NASA PROMISE Moon rover cost dispute centers on what reuse really saves
NASA’s Jared Isaacman rejected an outside cost estimate for the proposed PROMISE lunar rover, but the comparison excludes launch and landing.
By Dominic Okoye · Staff Writer
· 3 min read
NASA Administrator Jared Isaacman said NASA would not fly the proposed lunar rover if its costs, excluding launch and landing, reached even 20% of the low end of an outside estimate. The NASA PROMISE Moon rover cost dispute puts a hard, though incomplete, spending condition on a concept NASA is still considering, while underscoring the engineering work required to turn ground test hardware into a lunar mission.
PROMISE, short for Polar Rover for Observation, Mapping, and In-Situ Exploration, is a proposed vehicle for the Moon based on engineering models used to support NASA’s Curiosity and Perseverance Mars rovers. NASA announced on June 30 that it was considering the mission as part of its lunar-base efforts, according to SpaceNews. It has not been approved, funded or selected for launch in the reporting cited.
Casey Dreier, chief of space policy at The Planetary Society, estimated the mission at $723 million to $1.33 billion, including development, launch and one year of lunar operations. His assessment projected that PROMISE would likely not be ready to launch until the early 2030s. NASA did not provide a competing full-mission estimate at the June announcement, SpaceNews reported.
Why could the NASA PROMISE Moon rover cost so much?
The proposed reuse is not a matter of loading an existing rover onto a lander. Dreier’s assessment focused on converting OPTIMISM, the Perseverance engineering model at NASA’s Jet Propulsion Laboratory. It found that the testbed lacks several space-rated systems needed for a lunar mission, including communications, and does not have flight-ready science instruments.
Power is another unresolved piece. Perseverance operates with a radioisotope thermoelectric generator, or RTG. NASA has one spare RTG that could potentially be assigned to PROMISE, but the assessment said doing so would require approvals and potentially changes to the rover and lander, plus certification of the launch vehicle. Hardware designed to test rover operations on Earth would also need qualification for launch and adaptation to lunar conditions.
Isaacman responded in a July 31 post that launch and landing are expenses shared by any mission and should be removed from the comparison. On that basis, he said NASA would not fly PROMISE if its cost hit even 20% of Dreier’s $723 million low-end estimate. That threshold is about $144.6 million, but it is not an alternative full-mission price because Dreier’s published range includes launch and landing while Isaacman explicitly set those costs aside.
Isaacman argued that NASA should seek value from hardware taxpayers had already funded and from plutonium-238 fuel that he said loses roughly 2% of its potential each year. He did not contest individual elements of Dreier’s estimate in the post.
What would NASA give up to use the spare RTG?
Dreier also identified program trade-offs. Converting the rover could remove a working testbed from the Curiosity and Perseverance teams, which use the models for planning and diagnosing operations. Assigning NASA’s sole spare RTG to PROMISE could also limit the agency’s ability to pursue a future outer-solar-system planetary science mission, according to SpaceNews.
For NASA, the decision is therefore not only whether existing equipment can be repurposed. It is whether the conversion cost, mission schedule and loss of scarce test and power assets justify adding a lunar rover to the agency’s proposed Moon Base program.
This story draws on original reporting from The Register.
