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The Science Requirements

Introduction

Dusty phenomena such as wind-blown dust, dust storms, and dust devils are one of the most important, currently active, geological processes on Earth, Mars, and beyond. On Earth, the large electric fields (E-fields) produced by dusty phenomena can substantially affect the lifting of dust particles from the surface, while on Mars, saltation might produce electric fields large enough to cause electric discharges. Theoretical models predict that on Mars dust electrification has important effects on atmospheric chemistry.

There is evidence that electric forces might also lift dust on airless celestial bodies such as the Moon and asteroids. Measurements with space a flight version of the UM E-field sensor can be used to test this idea.

Typical E-field sensors have several drawbacks that limit their science application:

  1. They are grounded and distort the electric fields in their vicinity;
  2. They are incapable of providing information about the direction of the electric field, an important quantity;
  3. They produce large errors when subject to ion currents or the impacts of charged particles.

In addition, typical sensors have more than 10 cm of diameter and are not capable of measuring electric fields at distances as small as a few centimeters from the ground. Measurements this close to the ground are necessary to study the effects of electric fields on dust lifting.

To overcome these shortcomings, we developed and isolated E-field sensor capable of:

  1. Making in-situ measurements of DC E-fields in dusty phenomena;
  2. Making accurate measurements even when subject to the impact of charged particles;
  3. Measuring DC electric fields ranging from 10 to 106 V/m with accuracy of 10% and at rates of more than 1 Hz;
  4. Measuring E-fields as close as 2 cm from the surface.


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