Accession Number:

ADA012250

Title:

An Ablation Technique for Enhancing Reentry Antenna Performance; Flight Test Results

Descriptive Note:

Physical sciences research papers

Corporate Author:

AIR FORCE CAMBRIDGE RESEARCH LABS HANSCOM AFB MA

Report Date:

1974-11-14

Pagination or Media Count:

79.0

Abstract:

To develop alternative solutions to Air Force problems relating to signal transmission in the presence of ionization, AFCRL undertook an extensive investigation of techniques for modifying reentry plasmas. The program included laboratory tests and a series of reentry flight experiments. This report describes the flight test of one successful technique, Teflon ablation, a passive approach that requires no internal support systems. A reentry vehicle fitted with a Teflon-coated nosecap was instrumented to measure antenna impedance mismatch, interantenna coupling, signal attenuation, and charged-particle density. The probe data showed that the local boundary-layer electron density decreased by as much as a factor of 200. The Teflon coating effected a 25-dB decrease in S-band signal attenuation. High-power antenna breakdown was modified by the presence of the ablation products. Details of the vehicle design, flight dynamics, and ablation, are presented, and the results of the Teflon-ablation technique are contrasted with those of a successful liquid-injection technique that was tested on a previous flight. Author

Subject Categories:

  • Guided Missile Reentry Vehicles
  • Plasma Physics and Magnetohydrodynamics
  • Radiofrequency Wave Propagation

Distribution Statement:

APPROVED FOR PUBLIC RELEASE