The Asteroid Threat

[American Patriot]

The Asteroid Threat

by Rick Donaldson
Reality Check

Filed under: US Military, Science and Technology, Survival, Astronomy
Earth’s Busy Neighborhood


Somewhere out there is a great big piece of rock, with our name on it. Oh, it’s out there, and it’s headed for us. It’s going to slam into the Earth with enough energy to devastate a small country. The problem won’t be that the country is destroyed, but the entire human race and 90% of all other life forms will be eliminated.


That piece of rock is called an asteroid, and it will have what is called an “Earth Crossing Orbit”. Regardless of your feelings and belief in “mankind”, how we were created, whether by God or by evolution isn’t really very relevant. We can, and in all probability be completely wiped from the face of this planet by such a cataclysm in the future.


Unless we do something about it.


As human beings, we don’t think really about “what’s beyond the atmosphere” on a daily basis and I’d not advocate that you lose sleep over it, however, I would advocate that you start paying attention. Oh, sure some of you will say, “The human race has been here for thousands, perhaps millions of years on this world and we’ve survived other things. So what?”


Well, it is reasonable that the dinosaurs were wiped out by just such an event, 65 million years ago. It is also just as likely that several other known extinction events occurred due directly to asteroid impacts on our world.
Nothing “devastating” has happened in our known history, but there have been impacts that occurred on this planet that are known about. For instance, Tunguska Russia, at 7:17 AM on June 30, 1908 a massive explosion occurred. The event is sometimes referred to as the Great Siberian Explosion. It wasn’t until nearly twenty years later that people went to the region to examine what happened. It is believed to have been a cometary impact, the comet exploding some distance above the ground with devastating effects.


Meteor Crater in the desert of Arizona is just over a mile across and several hundred feet deep. This even occurred around 50,000 years ago and left a gaping hole in the ground.

The rock was a nickel-iron meteor, believed to be around 526 yards across and weighed in at about 300,000 tons. We’re pretty sure there were people present on the plains of the Americas 50,000 years ago.


Both of these events may very well have been “devastating” had they been over populated cities. We really do not know if people were indeed killed in the Tunguska impact, and of course there’s no evidence of people being present during the impact that left the scar in Arizona.


Why should we “worry”? In 2029, on Friday, April 13th an asteroid will pass very close to Earth. It’s name is 2004 MN4, now called by a the grim name Apophis. Apophis for those of you not up on your mythology was also known as Apep, and is the demon of Darkness for the Egyptian Mythos. This demon or god was the opposer of light, thus eventually known in the mythos as the opposer of Ra, or light. He was evil, wont to do evil things to humans and the gods. But this is all mythology and not science.


The fact that there are some massive pieces of rock out there whirling around space in orbits that periodically cross the Earth’s orbit however, is science. Right now, there are probably less than 30 or so scientists world wide who are working on collecting data for Near Earth Asteroids (NEOs) and Potentially Hazardous Asteroids (PHAs), but they have cataloged roughly 2000 out of an estimated 25-50 thousand such objects.


The problem comes from the fact that in the last three days we’ve had not one, but two close calls. Asteroids 2007 EH and 2007 EK narrowly missed (or will narrowly miss) the Earth. Yesterda, 2006 EH was discovered just before it made a swipe as the Earth. It passed within a few Moon-diameters of the Earth, passing between the Earth and moon.


The other rock should swing past us within the next 24 hours. I ran tracks on both of these using one of NASA’s java tools, and all I can say is “Holy COW, that was close.”


I still haven’t really answered the question about “Why worry”, not precisely. We should worry because we can do something about these things. In 1865, we could have done little save stand and watch as the planet was perhaps doomed to destruction by some giant chunk of rock, that humans probably didn’t know about, couldn’t see and couldn’t do a damned thing about. Today, we not only can see them, track them and calculate the exact impact point on the planet should they have our name on them, but we can DO something about them.


We have the technology to boost dangerous, Earth orbit crossing asteroids into a different orbit, thereby protecting something extremely precious. Ourselves, and our world. I’m concerned less about myself than I am my own legacy, my children and grandchildren. My great grandparents probably didn’t think twice about what happens beyond their own generation, but we damned sure ought to be worrying about it.


America, and humankind in general stand up on a great road to the future. Our technology will in short order take us off this world, perhaps to explore Mars within 30-50 years. Beyond that, I can only guess, but human kind can preserve itself and become someday, interstellar travelers if we try hard enough. Sometimes I think people are just too bogged down standing around and waiting for something bad to happen, instead of being proactive enough to make good things happen.


So, write Congress, asking your representatives to consider funding the space program, doing something about potentially hazardous asteroids, and rocks that can doom not only the United States, but the world to a coming dark age that the human race may never recover from. Write the president of the United States. If you live in another country, then write your own governments, asking… no demanding that they take time out of their busy political schedules to actually THINK about the future of the human race.

[American Patriot]

Would The United Nations Stop An Asteroid?
Creators Syndicate ^ | February 21, 2007 | Ben Shapiro



Scientists reported this week that on April 13, 2036, an asteroid has a 1 in 45,000 chance of hitting Earth. The good news: No Tax Day, 2036. The bad news: An entire city or region could bite the dust.



"We need a set of general principles to deal with this issue," explains former astronaut Rusty Schweickart. To that end, scientists are calling on the United Nations to take action. The Association of Space Engineers will present a plan to the UN in 2009 involving the construction of a "Gravity Tractor," which would alter the course of potentially threatening asteroids.

You can just imagine what the UN member states will have to say about this idea.





IRAN: "Space is a decadent Western lie. It does not exist. Asteroids are no more real than the Zionist Entity. It is possible, however, that the 12th imam is riding this so-called space rock. In that case, we can only hope that he steers it into a large building in a major American city."



