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Mission Extension Using Sensitive Trajectories and Autonomous Control (contd)
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| This proposal represents a continuation of a current funded proposal from AISRP. The goal is to show how dynamically sensitive trajectories about a planetary body, eg the Moon, can substantially reduce the fuel required to stay in orbit for extended periods of time. The trajectories move in a region about the Moon which supports chaotic motion where the spacecraft is between capture and escape about the Moon. It has been demonstrated by this proposer that a tiny delta V will stabilize the motion and where the spacecraft can orbit the Moon for several months with negligible delta V. Two spacecraft used this proposers trajectory design to demonstrate this motion about the Moon - Japan's Hiten in 1991 and ESA's SMART-1 in 2004. The current work by this proposer has made significant progress in his current research supported by AISRP showing how small the delta V can be to maintain the motion about the Moon with a simple trajectory control. An interesting discovery was recently made to show that the inclination of a spacecraft moving in this way can be changed from 0 to 180 degrees for nearly zero delta V. This 'free' inclination change has enormous potential to be further studied since it takes a lot of delta V and hence fuel to change inclination by conventional means. Also, it is being proposed to fully design an optimal orbit control algorithm that can keep the spacecraft in motion about the Moon for very long periods of time for almost no delta V. The current effort can only touch on this. After an algorithm is developed, it can be programmed into a program to give the spacecraft an autonomous capability to maintain its motion about the Moon.
This capability can give extended mission duration which will enable the spacecraft to mine substantially more data than previously for the same amount of fuel. In fact, less fuel could be stored on the spacecraft thereby reducing its size and mass.
There are two approaches used to see how to substantially reduce the delta V for control: The first is to perform a tiny delta V when the spacecraft is captured at the Moon in the chaotic region to stabilize it with minimal fuel. Then the trajectory is followed to see how it becomes unstable, and where it is best to perform another delta V. This process is continued. The second approach is to perform an analysis of the dynamic nature of the instability of the motion from a mathematics perspective to better understand it. This approach uncovers surfaces where the spacecraft will go to and follow when it becomes unstable (called invariant hyperbolic manifolds). These two approaches taken together enable algorithm definition.
The objectives of this proposal are significant since they
1. Enable autonomous operations of a spaceraft in motion about a planet
2. Data mining is substantially enhanced due to extended motion about the planet for much longer periods of time than using standard orbital mtion
3. The discovery of the ability to perform inclination changes for negligible delta V has enormous implications since by standard methods, inclination changes require a lot of fuel
4. Autonomous motion about the Moon for little delta V and to perform inclination changes for little delta V has important applications for returning to the Moon by substantially reducing the cost of orbital operations. |
Bibliography
| | Low Energy Motions in the Earth-Moon System, Chaos, and Weak Capture
Proceedings of the NASA NSTC, June 2007 (see http://esto.nasa.gov/conferences/nstc2007)
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| A New Class of Low energy Lunar Orbits And Mission Applications
New Trends in Astrodynamics and Application III, edited by E. Belbruno, American Institute of Physics, AIP Conference Proceedings, Volume 886 (Proceedings of the 2006 New Trends in Astrodynamics Conference and Applications), pp 3-19, 2007.
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| The Angel that Flew to the Moon
New Scientist, Turning Point Column, pp 51, February 24, 2007
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| Fly Me to the Moon: An Insiders Guide to the New Science of Space Travel
Princeton University Press
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| Fly Me to the Moon: An Insiders Guide to the New Science of Space Travel
Book
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| Low Energy Trajectories and Chaos: Applications to Astrodynamics and Dynamical Astronomy
New Trends in Astrodynamics and Applications:An International Conference, edited by E. Belbruno, New York Academy of Sciences, Volume 1065 (Proceedings of the 2005 New Trends in Astrodynamics Conference and Applications), pp 1-14, 2005.
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| Reduction of Lunar Landing Fuel Requirements by Utilizing Lunar Ballistic Capture
New Trends in Astrodynamics and Applications:An International Conference, edited by E. Belbruno, New York Academy of Sciences, Volume 1065 (Proceedings of the 2005 New Trends in Astrodynamics Conference and Applications), pp 139-151, 2005. (co-author M.D. Johnson)
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| Existence of Chaos Associated with Weak Ballistic Capture and Applications
Astrodynamics, Space Missions, and Chaos, edited by E. Belbruno, D. Folta, P. Gurfil, New York Academy of Sciences, Volume 1017 (Proceedings of the 2003 New Trends in Astrodynamics Conference and Applications), pp 1-10, 2004.
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| A Low Energy Lunar Transportation System Using Chaotic Dynamics
Advances in the Astronautical Sciences, edited by K. Howell, et al, Volume 123 (Proceedings of the 2005 AAS/AIAA Astrodynamics Specialists Conf., Lake Tahoe), pp 2059 2066, 2006.
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