Curiosity's unsung skill: scouting Mars for a human mission (+video)
NASA's Curiosity rover is on Mars to look for signs that Gale Crater was once suitable for microbial life. But Curiosity's weather instruments are providing insight into the environment astronauts might face on Mars.
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In Pictures Exploring Mars with Curiosity
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Earlier this month, two tiny twisters buffeted NASA's Mars rover Curiosity in the space of 11 minutes. They were two of 21 whirlwinds the rover has detected from its home in Gale Crater so far – with more expected as Mars' southern hemisphere enters its spring and summer.
In one sense, this seems like a ho-hum observation. Whirlwinds and dust devils are common on Mars, although no evidence of them had been found in images of Gale Crater taken from orbit.
But they represent a very important element of the planet's dust cycle, which is a key driver of Mars' climate, says Manuel de la Torre Juarez, a physicist at NASA's Jet Propulsion Laboratory in Pasadena, Calif. Their presence inside the crater, combined with the most sophisticated atmospheric monitoring station humans have landed on the planet, give scientists an unprecedented opportunity to unravel the role these mini-twisters play in Mars' current climate.
The opportunity highlights a little-heralded role for Curiosity, whose primary mission is to analyze rocks and soil to determine if the crater might have once been a suitable habitat for microbial life. The rover and its weather station and radiation monitor are monitoring today's environment, both with an eye toward understanding the evolution of the planet's atmosphere over billions of years, but also as a gauge of the hazards astronauts might face during a potential mission.
One story that is unfolding involves the changing thickness of the atmosphere with each Martian day, called a sol, and even with seasonal changes. Those changes impact the amount of radiation – cosmic rays and charged particles from the sun – reaching the surface.
For instance, sensors on the Rover Environmental Monitoring Station (REMS) have detected an unexpected and large day-night shift in atmospheric pressure, corresponding to changes the sun brings to the atmosphere. During the day, the atmosphere heats, expands, and grows less dense as it does so. This reduces the amount of pressure the atmosphere exerts on pressure sensors. At night, when temperatures drop to about minus 130 degrees Fahrenheit, the pressure increases as the atmosphere contracts and grows more dense.
At the same time, the rover's Radiation Assessment Detector (RAD) has found that cosmic and other forms of radiation peak during the day and drop at night as changes to the atmosphere thicken or thin this tenuous shield.