NASA’s Curiosity rover has felt what appear to be dust devils pass by as it samples the Martian atmosphere, mission scientists said Thursday.
Though the Mars Science Laboratory rover has yet to catch the whirlwinds on camera, its Rover Environmental Monitoring Station (REMS) has recorded pressure dips and wind shifts that often signal a vortex’s presence, said the Jet Propulsion Laboratory’s Manuel de la Torre Juarez, the instrument’s investigation scientist.
Curiosity has been photographing, laser-zapping and even eating rocks since its Aug. 5 landing in Gale Crater. It has spent some 40 Martian days in the Rocknest dune, where it scooped, sieved and sampled its first bits of soil on the Red Planet. Now its sensors are providing new information about how the air above those rocks behaves.
At roughly one-hundredth the density of Earth’s atmosphere, Mars’ envelope of air is too thin to protect against radiation from space, but it’s just thick enough to have wind and massive sandstorms, the scientists said. It’s also highly reactive to the sun's heat, expanding during the day (lowering pressure) and shrinking at night (raising pressure), thus creating daily atmospheric tides. The pressure also rises as winter gives way to summer, when the polar ice caps begin to melt, releasing the once-frozen carbon dioxide into the air.