The Mars mystique
After 50 years of missions to Mars, scientists are unlocking some of the mysteries surrounding a planet that has captivated mankind for millenniums. Will humans ever leave a boot print on Mars?
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"I didn't see this one coming," Dyar says of the evidence of the hidden glaciers and their implication for changes in Mars' climate.Skip to next paragraph
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As for the potential biological significance of the discoveries, she points to a recently published analysis of a microbial community in Antarctica. These bacteria live in tiny brine channels that snake through a sheet of ice at least 90 feet thick that caps Lake Vida in East Antarctica. Temperatures in the microbes' briny home hover around 8 degrees F.
The team, led by Alison Murray, a microbial ecologist with the Desert Research Institute in Reno, Nev., notes that a half-mile-thick layer of permafrost beneath the surrounding landscape isolates the frozen lake from any influx of ground water from the surrounding valley. The lightless depths at which the bacteria live isolate them from any seasonal meltwater that might pond on the surface of the ice.
The team estimates that the briny ecosystem has been isolated for millenniums. The microbes appear to be thriving on residual organic and inorganic matter trapped in the system after it was isolated and frozen, as well as on hydrogen produced by chemical reactions as brine interacts with layers of sediment in the ice.
Could there be similar microbial ecosystems on Mars?
Scientists speculate that microbes represent one possible source for wisps of methane detected in Mars' atmosphere. But the detection remains controversial, and methane can come from geological as well as biological processes.
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As early as 1948, Wernher von Braun, a German rocket scientist who later would head NASA's Marshall Space Flight Center in Huntsville, Ala., was already formulating serious plans for sending humans to Mars. His seminal book, "The Mars Project," envisioned a fleet of 10 spacecraft, assembled at a space station orbiting the Earth, traveling to the red planet with 70 crew members.
The space travelers would be ferried from ships orbiting Mars down to the surface in winged spacecraft, fitted with skis, that would land on one of the planet's frozen poles. They would spend 443 days on Mars before returning to Earth.
Von Braun's scheme put hard physics and rocket-fuel numbers to a vision typically the province of science fiction – a vision that many scientists and space agencies aspire to today. It's one more reason the search for water and other scientific data being sent back from the red planet is so important.
The extensive presence of ice near the surface of Mars, for instance, might represent a resource for human explorers some day for activities ranging from growing crops inside special habitat modules to making rocket fuel by separating and liquefying water's oxygen and hydrogen.
Curiosity is gathering information, too, that might one day be useful to architects of a human mission. Even as the rover scours Gale Crater for signs that it might once have boasted an environment capable of supporting life, it is measuring radiation levels at the surface. In fact, the instrument responsible for the measurements, known as the Radiation Assessment Detector (RAD), has been monitoring radiation levels since the craft left Earth.