Cold Jet Plume

A primary area of research for the Launch Systems Testbed is the effect of rocket exhaust plumes on ground systems. Preliminary cold jet tests have been performed, using an exit exhaust velocity of Mach 2.7. The acoustic levels measured during the testing indicated that there were ground and duct effects as a result of the supersonic core length of the exhaust plume being deflected. Current plans are to increase the exit supersonic flow to Mach 3.5, which is the typical condition for rocket launch exhaust. Data from high Mach number supersonic jet noise tests currently in progress at KSC are being studied for the effects of plume velocity, temperature and density. These analyses will adress the similarity of flow and acoustics between the model and full scale rockets.

Jet-induced cratering is another phenomenon undergoing analysis by the Launch Systems Testbed. During landing and launch on a granular surface (conditions encountered during lunar or martian missions), a rocket plume will erode the launch/landing surface and generate particulate contamination. The process by which this cratering occurs is not well understood. The Launch Systems Testbed is working to develop a methodology to analyze and model jet-induced cratering phenomena.
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NASA Official: James Heald ( , Director, Spaceport Engineering and Technology Directorate
Curator: Bruce Vu (
Last Revised: October 6, 2004

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