Artificial Spin-up and Fragmentation of Sub-kilometre Asteroids

Paper number

IAC-07-A3.4.09

Author

Dr. Claudio Bombardelli, Advanced Concepts Team, The Netherlands

Year

2007

Abstract

Understanding the internal structure and composition of asteroids is a top priority for the coming planetary exploration program of many international space agencies. Asteroids are often regarded as ‘celestial fossils’ whose interior could yield very important clues about the formation and evolution of our planetary system and possibly on the pre-biotic chemical evolution of life.
Up to date several approaches have been proposed in order to map the interior of asteroids including subsurface drilling and sampling as well as radio reflection tomography and seismology. The drawback of these techniques is their poor resolution in characterising the asteroid features at greater depth. 
Recently a different approach to the problem has been considered for the case of asteroid 99942 Apophis, which will make a close earth fly-by in year 2029. As the mechanical properties of Apophis will be considerably affected by the interaction with the earth gravitational field it is attractive to monitor its mechanical response during the fly-by with a suite of scientific instruments gaining unprecedented knowledge about the otherwise inaccessible asteroid interior.
This study makes one step further in this direction by introducing the possibility of radically modifying the dynamical status of a celestial object with artificial means. It is shown that by employing a tethered centrifuge of a few tens of kilometres anchored to the surface of a sub-km asteroid the latter can be gradually spun-up until it breaks up. In this way not only it becomes possible to study the asteroid response during the spin-up process but also a direct access to the inner layers of the fractured celestial body becomes possible providing unique scientific information on its interior.
The outline of the article is the following. Firstly a description of the asteroid spin-up apparatus and spin-up strategy is presented. Next, an analytical model is introduced to investigate the spin-up dynamics of the tether-asteroid system. Starting from the analytical model we assess the requirements in terms of fuel, power and mission lifetime and the technological feasibility of fragmenting sub-km asteroids with a relatively modest-size tether centrifuge.
Results show that, in the worse case scenario of expected material strength, asteroids of up to 200 meter diameter can be fractured in less than 5 years with a tether centrifuge of a few tens of km and employing less than 20 tons of overall system mass.

Abstract document

IAC-07-A3.4.09.pdf

Manuscript document

IAC-07-A3.4.09.pdf (🔒 authorized access only).

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