WASHINGTON - NASA's plan to repurpose a Mars rover engineering model into a lunar rover could set the agency back more than $1 billion, according to a new estimate that the administrator has dismissed with the enthusiasm of someone who didn't want to hear it.
On June 30, NASA announced it was considering sending a rover called PROMISE (Polar Rover for Observation, Mapping and In-Situ Exploration) to the moon. The rover would be based on the engineering models of Curiosity and Perseverance that currently sit on Earth, presumably doing a fine job of being testbeds and not being on the moon.
Administrator Jared Isaacman, ever the optimist, framed PROMISE as part of a grand effort to "raid the pantry at every one of our centers for payloads" for the lunar base. "We've got the hardware, and this is exactly what we should be trying to do to put wins on the board," he said, adding that the rover would bring "immense capability to the lunar south pole in short order.""
Neither Isaacman nor Carlos García-Galán, NASA's program executive for Moon Base, offered a price tag at the briefing, suggesting it could be done relatively quickly and inexpensively. Because what could possibly go wrong with converting a terrestrial test model into a space-faring vehicle?
A July 30 analysis by The Planetary Society begs to differ. Based on historical cost data and requirements, it concluded PROMISE would cost between $723 million and $1.33 billion to develop and launch, including one year of lunar operations. The rover likely wouldn't be ready until the early 2030s, which is a bit longer than "short order."
Casey Dreier, the author, noted that the engineering model OPTIMISM lacks many space-rated components, including a communications system and flight-ready instruments. Also, it needs power. Perseverance uses a radioisotope thermoelectric generator (RTG), and NASA has exactly one spare. Using it would require significant work to approve, modify the lander, and certify the launch vehicle. "There is no plausible version of this mission that is 'free,'" Dreier concluded, adding that even the low-end cost is equivalent to a mid-size planetary mission.
There are other downsides: repurposing the testbed would deprive Curiosity and Perseverance of a backup, and using the spare RTG would rule out outer solar system missions for the foreseeable future. Because who needs those?
Isaacman, in a social media post on July 31, pushed back. "If PROMISE costs even 20% of your low-end estimate, we simply will not fly it," he said, while defending the repurposing concept. He argued it would be "crazy not to take advantage of hardware taxpayers have already invested hundreds of millions of dollars in, along with Pu-238 that continues to decay and lose roughly 2% of its potential each year." Because nothing says fiscal responsibility like letting plutonium gather dust.
The RTG availability is also a factor in the delay of NASA's next New Frontiers mission call, now projected for fiscal year 2027. Louise Prockter, director of NASA's planetary science division, said at a July 21 forum that they're "looking at availability of nuclear power" and whether they'll have it for candidate missions. So the spare RTG is kind of a hot commodity.
Isaacman, in his post, defended his broader approach: "I understand the community sometimes likes to take a long time to reach consensus, but under this administration, we can just do things and put wins on the board." Because who needs consensus when you have momentum?