NASA Inspector General Paul Martin serves as an independent watchdog for the space agency’s myriad activities. For nearly the entirety of his time as inspector general, since his appointment in 2009, Martin has tracked NASA’s development of the Space Launch System rocket and Orion spacecraft.

Although his office has issued a dozen reports or so on various aspects of these programs, he has never succinctly stated his thoughts about the programs—until Tuesday.

Appearing before a House Science Committee hearing on NASA’s Artemis program, Martin revealed the operational costs of the big rocket and spacecraft for the first time. Moreover, he took aim at NASA and particularly its large aerospace contractors for their “very poor” performance in developing these vehicles.

Martin said that the operational costs alone for a single Artemis launch—for just the rocket, Orion spacecraft, and ground systems—will total $4.1 billion. This is, he said, “a price tag that strikes us as unsustainable.” With this comment, Martin essentially threw down his gauntlet and said NASA cannot have a meaningful exploration program based around SLS and Orion at this cost.

Breaking down the cost

Later in the hearing, Martin broke down the costs per flight, which will apply to at least the first four launches of the Artemis program: $2.2 billion to build a single SLS rocket, $568 million for ground systems, $1 billion for an Orion spacecraft, and $300 million to the European Space Agency for Orion’s Service Module. NASA, Martin said, had checked and confirmed these figures.

What is striking about these costs is that they do not include the tens of billions of dollars that NASA has already spent developing the Orion spacecraft since 2005 and the Space Launch System rocket since 2011. If one were to amortize development costs over 10 flights of the SLS rocket and Orion spacecraft, the $4.1 billion figure cited by Martin would easily double.

That figure is far higher than NASA might have hoped. Five years ago, a senior NASA official told Ars that the space agency would like to get its operational costs for a single mission a year down to $2 billion or less. Another source at the time said the internal goal was $1.5 billion.

Martin also said NASA is obscuring costs that it is spending on the Artemis program and that, in aggregate, his office believes NASA will spend $93 billion from 2012 to 2025 on the Artemis program.

“Without NASA fully accounting for and accurately reporting the overall costs of current and future Artemis missions, it will be much more difficult for Congress and the administration to make informed decisions about NASA’s long-term funding needs—a key to making Artemis a sustainable venture,” Martin said.