Alison Gibbings

Evidence-based robust design of deflection actions for near Earth objects

This paper presents a novel approach to the robust design of deflection actions for near Earth objects (NEO). In particular, the case of deflection by means of solar-pumped laser ablation is studied here in detail. The basic idea behind laser ablation is that of inducing a sublimation of the NEO surface, which produces a low thrust thereby slowly deviating the asteroid from its initial Earth threatening trajectory. This work investigates the integrated design of the space-based laser system and the deflection action generated by laser ablation under uncertainty. The integrated design is formulated as a multi-objective optimisation problem in which the deviation is maximised and the total system mass is minimised. Both the model for the estimation of the thrust produced by surface laser ablation and the spacecraft system model are assumed to be affected by epistemic uncertainties (partial or complete lack of knowledge). Evidence Theory is used to quantify these uncertainties and introduce them in the optimisation process. The propagation of the trajectory of the NEO under the laser-ablation action is performed with a novel approach based on an approximated analytical solution of Gauss’ variational equations. An example of design of the deflection of asteroid Apophis with a swarm of spacecraft is presented.

Manned sample return mission to phobos: A technology demonstration for human exploration of Mars

In order to reduce the knowledge gap associated with long-duration human exploration of Mars, a manned precursor mission destined for one of the Martian moons is currently considered a feasible option for testing and demonstrating critical technologies within the Martian system. The 2013 Caltech Space Challenge, a student mission design competition held at the California Institute of Technology, addressed the interest in human precursor missions. Two teams of 16 students, with varying backgrounds and nationalities, were allocated five days to design a mission to land at least one human on a Martian moon and return them, along with a sample, safely to Earth with a launch date no later than January 1, 2041. This paper provides an overview of Technology Advancing Phobos Exploration and Return (TAPER-1), the manned Phobos sample return mission devised by Team Explorer. As the first manned mission to the Martian system, TAPER-1 is designed as an opposition class mission to Phobos, carrying four astronauts, with a launch date in April 2033, and a nominal time of flight of 456 days. In addition, this paper demonstrates the feasibility and value of exposing students to the process of rapid mission design.