AN INJECTION SYSTEM FOR ALLEVIATION OF RADIO BLACKOUT DURING RE-ENTRY
Scientific rept. no. 2, 14 Oct 1964-14 Dec 1965
MITHRAS CAMBRIDGE MA
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This report outlines method of creating a window for radio communication through a re-entry plasma sheath. The results of non-equilibrium numerical calculations illustrate that the injection of a coolant gas will reduce the plasma sheath temperature but will not reduce the free electron density or plasma frequency. Plasma electron density can be reduced, however, by attachment to electrophilic gases. The chemical rates of attachment are computed and criteria are developed which specify the amount of electrophilic gas required to reduce the electron density a specified amount in a given time. As a practical application, a gas injection system for the total alleviation of S-band blackout throughout the re-entry of a Trailblazer II vehicle would have a total charged weight of 3.4 lbs., a volume of 215 cubic inches, and would discharge 0.28 lbs. of SF6 during re-entry. With a pulsed injection system, an even smaller system can be used.
- Unmanned Spacecraft
- Radio Communications