It will also permit NASA to increase the size of the American crew on the station, and double the amount of scientific research that the team can perform, according NASA spokesperson Stephanie Schierholz.

NASA awarded Boeing a $4.2 billion contract in September to develop a transportation capable of carrying human passengers, according to Kelly Kaplan, a spokesperson for Boeing. Other reports indicate Space X received $2.6 billion for manned space missions at the same time.

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Both companies, along with others, have other space contracts with NASA.

The commercial crew program is expected to improve the quality of the research being done on the station, by getting research samples from space to scientists on the ground faster; under the terms of the contract, crew have to be returned within an hour of landing and critical cargo have to be retrieved within two hours.

"The longer you have something from microgravity sitting in gravity," said NASA's Shierholz, "the more degradation there is, and the tougher it is to study it as it would be in space."

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Space station preps for 'space taxis'