Abstract: The presence of particular contaminants in optical sensor fields of view may result in spurious detector events that can be mistaken as point sources or cause an increase in background radiation. These particles come from spacecraft surfaces (where they dislodge through vibration induced from spacecraft movement), micrometeoroid impact, or operation of rocket motors of vents. Minimum detectable particle sizes as a function of distance from sensors for several infrared wavebands are estimated. Sensors operating in the 15 to 25 micron regime are most sensitive to this type of contamination. Calculations of particle trajectories indicate that particles produced at high earth orbit are likely to stay within fields of view of sensors for hours. Therefore, it would be highly desirable to have a device that is capable of quickly clearing such particles form the field of view. Four field-of-view particulate contaminant removal methods were investigated: (1) photon flux; (2) neutral molecular flux; (3) ion flux; and (4) electrostatic field. The neutral molecular flux method is the fastest but suffers from the disadvantage of unwanted thrust and limited gas supply. The ion beam method seems effective but slower as it requires rastering. The radiation pressure method is energy inefficient; a large power supply is necessary. The electrostatic field method can be effective only if the altitude is above 10,000 km. Further study of this method will require better flight data on the amount of charge likely to be present on free-floating particles at high orbital altitudes.!
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