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When Nasa pulled off the astonishing feat of lowering a $2.5bn robot onto Mars from a “sky crane” hovering above it on retrorockets, the US space agency also took a step towards restoring its reputation for cosmic wizardry and recapturing the public imagination after years of budget cuts and retrenchment.
The first grainy, black-and-white photos of the landing site in Gale Crater showed the Mini Cooper-sized rover had survived its hazardous descent, promoted in advance by Nasa’s formidable public relations machine as “seven minutes of terror” for the mission organisers.
Barely had the blue-shirted mission scientists and engineers at California’s Jet Propulsion Laboratory ceased their cheering than senior Nasa figures began to spell out the significance of the achievement.
“There are many out in the community who say that Nasa has lost its way, that we don’t know how to explore, that we’ve lost our moxie,” said John Grunsfeld, Nasa’s head of science.
“While [Curiosity] is certainly an international collaboration, this feat is something that only the US can do – and the rover is made in the USA.”
John Holdren, president Barack Obama’s science adviser, expressed similar sentiments about “this unprecedented technological tour de force”.
“If anybody has been harbouring doubts about the status of US leadership in space,” he said, “there’s a one-tonne automobile-sized piece of American ingenuity and it’s sitting on the surface of Mars right now.”
While Mr Grunsfeld was exaggerating when he compared the public excitement to the first Apollo moon landing in 1969, there was certainly enthusiasm about the landing across the US.
View Nasa images sent back from the Mars probe
Curiosity events were held at schools and colleges, while Nasa’s website crashed under the weight of people wanting to see the first pictures from Mars. In New York a large crowd chanted “Nasa! Nasa!” as news of the success at 1.30am lit up a big screen set up for the occasion in Times Square.
Even if Curiosity does help to turn the political and budgetary tide back in favour of space exploration, however, it will take several years to translate that into more high-profile missions to Mars and other planets. Billion-dollar projects take a decade of preparation and construction.
After it withdrew last year from a plan to collaborate with the European Space Agency on its ExoMars robot laboratory landing planned for 2018, pleading lack of funds, Nasa was left with no major planetary mission on its schedule. The agency is currently reformulating its Mars exploration programme and insists it will soon be back with plans for something big.
Meanwhile it and other space agencies are preparing a series of less ambitious Mars missions. Nasa’s contribution will be Maven – standing for Mars Atmosphere and Volatile Evolution – scheduled for launch next year, which will investigate the planet’s upper atmosphere and its interactions with the sun. Others, including India and China, are also targeting unmanned missions to the red planet.
Following Curiosity, Europe will take the lead with the two-part ExoMars mission, which is due to send an orbiter to Mars in 2016 followed by a rover in 2018. Roscosmos, the Russian space agency, stepped into the breach after Nasa’s withdrawal and will be working closely with Esa on the project, which will involve drilling far deeper into the Martian surface than Curiosity can.
In the mid 2020s the world’s space agencies hope to launch the first robotic mission to extract samples of Martian soil or rock and bring them back to Earth for analysis.
Beyond that, Nasa administrator Charles Bolden reminded Americans yesterday, the US still dreams of flying astronauts to the planet.
“President Obama has laid out a bold vision for sending humans to Mars in the mid-2030s, and [Curiosity’s] landing marks a significant step toward achieving this goal,” he said.
No rush to start roaming – power could last a decade
Now that Curiosity sits safely on Martian soil, its controllers 248,000,000km away on Earth are in no hurry to set the rover roaming across Gale Crater, writes Clive Cookson.
There is no rush because Curiosity’s plutonium-powered energy pack will last indefinitely – unlike the solar panels of previous rovers which degrade gradually with time. Although its technical design life is two years, Curiosity could well keep going for a decade. If all goes well, serious exploration will begin during the autumn and Curiosity will reach its main target, Mount Sharp, in the middle of next year.
Mission controllers chose Gale Crater and the strange mountain rise up in the middle of it, out of all possible landing sites on the red planet, because observations from orbiting spacecraft showed that it has particularly diverse geology. The rocks there include clays likely to have formed many millions of years ago when liquid water flowed on Mars and conditions were far more favourable to life than on today’s arid surface.
Scientists’ view of Mars has been transformed over the past two decades by accumulated evidence from orbiters and previous landers, showing that the Martian surface was shaped historically by water in hundreds of places, that a lot of ice still exists there and that liquid water may still emerge occasionally from the ground to flow briefly before freezing or evaporating.
Since biologists cannot conceive of life forms surviving in the complete absence of water and since all known life is based on carbon chemistry, Nasa’s Mars exploration is based on the twin strategy of “follow the water” and “follow the carbon”.
The 10 scientific instruments on Curiosity will analyse soil and rock samples extracted by the rover’s drill and scoop. They cannot detect active biological metabolism or image micro-organisms in the samples – that would have been beyond the capability of the robotic laboratory.
But the experiments will scrutinise the Martian environment for its biological potential, now and in the past, by searching for the chemical building blocks of life and in particular looking for organic carbon compounds.
The instruments will also scrutinise the chemistry of the atmosphere and the rocks in the crater, to see how the planet’s habitability has changed over geological time. And, even if no clear evidence about Martian life emerges, the rover’s cameras are expected take the most spectacular photographs of an alien environment in the history of planetary exploration.