Deflection of Earth-Crossing Asteroids/Comets Using Rendezvous Spacecraft and Laser Ablation
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Deflection of Earth-Crossing Asteroids/Comets Usi ng Rendezvous Spacecraft and Laser Ablation 1 Sang-Young Park2 and Daniel D. Mazanek' Abstract Space missions are presented to deflect four fictitious Earth impacting objects by using an advanced magnetoplasma spacecraft designed to deliver a laser ablation payload. The laser energy required to provide sufficient change in velocity is estimated for one longperiod comet and three asteroids, and an optimal rendezvous trajectory is provided for each threat scenario. The end-to-end simulations provide an overall concept for solving the deflection problem. These analyses illustrate that the optimal deflection strategy is highly dependent on the size and the orbital elements of the impacting object, as well as the amount of warning time. A rendezvous spacecraft with a multi-megawatt laser ablation payload could be available by the year 2050. This approach could provide a capable and robust orbit modification approach for altering the orbits of Earth-crossing objects with relatively small size or long warning time. Significant technological advances, multiple spacecraft, or alternative deflection techniques are required for a feasible scenario to protect Earth from an impacting celestial body with large size and short warning time.
Introduction It is estimated that there are at least 1,000 Earth-crossing asteroids and comets capable of causing global environmental catastrophe upon Earth-impact, and a vast number of smaller objects capable of inflicting widespread damage [1]. The impact threat has been discussed in great depth in a wide range of publications [2]. Many methods for altering the orbit of an asteroid or comet have been proposed. A popular approach for deflecting asteroids and comets is to change their orbital velocity [3-9]. To provide sufficient energy to alter an asteroid or comet's orbit, it is usually necessary to use a spacecraft to intercept or rendezvous with the celestial 'Presented as paper AIAA-04-1433 at the 2004 Planetary Defense Conference: Protecting Earth from Asteroids, Orange County, CA, Feb. 23- 26, 2004. 2Associate Professor, Center for Astrodynamics and Space Technology, Dept. of Astronomy and Space Science, Yonsei University, Seoul 120-749, Republic of Korea. [email protected]. 3Aerospace Engineer, Spacecraft and Sensors Branch, MS 328, NASA Langley Research Center, Hampton, VA 23681, [email protected].
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object. Fast space trips are important for rapidly engaging an Earth impacting asteroid or comet, particularly those that are massive or have not been detected many years in advance. The earlier that the deflection effort begins, the less change in velocity (d V) required to alter the object's trajectory [7]. A rapid rendezvous spacecraft utilizing a multi-megawatt advanced nuclear or plasma propulsion system could be available by the year 2050. Given such a spacecraft, one deflection approach would be to physically attach to the object and thrust in the proper direction to change the impactor's o
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