Daniel J. Scheeres

Learn More
High-resolution images of the surface of asteroid Itokawa from the Hayabusa mission reveal it to be covered with unconsolidated millimeter-sized and larger gravels. Locations and morphologic characteristics of this gravel indicate that Itokawa has experienced considerable vibrations, which have triggered global-scale granular processes in its dry, vacuum,(More)
The purpose of this paper is to describe the general setting for the application of techniques from geometric mechanics and dynamical systems to the problem of asteroid pairs. The paper also gives some preliminary results on transport calculations and the associated problem of calculating binary asteroid escape rates. The dynamics of an asteroid pair,(More)
We present a numerical method that incorporates particle sticking in simulations using the N-body code pkdgrav to study motions in a local rotating frame, such as a patch of a planetary ring. Particles stick to form non-deformable but breakable aggregates that obey the (Eulerian) equations of rigid-body motion. Applications include local simulations of(More)
For low energy spacecraft trajectories such as multimoon orbiters for the Jupiter system, multiple gravity assists by moons could be used in conjunction with ballistic capture to drastically decrease fuel usage. In this paper, we investigate a special class of multiple gravity assists which can occur outside of the perturbing body's sphere of influence (the(More)
We present a combination of tools which allows for investigation of the coupled orbital and rotational dynamics of two rigid bodies with nearly arbitrary shape and mass distribution , under the influence of their mutual gravitational potential. Methods for calculating that mutual potential and resulting forces and moments for a polyhedral body(More)
— Given a nonlinear system and performance index to be minimized, we present a general approach to evaluating the optimal feedback control law for this system that can be easily modified to satisfy different types of boundary conditions. Formulated in the context of Hamiltonian systems theory, this work allows us to analytically construct optimal feedback(More)
Spacecraft missions to small celestial bodies face sensitive , strongly non-Keplerian dynamics that motivate the employment of automated sampling-based trajectory planning. However, the scarcity of onboard computing resources necessitates careful formulation of heuristics for efficiently searching the reachable sets, which exhibit complex and(More)
—The orbital environment of Resident Space Objects (RSO) is highly structured and deterministic in general, with stochastic effects only arising due to mis-modeling and to some variability in the physical environment in which they orbit. Due to this RSO can be well modeled as following Hamiltonian Dynamics, and thus their state space can be expressed as(More)
— A new type of estimator that incorporates optimal control and outputs a control policy is developed and analyzed in this study. The estimator is developed in a similar manner to a Kalman Algorithm with an almost identical form, but has additional properties for more accurate tracking, maneuver detection, and maneuver reconstruction. Unlike the Kalman(More)