BUSAN, South Korea — NASA has canceled a robotic lunar rover mission that would have searched for ice at the south pole of the moon, citing development delays and cost overruns.
NASA announced July 17 that it would end development of the Volatiles Investigating Polar Exploration Rove (VIPER) mission. The rover, to be sent to the south polar region of moon on a commercial lander called Griffin from Astrobotic Technology, would have explored terrain including permanently shadowed regions to better understand the extent and form of water ice there.
At a briefing to announce the cancellation, agency officials said costs of VIPER had grown by more than 30%, triggering a termination review by the agency. NASA had confirmed VIPER in 2021 at a cost of $433.5 million. Joel Kearns, deputy associate administrator for exploration in NASA’s Science Mission Directorate, said the latest estimate was $609.6 million, with a launch estimated in September 2025.
“In this case, the projected remaining expenses for VIPER would have resulted in either having to cancel or disrupt many other missions in our Commercial Lunar Payload Services line,” said Nicky Fox, NASA associate administrator for science. “Therefore, we have made the decision to forgo this particular mission.”
Kearns said VIPER suffered from a series of supply chain issues that delayed deliveries of key, unspecified components dating back to the pandemic. “The delays occurred over and over for several key components,” he said, with small incremental delays that were harder for the mission to plan around than a single large delay.
That complicated the construction of the rover, which he described the size of a small car that is built from the inside out. “Many of the components that were delayed were actually in the inner section of VIPER, so as the components were delayed, it started forcing the VIPER team to delay the assembly and delay the integration and initial testing.”
The rover is now complete, but is only now starting environmental testing. Kearns said the revised cost and schedule assumed that VIPER would get through that environmental testing without any problems. “I will you tell you that in general, spacecraft development system-level environmental testing does uncover problems that do need to be corrected, which would take more time and money.”
Canceling VIPER now will save NASA a minimum of $84 million. That could grow, he said, if VIPER’s launch were to slip beyond November 2025, which would require waiting 9 to 12 months until the right lighting conditions return at the landing site in the polar region.
Kearns and Fox said much of the science that VIPER would have performed will be done by other missions, including landers and orbiters. The mobility that VIPER would have provided, though, may not be available until NASA’s Lunar Terrain Vehicle, a rover for crewed Artemis missions but which can also be teleoperated, is delivered late this decade.
NASA plans to disassemble VIPER to reuse its instruments and other components. First, though, NASA will consider proposals from American companies and international partners to fly VIPER on their own at no cost to the government. Proposals are due to NASA Aug. 1.
Revising Griffin’s mission
Separate from its own development problems, VIPER faced delays from Griffin, Astrobotic’s lander that would deliver the rover to the moon under a CLPS task order worth $322 million. NASA said Griffin was now expected to be ready for the mission no earlier than September 2025.
With VIPER canceled, NASA will retain the task order for Griffin. The mission will instead become a technology demonstrator, carrying a mass simulator in place of the rover to test Griffin’s ability to land large payloads.
Kearns said NASA considered flying science payloads instead, but since the lander was designed for carrying a rover, it lacked payload accommodations and capabilities like power and communications those payload would need.
“We believe that if we were to ask Astrobotic to make changes like that, it would further delay their schedule,” he said of potential modifications to accommodate payloads. “It would lead to more cost for the government. It would lead to a delay of the demonstration of a successful south pole landing by the large Griffin lander, which we are very interested in seeing.”
Astrobotic will also be free to fly their own commercial payloads. John Thornton, chief executive of Astrobotic, said in an interview that the company is considering flying a test of its LunaGrid power generation service on Griffin. “We do want to fly quickly but we also want to make a mission that is more impactful than just the lander itself.”
A VIPER-less Griffin would still land at the south polar region of the moon, he said, although not necessarily at the same site NASA selected for VIPER. It will depend on any new payloads it signs up for the lander, with the option of going to a safer landing site to reduce the risk for the mission.
Both Kearns and Thornton said that the agency informed the company of the decision very recently, but were not more specific. One industry source said NASA informed Astrobotic of the decision just a day before it was publicly announced.
“This has been certainly a year of tumult and challenge for Astrobotic as a company,” he said, a reference to the launch in January of its first lunar lander, Peregrine, which suffered a propellant leak after launch and could not attempt a lunar landing. The VIPER cancellation is “certainly another punch to the gut here, but we’ll roll with it.”
Kearns said that NASA believed that Griffin would be able to land safety on the moon, with or without VIPER on board, noting the work NASA funded the company to do to perform additional propulsion system tests. “We do have confidence in them to go out and attempt this landing, or we wouldn’t be continuing to work with them.”
“I’m an eternal optimist. You kind of have to be in the space industry,” Thornton said. “I’m excited about what we can turn this into.”