Interception and deviation of Near Earth Objects via solar collector strategy

Paper number

IAC-08.A3.I.6

Author

Ms. Camilla Colombo, University of Glasgow, United Kingdom

Coauthor

Dr. Massimiliano Vasile, University of Glasgow, United Kingdom

Coauthor

Dr. Gianmarco Radice, University of Glasgow, United Kingdom

Year

2008

Abstract

The ongoing panel discussion about asteroids aims at assessing the level of technology to detect, track, study and deviate potentially dangerous Near Earth Objects. Among the possible responses to an asteroid impact hazard, one strategy would be to produce a sublimation of the surface material through a laser beam or a solar concentrator. This deflection strategy exploits the benefits of a slow-push technique and makes use of a free power source.

In order to have an effective and efficient mitigation scheme, the total mass of the spacecraft into orbit and the warning time should be minimal for a given deviation. An optimal solution can be obtained by the integrated design of the interception phase (transfer from the Earth to the asteroid) and the deflection phase.
This paper presents the design and optimisation of a number of mission opportunities to deviate potentially hazardous Near Earth Objects by means of a solar collector.
The two phases of the mission are optimised together through a global search, over a wide range of launch windows and masses into space; the mission characteristics are then selected in order to achieve a safe distance from the Earth, within a reasonable warning time.
For the interception phase a low-thrust direct transfer is designed to rendezvous with the asteroid in favourable conditions. A novel algorithm based on the Differential Dynamic Programming is adopted for the refinement of the solution. This successive approximation technique applies recursively, backwards in time, Bellman’s principle of optimality in the neighbourhood of the nominal trajectory, finding an improved control law. In this way the large scale problem associated with the optimisation of a low-thrust trajectory is translated into a series of problems of small dimensions.
The deviation achieved by the solar concentrator strategy, during the second phase of the mission, is computed through the relative motion equations which, coupled with Gauss’ planetary equations, provide a straightforward way to describe the displacement of the asteroid as a function of the continuous variation of the orbital elements.
The paper presents an analysis of a wide range of mission opportunities and a study of the optimal direction of the thrust vector applied to the asteroid, in order to maximise the resulting deviation. A selected number of asteroids will be considered. In fact, as will be shown, the interception phase, and therefore the consequent deviation phase, are deeply influenced by the orbital characteristics of the asteroid.

Abstract document

IAC-08.A3.I.6.pdf

Manuscript document

IAC-08.A3.I.6.pdf (🔒 authorized access only).

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