BUSAN, South Korea — NASA has canceled a robotic lunar rover mission that would have searched for ice at the moon’s south pole, citing development delays and cost overruns.
NASA announced July 17 that it was ending development of the Volatiles Investigating Polar Exploration Rove (VIPER) mission. The rover, which was to be sent to the moon’s south polar region aboard a commercial lander called Astrobotic Technology’s Griffin, would have explored terrain that included regions of constant shadow to better understand the extent and shape of water ice there.
In a briefing announcing the cancellation, agency officials said VIPER’s costs had increased by more than 30%, prompting a review of the termination by the agency. NASA had confirmed VIPER in 2021 at a cost of $433.5 million. Joel Kearns, associate deputy administrator for exploration in NASA’s Science Mission Directorate, said the latest estimate was $609.6 million, with a launch scheduled for September 2025.
“In this case, the remaining planned expenditures for VIPER would have resulted in the cancellation or disruption of many other missions in our commercial lunar payload service portfolio,” said Nicky Fox, NASA’s associate administrator for science. “So we made the decision to forgo this particular mission.”
According to Kearns, VIPER has suffered from a series of supply chain issues that have delayed deliveries of unspecified key components since the pandemic. “The delays have occurred repeatedly for multiple key components,” he said, with small incremental delays that were more difficult for the mission to manage than a single major delay.
That complicated the construction of the rover, which he described as being like a small car built from the inside out. “A lot of the components that were delayed were actually in the interior of the VIPER, so as the components were delayed, the VIPER team started to delay assembly and delay integration and initial testing.”
The rover is now complete, but it is just beginning environmental testing. Kearns said the revised cost and schedule assumed VIPER would pass those environmental tests without any problems. “I can tell you that typically, environmental testing at the spacecraft development system level reveals problems that need to be fixed, which would take more time and money.”
Canceling VIPER would save NASA at least $84 million. That amount could increase, he added, if VIPER’s launch were to be delayed beyond November 2025, which would require a nine- to 12-month wait for lighting conditions to return to the polar landing site.
Kearns and Fox said much of the science VIPER would have done would be done by other missions, including landers and orbiters. The mobility VIPER would have enabled, however, may not be available until NASA delivers its Lunar Terrain Vehicle, a rover designed for crewed Artemis missions that can also be remotely operated, later this decade.
NASA plans to disassemble VIPER to reuse its instruments and other components. But before that, NASA will consider proposals from U.S. companies and international partners that want to fly VIPER on their own, at no cost to the government. Proposals are due to NASA by August 1.
Griffin’s Mission Review
In addition to its own development problems, VIPER has faced delays from Griffin, Astrobotic’s lander that was supposed to deliver the rover to the Moon as part of a $322 million CLPS order. NASA has said Griffin is now not expected to be ready for the mission until September 2025.
With the VIPER mission canceled, NASA will keep the Griffin mission. The mission will instead become a technology demonstrator, carrying a mass simulator in place of the rover to test Griffin’s ability to land heavy payloads.
Kearns said NASA had considered flying scientific payloads instead, but because the lander was designed to carry a rover, it lacked payload amenities and capabilities like power and communications that those payloads would need.
“We believe that if we were to ask Astrobotic to make such changes, it would further delay their schedule,” he said of potential modifications to accommodate payloads. “It would result in additional costs to the government. It would delay the demonstration of a successful landing of the large Griffin lander at the South Pole, which we look forward to.”
Astrobotic will also be free to fly its own commercial payloads. John Thornton, Astrobotic’s chief executive, said in an interview that the company plans to test its LunaGrid energy-generation service aboard 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 in the moon’s south polar region, he said, but not necessarily in the same location NASA chose for VIPER. That will depend on what new payloads it records for the lander, with the possibility of going to a safer landing site to reduce mission risk.
Both Kearns and Thornton said the agency informed Astrobotic of its decision very recently, but did not provide further details. An industry source said NASA informed Astrobotic of its decision just a day before it was announced publicly.
“This year has been a year of tumult and challenges for Astrobotic as a company,” he said, referring to the January launch of its first lunar lander, Peregrine, which suffered a propellant leak after launch and was unable to attempt a lunar landing. The cancellation of VIPER is “certainly another blow, but we’ll deal with it.”
Kearns said NASA is confident that Griffin will be able to land safely on the moon, with or without VIPER on board, and pointed to the work NASA has funded for the company to conduct additional testing of the propulsion system. “We have confidence in them 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.”