CHINA: "Such use of space simply escalates the global arms race. Who is to say that America will not construct such a 'Gravity Tractor' in an attempt to nullify our missile capabilities? Of course, we were never thinking of using such missiles anyway, but it's the principle of the thing!"



VENEZUELA: "This is a plot by the Bush administration to escape culpability for America's part in the global warming crisis. Satan W. Bush is deflecting attention from the fact that America is heating Earth up like a giant microwave. Bush is hoping that the asteroid hits Venezuela, ending the global warming crisis by blotting out the sun."



NORTH KOREA: "Kim Jong Il is the Lode Star of the 21st Century, the Master of the Computer Who Surprised the World, Power Incarnate with Endless Creativity, Guardian Deity of the Planet. Fear not, Earthlings! Kim Jong Il will save us yet. By the way, will saving Earth get Kim Jong Il a headline? He'd really like one."



SAUDI ARABIA: "This all stems from the Israeli-Palestinian conflict. We will be proposing a seven-point plan designed to create a Palestinian state."

MEXICO: "All we ask is that the prospective inhabitants of this asteroid be allowed free emergency medical care in the United States."

FRANCE: "There is nothing to worry about. When the asteroid shows up, we will provide token resistance before allowing it to roll down the Champs-Elysees. Wait, are you saying that this thing could hit the Louvre?"

CUBA: "This asteroid represents the impending victory of international communism. The exploitation of the bourgeoisie has created an underclass that will rise up in the aftermath of this glorious strike against capitalist society."



RUSSIA: "Is there any way we can sell pieces of this rock? Anybody?"

SWITZERLAND: "We will do everything in our power to prevent this asteroid from hitting Earth. Unless that means doing something. In that case, we'd prefer to stay out of it."



On September 21, 1987, President Ronald Reagan spoke before the United Nations. "Perhaps we need some outside, universal threat to make us recognize this common bond," he said. "I occasionally think how quickly our differences worldwide would vanish if we were facing an alien threat from outside this world. And yet, I ask you, is not an alien force already among us? What could be more alien to the universal aspirations of our peoples than war and the threat of war?"



It was a nice sentiment, but Reagan was mistaken. The UN would not be able to get together over something as simple and universal as the threat of an asteroid striking our planet. They would quarrel and babble; they might send a slightly perturbed radio message to the asteroid. And, in the end, the asteroid would nail us.



What hope, then, for the UN actually coming together to mitigate the threat of war by hemming in aggressive and hostile countries like Iran and Syria? The probability that one of the two nations will foment major acts of terrorism is far higher than 1 in 45,000. Yet the UN will do nothing.

The good news: We have 29 more years before we have to worry about the asteroid. The bad news: We don't have anywhere near that kind of time with our earthly foes.

[American Patriot]

Scientists investigate path of asteroid By Chris Mader Publication Date: 03/19/07 Staff Writer

Experts say an asteroid 300 meters in diameter could hit Earth in less than 30 years. There has been recent talk in the scientific community about Apophis, an asteroid discovered in June 2004. Initially, it was believed it could hit the Earth in 2029, but it's path was later recalculated. Further investigation shows that it will enter a "gravitational keyhole" and renew it's chance of hitting the Earth by 2036. Matthew Lister, assistant professor of physics, said that based on past records, an asteroid this size hits Earth about once every 10,000 years. "As far as asteroids go, Apophis is a rather small one," he said. The last encounter with an asteroid happened in the Tunguska region of Siberia in 1908 when it exploded in the atmosphere and caused a 15 megaton explosion and felled about 80 million trees. Lister says the explosive yield of Apophis could be the equivalent of 1,000 megatons of TNT. The largest thermonuclear bomb ever detonated by the United States was 15 megatons. He said if Apophis landed in a populated area, it could easily wipe out a large city. Since the Earth's surface is 70 percent water, a tidal wave is a more likely prediction, however. The majority of asteroids do not cross into Earth's orbit, but it is the few others that pose a threat. "So far, about 4,000 have been catalogued," he said. Experts said Apophis has a one in 45,000 chance of hitting Earth in 2036. But Lister says there are more asteroids waiting to be discovered. High-powered telescopes are being used to find asteroids, and in 2013, the birth of the Large Synoptic Survey Telescope will make an enormous impact in tracking these objects. Project coordinator Suzanne Jacoby said the telescope will operate in survey mode, scanning the visible sky every few nights. It will be able to address the NASA mandate to catalog Near Earth Objects larger than 140 km in diameter. In January, Google announced they will join the effort. Jacoby said "Individuals at Google are working with our data management team as processing pipelines and file retrieval techniques are being designed to handle the 30 terabytes per night data rate of (the telescope)." The device will be located on top of Cerro Pach'n in Chile to maximize its viewing capacity without the disturbance of light. "Ironically, light pollution from cities on Earth is making it more and more difficult to spot these objects with telescopes," said Lister. "Many of the closest close calls we've had with asteroids have actually been spotted after they've passed by the Earth, which is a sobering thought."

[American Patriot]

Independent Analysis of Alternatives To Divert a NEO on a Likely Collision Course With Earth
STATUS REPORT
Date Released: Monday, March 19, 2007
Source: B612 Foundation

19 March 2007

Mr. Michael Griffin
Administrator
National Aeronautics and Space Administration
300 E St. SW
Washington, DC 20546

Dear Mike:

Based on our recent email exchange and your invitation to, "Send us your specific criticisms, or come in and talk, either way, and we will hear your concerns, and respond" I have put together an independent analysis for your consideration.�

What I attach is approximately a parallel analysis of the various alternatives for diverting a threatening NEO to that which NASA submitted to the Congress. In it I provide the basic logic and resultant conclusions and then juxtapose them with the NASA response commenting on why the apparent difference.

