NASA is moving ahead with its plan to repurpose a Mars rover engineering model as a lunar trundlebot for less than $400 million. The robot, dubbed PROMISE (Polar Rover for Observation, Mapping, and In-Situ Exploration), is a cut-and-shut of engineering test articles used for the Perseverance and Curiosity rovers, currently rolling around the Red Planet. During a weekend briefing , NASA outlined the plan for PROMISE: to land the robot on the lunar surface by late 2028 for an 18-month mission. PROMISE will be preceded by NASA’s VIPER trundlebot, which is expected to survive only 100 days on the Moon’s surface. PROMISE will carry copies of VIPER’s science instruments, including a drill capable of boring 1 meter into the lunar regolith. Power will come from a Radioisotope Thermoelectric Generator (RTG) left over from the Cassini mission. NASA acknowledged the fuel was processed some time ago – the Cassini mission to Saturn was launched in 1997 – but anticipates there will be plenty of heat and power for PROMISE’s components. Blue Origin is to deposit the rover on the Moon. NASA awarded the company a $94 million base contract, "with an option period worth an additional $140 million based on performance to deliver PROMISE to the lunar South Pole." The figures make it difficult to ascertain the exact cost of the PROMISE mission…