaser plane similar to the space shuttle.