NASA is exploring a highly unconventional way to strengthen its Artemis lunar exploration program: packing up a spare version of its Mars rover and sending it to the Moon.
During the agency’s latest Moon Base program update, NASA Administrator Jared Isaacman revealed that the agency is seriously considering repurposing PROMISE, a full-scale engineering model originally built to support the Curiosity and Perseverance Mars missions. If approved, the decades-old Earth-bound test vehicle will be transformed into a functional lunar rover capable of exploring the Moon’s rugged, perpetually shadowed south pole.
Here is why NASA is looking to give this test rover a second life, and why its unique power source makes it the perfect fit for the Moon.
From Testbed to Lunar Explorer
PROMISE—short for Polar Rover for Observation, Mapping, and In-Situ Exploration—was originally developed at NASA’s Jet Propulsion Laboratory as a ground-based engineering model.
Previously known by the acronym OPTIMISM, the vehicle has spent years helping engineers safely test software updates, commands, and hardware fixes before sending those instructions millions of miles away to the actual rovers on Mars. Whenever NASA wants to validate a major change for Curiosity or Perseverance, they try it on PROMISE first.
However, after years of successful operation on the Red Planet, NASA has accumulated enough operational data that the engineering model is no longer strictly needed as a test platform on Earth.
The Nuclear Advantage
The biggest reason NASA is eyeing PROMISE for lunar exploration is what sits under its hood: a radioisotope thermoelectric generator (RTG).
This is the exact same nuclear power system used by Curiosity and Perseverance on Mars. Unlike traditional solar-powered lunar vehicles, an RTG generates continuous electricity and heat from the natural decay of radioactive material. This means the rover can continue operating indefinitely, entirely independent of sunlight.
This capability is a game-changer for the Moon's south pole. While the region contains strategic deposits of water ice—which could eventually provide drinking water and rocket fuel—it is heavily scarred by deep craters that remain in permanent, freezing shadow. A solar-powered rover would simply die in the dark, but a nuclear-powered PROMISE could drive straight into these shadows and keep collecting scientific data.
Paving the Way for Artemis
The potential deployment of PROMISE aligns with NASA’s broader push to establish a permanent human presence on the lunar surface.
During the same update, NASA announced new commercial lunar landing contracts awarded to Astrobotic, Firefly Aerospace, and Intuitive Machines under the Commercial Lunar Payload Services (CLPS) program. These companies will deliver essential scientific instruments and technology demonstrations over the next several years to lay the groundwork for human arrivals.
Before Artemis astronauts can safely begin living and working in long-duration habitats, NASA needs to map the terrain, study resource deposits, and identify safe locations for infrastructure. Carlos Garcia-Golan, NASA’s Moon Base program manager, noted that while sending a repurposed Mars rover to the Moon sounds like science fiction, it reflects the agency’s pragmatic willingness to make the most of the advanced technology they already have sitting in the lab.