  Among the approaches to the proposed mitigation and remediation of the space
debris problem is the de-orbiting of objects in low Earth orbit through
irradiation by ground-based high-intensity pulsed lasers. Laser ablation of a
thin surface layer causes target recoil, resulting in the depletion of orbital
angular momentum and accelerated atmospheric re-entry. However, both the
magnitude and direction of the recoil are shape dependent, a feature of the
laser-based remediation concept that has received little attention. Since the
development of a predictive capability is desirable, we have investigated the
dynamical response to ablation of objects comprising a variety of shapes. We
derive and demonstrate a simple analytical technique for calculating the
ablation-driven transfer of linear momentum, emphasizing cases for which the
recoil is not exclusively parallel to the incident beam. For the purposes of
comparison and contrast, we examine one case of momentum transfer in the
low-intensity regime, where photon pressure is the dominant momentum transfer
mechanism, showing that shape and orientation effects influence the target
response in a similar, but not identical, manner. We address the related
problem of target spin and, by way of a few simple examples, show how ablation
can alter the spin state of a target, which often has a pronounced effect on
the recoil dynamics.
