(Considered) Action Presented at the National Space Society International Space Development Conference, Washington, DC
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B612 Foundation B612 Foundation Occasional Paper 0501, May B612 125 Red Hill Circle 2005 Tiburon, CA 94920 Foundation A Call to (Considered) Action Presented at the National Space Society International Space Development Conference, Washington, DC By Russell L. Schweickart, Chairman, B612 Foundation May 20, 2005 Abstract: The purpose of this paper is to call upon the Congress of the United States to initiate, via the National Research Council or other appropriate body, a formal analysis of the circumstances presented by the close encounter between the Earth and asteroid 2004MN4 in April 2029, and the potential for a subsequent collision with Earth in 2036. Informal analysis indicates that the accuracy of our knowledge of the asteroid’s trajectory using optical and radar tracking is likely to be inadequate to make a timely deflection decision in the improbable event that one should be needed. Should this claim prove to be correct after formal analysis serious consideration should be given to placing a radio transponder on 2004MN4, perhaps as one of several scientific objectives. This mission should be launched in the near future in order to provide adequately accurate trajectory information about the asteroid by 2014, the approximate date by which a deflection mission decision, if required, would have to be made. (Author’s note1: While the primary public and policy makers. Since the data for all analyses and graphics in conversion processes utilized are this paper are obtained from official replete with subtle calculations and governmental sources the approximations the author’s first conversion of these primary data to call is to have the fundamental graphical form is the responsibility elements of the logic presented of the author alone. The conversion herein independently and of the official data to the graphical professionally verified. form herein is done primarily to make this data accessible and Unfortunately at the present time understandable to the general there is no agency of the US Government to which the issue of 1 protection of the public and property B612 Foundation, 125 Red Hill Circle, Tiburon, CA 94920. (http://www.B612Foundation.org) from the impact of near-Earth asteroids is assigned. The driver having an auto accident on secondary call of the author is any given dayiv) Due to the near- therefore to call on the US Congress center location of the 2036 keyhole to initiate a process wherein such in the error ellipse it is anticipated assignment of responsibility will be that the probability of impact will made.) gradually increase to about 1 in 3,000 over the period of the next year v. From mid-2006 through late Introduction 2012 the asteroid will be largely out of sight of the Spaceguard The near-Earth asteroid (NEA) telescopes with only two potential 2004MN4, discovered in 2004 opportunities during that time to through the efforts of NASA’s further refine its orbit. Spaceguard Surveyi, will make an unusually close pass by the Earth When 2004MN4 comes back into on April 13, 2029ii. This asteroid, view in late 2012 it is highly likely estimated by NASA’s Jet Propulsion that we will learn that it is no longer Laboratory (JPL) to be 320 meters in a threat to Earth. However there is diameter, will come within 30,000 a slim chance that we will not be km. of the Earth, passing just able to draw this conclusion and behind the Earth in its orbit but well that an impact will still be possible. within the geostationary satellite orbit. A collision with the Earth Due to the unique orbital during this 2029 close encounter circumstances posed by this has been definitively ruled out. asteroid’s close encounter with the Observers in Europe and North Earth in 2029, unusually accurate Africa, however, will be treated to an knowledge of its orbit is required in unusual sight; the opportunity to order to know, in time to take view an asteroid with the unaided protective action, whether or not it eye as it passes through the early is headed for an impact. Given that evening sky toward the just set Sun. a decision to mount a deflection mission would be required by 2014 This close encounter with Earth will in order to design, manufacture, significantly alter the orbit of the launch, and operate such a mission, asteroid and create a low, but real we are currently confronted with the possibility that the asteroid will circumstance that our best optical return to impact the Earth seven tracking will be inadequate to years later on April 13, 2036iii. The enable us to make such a probability of this impact, based on momentous decision. Using optical our current best information, is information alone, it will appear that slightly less than 1 in 10,000. the maximum probability of impact (while seemingly a low probability 1 is approximately 1 in 100, even if in 10,000 is almost identical to the the asteroid is in fact headed for a probability of the average American direct impact with Earth. Given 2 that the corollary to this probability of the probability of the event statement is that there will appear occurring and the cost of the event to be 99 chances out of 100 that the were it to occur. In this instance asteroid will miss us, launching an where the impact “path of risk” expensive deflection mission will be passes from the western Pacific problematic at best. Ocean north of Japan, along the Mexican west coast, through Central There is a possibility in January America and out into the Atlantic 2013 that we will be able to see Ocean, the most likely result of a 2004MN4 using active Earth-based collision with asteroid 2004MN4 in radarvi, albeit this is far from 2036 is a massive tsunami. The certain. If this attempt is successful societal cost of a tsunami which the accuracy of our impact would be generated by the impact of prediction will improve to perhaps 1 this asteroid is estimated to be in 50. $400Bviii. Given that the current probability of impact is 1 in 10,000 If, however, a scientific mission to the justifiable investment in current the asteroid is performed prior to action to mitigate against this 2014 our knowledge of its impact eventuality is $40M. By mid-2006 probability in 2036 will be materially the probability of impact (and with it improved. Any such mission will the justifiable investment in routinely carry with it a radio mitigation) is likely to increase by a transponder which would, by its factor of 4 and by mid-2012 by a presence, improve our knowledge of factor of 10. The cost of a $3-400M the asteroid’s orbit by approximately scientific mission to the asteroid a factor of 10 over optical would therefore be a rational and measurementsvii. In the low prudent investment in public safety. probability case that the asteroid is indeed headed for an impact, we will The analysis presented in this paper be able, with a transponder on the is, of necessity, a first order asteroid, to judge by 2014 whether a approximation only. It needs to be deflection mission is necessary. A formally investigated and refined by probability of impact of 1 in 10 competent experts. should provide a more than adequate basis for preparing a There is, however, no agency of the deflection mission. US Government whose responsibility it is to address the The question arises as to whether issue of asteroid impacts with the the expense of an immediate science Earth and the multitude of policy mission to asteroid 2004MN4 is issues raised by NEA impacts and warranted. From an economic point deflection operations. While the of view the justifiable expense to general public may assume that mitigate the cost of an undesired NASA has such responsibility this is event is determined by the product not the case; NASA has no such 3 responsibility and is, in fact, a somewhat reluctant agent in the Each of these resonant return current NEA discovery program. possibilities has associated with it a “keyhole”, a small region slightly The purpose of this paper then, further from the Earth than the based on both the specific situation resonance line per se, which would, re asteroid 2004MN4 and the should the asteroid pass through it general circumstance of no assigned result in an impact at the time of responsibility for protection of the the resonant return. The width of Earth with respect to asteroid the 2036 keyhole is approximately impacts, is to call upon the 600 meters. The critical question to Congress to act. Congress is called be answered then, in time to do upon to investigate this matter and something about it, is whether or to direct the National Research not the asteroid will pass through Council or other competent body to this narrow keyhole in space in recommend 1) appropriate action in 2029. the specific instance of asteroid 2004MN4 and 2) in the general case Another powerful effect of the 2029 an appropriate assignment of close encounter is that it separates governmental responsibility for NEA the potential deflection challenge matters. into two very different regions; a deflection prior to the 2029 encounter and a deflection The Threat afterwards. The most obvious issue here is that there are only 7 years to The basic scenario, albeit highly act between the 2029 close improbable, which might require a encounter and the potential impact deflection mission for 2004MN4, is and therefore waiting until after the entirely driven by the asteroid’s encounter to confirm the orbit, and close encounter with the Earth on then to plan and execute a mission April 13, 2029.