NASA “overpaid” Boeing by hundreds of millions of dollars on a fixed contract to develop a spaceship to carry astronauts to the International Space Station an audit report has said, compensation it called “unnecessary.”

The US has relied on Russia to transport its crews to the ISS since the end of the Space Shuttle program in 2011, but has hired Boeing and SpaceX under multi-billion dollar contracts, with the two companies already two years behind schedule.

The auditors determined the amount of additional spending was not required because the risk of such a gap occurring was minimal, and SpaceX was not provided an opportunity to propose a solution “even though the company previously offered shorter production lead times than Boeing.”

What’s more, NASA failed to consider in their analysis that they could overcome any perceived gap by purchasing more seats either directly from Russia or from Boeing.

But the report’s authors added: “We acknowledge the benefit of hindsight and appreciate the pressures faced by NASA managers at the time to keep the program on schedule to the extent possible.”

The Commercial Crew Program has been beset by delays as the two companies face technical and safety challenges.As of May 2019, Boeing and SpaceX’s contracts were valued at $4.3 billion and $2.5 billion, with each company awarded six round-trip missions to the ISS.

Assuming four astronauts per flight, the inspector general estimated average cost per seat at $90 million for Boeing and $55 million for SpaceX.

NASA contested the findings, saying in a written response that “We do not agree that the dollar amounts cited were questionable, unnecessary, or unreasonable.”