When NASA awarded Elon Musk's SpaceX company and Boeing the contract to start bringing astronauts to the International Space Station as early as 2017, the Sierra Nevada Corp. was not happy.

They're planning to legally contest NASA's decision to choose those companies, instead of them, so they can one day be part of space missions run by a commercial company.

The Sierra Nevada Corp. filed a complaint to the U.S. Government Accountability Office on Sept. 26, alleging there were "serious questions and inconsistencies," according to Space News.

Now the company has a plan for how it could get said astronauts into space, announcing it plans to power its spacecraft by hitching it to the Stratolaunch plane, a plane said to be the largest ever.

The plane was designed by Stratolaunch systems, a company started in 2011 by Microsoft co-founder Paul Allen and Scaled Compositions founder Burt Rutan.

This is a different approach than SpaceX or Boeing, which plan to launch their spacecrafts with traditional rockets.

The Dream Chaser was originally planned to be mounted on an Atlas V rocket, but they have since changed their plans. The executive director of Stratolaunch Systems claims they can get astronauts from low earth orbit to land within 24 hours.