BUSAN, South Korea — NASA has canceled a robotic lunar rover mission that was to search for ice at the moon’s south pole, citing development delays and cost overruns.
NASA announced on July 17 that it was ending development of the Volatiles Investigating Polar Exploration Rove (VIPER) mission. The rover, which would have been sent to the moon’s south polar region aboard a commercial lander called Griffin from Astrobotic Technology, would have explored terrain, including permanently shadowed areas, to better understand the extent and shape of water ice there.
At a briefing to announce the cancellation, agency officials said VIPER’s cost had increased by more than 30%, prompting a termination review by the agency. NASA had confirmed VIPER in 2021 at a cost of $433.5 million. Joel Kearns, principal deputy associate administrator for exploration in NASA’s Science Mission Directorate, said the latest estimate was $609.6 million, with a launch estimated for September 2025.
“In this case, the projected remaining costs for VIPER would have required us to cancel or disrupt many other missions in our Commercial Lunar Payload Services line,” said Nicky Fox, NASA associate administrator for science. “As a result, we have decided to forgo this particular mission.”
Kearns said VIPER has faced a series of supply chain issues that delayed the delivery of key, unspecified components, dating back to the pandemic. “The delays have happened repeatedly across multiple key components,” he said, with small, incremental delays more difficult to plan for in the mission than a single major delay.
That complicated construction of the rover, which he described as the size of a small car built from the inside out. “A lot of the components that were delayed were actually in the internals of VIPER, so when the components were delayed, the VIPER team started delaying assembly and integration and initial testing.”
The rover is now complete, but it is only now beginning environmental testing. Kearns said the revised cost and schedule assumed VIPER would pass those environmental tests without incident. “I will tell you that generally, environmental testing at the spacecraft development level reveals problems that do need to be corrected, which would take more time and money.”
By canceling VIPER now, NASA will save at least $84 million. That could grow, he said, if VIPER’s launch were delayed beyond November 2025, which would mean waiting nine to 12 months for the right light conditions to return to the Arctic landing site.
Kearns and Fox said much of the science VIPER would have done would have been done by other missions, including landers and orbiters. However, the mobility VIPER would have provided might not be available until NASA’s Lunar Terrain Vehicle, a rover for crewed Artemis missions that can also be teleoperated, arrives late this decade.
NASA plans to disassemble VIPER to reuse its instruments and other components. First, however, NASA will consider proposals from U.S. companies and international partners to fly VIPER autonomously at no cost to the government. Proposals must be submitted to NASA by August 1.
Revision of Griffin’s Mission
In addition to its own development issues, VIPER has faced delays to Griffin, the Astrobotic lander that was supposed to take the rover to the moon under a $322 million CLPS task order. NASA said Griffin is now not expected to be ready for the mission until September 2025.
With VIPER canceled, NASA is retaining the task order for Griffin. The mission will instead become a technology demonstrator, with a mass simulator in place of the rover to test Griffin’s ability to land large payloads.
According to Kearns, NASA considered carrying science payloads instead, but since the lander was designed to carry a rover, it lacked the necessary payloads and capabilities, such as power and communications, required for that payload.
“We believe that if we were to ask Astrobotic to make such changes, it would further delay their schedule,” he said of possible adjustments to accommodate payloads. “It would result in more costs for the government. It would result in a delay in the demonstration of a successful landing at the South Pole by the large Griffin lander, which we are very excited about.”
Astrobotic will also be free to fly its own commercial payloads. Astrobotic CEO John Thornton said in an interview that the company is considering conducting a test of its LunaGrid power generation service on Griffin. “We want to fly fast, but we also want to do a mission that has more impact than just the lander itself.”
A Griffin without VIPER would still land on the moon’s south polar region, he said, though not necessarily at the same spot NASA had selected for VIPER. It would depend on any new payloads the lander brings on, with the option of moving to a safer landing site to reduce risk to the mission.
Both Kearns and Thornton said the agency only recently informed the company of the decision, but were not more specific. An industry source said NASA informed Astrobotic of the decision only a day before it was made public.
“This has certainly been a year of turmoil and challenge for Astrobotic as a company,” he said, referring to the January launch of its first lunar lander, Peregrine, which suffered a fuel leak after launch and failed to attempt a landing on the moon. The cancellation of VIPER is “certainly another slap in the face, but we’re going to keep going.”
Kearns said NASA believed Griffin could land safely on the moon with or without VIPER on board, noting that NASA was funding the company to conduct additional testing of the propulsion system. “We have confidence they’re going to attempt this landing, otherwise we wouldn’t continue to work with them.”
“I’m an eternal optimist. You have to be in the space industry,” Thornton said. “I’m excited about what we can do with this.”