Space Experiments Aboard Rockets: SPEAR III
NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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The SPEAR III experiment was conducted in an effort to better understand and compensate for the effects of satellite charging, at levels up to KV. This experiment was designed as a lower-ionosphere test to both record vehicle charging and the effect of neutral-gas grounding systems. Prelaunch tests were conducted at the NASA-Plum Brook facility launch took place at the NASA-Wallops facility. Electrostatic analyzer data provided a record of the rocket body potential, and indications of ion production, or energy-angle scattering within the plasma sheath. Plasma wave information was extracted from floating probe data and skin current probe data. Both provided sampling to resolve signals up to 10 KHz the skin current probe also provided burst-mode sampling up to 500 MHz. There were no obvious signals in the 0-10 KHz data, other than a diffuse, low-frequency noise. The burst-mode data, acquired at the initiation of each 5-second charging sequence, showed a strong signal at around 100 KHz. This roughly corresponds to the lower-hybrid resonance frequency. It is possible, that LHR waves are responsible for energy-angle scattering of the ion flux accelerated to the charged rocket body.
- Atmospheric Physics