NASA is considering converting an Earth-based engineering replica of its Mars rovers into PROMISE, a rover designed to explore the Moon’s south pole. The proposal could support future lunar bases by mapping the surface and subsurface in an area thought to contain significant water ice.

PROMISE may combine elements of Perseverance and Curiosity’s test models, with Perseverance’s former test rover OPTIMISM expected to form the basis. NASA intends to equip it with a plutonium-powered radioisotope generator, allowing it to operate through lunar night and in permanently shadowed areas, but the vehicle still lacks key flight-ready systems and protection against sharp lunar dust. Estimates put its cost at $700 million to $1.3 billion, with a possible launch in the early 2030s.