An analysis of some methods of asteroid hazard mitigation for the Earth

Ивашкин, В. В.; Смирнов, В. В.

doi:10.1016/0032-0633(94)00225-g

Cited by 26 publications

(10 citation statements)

References 1 publication

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“…The idea of sending a spacecraft to impact against an asteroid has been found as one of the most efficient methods for deflection [20,21]. The design of the interplanetary trajectory in this case will aim at obtaining the maximum performance index Jx f ; t f as given by Eq.…”

Section: A Kinetic Impactormentioning

confidence: 99%

Optimization of Interplanetary Trajectories for Impulsive and Continuous Asteroid Deflection

Izzo

2007

Journal of Guidance, Control, and Dynamics

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The chaotic dynamic of near earth objects and our limited knowledge on the asteroid population makes it impossible to predict the next impact of an asteroid with our planet. The collision at Jupiter of the comet ShoemakerLevy 9, the more recent discovery of the asteroid 99442 Apophis, and other similar events, have stimulated the discussion on our capabilities of deflecting an asteroid in collision route with Earth. We propose a simple expression to evaluate the merit of a given deflection strategy. We then specialize the derived analytical expression in the special cases of a kinetic impactor and of a long duration thrust deflection. We then study two examples. The first deals with a massive spacecraft equipped with an advanced low-thrust propulsion system. We show, fictitiously, that it is convenient to send such a spacecraft to impact the asteroid rather than to rendezvous and push it. In the second example, we solve the optimal interplanetary trajectory problem to deflect the asteroid 99942 Apophis. We find that several optimal interplanetary trajectories exist that allow a 750-Kg spacecraft to be launched from 2015-2026, and impact 99942 Apophis allowing prekeyhole deflections of orders of magnitude larger than the likely required amount. Nomenclature At= deflection strategy a = asteroid semimajor axis f = focusing factor gt = gravitational and disturbance forces acting on the asteroid i v = velocity unit vector i p = unit vector inertially fixed in the heliocentric frame M = mean anomaly m = mass m c = fuel mass available at asteroid rendezvous N = number of available observations n = mean motion p = asteroid momentum Q = function of the squared residuals used to define the virtual asteroid R E = Earth orbit radius t = encounter time t c = coast time t p = deflection duration or push time t s = time to encounter when the deflection starts

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Section: A Kinetic Impactormentioning

confidence: 99%

Optimization of Interplanetary Trajectories for Impulsive and Continuous Asteroid Deflection

Izzo

2007

Journal of Guidance, Control, and Dynamics

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“…However, this strategy can easily control motion of an asteroid/comet because it has many opportunities to choose the direction and time of impulse application (ref. 3). Kinetic deflection and nuclear detonation demand much less "cost" than the propulsive mode and, consequently, require much less initial mass for deflection missions (ref.…”

Section: Introductionmentioning

confidence: 99%

Mission Functionality for Deflecting Earth-Crossing Asteroids/Comets

Park

Mazanek

2003

Journal of Guidance, Control, and Dynamics

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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.

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“…The scientists' promotion of the impact threat shared this assumption of technological progress. Like the US Air Force study, their technical papers on mitigation systems considered speculative technologies such as solar sails and mass drivers as well as more established explosive technologies (e.g., Ahrens and Harris, 1992;Melosh and Nemchinov, 1993;Ivashkin and Smirnov, 1995;Gritzner and Kahle, 2004).…”

Section: The Narrative Imperativementioning

confidence: 99%

Colliding Worlds

Mellor

2007

Soc Stud Sci

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Over the past twenty years a small group of astronomers and planetary scientists have actively promoted the idea that an asteroid might collide with the Earth and destroy civilisation. Despite concerns about placing weapons in space, the asteroid scientists repeatedly met with scientists from the Strategic Defense Initiative to discuss mitigation technologies. This paper examines the narrative context in which asteroids were constructed as a threat and astronomy was reconfigured as an interventionist science. I argue that conceptualising asteroids through narratives of technological salvation invoked a 'narrative imperative' which drew the astronomers towards the militaristic endings that their stories demanded. Impact-threat science thus demonstrates both the ways in which scientific research can be framed by fictional narratives and the ideological ends which such narratives can serve. They foretell a large impact causing global fires, the failure of the world's agriculture and the end of human civilisation. But, these scientists assure us, we live at a unique moment in history when we have the technological means to avert disaster. They call for support for dedicated astronomical surveys of near-Earth objects to provide early warning of an impactor and they have regularly met with defence scientists to discuss new technologies to deflect any incoming asteroids.The scientists who have promoted the asteroid impact threat have done so by invoking narratives of technological salvation -stories which, like the Strategic Defense Initiative (SDI), promised security through a superweapon in space. The asteroid impact threat can therefore be located within the broader cultural history of fantasies about security and power which Bruce Franklin (1988) has argued is inextricably linked to the century-old idea that a new superweapon could deliver world peace. Howard McCurdy (1997: 78-82), in his study of the ways in which the US space programme was shaped by popular culture, has suggested that the promotion of the impact threat can be seen as the completion of Cold War fantasies which had used a politics of fear to justify space exploration. McCurdy highlights the alignment between the promotion of the impact threat and works of fiction.In this paper, I consider the reconceptualisation of asteroid science which this alignment entailed.It is beyond the scope of this paper to give a complete history of the science of planetary impacts. My focus is on how a group of scientists moved from seeing impacts as significant events in Earth history to seeing them as threatening events in the human future -a move from historical to futurological narratives. Nor is there space to give a full account of the empirical developments which were used to support the construal of asteroids as a threat. Rather, I wish to make the case that these empirical developments were given meaning within a specific narrative context which drew civilian astronomers into contact with defence scientists, especially those working on SDI.

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An analysis of some methods of asteroid hazard mitigation for the Earth

Cited by 26 publications

References 1 publication

Optimization of Interplanetary Trajectories for Impulsive and Continuous Asteroid Deflection

Optimization of Interplanetary Trajectories for Impulsive and Continuous Asteroid Deflection

Mission Functionality for Deflecting Earth-Crossing Asteroids/Comets

Colliding Worlds

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