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What Curiosity Will and Won't Teach Us About Martian Life
NASA's new Mars rover boasts an unprecedented suite of instruments, but it won't be able to answer all our questions
By Jeffrey L. Bada
Posted 2 Aug 2012 | 15:36 GMT
Illustration: JPL/Caltech/NASA
At around 5:25 a.m GMT on Monday, 6 August, the NASA Mars Science Laboratory spacecraft will reach the edge of the Martian atmosphere and attempt to deliver the biggest and heaviest robotic explorer yet sent to the Martian surface. If the Curiosity rover survives the landing, it will be set to scrutinize the Martian surface with the most sophisticated instrument package ever landed on another planet. The expectation is great that the US $2.5 billion mobile laboratory will be able to tell us once and for all whether Mars could once have harbored - or might still be able to support - some form of life. But whatever Curiosity finds, it won't be the final word on Martian life.
If Curiosity's mission is successful, it will be at best an incremental step - albeit an important one - in our exploration of the Red Planet. Speculation about the possibility of life on Mars has long outstripped our ability to investigate it, and our technology is only now beginning to catch up. In the years to come, we may look back on Curiosity as the spacecraft that began to answer questions that researchers have been asking, in one form or another, for centuries.
For a long time, we struggled to pin down whether Mars ever had the most basic ingredient needed for life: liquid water. In 1907, after astronomer Percival Lowell claimed to have found evidence of canals built by intelligent Martians, the British naturalist Alfred Russel Wallace wrote: "The first essential of organic life - water - is nonexistent. Mars, therefore, is not only uninhabited by intelligent beings such as Mr. Lowell postulates, but is absolutely UNINHABITABLE." Later telescope observations supported Wallace's conjecture, and by the 1960s, when the first spacecraft finally flew past the planet, the pictures they snapped showed scientists a vast desertlike surface, pockmarked with craters - a cold, dry, and desolate world.
Nowadays, we know the truth is more complex. Thanks to data collected by both orbiting and landed spacecraft, planetary scientists now have reason to believe that water once flowed across the surface of Mars and perhaps even formed lakes and small oceans. Liquid water might still exist in isolated spots beneath the surface, in thin melted layers that sit atop subsurface water ice.
That said, it's still far from clear