Without having access to the NASA Final Report (2006 Near-Earth Object Survey and Deflection Study) there is little more I can do to identify the actual source of the differences. Your team, perhaps in consultation with outside experts, can examine what I present here and decide whether or not the bases for the different conclusions justify any changes in the NASA report.

A few words re what is covered. Neither I personally nor B612 Foundation in general have any specific knowledge of the life cycle cost numbers used in the first portion of the NASA Report to Congress (options for meeting the 140 meter Spaceguard goal) and hence I have little to offer for this section of the Report. The only observations of note are, 1) that the life cycle costs for most of the alternatives considered exceed the equivalent life cycle cost estimates made in the August 2003 NASA SDT report, Study to Determine the Feasibility of Extending the Search for Near-Earth Objects to Smaller Limiting Diameters by a factor of over 2, and 2) that the Venus-like orbiting IR telescope is undervalued in that quite separate from meeting the Congressional 140 meter discovery goal, such an asset dramatically improves the discovery and tracking of the most challenging NEO cohort, those objects in Earth-like orbits and the Aten class of objects in general. Without an interior-orbit telescope there will be large, even decade-long dropouts in the critical tracking information so necessary for deflection decision-making.

The subject of my analysis is the third charge issued by Congress, an "analysis of possible alternatives that NASA could employ to divert an object on a likely collision course with Earth". In my analysis, with limited time and resources, I have had to make a number of what I believe to be reasonable assumptions. You will note throughout the use of phrases such as "for the purposes of this analysis" and the like. The specific results are therefore of necessity approximate. However the differences evident between my conclusions and those appearing in the Congressional Report are not due to these approximations but to basic differences in approach and to apparent disregard (or misunderstanding) of critical information presented to NASA in the White Papers presented in the NEO workshop conducted in Vail, Colorado in June 2006.

The attached analysis is my own and is not a B612 Foundation product. While many of the points I make in this analysis, perhaps most, are shared by colleagues both in and outside B612 Foundation, I take full responsibility for them. I feel certain that there are errors in detail which I have not caught, but the primary findings are not dependent on minor errors, but rather on larger issues which should be openly and widely debated. This issue can have very serious consequences for the future and I strongly believe that open debate and transparency in analysis is an obligation. I am therefore making this letter and analysis available to the wider NEO "community" and I encourage you to reconsider your policy with regard to the December 2006 Final Report which is the basis for the recently submitted Congressional Report.

I am at your service re clarifying or elaborating on any aspect of this analysis. And while I cannot speak directly for them I know that many members of the extended NEO community are ready and willing to join me in addressing these and other issues of concern with the NASA Congressional Report.

Sincerely,

Russell L. Schweickart
Chairman, B612 Foundation

Encl: Independent Analysis of Alternatives

Independent Analysis of Alternatives that could be employed to divert a NEO on a likely collision course with Earth

Summary Findings:

1. There are three current NEO deflection concepts which I consider in this analysis to be essentially ready for development, testing and deployment if needed; the gravity tractor, the kinetic impactor, and nuclear explosion, in ascending order of total impulse available. I therefore limit this analysis to these available options.

# 98% of the pragmatic NEO threat can be diverted by the use of the gravity tractor and kinetic impactor concepts. I.e. 98% of the realistic threat posed by NEO impacts will require no more total impulse for diversion than is available using the combination of kinetic impactor and gravity tractor.

# The use of the sufficient capability of the kinetic impactor/gravity tractor combination is highly valued not simply because the nuclear explosion capability is excessive but because the precision of the resulting deflection provides full assurance to a concerned world public that the deflection has been successful and has not resulted in the possibility of a near-term return of the NEO.

# The statistical probability of having to resort to the use of nuclear explosives to divert a threatening NEO in the next 100 years is approximately 1 in 1000. Stated differently, the frequency at which a NEO requiring the use of nuclear explosives for diversion would otherwise impact the Earth is approximately 1 in 100,000 years. Nevertheless it is available should such an improbable need arise.

# The characteristics of the gravity tractor and kinetic impactor are such that they nicely compensate for each others' limitations. Most importantly the combined use of the kinetic impact/gravity tractor provides not only the capability to divert over 98% of the threat but also the ability to state with confidence that a NEO once deflected will not be left on a trajectory with a near term return impact.

# With the exception of testing the nuclear explosion option all three concepts should be analyzed in detail. Consideration should be given in the future to flight testing the kinetic impactor/gravity tractor combination to validate the capability and provide confidence to the world public. The further development of deflection concepts not considered in this analysis should also be encouraged.

# Attention should be given to the importance of timely decision-making. If timely decisions are not made when a NEO threat arises the window of opportunity for the use of non-nuclear means for deflection can irrevocably be passed thereby leaving the world with the Hobson's choice of using nuclear explosions in space for deflection or taking the chance of a devastating impact. This timing challenge applies even for the case of very small NEOs.

# Considerable information characterizing the nature of the NEO threat is available in the current Spaceguard Survey database and should be extracted from it to more fully understand both the frequency of resonant return impacts and the decision timing challenge in the light of episodic tracking opportunities.

Definitions, abbreviations, etc.

For the purpose of this analysis I will use the following terms for brevity.

Congressional report - The Near-Earth Object Survey and Deflection Analysis of Alternatives, Report to Congress., March 2007

Final report - 2006 Near-Earth Object Survey and Deflection Study, Final Report, Dec 2006 (internal distribution only, access denied to public and outside experts)

KI - kinetic impact or kinetic impactor; a deflection method utilizing the energy and momentum of a spacecraft directly impacting a NEO to achieve a change in its orbit.

