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Astrobiology 2020 02;20(2):163-166

NASA Ames Research Center, Moffett Field, California.

There has been considerable attention on how to detect life on other worlds by searching for biomolecules. However, there has been much less clarity as to when it becomes warranted to focus a mission on the search for life on another world. At a minimum, a life-detection mission should follow convincing evidence of (1) Liquid water of suitable salinity, past or present; (2) Carbon in the water; (3) Biologically available N in the water; (4) Biologically useful energy in the water; (5) Organic material that can possibly be of biological origin and a plausible strategy for sampling this material. Read More

Nat Commun 2019 04 12;10(1):1716. Epub 2019 Apr 12.

Cornell University, Cornell Center for Astrophysics and Planetary Science, 442 Space Science Bldg, Ithaca, NY, USA.

Sublimation of ice is rate-controlled by vapor transport away from its outer surface and may have generated landforms on Mars. In ice-cemented ground (permafrost), the lag of soil particles remaining after ice loss decreases subsequent sublimation. Varying soil-ice ratios lead to differential lag development. Read More

Sci Total Environ 2018 Apr 31;621:1163-1175. Epub 2017 Oct 31.

Icelandic Institute of Natural History, Borgum við Norðurslóð, 602 Akureyri, Iceland.

On the 20th September 2012, a large debris slide occurred in the Móafellshyrna Mountain in the Tröllaskagi peninsula, central north Iceland. Our work describes and discusses the relative importance of the three factors that may have contributed to the failure of the slope: intense precipitation, earthquake activity and thawing of ground ice. We use data from weather stations, seismometers, witness reports and field observations to examine these factors. Read More

Astrobiology 2013 Apr 5;13(4):334-53. Epub 2013 Apr 5.

NASA Ames Research Center, Moffett Field, California 94035, USA.

The search for evidence of life on Mars is the primary motivation for the exploration of that planet. The results from previous missions, and the Phoenix mission in particular, indicate that the ice-cemented ground in the north polar plains is likely to be the most recently habitable place that is currently known on Mars. The near-surface ice likely provided adequate water activity during periods of high obliquity, ≈ 5 Myr ago. Read More

Antarct Sci 1998 Mar;10(1):31-8

Space Science Division, NASA Ames Research Center, Moffett Field, CA 94035, USA.

Year-round temperature measurements at 1600 m elevation during 1994 in the Asgard Range Antarctica, indicate that the mean annual frost point of the ice-cemented ground, 25 cm below the surface, is -21.7 +/- 0.2 degrees C and the mean annual frost point of the atmosphere is -27. Read More