IntroductionAn infrequent but significant hazard to life and property due to impacting asteroids and comets exists. Earth-approaching asteroids and comets also represent a significant resource for commercial exploitation, space exploration, and scientific research. The impact problem and those planetary bodies that could be a threat have been discussed in great depth in a wide range of publications. A popular planetary defense method is the deflection of asteroids and comets on a collision orbit with the Earth by changing their orbital velocities. It is fundamental to estimate required changes in the orbital velocities of dangerous objects to avoid a collision.A detailed optimization problem is formulated to calculate optimal impulses for deflecting Earthcrossing asteroids/comets, using nonlinear programming. The constrained optimization problem is based on a three-dimensional patched conic method to include the Earth's gravitational effects and the asteroid/ comet's orbital inclination. The magnitudes and impulse angles of optimal impulse change in velocity (∆V) are accurately computed at various points on the asteroid/comet's orbit to provide a given target separation distance. Based on these change in velocity analyses, we can establish the approximate cost and build strategies to prevent possible catastrophe due to the objects.
This paper summarizes key findings of Asteroid Redirect Mission pre-formulation concept development efforts, including mission architecture and design drivers, flight system concepts and trades, advanced solar electric propulsion component and system options, and asteroid capture option trades and risk reduction efforts. This paper also provides a summary of concept development findings with a focus on extensibility to future mission applications and risk reduction and early testing of astronaut extra-vehicular activities.
Abstract-The Constellation Program Architecture Team and the Lunar Surface Systems Project Office have developed an initial set of lunar surface buildup scenarios and associated polar outpost architectures, along with preliminary supporting element and system designs in support of NASA's Exploration Strategy. The surface scenarios are structured in such a way that outpost assembly can be suspended at any time to accommodate delivery contingencies or changes in mission emphasis. The modular nature of the architectures mitigates the impact of the loss of any one element and enhances the ability of international and commercial partners to contribute elements and systems. Additionally, the core lunar surface system technologies and outpost operations concepts are applicable to future Mars exploration. These buildup scenarios provide a point of departure for future trades and assessments of alternative architectures and surface elements. 1 2
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