Solar-Sail Earth Defense (SOSED) from NEO Impacts

Paper number

IAC-06-C4.6.04

Author

Dr. Gregory L. Matloff, Bangs / Matloff Aerospace Consulting Co., United States

Year

2006

Abstract

Near Earth Objects (NEOs) capable of destroying a city impact Earth at ~100 year intervals. Observational programs are currently underway to categorize the magnitude of this threat. NEO-impact mitigation approaches suggested to date are typically of two classes : (I) Impulsive (nuclear) explosions that impart large amounts of kinetic energy to the threatening NEO in a very short (microsecond) time interval and (II) Solar-deflection concepts using solar-radiation pressure to alter the NEO linear-momentum vector over a much longer (multiyear or decade) time interval. Disadvantages of Class I are calving the NEO to form multiple radioactive fragments, each targeting the Earth. Disadvantages of Class II strategies include multi-year deflection-system operation times and  the required very accurate knowledge of NEO trajectories. The NEO deflection approach proposed here combines aspects of both of these classes. A non-nuclear 
impact technique is utilized in which a solar-sail is unfurled as close to the Sun as possible and accelerated by solar-radiation pressure to 600-900 km/sec. The sail-interceptor is then impacted against the offending NEO, at approximately a right angle to the NEO�s solar trajectory. Linear-momentum transfer alone is sufficient to divert a small NEO and prevent Earth impact if the 
collision occurs decades before the NEO would impact the Earth. Interceptor kinetic energy transferred to the NEO might reduce the required pre-impact intercept time. Crater-theory and models of  energy-interchange between sail and NEO are applied to this problem. Elements of sail near-Sun trajectory analysis relating to hit/miss probability are also considered. 

Abstract document

IAC-06-C4.6.04.pdf

Manuscript document

IAC-06-C4.6.04.pdf (🔒 authorized access only).

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