Thousands of scientists have protested to the US Congress over the “unprecedented and indefensible” decision by Nasa to cancel its Viper lunar rover mission.
In an open letter to Capitol Hill, they have denounced the move, which was revealed last month, and heavily criticised the space agency over a decision that has shocked astronomers and astrophysicists across the globe.
The car-sized rover has already been constructed at a cost of $450m and was scheduled to be sent to the moon next year, when it would have used a one-metre drill to prospect for ice below the lunar surface in soil at the moon’s south pole.
Ice is considered to be vital to plans to build a lunar colony, not just to supply astronauts with water but also to provide them with hydrogen and oxygen that could be used as fuels. As a result, prospecting for sources was rated a priority for lunar exploration, which is scheduled to be ramped up in the next few years with the aim of establishing a permanent human presence on the moon.
Construction of Viper – volatiles investigating polar exploration rover – began several years ago, and the highly complex robot vehicle was virtually complete when Nasa announced on 17 July that it had decided to kill it off. The agency said the move was needed because of past cost increases, delays to launch dates and the risks of future cost growth.
However, the claim has been dismissed by astonished and infuriated scientists who say the rover would have played a vital role in opening up the moon to human colonisation.
“Quite frankly, the agency’s decision beggars belief,” said Prof Clive Neal, a lunar scientist at the University of Notre Dame, in Indiana.
“Viper is a fundamental mission on so many fronts and its cancellation basically undermines Nasa’s entire lunar exploration programme for the next decade. It is as straightforward as that. Cancelling Viper makes no sense whatsoever.”
This view was backed by Ben Fernando of Johns Hopkins University, who was one of the organisers of the open letter to Congress. “A team of 500 people dedicated years of their careers to construct Viper and now it has been cancelled for no good reason whatsoever,” he told the Observer last week.
“Fortunately I think Congress is taking this issue very seriously and they have the power to tell Nasa that it has to go ahead with the project. Hopefully they will intervene.”
Several other water-prospecting missions to the moon have been planned for the next few years. However, most will involve monitoring the lunar surface from space or by landing a single excavator that will dig for ice at a single, fixed location.
“The crucial advantage of Viper was that it could move around and dig into the lunar soil at different promising locations,” said Ian Crawford, professor of planetary science and astrobiology at Birkbeck, University of London.
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Astronomers have long suspected that ice – brought by comets and asteroids – exists in the permanently shadowed craters near the moon’s south poles, an idea that was strongly supported in 2009 when Nasa deliberately crashed a Centaur rocket into the crater Cabeus.
By studying the resulting plumes of debris, scientists concluded that ice could account for up to 5% of soil there. “China, Japan, India and Europe have all got plans to prospect for water on the moon, but now the US seems to have just given up,” added Crawford. “It is very, very puzzling.”
Scientists also point out that ice and other materials brought to the moon by comets or asteroids will have remained there in a pristine state and could provide scientists with a history of the inner solar system and the processes that shaped it for millions or even billions of years into the past. “There is an incredible scientific treasure trove there that is begging to be explored,” added Neal.
When Nasa announced its decision to abandon Viper, the space agency said it planned to disassemble and reuse its components for other moon missions – unless other space companies or agencies offered to take over the project. More than a dozen groups have since expressed an interest in taking over Viper, a Nasa spokesperson told the Observer last week. Whether these organisations are interested in Viper as a complete craft or as a source of components is not yet clear, however.
“We simply do not know how practical or serious these offers are,” said Fernando. “Nasa keeps saying it had to cancel projects because of budgetary problems, but why on earth did they pick such an important mission on which to start making those cuts?”