Download or read book An Ablation Technique for Enhancing Reentry Antenna Performance Flight Test Results written by Dallas T. Hayes and published by . This book was released on 1974 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Interpretation of Microwave Antenna Results from a Reentry Flight Test written by John F. Lennon and published by . This book was released on 1974 with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is one of a series of reports on the Trailblazer II program. The particular aspect treated here involves the unmodified expansion-region plasma and its effect on an antenna located on the vehicle shoulder. This report describes some of the theoretical approaches used, discusses the levels of approximation involved, and shows the agreement between these various methods and the test data. The failure of a single set of assumptions to yield consistent agreement over a range of altitudes confirms the need to adopt flow models appropriate to the changing regimes encountered during reentry. One significant conclusion is that performance characteristics such as reflection and interantenna coupling which depend mostly on the level of peak electron density can be represented by simple plane wave, as well as by the more sophisticated slot antenna models. The latter approach, however, is necessary to describe propagation across the entire plasma sheath.

Download or read book Effects of the Reentry Plasma Sheath on Microwave Antenna Performance written by J. Leon Poirier and published by . This book was released on 1969 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt: A Trailblazer II rocket was launched on 18 June 1967 from the NASA wallops Island (Va.) Rocket Test Facility to study the properties of the reentry plasma sheath and its effects on microwave antenna performance. The reentry payload consisted of three major subsystems: a plasma diagnostic system, an S- band transponder system, and an X-band telemetry system. The flight data yielded (1) measurements of the influence of the plasma on the radiation pattern distortion, signal attenuation, and impedance mismatch for an S-band slot antenna located at the stagnation point of the nose cone; (2) measurements of the plasma sheath effects on the interantenna coupling between two S-band antennas on the nose cone; and (3) determinations of the electron density profile and gradients in the boundary layer about the nose cone.

Download or read book Government Reports Annual Index written by and published by . This book was released on 1975 with total page 882 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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Download or read book Government Reports Announcements written by and published by . This book was released on 1975-09-05 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Government Reports Announcements Index written by and published by . This book was released on 1976 with total page 1346 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Government reports annual index written by and published by . This book was released on 199? with total page 880 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Government Reports Index written by and published by . This book was released on 1975 with total page 908 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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Download or read book Aerothermodynamics and Planetary Entry written by Alfred L. Crosbie and published by . This book was released on 1981 with total page 472 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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Download or read book Technical Abstract Bulletin written by and published by . This book was released on with total page 850 pages. Available in PDF, EPUB and Kindle. Book excerpt: