Reap the Martian Whirlwinds

NASA Phoenix Lander Sees Dust Devils

Phoenix Lander catches sight of a dust devil near its landing site. (NASA/JPL-Caltech/University of Arizona/Texas A&M University)

The Phoenix Lander that’s currently checking out the conditions near Mars’s north pole caught some dust devil action a few days ago, and sent back some images to prove it. Dust devils are these little whirlwinds that occur when the Sun heats a planetary surface like Mars or Earth. If conditions are right (i.e. dry, dusty), the surface radiates the heat back up to the atmosphere, and that causes currents in the air. If there’s enough of it, the currents whirl around, creating dust devils.  I’ve seen them in the American Southwest and in movies shot in the Australian Outback.

These dust devils were quite a surprise to the Phoenix scientists, although they were hoping and expecting to see some. At least six different dust devils appear in a series of 12 images and they range in size from about two meters to five meters across. The Phoenix team is not worried about any damage to the spacecraft from these swirling winds. “With the thin atmosphere on Mars, the wind loads we might experience from dust devil winds are well within the design of the vehicle,” said Ed Sedivy, Phoenix program manager at Lockheed Martin Space Systems Company, Denver, which made the spacecraft. “The lander is very rigid with the exception of the solar arrays, which once deployed, latched into position and became a tension structure.”