Accession Number : ADA309277

Title :   Flight Test of Carbon-Phenolic on a Spacecraft Launched By the Pacemaker Vehicle System.

Descriptive Note : Technical memo.,

Corporate Author : NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HAMPTON VA LANGLEY RESEARCH CEN TER

Personal Author(s) : Walton, Thomas E., Jr. ; Witte, William G.

PDF Url : ADA309277

Report Date : MAR 1972

Pagination or Media Count : 91

Abstract : Carbon phenolic material consisting of 50 percent carbon fibers and 50 percent phenolic resin was flight tested on a recoverable spacecraft launched by the Pacemaker vehicle system. The heat shield of the spacecraft was fabricated so that the carbon fibers in the ablator material had different orientations over several areas of the spacecraft. The environment in which the spacecraft was tested produced heating rates on the hemispherical nose up to 13.6 Mw/m2 (1200 Btu/ft2-sec) and stagnation point pressures up to 1.27 MN/m2 (12.5 atm). The experimental results are presented. Due to high heating rates and possible spallation and mechanical char removal the greatest mass loss occurred in the nose region. Essentially uniform surface recession and char thickness were observed on the conical section of the spacecraft. A comparison of measured heating rates with computed turbulent and laminar heating rates, as well as measurements of sound pressure fluctuations in the boundary layer obtained with acoustic sensors, indicated that the boundary layer underwent transition. The acoustic sensor provides an interesting new data form for the general study of boundary layer transition for free flight investigations.

Descriptors :   *ABLATIVE MATERIALS, *RECOVERABLE SPACECRAFT, *NOSE CONES, FLIGHT TESTING, THICKNESS, MECHANICAL PROPERTIES, HIGH RATE, MASS, TURBULENCE, CARBON FIBERS, HEAT SHIELDS, VEHICLES, BOUNDARY LAYER TRANSITION, LAMINAR FLOW, HEMISPHERES, CONICAL BODIES, SOUND PRESSURE, STAGNATION PRESSURE, ACOUSTIC DETECTORS, SPALLATION, VARIABLE PRESSURE, STAGNATION POINT, CARBON PHENOLIC MATERIALS, FREE FLIGHT, CHARRING.

Subject Categories : Unmanned Spacecraft
      Ceramics, Refractories and Glass

Distribution Statement : APPROVED FOR PUBLIC RELEASE