An Analysis Of The Orbital Distribution Of Solid Rocket Motor Slag

Paper number

IAC-07-A6.2.03

Author

Mr. Matthew Horstman, ESCG/ERC, United States

Coauthor

Dr. Mark Mulrooney, United States

Year

2007

Abstract

\indent The contribution made by orbiting solid rocket motors (SRMs) to the orbital debris environment is both potentially significant and insufficiently studied.  A combination of rocket motor design and the mechanisms of the combustion process can lead to the emission of sufficiently large and numerous by-products to warrant assessment of their contribution to the orbital debris environment.  These particles are believed formed during SRM tail-off by the rapid expansion, dissemination, and solidification of the molten Al2O3 slag pool accumulated during the main burn phase of SRMs utilizing immersion-type nozzles.

\indent Though the usage of SRMs is low compared to the usage of liquid fueled motors, the propensity of SRMs to generate particles in the 100 micron and larger size regime leads to concerns about such additional mass contributing to the debris environment.  Particle sizes as large as 1 cm have been witnessed in ground tests conducted under vacuum conditions and comparable sizes have been estimated via ground-based telescopic and in-situ observations of sub-orbital SRM tail-off events.

\indent Using such sub-orbital and post recovery observations, a simplistic number-size-velocity distribution of slag from on-orbit SRM firings was postulated (Mulrooney 2007). In this paper we have developed more elaborate distributions and emission scenarios and modeled the resultant orbital population and its time evolution by incorporating a historical database of SRM launches, propellant masses, and likely location and time of particulate deposition.  From this analysis a more comprehensive understanding has been obtained of the role of SRM ejecta in the orbital debris environment, indicating that SRM slag is a significant component of the current and future population.

Abstract document

IAC-07-A6.2.03.pdf

Manuscript document

IAC-07-A6.2.03.pdf (🔒 authorized access only).

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