Blue Origin, Jeff Bezos' space company, has filed a lawsuit against NASA, claiming a $2.9 billion lunar lander contract was unfairly awarded to rival Elon Musk's SpaceX earlier this year.

The suit, filed in the U.S. Court of Federal Claims on Monday, is sealed, but according to another filing, it 'challenges NASA´s unlawful and improper evaluation of proposals.' 

Blue Origin was originally in competition with SpaceX and a third firm called Dynetics for what was expected to be two NASA contracts.

After Congress trimmed the space agency's budget, NASA announced in April 2021 that SpaceX's Human Landing System (HLS) would be the sole contractor.

That month, Blue Origin and Alabama-based Dynetics filed a 50-page protest with the Government Accountability Office (GAO), a congressional watchdog.

In response, Elon Musk rolled his fellow multibillionaire Bezos, tweeting he 'can't get it up (to orbit).'

In July, the GAO rejected Blue Origin and Dynetics' protest, finding 'NASA did not violate procurement law or regulation when it decided to make only one award,' striking down Blue Origin's main argument.