In recent years NASA has acknowledged that its large Space Launch System rocket is unaffordable and has sought to bring its costs down to a more reasonable level. The most recent estimate is that it costs $2.2 billion to build a single SLS rocket, and this does not include add-ons such as ground systems, integration, a payload, and more.
Broadly speaking, NASA's cost-reduction plan is to transfer responsibility for production of the rocket to a new company co-owned by Boeing and Northrop Grumman, which are key contractors for the rocket. This company, "Deep Space Transport," would then build the rockets and sell them to NASA. The space agency has said that this services-based model could reduce the cost of the rocket by as much as 50 percent.
However, in a damning new report, NASA's inspector general, Paul Martin, says that is not going to happen. Rather, Martin writes, the cost of building the rocket is actually likely to increase.
"Our analysis shows a single SLS Block 1B will cost at least $2.5 billion to produce—not including Systems Engineering and Integration costs—and NASA’s aspirational goal to achieve a cost savings of 50 percent is highly unrealistic," Martin wrote in an audit of the agency's plans, which was published on Thursday.
Extremely high costs
The main problem with the SLS rocket is not its performance—the vehicle's debut during the Artemis I mission in late 2022 was virtually flawless—but rather its extremely high cost. Independent reviews of the vehicle, which Congress mandated that NASA build more than a decade ago, have found that NASA is unlikely to have a sustainable deep space exploration program built around such an expensive heavy-lift rocket.
Digging into Martin's report, it's not difficult to see why. The SLS rocket is powered by four main engines derived from the Space Shuttle program. The cost of these four engines is $582.7 million, or $146 million per engine. This means that a single engine on NASA's rocket costs roughly the same amount that the space agency paid for an entire mission on the Falcon Heavy rocket—$178 million for the Europa Clipper spacecraft.
Seriously, stop and think about that.
"Given the enormous costs of the Artemis campaign, it is crucial that NASA achieve some significant measure of its affordability goals," Martin wrote in the new report. "Failure to do so will significantly hinder the sustainability of NASA’s deep space human exploration efforts."
Cost savings are unlikely
However, he said, NASA's approach to saving money is unlikely to work. Martin bases his conclusion on a number of persuasive factors. But the main reason is that NASA's estimate of a 50 percent cost reduction appears to be based on magical and wishful thinking.
Boeing is the contractor that builds the core stage of the SLS rocket, which includes the propellant tanks and four main engines. Martin notes that Boeing only reduced its workforce by 13 percent as it moved from building the rocket's first core stage to the second one. Then, the report drily adds, "Boeing historically has increased costs under their contracts."
Nor are savings likely to come from the engines, despite the fact that their per-unit cost is nearly $150 million. Rather, Martin's analysis finds that the cost of future engines is likely to go up: "Despite initiatives aimed at cutting costs by gaining manufacturing efficiencies utilizing 3D printing and using less costly materials for RS-25 engines beyond Artemis VII, we instead found cost increases for future engines."
Martin also notes that there is no incentive for Deep Space Transport to lower its prices. The agency has not committed to move to fixed-price contracting and has allowed Boeing to incorporate limited rights data into the design of the core stage. In other words, no one else can build the SLS rocket, so if the space agency wants to continue to buy them, it must do so from Boeing and Northrop.
Finally, Martin cites history. In the mid-1990s NASA transferred the Space Shuttle production from agency management to a commercial services contract, citing the goal of saving money. Boeing and Lockheed Martin created a new company, United Space Alliance, to provide Shuttle services on a sole-source basis to NASA, like what will be done with the SLS rocket.
So, did costs go down? Alas, no. "As a result of the transfer of Shuttle production and operations responsibilities from NASA-managed contracts to a commercial services contract, we estimate Space Shuttle operations costs increased approximately 38 percent to $1.45 billion per launch," Martin wrote.
Consider buying commercial
As part of his report, Martin makes several recommendations to NASA. Perhaps most strikingly, the inspector general suggests that NASA consider using commercial heavy-lift vehicles as an alternative to the SLS rocket for future Artemis missions.
"The Agency may soon have more affordable commercial options to carry humans to the Moon and beyond," the report states. "In our judgment, the Agency should continue to monitor the commercial development of heavy-lift space flight systems and begin discussions of whether it makes financial and strategic sense to consider these options as part of the Agency’s longer-term plans to support its ambitious space exploration goals."
The politics of this are messy, of course. In 2010, Congress directed NASA to build a heavy-lift rocket and crew capsule using existing contracts from the canceled Constellation effort, and this resulted in the SLS rocket and Orion spacecraft. Congress has tended not to care as NASA has racked up tens of billions of dollars in development costs for these vehicles.
This may or may not change given the likelihood of budget cuts in the near future. But what now seems clear is that the SLS rocket will never cost less than it does now, and it probably will cost more in the future. Perhaps it is, indeed, time to consider an offramp before NASA signs contracts to buy SLS rockets for the next decade or two.
