Orbital Dispersion Simulation of Near-Earth Objects Deflection/Fragmentation by Nuclear Explosions

Paper number

IAC-09.C1.10.2

Author

Mr. Brian Kaplinger, Iowa State University, United States

Coauthor

Prof. Bong Wie, Iowa State University, United States

Year

2009

Abstract

A hovering gravity tractor (GT)  in a  static equilibrium standoff position  requires canted thrusters to avoid plume impingement on the target asteroid surface.  Consequently,  McInnes [1]  has investigated  a GT spacecraft flying  in   a displaced  non-Keplerian orbit (also often called  a halo orbit) for a possible   fuel-efficient way  of towing asteroids.     However,  a GT    in a displaced orbit  will  require   a much heavier spacecraft (about 2.8 times heavier than  a single hovering GT)  if its x-axis location is the  same  as the standoff distance    of a hovering GT. Or  it will need  to be placed much closer to the target asteroid (at about 59\%  of  the standoff distance of a hovering GT) if it  has the same mass as a hovering GT.   Despite such drawbacks, a displaced  orbit   simply allows  many GTs  for towing a  target asteroid.   In [2], a system of multiple gravity tractors (MGTs) flying in    halo orbits   near a target asteroid  is proposed as a viable near-term option  for  deflecting a certain class of  near-Earth asteroids such as asteroid 99942 Apophis or other  highly porous, rubble-pile asteroids. A system of orbiting   MGTs has many advantages over a single  hovering gravity tractor. They include:  its larger  total  $\Delta$V capability,   multi-spacecraft redundancy,   and   mission design flexibility  with  smaller satellites equipped with  lower-risk propulsion systems.    In this paper,  we further explore the practical feasibility of   such MGTs by investigating  the halo orbit insertion and stationkeeping control problems of  MGTs near a very  irregular shaped asteroid.  A vision-based guidance and navigation system provides  an autonomous rendezvous with a target asteroid and insert a gravity tractor  at a given position with a given velocity to initiate its orbiting phase. This paper presents the preliminary GNC design and simulation results for multiple gravity tractors near a very  irregular shaped asteroid.

[1] McInnes, C. R.,  “Near Earth Object Orbit Modification Using Gravitational Coupling,”   Journal of Guidance, Control, and Dynamics,  Vol. 30, No. 3, 2007. 

[2] Wie, B., “Dynamics and Control of Gravity Tractor Spacecraft for Asteroid Deflection,” Journal of Guidance, Control, and Dynamics, Vol. 31, No. 5, 2008. 
 

Abstract document

IAC-09.C1.10.2.pdf

Manuscript document

IAC-09.C1.10.2.pdf (🔒 authorized access only).

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