Journal Article

Aeolian processes at the Mars Exploration Rover Meridiani Planum landing site

Fike, D., Malin, M., Yen, A., Jerolmack, D., Herkenhoff, K., Thompson, S., Calvin, W., Watters, W. A., Ming, D., Bell, J. F., Sullivan, R., Banfield, D., Golombek, M., Grotzinger, J., Greeley, R., Squyres, S. W., Weitz, C. M., Soderblom, L. A.

2005

Overview

Martian vistas The cover shows part of the Larry's Lookout panorama, seen from the Mars Exploration Rover (MER) Spirit during its drive up Husband Hill: the summit is about 200 metres from the rover. Six papers this week report in detail on the MER mission. An Analysis compares predictions used to select a landing site with the conditions actually encountered. This ‘ground truth’ will be invaluable for interpreting future remote-sensing data. Surface chemistry suggests that the upper layer of soil may contain 1% meteoritic material. MER provides a unique glimpse of solar transits of the moons Phobos and Deimos. Rover Opportunity examined wind-related processes, and spectroscopy indicates a dry origin for atmospheric dust. Features from within the Gusev crater give more information on the role of liquid water in Mars's past. An accompanying News and Views puts the MER data in context. The martian surface is a natural laboratory for testing our understanding of the physics of aeolian (wind-related) processes in an environment different from that of Earth. Martian surface markings and atmospheric opacity are time-variable, indicating that fine particles at the surface are mobilized regularly by wind 1 , 2 , 3 . Regolith (unconsolidated surface material) at the Mars Exploration Rover Opportunity's landing site has been affected greatly by wind, which has created and reoriented bedforms, sorted grains, and eroded bedrock. Aeolian features here preserve a unique record of changing wind direction and wind strength. Here we present an in situ examination of a martian bright wind streak, which provides evidence consistent with a previously proposed formational model 4 , 5 for such features. We also show that a widely used criterion for distinguishing between aeolian saltation- and suspension-dominated grain behaviour is different on Mars, and that estimated wind friction speeds between 2 and 3 m s -1 , most recently from the northwest, are associated with recent global dust storms, providing ground truth for climate model predictions.

• Publisher: Nature Publishing Group UK,Nature Publishing,Nature Publishing Group
• Subject: Astronomy / Climate models / Dust storms / Earth, ocean, space / Eolian processes / Exact sciences and technology / Humanities and Social Sciences / Mars / mars-letters / multidisciplinary / Opacity / Planets, their satellites and rings. Asteroids / River beds / Rocks / Saltation / Science / Science (multidisciplinary) / Sedimentary structures / Solar system / Space exploration / Wind