Flow field investigation of atmospheric braking for high drag vehicles with forward facing jets

Flow field phenomena associated with a supersonic jet issuing upstream into a hypervelocity flow field were investigated experimentally in support of a new space vehicle aerobraking concept developed by Boeing for Orbital Transfer Vehicles (OTV's). Tests were made on OTV models in the NASA Langley 22 in., Mach 20 helium tunnel with jet exit Mach numbers from 1.0 to 6.18 and ballute half angles of 45 and 60 deg. Force data were taken at zero angle of attack to determine the effect of ballute angle, jet Mach number and jet flow rate on vehicle drag. Bow shock structures were examined in terms of flow steadiness to define acceptable jet flow rate regimes for use in drag modulation. Limited tests were made to obtain pressure and temperature distributions around the ballute and to determine the ballute center of pressure. Test results are presented and discussed relative to OTV application and similar previous experimental investigations.