SNOOPY

Student Nanoexperiments for Outreach and
Observational Planetary InquirY

Hypothesis:

The angle of repose of Martian dust can be determined by photographing dust deposition on small spherical or cylindrical surfaces deployed on the planet surface.

Mission History:

This experiment was originally accepted by NASA and The Planetary Society as a winner in the 1999-2000 Student Nano-Experiment Challenge when I was in the fifth grade. As a part of this competition the experiment was fabricated, flight tested and scheduled to go on the 2001 Mars Odyssey Surveyor Lander as a part of the Mars Environmental Compatibility Assessment (MECA) patch plate array designed for the Lander. However, this mission was canceled following the crash of the NASA 2000 Polar Lander. In 2001-2, the experiment was incorporated into the environmental sensor suite of the ESA Beagle 2 Lander that was to land on Mars in December 2003. The Beagle 2 Lander crashed into Mars on Christmas day 2003. The Mars Dust experiment is in consideration for the 2007 NASA Phoenix mission. Additional mission history and photos are available here.

Introduction:

Martian dust and windblown particulates will present significant difficulties in the future exploration of Mars [Kahn, R.A. et al., 1992]. These difficulties include the environmental challenges to materials, machines and people. Knowledge of the angle of repose of Martian dust, qr, would be useful in the design of exploration and support systems. In particular, accumulation of wind-blown dust particles on solar panels and other instruments is a great challenge for the exploration of Mars, significantly reducing their lifetime, durability, and power output. For future Mars Lander missions it is crucial to gain information about the ideal angle at which solar panels can be positioned to minimize dust deposition and thus, maximize the power output and lifetime of the solar cells.

A major determinant for an optimal solar panel angle is the angle of repose, qr, of the dust particles that is dependent on a variety of physical and chemical properties of the particles, the panel surface, and the environmental conditions on the Mars surface. Primary factors determining the angle of repose are the particle angularity, roughness, size, and surface charge, the humidity, temperature, and chemical composition of the Martian atmosphere, and the properties of the panel surface. While the effects of many of these factors are well understood qualitatively, quantitative analyses, especially under physical and chemical conditions prevailing on the Mars surface are lacking. Airborne particles deposited on surfaces interact with the surface and with other particles. The angle of repose is defined as the “steepest angle of a surface at which a mass of loose or fragmented material will remain standing in a pile, rather than sliding or crumbling”. A sand pile with slope equal to the angle of repose is in a metastable configuration which becomes unstable if perturbed.

To learn more about Mars dust and this experiment, I have put a copy of my NASA Student Involvement Program (NSIP) presentation here. You are welcome to download copies of my technical papers describing my Mars dust research here.