Long-term Stable Orbits for Passive Tracking Beacon Missions to Asteroids
- Paper number
IAC-09.C1.10.6
- Author
Prof. Benjamin Villac, University of California, United States
- Coauthor
Ms. Katherine (Yi-Yin) Liu
- Year
2009
- Abstract
The accuracy of the orbit determination for an asteroid orbit can be improved significantly if a spacecraft is present that can be tracked with radiometric measurements. Long-term precision tracking of an asteroids orbit can measure the effects of small forces on the asteroid orbit (e.g., Yarkovsky and YORP accelerations) and improve predictions of the future asteroid ephemeris. Such tracking could be particularly useful for characterizing an asteroid orbit that has a potential to impact the Earth. A ``beacon'' spacecraft with minimal capabilities can provide asteroid tracking for minimal cost. In the case of a potentially impacting asteroid, a beacon could be used to determine if a threat actually exists before implementing a mitigation strategy. Here, a methodology is presented for identifying spacecraft orbits near an asteroid that are stable over many heliocentric asteroid orbits _without the need for translational control_. As a results, simplified spacecraft design and reduced operations costs are achieved, making such mission very attractive. A modern numerical method developed by the authors that uses a combination of periodic orbit and chaoticity analyses to assess long-term orbit stability properties [1,2] will be applied to the example of a beacon spacecraft design at the asteroid (99942) Apophis, which currently has a non-zero chance of impacting the Earth in 2036 or 2037. This method of stability characterization allows us to deal with the challenges associated with small body orbiter dynamics (large ratio of gravitational to solar radiation pressure forces, uncertainty in the model parameters) and use realistic modeling of the spacecraft dynamics over long time intervals. Initial studies have identifies ``terminator orbits''as good candidates for beacon missions. These orbits lie in the plane orthogonal to the Sun-asteroid direciton and thus present no solar eclipses. Such orbits provide a consistent thermal environment for the spacecraft and further simplification of the beacon design. Integration over 38 years of such trajectories in realistic models around the asteroid Golevka [2] indicate the strong stability of such orbits, even under perturbations. References [1] ``Identification of Non-Chaotic Terminator Orbits near 6489 Golevka'', S.Broschart and B.Villac, Paper AAS 09-156, Proceeding of the 19th AAS Spaceflight Mechanics Conference, Savannah, GA, Feb. 2009. [2] ``Applications of Chaoticity Indicators to Stability Analysis around Small Bodies'', B.Villac and S.Broschart, Paper AAS 09-221, Proceeding of the 19th AAS Spaceflight Mechanics Conference, Savannah, GA, Feb. 2009. NOTES: These results that will be presented are original and have not been published elsewhere. One author has secured enough funding to attend the conference.
- Abstract document
- Manuscript document
IAC-09.C1.10.6.pdf (🔒 authorized access only).
To get the manuscript, please contact IAF Secretariat.