GT - gravity (or gravitational) tractor; a deflection method utilizing the mutual gravitational attraction of a spacecraft "hovering" immediately in front of or behind a NEO to affect a desired change in its orbit.

Nuclear - any deflection method using a nuclear explosion to affect a desired change in the orbit of a NEO.

Beta - the multiplier of the KI impact momentum resulting from the ejecta of NEO material from the NEO surface. Based on data presented at the recent PDC07 (AIAA Planetary Defense Conference) I will conservatively assume the value range of 4 +/- 2 for this key variable.

Total impulse - the change in momentum required to deflect a NEO or the momentum change available from any given deflection method. (units; kg-m/s or Ns)

PoR - the Path of Risk. The narrow corridor across the face of the Earth within which a specific NEO will impact IF it does indeed collide with the planet.

PDC07 - The recent (5-8 Mar 07) AIAA Planetary Defense Conference held in Washington, DC

The world - this phrase is used as a proxy for the yet to be determined process by which nations will ultimately chose what action is appropriate in consideration of a NEO threatening an impact. As in "the world will not likely opt to "take the hit" for objects of Tunguska size."

Pragmatic threat - that range of NEOs which the world will likely opt to deflect, assuming prior knowledge of a potential impact and the capability for deflecting it. This definition of NEO threat breaks strongly from the actuarial risk which is heavily biased toward the largest undiscovered NEOs. The pragmatic threat is characterized by the observation made at PDC07 that "a hit is a hit is a hit" vs. the actuarial measure of annualized lives lost globally. As pointed out by Alan Harris at PDC07, in an actuarial sense the annualized lives lost will always be dominated by that fractional large NEO that has not yet been discovered.

What deflection concepts are available and should be considered?

There are three concepts for deflecting NEOs which employ currently available technology and which require a minimum of additional analysis, development, and for the non-nuclear options, testing and demonstration. These three are, in ascending order of total impulse capability, the gravity tractor, kinetic impact, and nuclear explosions, and are the only three options dealt with in this analysis.

Several other deflection concepts have been put forward but these are not considered due either to the need for considerable advancement in technological capability or the requirement for specific, currently unavailable knowledge about NEOs themselves such as how attach securely to the surface of an asteroid. In this category are large space mirrors or powerful lasers for ablating NEO surface materials, the Asteroid Tugboat which attaches to and pushes directly on the asteroid, mass drivers in a variety of configurations which must also attach to the NEO and require considerable in situ construction, and suggestions of deflection by altering the coloration and thermal characteristics of the NEO surface.

Gravity Tractor Of the three concepts considered viable in the near term, the gravity tractor (GT) offers the least total impulse but imparts that limited impulse in a fully controlled manner. The gravity tractor (Nature, November 2005) must execute a full rendezvous with the NEO (velocity matching) and then actively "hover" either immediately in front of the NEO or behind it in order to either increase or decrease the NEO's velocity respectively. Since a gravity tractor spacecraft, in any configuration, will carry aboard an active radio transponder its position and velocity are very well known before, during and following the deflection maneuver. These characteristics of the GT provide a dramatic improvement in the knowledge of the NEO orbit both prior to any deflection maneuver and, if a deflection is required and performed, precise knowledge of the resultant NEO orbit.

Of note is the fact that through the use of its transponder a GT, deployed to a NEO with a high probability of impact, will discover in many instances that there is no need for a deflection. In those instances where a deflection is indeed found to be required, either the GT itself can be used to provide the required deflection, or if the total impulse required is outside its capability, observe the deflection impulse provided by a kinetic impactor (KI) and subsequently determine precisely the result and even "trim" the outcome if necessary. This synergetic use of the GT and KI offers a very powerful combination.

Kinetic Impactor The KI imparts a desired change in a NEO's orbit by crashing into it, in the desired direction and with a predetermined impact velocity and impactor mass. The change in velocity of the NEO is controlled by two factors; the momentum directly transferred to the NEO by the KI and the additional momentum provided by the mass and velocity of the NEO material ejected from the impact site per se. In many if not most

cases the ejecta component of the momentum change exceeds that due directly to the momentum transferred directly by the KI. The ratio of the total momentum realized to the momentum of the KI at impact is expressed as the parameter beta, or the momentum multiplier.

The specific value of beta for any given impact is known very imprecisely. Recent work by Keith Holsapple and others indicates that beta increases with the energy of the impactor but is highly dependent on the specific characteristics of the particular NEO being impacted. For relative impact velocities typically between 5 and 15 km/s beta appears likely to have values no lower than 2 and not likely higher than 10. For the purposes of this analysis beta is considered to have a value of 4 +/- 2. Since beta is a very powerful influence on deflection performance and its maximum value could be much higher it should be a priority for further research, both analytic and (hopefully) empirical. In summary the total impulse imparted to the NEO for a KI is equal to beta x the impactor momentum. Given that the total impulse delivered to a NEO can vary by a factor of at least 3 the resultant orbit of the NEO is uncertain. This unavoidable uncertainty in the result of the deflection is the reason a KI (or nuclear) deflection is described here as uncontrolled.

There is, as was presented at PDC07, an opportunity for the use of a series of KI impacts should the total impulse required exceed that available in a single KI mission. Nevertheless the uncertainty in the resulting NEO orbit due to the variability in beta remains whether for a single or multiple impact deflection.

