Mission Design to Binary Asteroid Systems
- Paper number
IAC-07-C1.4.05
- Author
Ms. Julie Bellerose, University of Michigan, United States
- Coauthor
Dr. Daniel J. Scheeres, University of Michigan, United States
- Year
2007
- Abstract
Over the past decade, a few robotic missions have been sent to small solar system bodies, providing a basic understanding of their environment. For future scientific investigations, rendezvous missions with small rovers now become more interesting as rovers can perform surface experiments, take surface measurements and pictures, and determine the fine scale structure of these bodies. In this paper, we look at the conditions and requirements involved in a possible mission design involving surface investigation to a binary asteroid system.
To define mission design parameters, we model a binary system taking into account the mass distribution of the two bodies, referred to as the Full Two-Body Problem (F2BP), in this case modeled as an ellipsoid-sphere system. The dynamics of a particle in such a system is referred to as the Restricted Full Three-Body Problem (RF3BP). Assuming a relative equilibrium of the binary bodies, we can map the allowable regions of motion for a spacecraft as a function of its energy. Using this technique, we discuss safe insertion orbits that encircle the binary system and approach orbits from which the spacecraft can place a vehicle on the surface. Once on the surface the rover can explore one of the binaries and eventually “hop” to the other for further exploration.
For the RF3BP, the libration point structure mimics that of the classical R3BP. With sufficiently low energy, the spacecraft could “enter” a region closer to the bodies through L 2 or L 3. This limits the probability of escaping from the system as the spacecraft could only exit from the same entrance region. We are especially interested in the case of a small ellipsoid where the Lagrangian point closest to it opens first. This case of binary system is commonly found in nature where the massive spheroidal primary usually has its own more rapid spin rate. Hence, considering a locked configuration of the bodies and a spinning primary, direct access to the small ellipsoid is the most logical approach to take.
To investigate the entire binary system surface, we define the surface conditions and possible transit trajectories between the bodies. As the gravity on an asteroid is low, a vehicle would most likely bounce back from hitting the surface; wheeled rovers might be difficult to control and keep track of. A hopper could investigate the small ellipsoid body and then travel across the L 1 region using a simple jump to investigate the massive spinning spheroidal body. For transfer between the bodies, we develop an algorithm that relates possible transfer trajectories through L 1 and surface conditions. Finally we use the binary system 1999 KW4 as a case study.
- Abstract document
- Manuscript document
IAC-07-C1.4.05.pdf (🔒 authorized access only).
To get the manuscript, please contact IAF Secretariat.