Dr. John Marshall

December 21, 2006

SETI Institute Principal Investigator


Dust is often a mere inconvenience in our lives, ruining our machinery and layering the furniture, but it is also an intregal part of our existence when we realize that materials ranging from cement, plastics, and fertilizers, to photocopying cartridges, baby powder, and pharmaceuticals, start as tiny, dust-sized particles.  On a completely different scale, tiny particles are important components of the immense dusty nebulae that ultimately condense into stars and planets. 

Knowing how these particles behave helps us understand how worlds like our own are formed.  It aslo helps us understand the behavior of the Martian surface, and what problems human explorers might encounter when the dust coats the visor of a space suit and becomes a serious hazard.  John Marshall studies the electrostatics of dust forces that cause clustering of particles in space or adhesion of dust to a visor.  These electrostatic studies will include examining Martian dust under the microscope as part of the Phoenix mission scheduled to launch in 2007.

As a Co-Investigator on the mission, John Marshall will also be helping coordinate a team of engineers and scientists assessing how swirling dust produced by the spacecraft's descent engines might contaminate solar panels and scientific instruments.  Some of the founding principles for the behavior of particulate systems whether they be dusty nebulae or dusty spacecraft were established by Marshall's experiments flown twice on board space shuttle Columbia.

John Marshall has designed flight instruments for four NASA missions.  His latest flight concept is a device that could sidle up to Martian rocks to check out their composition.  This "mechanical geologist" would use X-ray diffractioin and fluorescence, as well as a built-in microscope, to unveil the secrets of boulders, sand, dust, and Martian soil.

- SETI Institute Explorer, Special Edition 2005


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