Development and Testing of Quartz Crystal Microbalances For Spacecraft Missions To Measure Particle Fluxes From Minor Airless Solar System Bodies
Abstract
We are developing an instrument to measure the mass flux and size distribution of particles striking a spacecraft operating in the vicinity of airless minor solar system bodies including asteroids, small moons, and particularly, comets. The effort centers on developing and testing specialized quartz crystal microbalances (QCMs) with ro- bust particle capture coatings together with associated advanced oscillator electron- ics. The instrument is to be an advanced version of the QCMs that are part of the Grain Impact Analyzer and Dust Accumulator (GIADA) instrument that will be car- ried aboard the European Space Agency (ESA) Rosetta Spacecraft. Robust particle capture coatings are required that will survive the interplanetary environment for long periods and still provide effective particle capture and coupling to a QCM to allow mass measurements during rendezvous encounters. Our approach is to use aerogel for particle capture since aerogel consists of a very low density (99% void volume) web of rigidly connected, sub-micron silica fibers. In order to effectively oscillate a QCM with a thick particle capture coating, and retain its high mass sensitivity, so- phisticated oscillator circuits are required. Previously we reported on measurements of the electro-mechanical properties of thick (100 mm) layers of aerogel bonded to QCMs driven by sophisticated oscillator circuits. In this work we report the results of firing small (100-500 mm) grains at aerogel coated QCMs using a light gas gun at the University of Florida. We measured the particle capture efficiency of the aerogel lay- ers as a function of particle size, velocity, and material composition. The response of the aerogel/QCM combination to known number of captured particles was also mea- sured. The results will help guide the design of a second generation of aerosol capture coatings for QCMs.
- Publication:
-
EGS General Assembly Conference Abstracts
- Pub Date:
- 2002
- Bibcode:
- 2002EGSGA..27.1968S