A further consideration of the KI employed alone, is that since it does not rendezvous with the NEO but rather simply crashes into it, it cannot determine whether or not, in fact, a deflection is required. For this reason the European Space Agency (ESA) in the development of its Don Quijote mission, has come to believe that a precursor rendezvous mission with a transponder is needed prior to the launch of an impactor, both to collapse the uncertainty in the NEO orbit (and therefore determine whether a deflection is in fact required) and to determine post-impact the resultant NEO orbit. ESA's position is that a KI should not be used as a stand-alone but rather in combination with a precursor spacecraft which first rendezvous with the NEO and provides both pre- and post-impact precision tracking. I fully concur in this finding and see the KI as a viable deflection concept only in combination with a transponder-bearing spacecraft which plays this crucial pre- and post-impact role.

It is clear, based on the above, that the performance of the KI is considerably enhanced, both prior to and post impact, by the presence of a supporting transponder mission. Later in this analysis I show an even greater value in the KI/GT combination in the potential for the GT subsequent to the KI impact to not only determine the precise result of that impact but also to "trim" or slightly modify the deflection to insure that the NEO does not end up in an orbit with a resonant return impact within the next few decades.

Nuclear explosive The use of nuclear explosives for NEO deflection has been proposed in several forms ranging from subsurface emplacement to stand-off explosion. There are many technical unknowns about all of these configurations and I will not in this analysis attempt to delve into them. Suffice to say, for the purposes of this analysis, that while there are many unknown technical factors to be examined the nuclear explosives option offers a larger total impulse capability than any other available concept albeit with a very high uncertainty as to the momentum transfer achieved. Once again, as with the KI, the deflection is uncontrolled with considerable uncertainty in the post-deflection NEO orbit. Whether a stand-off GT could be used to serve both the pre- and post-deflection functions listed above for the KI would depend on it being able to survive the nuclear explosion itself.

The other obvious considerations re the nuclear option are the international legal prohibitions and the world-wide public concern with most things nuclear and especially weapons. The challenge of obtaining widespread international agreement that a nuclear explosion should be used in deflecting a NEO will be daunting, to understate it. Nevertheless, if the world is unable to come to agreement in time to utilize a non-nuclear deflection method the final option, due to its greater total impulse capability, will be nuclear. The ultimate alternative to using a nuclear device for diverting a NEO is "taking the hit". This is an ominous choice given the psychological and physical implications of mass evacuations, refugees, destruction of infrastructure and the like. This reality should put strong emphasis on the world dealing early with the challenge of making timely NEO deflection decisions.

JUXTAPOSITION with NASA's Congressional Report

The conclusions in NASA's Congressional Report regarding the technological readiness and costs of a variety of deflection concepts appear to be seriously flawed. Without access to the Final Report however it is not possible to specifically examine the basis for these judgments. The primary differences between this analysis and NASA's are the more limited set of deflection concepts considered (I consider only those which I believe will be available for use within the next several decades), and the extreme underestimate of the technological readiness level and equally extreme overestimate of the cost of the gravity tractor. While not available for detailed review without access to the Final Report, it appears from graphics shown briefly during PDC07 that the Report has erroneously equated the GT concept with the extremely expensive and technically immature Prometheus spacecraft. (NASA cancelled this program two years ago, largely for run-away cost reasons) The GT concept, as presented in NASA's NEO Workshop held in Vail, Colorado in June-July 2006, is adaptable to any size spacecraft and was specifically presented and evaluated in White Paper 42 (the only professional paper presented on the gravity tractor) based on NASA's Deep Space 1 spacecraft flown successfully from 1998-2000 and costing (based on the official NASA website, http://nmp.nasa.gov/ds1/quick_facts.html) $149.7 million (FY 95-99). Given that the presentations at NASA's Vail Workshop explicitly presented and evaluated the GT concept based on the Deep Space 1 mission technology, and not on the cancelled Prometheus, it is mystifying why, in NASA's Report to Congress the GT was presented as technically immature and extremely costly. Without access to the Final Report it cannot be stated with certainty but it appears that NASA inappropriately used the low technological readiness level and extreme cost of the cancelled Prometheus spacecraft as a proxy for the GT. In this analysis I use the GT as it was presented to the NASA study team in the NASA NEO workshop in Vail, Colorado.

What is to be deflected?

In order to analyze the efficacy of any NEO deflection method one must first determine or define the challenge being addressed. In this instance it is the range of total impulse required to deflect the NEOs most likely to trigger a deflection decision.

The bottom of this range is assumed herein to be a Tunguska-like NEO based on the assumption that nations, knowing that a Tunguska class object is threatening an impact, and knowing that the means to deflect it are available, will not sit idly by and "take the hit". While the consequences of such an impact are, from an actuarial point of view, not likely to kill many people, the public presumption will be that the NEO will impact in the worst possible spot along the PoR where it crosses the territory of concern. For many of these small NEOs the PoR will not have resolved to a specific local area, let alone a point, by the time a decision to deflect it will have to be made. The image of Tunguska entering over London vs. Siberia will not be dispelled by probabilistic assurances of how unlikely it would be that any particular city would be located at "ground zero".

From recent work by Mark Boslough of Sandia National Laboratory presented at PDC07 the most likely impact energy of the Tunguska asteroid is ~ 5 MT. His impressive simulations indicate that due to a finite "pancake" form (vs. a point source) of the NEO, and its downward momentum, past analysis of damage done on the ground at Tunguska has been overestimating the impact energy by a factor of 3 to 4. Further consultation with Alan Harris convinces me to use 5 MT as the current best estimate of the Tunguska impact energy.

Using Alan Harris' most recent analysis of the size-frequency plot for NEOs we see (Fig 1) that a 5 MT impact energy equates to a NEO 45 meters in diameter with an impact frequency of just under 1 in 1000 years. The population of objects this size is estimated at 400,000 according to the most recent size-frequency plot.

