Several months after the Sierra Nevada Corporation filed a protest with the Government Accountability Office, asserting NASA had unfairly awarded contracts to Boeing and SpaceX, the watchdog agency dismissed the claims.

In September of last year, NASA announced the $6.8 billion Commercial Crew Transportation Capability (CCtCap) contract -- a contract to build the spacecraft necessary to shuttle astronauts to and from the International Space Station -- would be split between Boeing and SpaceX.

The Sierra Nevada Corporation, which continues to work on a variety of other missions for NASA, quickly filed a complaint alleging there were "serious questions and inconsistencies" about the manner in which the contract was written and awarded.

But on Monday, the GAO confirmed that NASA had done everything by the books -- signing off on the legitimacy of the joint contract.

"The GAO has notified NASA that it has denied Sierra Nevada Corporation's protest of the Commercial Crew Transportation Capability contract awards," space agency officials confirmed in a press release. "NASA is pleased the GAO's decision allows the agency to move forward and continue working with Boeing and SpaceX on the Launch America initiative."

Boeing and SpaceX had already been instructed by NASA to get to work on the design and construction of an ISS shuttle service, despite the then-pending protest. Boeing has since met its first two contract milestones, while SpaceX has met its first.

Once complete, the space taxis will allow NASA to end its reliance on Russia and its expensive ferry services to get astronauts to the space station.