Washington, Sep 17 (IANS) US space agency NASA said Tuesday it will make a "major announcement" regarding the awarding of contracts to build commercial spaceships that will send the country's astronauts to space soil by 2017.

"NASA is poised to announce the final phase of development and certification to provide safe, reliable and cost-effective transportation to and from the International Space Station from the," Xinhua reported the agency saying in a YouTube video.

Boeing Co., Sierra Nevada Corp. and SpaceX are considered the leading contenders for the multi-billion-dollar contracts.

The Wall Street Journal reported Monday that Boeing is likely to be the primary winner of NASA's commercial crew contract and that SpaceX or Sierra Nevada Corp. is expected to "obtain a smaller contract as a second source."

The NASA's commercial crew programme is aimed at ending the US dependence on Russia for crew access to the International Space Station and all of the spacecraft are American-built.

The space agency has signed deals with two US companies -- SpaceX and Orbital Sciences Corp. to supply commercial cargo to the International Space Station.

Since the space shuttle programme retired in 2011 amid funding concerns, the only vehicle available to ferry humans to the space station is Russia's Soyuz spacecraft.

Currently, NASA pays Russia $70 million a seat to take US astronauts to the orbiting laboratory. The agency typically purchased six seats per year.