NASA announced today that, aside from scooping and analyzing Martian soil, Mars rover Curiosity's measurements of wind and radiation patterns on Mars are helping researchers better understand the environment near the surface of Mars.
Researchers with the Mars Science Laboratory mission have identified transient whirlwinds, mapped winds in relation to slopes, tracked changes in air pressure, and linked radiation changes to atmospheric changes. The goal of the mission is to discover whether the environment in Gale Crater, where Curiosity landed earlier this year, could ever have been habitable for microbes.
Since the rover touched down on Mars, researchers have analyzed 20 atmospheric events recorded by Curiosity's Rover Environmental Monitoring Station (REMS), one of which is characteristic of a whirlwind. In the past, dust-devil track and shadows have been seen on the surface of Mars from orbit, but no such tracks have been seen in Gale Crater. NASA suggests that it is possible vortex whirlwinds in the crater do not lift as much dust as they do elsewhere on the red planet.
"Dust in the atmosphere has a major role in shaping the climate on Mars," said Manuel de la Torre Juarez, investigation scientist for REMS at NASA's Jet Propulsion Laboratory. "The dust lifted by dust devils and dust storms warms the atmosphere."
Researchers were expecting to find that slope effects from the mountain just south of Curiosity would produce north-south winds in the crater, but have found that east-west winds predominate.
"With the crater rim slope to the north and Mount Sharp to the south, we may be seeing more of the wind blowing along the depression in between the two slopes, rather than up and down the slope of Mount Sharp," said Claire Newman, an REMS investigator at Ashima Research. "If we don't see a change in wind patterns as Curiosity heads up the slope of Mount Sharp -- that would be a surprise."
Curiosity's REMS has also been tracking a seasonal increase and daily rhythm in air pressure. Researchers will use this information to understand atmospheric cycles on Mars and estimate how cycles may have operated in the past. NASA stated that the seasonal air pressure increase comes as a result of tons of carbon dioxide frozen in Mars' southern ice caps returning to the atmosphere as the southern summer begins. The daily rhythm comes from a thermal tide - a wave of heated atmosphere that moves along with the daytime heat from the Sun. Along with the thermal tide comes high-energy radiation detected by Curiosity's Radiation Assessment Detector (RAD).
"We see a definite pattern related to the daily thermal tides of the atmosphere," said Don Hassler, RAD principal investigator at the Southwest Research Institute's Boulder, Colo., branch. "The atmosphere provides a level of shielding, and so charged-particle radiation is less when the atmosphere is thicker. Overall, Mars' atmosphere reduces the radiation dose compared to what we saw during the flight to Mars."
(Image courtesy NASA/JPL-Caltech)