Minimum energy asteroid reconfigurations and catastrophic disruptions 1 Daniel J. Scheeres ECOT 611, 429 UCB University of Colorado at Boulder Boulder, Colorado 80309-0429, USA Abstract Dramatic alteration of an asteroid’s morphology need not involve high energy impacts between bodies. Simple sunlight shining on an asteroid can, through the YORP effect, cause it to undergo dramatic reconfigurations, fission into a binary asteroid or, in some cases, even undergo a catastrophic disruption with the asteroid losing a large frac- tion of its initial mass. This paper discusses the system level con- straints and conditions for these reconfigurations to occur as a body’s spin rate changes. 1 Introduction This paper generalizes the conditions for reconfiguration and fission of a rubble pile composed of rigid bodies resting on each other and discusses the- oretical limits for when such transitions occur. Given a clear understanding of these transitions, it becomes possible to map out the evolution of a rubble pile as its spin rate changes due to the YORP effect [9] or to a planetary flyby [10]. We will focus on the effect of an increasing spin rate, but some of the results we present also apply to a body subjected to a decreasing spin rate. The theory described is intended to provide a context within which more general numerical analysis of this problem can be formulated. Our physical model focuses on a rubble pile asteroid consisting of a col- lection of rigid bodies resting on each other. Interesting questions to ask regarding such rubble pile asteroids include at what spin rate will the body undergo a reconfiguration of its components, at what spin rate will fission occur, and what will the dynamical outcome of fission be. Our analysis is 1 Submitted to Planetary and Space Science, February 1, 2008 1