NASA has spent $450 million designing and building a unique robot that will drive into the eternally dark craters at the moon’s south pole. But the agency announced Wednesday that it will not be launching the rover due to delays and budget overruns.
“NASA is planning to abandon the VIPER mission,” said Nicky Fox, director of the agency’s Science Mission Directorate. “Decisions like this are never easy and we have not taken them lightly in any way. In this case, the expected remaining expenditure on VIPER would have required us to cancel or disrupt many other missions in our Commercial Lunar Payload Services (CLPS) line.”
NASA has canceled science missions before due to development delays and cost overruns, but it is rare for a mission to be canceled with a spacecraft that has already been built.
The Volatiles Investigating Polar Exploration Rover (VIPER) mission was to be a robotic explorer for NASA’s Artemis program, which aims to return astronauts to the lunar surface in the coming years. VIPER was originally scheduled to launch in late 2023 and would fly to the moon aboard a commercial lander from Pittsburgh-based Astrobotic, which won a contract from NASA in 2020 to bring the VIPER rover to the lunar surface. Astrobotic is one of 14 companies in the contractor pool for NASA’s CLPS program, which aims to ferry government-sponsored scientific payloads to the moon.
But VIPER has been delayed by at least two years — the most recent schedule called for a September 2025 launch — pushing its cost from $433 million to more than $609 million. The escalating costs automatically triggered a NASA review to determine whether to continue or cancel the mission. Ultimately, officials said they determined that NASA could not afford the added costs for VIPER without affecting other lunar missions.
“That’s why we decided to skip this particular mission, the VIPER mission, so we could continue the entire program,” Fox said.
“We’re disappointed,” said John Thornton, CEO of Astrobotic. “It’s certainly tough news… VIPER is a great team to work with, and we’re disappointed that we won’t get the chance to fly them to the moon.”
NASA said it will consider “expressions of interest” submitted by U.S. industry and international partners by Aug. 1 for use of the existing VIPER rover at no cost to the government. If NASA cannot find someone to take over VIPER and pay to fly it to the moon, the agency plans to disassemble the rover and assemble instruments and components for future lunar missions.
Scientists were shocked by VIPER’s cancellation.
“It’s absurd, frankly,” said Clive Neal, a planetary geologist at the University of Notre Dame. “It made no economic sense to me. You’re canceling a mission that’s completed, built and ready to go. It’s in the middle of testing.”
“This is a big mistake,” Phil Metzger, a planetary physicist at the University of Central Florida, wrote in a post on X. “This was the premier mission to measure lateral and vertical variations of lunar ice in the soil. It would have been revolutionary. Other missions will not replace what was lost here.”
Built with nowhere to go
Engineers at NASA’s Johnson Space Center in Houston assembled the VIPER rover last month, and managers gave the go-ahead to begin environmental testing to ensure the spacecraft could withstand the acoustics and vibrations of launch and the extreme temperature swings it would encounter in space.
Instead, NASA canceled the mission after spending $450 million to get it to this point. “This is a very difficult decision, but it’s a decision based on budgetary concerns in a very constrained budget environment,” Fox told reporters Wednesday.
About the size of a golf cart, VIPER carries four wheels, headlights, a drill and three science instruments to search for water ice in depressions near the moon’s south pole that have been shielded from sunlight for billions of years. This has turned these so-called permanently shadowed regions into cold traps, allowing water ice to collect on or near the surface, where it could be accessible to future astronauts to use as a source of drinking water or oxygen, or to convert into electricity and rocket fuel.
But first, scientists need to know exactly where the water is and how easy it is to reach. VIPER should be the next step in mapping lunar resources, providing ground-truth measurements to corroborate remote sensing data from orbiting satellites.
But late deliveries of parts delayed construction of the VIPER rover, and in 2022 NASA ordered additional testing of Astrobotic’s Griffin lunar lander to increase the chances of a successful VIPER landing. This pushed VIPER’s launch from late 2023 to late 2024, and earlier this year, more supply chain issues with the VIPER rover and Griffin lander pushed the launch back to September 2025.
This latest delay increased the expected cost of VIPER by more than 30 percent over the original mission cost, leading to a NASA termination review. Although the rover is now fully assembled, NASA still had to put it through a long series of tests, complete development of the ground systems to operate VIPER on the moon, and deliver the craft to Astrobotic for integration into the Griffin lander.
According to Kearns, the remaining work to complete VIPER and operate it for 100 days on the lunar surface would have cost about $84 million.