NASA announced Wednesday that it was canceling the VIPER (Volatiles Investigating Polar Exploration Rover) project. It is the second time in less than a decade that NASA has canceled plans for a roving rover to explore the Moon for water ice, a decision that comes six years after canceling a similar mission, Resource Prospector.
The 430-kg (948 lb.) rover was designed to fly to the Moon's South Pole aboard Astrobotic's Griffin lander, the Pittsburgh-based company's second planned Moon mission. Astrobotics' first mission, the smaller Peregrine lander, ended prematurely in January when a propulsion problem prevented it from reaching the Moon.
During a teleconference with members of the press, Joel Kearns, NASA's deputy associate administrator for exploration within the Science Mission Directorate, pointed to rising costs as a big driver for VIPER's cancellation.
“When we formalized the VIPER project, we told Congress that the budget for the project would be $433.5 million and that landing would be in late 2023,” Kearns said. “We had already made the decision to reschedule landing to 2024 so that Astrobotic could conduct additional propulsion testing on the lander.
“When we made that decision, we updated the VIPER work plan and reset the budget to $505.4 million with a landing in late 2024. But our latest estimate, done earlier this year, showed that since we were no longer planning to land on VIPER in late 2024, but would instead need to do so by the 2025 science window, the cost of the VIPER project was projected at $609.6 million.”
Kearns said increasing the budget beyond the original 30 percent was going too far and automatically triggered what he called a cancellation termination review, which took place in June. In 2019, when VIPER was first announcedNASA cited the original estimate for the gold-car-sized rover at $250 million with delivery to the Moon in 2022.
In a May 2024 blog post, VIPER project manager Dan Andrews shared that the lander passed a system test readiness review in April, allowing VIPER to move on to stress testing and environmental testing.
“These environmental tests are important because they force our rover to experience the conditions it will see during launch, landing, and the thermal operating environment at the lunar South Pole,” Andrews wrote in May. “Specifically, acoustic testing will simulate the harsh vibrational experience of a launch ‘rock concert,’ while thermal vacuum testing will expose VIPER to the highest and lowest temperatures it will see during the mission, all while operating in the vacuum of space. It’s a tall order, but we need to make sure we’re prepared for it.”
During his remarks Wednesday, Kearns said that at this time, VIPER had not completed system-level environmental testing and that some ground systems needed to operate the rover on the Moon were also not complete.
He said that by canceling VIPER, NASA would save a minimum of $84 million, “which is the cost to continue finishing the roadway for the flight and ground systems and then operate the mission, which now cannot be done in 2024.”
When pressed to explain why this decision was made when NASA has faced budget increases of similar or larger amounts and has not canceled programs, Kearns said that not only were they bound by Congressional budget constraints, but also that the estimates cited might not be the end of the story.
“One concern we had was the immediate cost we would have to take out of something else at NASA Science to prepare for the September 2025 landing, but another concern we had was that the landing would not happen in September 2025 and if it did happen later than November, it would likely happen in 2026, which would likely require a similar amount of money to continue into 2026,” Kearns said.
A notable part of that schedule concern came from the fact that Kearns said the Griffin lander would not be ready before September 2025.
“We also took into account the fact that it might be at least possible that the Griffin lander’s availability for launch could be delayed beyond September 2025. The Griffin lander itself would have to be able to launch in November 2025 or else it would miss VIPER’s science operations window for that 100-day mission after its landing,” Kearns said. “VIPER can only take its measurements during particular conditions at the South Pole when there’s plenty of sunlight available — what we call South Pole summer — and also a way to communicate directly by radio with Earth.”
“This is a challenge for any long-duration mission to the South Pole that doesn’t use, for example, nuclear energy for heating or generating electricity,” Kearns added. “You have to be very careful about how much time you spend in the dark.”
What happens now?
NASA will maintain its $323 million contract with Astrobotic, allowing Griffin Mission One to move forward toward a 2025 launch. Kearns said the lander will now travel to the Moon with a mass simulator, which will weigh about the same as VIPER.
He added that Astrobotic may look into additional commercial payloads for the lander and, if necessary, the mass simulator size could be reduced to compensate.
“We at NASA have decided, given the scope, schedule and cost, the fixed price that we agreed to with Astrobotic for the Griffin mission, that we will not replace the additional science instruments on Griffin because we believe that if we did, it could mean schedule delays and increased costs to the government,” Kearns said. “So, our focus now on Griffin is getting the data from the successful landing, from how its propulsion system is working.”
Asked whether VIPER could switch to another of NASA’s reserved lunar landers, such as the cargo version of Blue Origin’s Blue Moon lander, Nicola Fox, associate administrator for NASA’s Science Mission Directorate, said that could have negative budget impacts for other CLPS missions.
“It's more about cost risk and the threat to the rest of NASA's program,” Fox said.
He said NASA has informed Congressional appropriators of its decision and is awaiting their response.
In a post on X, formerly Twitter, Astrobotic said it aims to launch its Griffin lander in the third quarter of 2025. In April, the company announced it would launch its own shoebox-sized rover called the CubeRover in partnership with Mission Control, as part of Griffin Mission One.
The lander will also carry the LandCam-X payload on behalf of the European Space Agency and French company Lunar Logistics Services. It is designed to “take photographs as it approaches the Moon to improve the accuracy and safety of future lunar landings.”
Astrobotic has not yet released a full list of its commercial customers.
Leave feedback about this