[note: The best estimate of the size-frequency distribution of NEOs is judged (by Alan Harris and others) to be represented in Fig. 1 by the observations below the constant power law line (long blue dash) which Harris believes best represents the actual size-frequency distribution. For this reason I have conservatively chosen to use the "dip" vs. the constant power law distribution in this analysis. Were I to use the constant power law line the population of Tunguska-like NEOs would be over 1 million (vs. 400,000) and the frequency of impact 1 in 500 years (vs. 1 in 1000 years)]

With this defining the lower bound for the analysis of total impulse required, I then determine the upper bound of the most likely 99% of NEOs to be deflected by decreasing the population by two orders of magnitude (i.e. 4,000) which corresponds with a 400 meter diameter object with an impact energy of 3500 MT and an impact frequency of just under 1 in 100,000 years.

99% of the pragmatic threat then originates with objects between 45 and 400 meters in diameter, and it is heavily skewed toward the much larger numbers of the smallest objects.

JUXTAPOSITION with the NASA Congressional Report:

The Congressional report assumes a set of 7 challenging cases (1A through 6) which are highly improbable if one considers the most likely deflections to be called for. All but the Apophis 1A & 1B cases (addressed below) lie within the least likely 10% of potential NEO impacts that statistically threaten the world. My analysis determines the most likely 99% of NEOs to call for deflection and evaluates the deflection options against this challenge.

The Congressional Report presentation of the Apophis 1A and 1B scenarios is, on plain reading of the description, erroneous. It is likely that the Full Report goes into greater detail in the definition of these scenarios, but absent access to it no detailed critique can be made. However, in addressing the Apophis case de novo, it is an extremely moderate deflection challenge and lies well within the capability of the most modest GT. Furthermore, in employing a GT for such a deflection the uncertainty in the outcome of the deflection is very low due to the transponder availability on the GT. Therefore a deflection resulting in a 2036 Earth miss distance of 3 Earth radii (from the geocenter) is more than adequate to reach a collision probability in 2036 of less than e-6.

The selection of scenarios used in the NASA Congressional Report drive the conclusions. It would seem to go without question that if one selects for the evaluation scenarios exceptional challenges (challenges requiring exceptionally high total impulse) then the inevitable conclusion will be that nuclear explosions are the preferred response. Clearly this is circular reasoning and the basis for the selection of hypothetical scenarios must be examined. In this analysis I identify what I believe to be the minimum sized NEO likely to trigger a deflection decision and then extend the analysis to include the deflection of NEOs 100 times less frequent, i.e. the most likely 99% of deflections likely to be called for. Nuclear explosions may be needed in certain extreme and unlikely circumstances, but excessive force is not to be valued when more than adequate and far less controversial means are available. The nuclear option should be the choice of last resort.

What is the range of total impulse required for deflection of the pragmatic threat?

The lower bound is defined by the smallest NEOs of concern; those ~45 meters in diameter. The mass of such an object is roughly 130,000 metric tons. The total impulse required for deflection requires mass to be multiplied by the change in velocity needed to divert the object, and this number is highly variable, depending on the circumstances. In this portion of the analysis I will consider only the case of a direct impact with Earth, i.e. no intervening close gravitational encounter between the discovery of the threat and the nominal impact. The very powerful effect of such close gravitational passes on the velocity change required for deflection of a NEO will be dealt with separately below.

The velocity change required in a direct impact is strongly dependent on the time between the deflection maneuver and the nominal impact and somewhat weakly dependent on the particular orbit of the NEO. The goal of the Spaceguard Survey is to provide the world with "decades of early warning" of a pending impact and for the purposes of this analysis I will assume that a deflection will be executed 10-20 years prior to impact. Considering the change in velocity required for several known cases (Apophis and 2004 VD17) I will consider, for this analysis, the typical delta v required for each Earth radius of deflection to be 0.1 - 0.3 cm/s, and therefore use the average of 0.2 cm/s as representative.

The lower bound then on the total impulse for deflecting the smallest objects considered is approximately 2.6e5 kg-m/s per Earth radius of deflection. The comparable value for NEOs 100 times less likely to impact Earth, i.e., those ~400 meters in diameter is 1.8e8 kg-m/s. The remaining cohort of NEOs larger than 400 meters (i.e. less than 1 % of the pragmatic threat) are simply considered to require greater than this total impulse.

What is the range of total impulse available using the two non-nuclear deflection methods?

The GT performance is dependent on the mass of the GT spacecraft and the distance at which it hovers ahead of or behind the NEO center of mass. For the purposes of this analysis I will consider only a very modest GT based primarily on hardware already flown and tested, specifically the Deep Space 1 mission of 1998-2001. Assuming the spacecraft mass at 1 metric ton and hovering at 1.5 NEO radii above the center of mass of a 45 meter diameter NEO, I arrive at a total impulse applied of 658 kg-m/s per day, or a deflection period of 395 days to cause the NEO impact point to be displaced by 1 Earth radius. Since an actual deflection will need to be targeted to miss impacting the Earth by 3 or more Earth radii (see below), the minimum sized asteroid of concern would require a 1 metric ton GT to "tow" it for more than three years to accomplish a deflection. This is then a marginal case.

For a KI the calculation is simple but leaves one with a large uncertainty. A one metric ton KI with a relative velocity at impact of 15 km/s will impart a direct momentum transfer of 15e6 kg-m/s. Assuming a nominal beta of 4 this results in a nominal total impulse capability of 6e7 kg-m/s or a range of 3-9e7 kg-m/s. Translated this results in a more than adequate capability to deflect a 45 meter NEO or, at the upper end of the distribution the need for 6 KI impacts of this capability to deflect a 400 m NEO by 3 Earth radii assuming a minimum value of 2.0 for beta

I assume, albeit without any specific evidence or knowledge, that some form of the nuclear option may be able to divert a 400 meter object with a single explosion. In any event, whether single or multiple nuclear explosions are required the end result will be a priori highly uncertain. Furthermore whether or not this can be accomplished without fragmentation of the NEO is an unknown requiring further study.

