in-Situ Individual Particle Sizer (iSIPS) apparatus

Abstract

Aerosols are well known to have significant negative impacts on human health. For space instrumentation, they can also be detrimental to the proper operation and integrity of mechanical device dynamics. Therefore, the continuous monitoring of aerosols and particulate materials in suspension is important for space missions, both inside spacecraft and lander habitation areas and airlocks, and outside for Lunar or Martian missions. To address this important problem, an innovative in-situ particle in suspension monitoring approach is presented. This approach allows for characterization of particle size distribution and concentration based on the Mie theory through forward scattering of light by particulates. It does not require air to be sampled through pumping or ventilators and thus provides a very convenient way to address characterization of particles in suspension in vacuum or low-pressure environments like the Lunar or Martian surface. Supplemental characterization modalities of particle shape and indicators on composition can be implemented. The latter provides clues on the presence of carbonaceous particles that can be a trigger to assess early detection of fire or slow combustion. First results from a bench top prototype show a size detection limit of 0.3 �m and sizing accuracy of better than 20% on actual size for sebacate oil spherical particles. These also show the relative independence of the particle sizing accuracy with respect to its composition for carbonaceous material particles, while information can be extracted to discriminate sebacate oil particulates from carbonaceous ones. Possibilities to implement fluorescence and polarisation measurements for enhanced information to monitor specific particulate composition and shapes, using easy to integrate supplemental components, is also presented.