(Reuters) - NASA will partner with Boeing and SpaceX to build commercially owned and operated "space taxis" to fly astronauts to the International Space Station, ending U.S. dependence on Russia for rides, officials said on Tuesday. The U.S. space agency also considered a bid by privately owned Sierra Nevada Corp, but opted to award long-time aerospace contractor Boeing and California's SpaceX with contracts valued at a combined $6.8 billion to develop, certify and fly their seven-person capsules. The contract has taken on new urgency given rising tensions between the United States and Russia over its annexation of the Crimea region of Ukraine and support for rebels in eastern Ukraine. By flying astronauts commercially from the United States, NASA could end Russia's monopoly on space station crew transport. The agency pays $70 million per person for rides on Russian Soyuz capsules, the only flights available for astronauts since the retirement of the U.S. space shuttle fleet in 2011. The companies retain ownership of their vehicles and can sell rides to customers outside of NASA, including private tourists. “The work that we have underway … is making the possibility for everyone to someday see our planet Earth from space,” said Kennedy Space Center director and former astronaut Bob Cabana. via Reuters.