Targetting considerations

A key question to be answered is what should the end target be when deflecting an asteroid? The worst case challenge is if the nominal impact point for the NEO of concern is located at the midpoint of the PoR.. the locus of potential impact points across the Earth. A deflection of 1 Earth radius, assuming the PoR lies near the equator would cause the deflected NEO to skim the Earth's atmosphere.

Clearly this is an unacceptable lower bound for a deflection. More realistically one would want to deflect a threatening NEO to take it outside the Roche limit, the minimum distance at which the asteroid would not fragment into several pieces. While the calculation of the Roche limit is a complex one a value of 2.5 Earth radii from the geocenter is roughly correct. Therefore for the purposes of this analysis a reasonable minimum target for the NEO miss distance will be assumed to be 3 Earth radii from the geocenter.

Conclusion re NEOs on a direct impact course

For NEOs on a direct impact trajectory the GT is inappropriate for use with even the smallest NEOs (45 meters) in the pragmatic threat cohort. Were a GT to be used to deflect a 45 meter NEO to a distance of 3 Earth radii it would require a deflection duration of 1185 days or 3.25 years.

The KI method, using a single KI, would however be adequate for NEOs up to 220 meters in diameter using the nominal value of beta or objects of 155 meters diameter using the minimum value of 2. Multiple KI impacts could extend this capability.

In conclusion then while the GT is impractical for diverting any asteroids of concern on a direct impact trajectory with Earth, the KI can deflect objects up to 155 meters in diameter with a single impact and the minimum value of beta. If one considers multiple impacts it would require 3 in order to successfully deflect a 225 meter asteroid by 3 Earth radii with a beta of 2.0. Were a beta of 6.0 assumed a single KI impact could deflect a 225 meter NEO by 3 Earth radii or, with three impacts, a 325 meter NEO.

These performance numbers result in a single KI mission of 1 metric ton and relative velocity at impact of 15 km/s and a minimum beta value of 2 being able to deflect by 3 Earth radii 97% of the pragmatic NEO threat with a single impact or 98% with three impacts. If a NEO in the largest 2% of the pragmatic threat were to threaten an impact a nuclear explosive may have to be used.

JUXTAPOSITION with the NASA Congressional Report:

6 of the 7 "hypothetical scenarios" of NEO impacts used in NASA's Congressional Report require greater total impulse for deflection than is available using the highest beta KI deflection. In this analysis, using the pragmatic threat cohort of NEOs all but approximately 1% of the threat can be deflected by use of a 1 metric ton KI with a relative impact velocity of 15 km/s.

How is this analysis affected by taking into account resonant return trajectories and associated keyholes?

This issue, dealt with specifically in White Paper #39 presented at NASA's NEO workshop in Vail, has a very powerful influence, not only on the total impulse required to deflect an incoming NEO, but also on deflection targeting and the ability of a deflecting agency to assure the world that the deflection has been successful. For reasons not evident in the Congressional Report it appears that none of these influences were taken into account in the NASA analysis.

Resonant returns and their associated keyholes are defined by the NEO returning to the impact intersection an integral number of years later if it passes through the keyhole. E.g. for the asteroid Apophis, which will make a very close pass by the Earth on 13 April 2029 there is a keyhole close to its point of closest approach to the Earth such that if it passes within that very narrow region (in this case 600 meters wide) it will end up in an orbit with a period of 426.125 days and therefore return 7 years later (6 Apophis orbits around the Sun) and impact Earth.

If one looks at the NEOs with a non-zero probability of impacting Earth and travels backward in time from the potential impact one finds that in many cases there is a prior close pass by the Earth which sets the asteroid onto a course leading to the potential impact. The potential impact of Apophis in 2036 is such a case. In this instance if Apophis were to impact the Earth in April 2036 it would first have had to pass through the 7/6 keyhole as it passed the Earth in 2029.

The good news about keyholes is that if one deflects a threatening NEO prior to it passing through the keyhole the total impulse required to insure that it misses the Earth is reduced by orders of magnitude. Just how much lower the required total impulse is for deflection depends strongly on the specific orbital dynamics but it commonly ranges from 1 to 4 orders of magnitude and occasionally more, such as in the case of Apophis.

The effect of this is that for threatening NEOs that must pass through a keyhole prior to impact considerably less total impulse is required for deflection in order to avoid an impact, provided the deflection is performed prior to keyhole passage. E.g. while a 1 metric ton GT cannot deflect a small 45 meter diameter NEO on a direct impact trajectory in less than approximately 3 years, it can deflect the 280 meter Apophis in less than 40 days.

The relevant question then is what percentage of the population of Earth impactors will have first had to pass through a keyhole prior to impact, and how great a reduction in total impulse required for deflection is realized? Unfortunately the answer to this question is not known, though data mining of the current NEO database could provide us an excellent statistical answer. This research should be done but it is not on NASA's work plan primarily because no one is currently funded to work on the issue of deflection in the NASA/JPL program.

What can be said however is that the incidence of close prior encounters with the Earth prior to impact (another way of saying passage through a keyhole) are not uncommon and may range up to 30% of cases or higher. Again, for the purposes of this analysis the fraction of these instances is assumed to be 30%.

