- Written by Jonathan Amos
- Science Reporter
The mission to return rock samples from Mars to Earth to see if they contain traces of past life will undergo a major overhaul.
The US space agency says the current mission design cannot return materials before 2040 on existing funds, and the $11bn (£9bn) to achieve it sooner is not sustainable.
NASA will study ideas to find a cheaper and faster alternative.
She hopes to have a solution on the drawing board later this year.
Bringing back rock samples from Mars is the most important priority in planetary exploration, and has been for decades.
Just as the moon rocks brought home by Apollo astronauts revolutionized our understanding of the early history of the solar system, material from the Red Planet is likely to reshape our thinking about the possibilities for extraterrestrial life.
But NASA now admits that its approach to achieving sample returns is simply not realistic in the current financial environment.
“The bottom line is $11 billion is too expensive, and not returning samples until 2040 is unacceptably too long,” NASA Administrator Bill Nelson told reporters on a conference call on Monday.
The former US senator said he would not allow other agencies' scientific missions to be “dismantled” through the Mars Project.
So he's looking for new thinking from within NASA and from industry.
The Mars Sample Return Program, or MSR, is a joint endeavor with the European Space Agency (Esa).
The current architecture is already underway, meaning the rock samples that will be brought home are in the process of being collected and cataloged on Mars today by NASA's Perseverance rover.
A dedicated follow-on mission was scheduled for later this decade that would carry a rocket to the surface of the red planet.
Once loaded into this ascent vehicle, the Perseverance samples will be launched skyward to rendezvous with a European-built spacecraft that can pick them up and head to Earth.
Nearly 300 grams of Martian material was expected to land in a capsule in the western United States state of Utah in 2033.
But an independent review published in September last year found faults in the way the mission design was carried out. She expressed doubt that the schedule could be maintained, and even if it were possible, the cost would likely rise to between $8 billion and $11 billion.
In its response published on Monday, NASA did not dispute this assessment, hence the desire now to reopen the debate on how best to move forward.
“We are looking at unconventional capabilities that could return samples earlier and at a lower cost,” said Dr. Nicola Fox, director of NASA's Science Directorate.
“This is certainly a very ambitious goal, and we will need to pursue some very innovative new possibilities in design, and we will certainly leave no stone unturned.”
She said these new possibilities could include a smaller, simpler missile.
Dr Fox told BBC News that the European Space Agency remained central to this endeavour. In fact, Europe's major contribution – the Earth Reentry Orbiter (ERO) – will likely be launched albeit a little later than currently envisaged, perhaps in 2030.
Dr. Orson Sutherland, leader of ESA's Mars Exploration Group, said his organization will carefully review NASA's response plan.
“Our priority remains ensuring the best path forward to achieve the groundbreaking science goals of the MSR and lay the foundation for future human missions to Mars,” he said.
Nelson stressed that NASA remains fully committed to the MSR project.
However, it was necessary to fit within the sustainable budget envelope, which he described as between $5 billion and $7 billion.
The overwhelming scientific necessity behind the MSR has been underscored in recent days by Perseverance's latest investigations.
The robot is working in a vast crater called Jezero, which appears to have contained a large lake about 3.8 billion years ago, an extremely promising scenario for the existence and preservation of microbial organisms.
Perseverance excavated and temporarily stored rocks that appeared to have been placed at the edge of the lake.
One of the rover's senior scientists, Professor Bryony Horgan from Purdue University, said these samples were particularly exciting.
She told the BBC: “At the moment, on board Perseverance we carry three samples of silica and carbonate rocks, and on Earth, these two minerals could be great at preserving ancient features of life.”
“We think it's possible that some of the samples are sandstones laid down in the ancient lake, but we're still assessing other origins as well. Either way, these rocks are exactly the types of samples we came to Mars to find, and we're very much looking forward to that.” “. “Many want to bring them back to our laboratories on Earth.”
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