Time-resolved Spectroscopy of Plasma Flash from Hypervelocity Impact on Debrisat

Abstract

Time-resolved spectroscopic measurements were made on the intense plasma flash that accompanied a hypervelocity impact on "DebriSat" conducted in April 2014 at the Arnold Engineering Development Complex (AEDC) in Tennessee. The DebriSat project was a unique hypervelocity event aimed at simulating an on-orbit destructive collision of a modern satellite with a hypervelocity projectile in a single strike. Collaborators on the project included NASA's Orbital Debris Program Office at NASA Johnson Space Center (JSC), US Air Force Space and Missile Systems Center (SMC), The Aerospace Corporation, The University of Florida, and AEDC. The primary hypervelocity test object, DebriSat, was a 56 kg structure representative of a modern LEO spacecraft, assembled at University of Florida following design guidance provided by Aerospace's Concept Design Center. It comprised a hexagonal body with an arrangement of seven compartmentalized bays. The main panels and the structural ribs between the bays were constructed from Al 5052 honeycomb and carbon fiber composite face sheets. Each bay had a set of structures with components intended to represent those used in a modern satellite design. The AEDC projectile was a 570 g nylon-aluminum cylinder travelling at 6.8 km/s. An analysis of the first several frames of the DebriSat flash shows that the rate of radial expansion of the plume decreased from 4750 m/s at t = 0 to 2250 m/s at t = 156 s. Timeresolved spectral measurements were conducted on the plasma flash with multiple frames acquired with a 10 s gating interval. Numerous emission lines were observed and were consistent with the materials of structural components located in the specific bay of DebriSat that was impacted. A background was observed in all the spectral frames and could be fitted to a blackbody temperature of ~ 2900 K. A detailed description of the plasma flash and its spectroscopic investigation is presented.