Integrated into this analysis this factor reduces by 30% the number of NEOs which otherwise would require a nuclear explosion for deflection making them available for deflection by either the GT or KI. Indeed it further translates into a number somewhat below 30% of the entire pragmatic threat that are available to the GT alone, e.g. Apophis.

In summary the cohort of NEOs in the pragmatic threat category that can be deflected by non-nuclear means exceeds about 98% and many of them can be deflected by the GT alone.

JUXTAPOSITION with the NASA Congressional Report:

The NASA Congressional Report makes no specific mention of resonant returns or keyholes. The only implied recognition of their existence is found in "hypothetical scenario" A (Apophis) which uses the phrase "before its close approach to Earth in 2029" in describing the case. This in combination with the low total impulse required for Example A2 in Figures 4 and 5 leads one to the conclusion that this case assumes a predicted keyhole passage and a deflection prior to that event. The scenario then specifies however that Apophis must be deflected by 5 km to achieve a probability of collision less than e-6. The basis for this targeting goal (the only targeting addressed in the Report) is presumably contained within the NASA Final Report, but not available here for analysis. However, if taken as the deflection targeting miss distance (from the center of the 2029 keyhole) this requirement would result in a miss distance in 2036 of 17 Earth radii! Given that the Roche limit is at approximately 2.5 Earth radii and a very precise deflection of Apophis can easily be accomplished using a 1 metric ton GT (~a 40 day deflection maneuver), a deflection to 3 Earth radii is more than adequate. If, on the other hand, an uncontrolled deflection with a substantial uncertainty re the final Apophis orbit is assumed then, depending on the specific assumptions used the 17 Earth radii miss distance may be necessary.

In other words, if one assumes that the GT is not used for the A2 case and that it is not available to trim an uncontrolled deflection by either a KI or nuclear explosion, then the uncertainty in the result of the deflection may well require a very large targeted miss distance. However a very modest 1 metric ton GT can precisely deflect Apophis prior to its keyhole passage with a target of only 3 Earth radii. This is completely missed in the Congressional report.

Further implications of resonant returns and keyholes

One further consideration alluded to earlier is the issue of keyholes along the deflection path and their significance for uncontrolled deflections.

If one considers any deflection by a KI and assumes that the minimum value of beta is used to target the deflection so that the entire range of possible results lies at 3 Earth radii or greater, then clearly the outer limit of possibilities ranges out to 9 Earth radii. Along that very long path between 3 and 9 Earth radii lie thousands of resonant returns and keyholes through any one of which, albeit with low probability, the deflected NEO may pass. A significant percentage of these keyholes have uncomfortably short return times and, in the limit, can result in return impacts in less than 5 years.

Unless some means is employed to insure that a deflected NEO has not been "dropped" into one of these keyholes the world may find itself having avoided one impact only to have caused there to be another even more challenging impact by the same NEO. Despite the probability of this risk being fairly low (again, this can and should be specifically analyzed) without some means to positively control the deflection the best that can be said is "Yes, we deflected the NEO and it probably will not come back". However, when dealing with the world public, especially after the anxiety surely to have accompanied the initial deflection, to not be able to assure positively that it was not dropped into yet another keyhole will certainly be difficult for the world to accept.

For this reason it is highly desireable that any uncontrolled deflection be immediately followed by a precise determination of the result and a means to adjust the deflection to avoid all keyholes if necessary.

Both of these conditions can be met with the combination of KI/GT. I.e. if a GT is always used as the precursor mission to a KI, then it is also in place to determine precisely (with its transponder) the actual result of the KI deflection and to determine whether or not the actual residual uncertainty includes a keyhole. In general it will not, but should this be the case then the GT can quite easily tow the asteroid slightly toward or away from the Earth in order to insure that there are no keyholes within the residual uncertainty of the deflection. In other words, the GT is there to both precisely determine the outcome of the KI deflection and, if necessary to trim it, thereby guaranteeing the world that the deflection will not result in a short term resonant return.

Thus the modest total impulse capability of the GT can easily compensate for the uncertainty in the KI deflection and the greater total impulse capability of the KI can be used with precision via the transponder and impulse trim capability of the GT.

JUXTAPOSITION with the NASA Congressional Report:

The NASA Congressional Report makes no mention of the possibility of a deflection placing the deflected NEO on a resonant return impact course. While the probability of such an eventuality is low it is by no means zero. The unavoidable consequence of an uncontrolled deflection is that the best that can be said, post deflection, is that the immediate impact has been avoided and that it is unlikely to return any time soon. With the use of a controlled deflection one will be able to provide positive assurance to an anxious world that there will be no short term resonant return.

In summary

On the order of 98% of the total pragmatic threat posed by NEOs impacting the Earth can be diverted from impact by the use of either the GT alone (for some resonant return NEOs) or the KI/GT combination. Only the least likely 1% of the threat (on the order of 1 in 100,000 years) will require the use of nuclear explosives for a successful deflection.

JUXTAPOSITION with the NASA Congressional Report:

Because of the "hypothetical scenarios" presented in the NASA Report to Congress the nuclear options are either best suited to the task or absolutely required. This selection of specialized scenarios is not, however, representative of the deflection cases most likely to be encountered. The highest probability impacts will always correlate with the smallest NEOs and, based on the assumption that the world will not choose to "take the hit" of a Tunguska-like object if its potential impact is known ahead of time, this cohort of NEOs is selected in this analysis as the lower limit of the pragmatic threat cohort. 99% of the NEOs in this cohort are more likely to call for deflection than those cases selected in the NASA Congressional Report. If those cases considered as examples require the use of nuclear explosions for deflection than it follows logically that the analysis will conclude that indeed nuclear explosives are required. There is no basis for arguing that excessive capability (i.e. nuclear explosion) is to be preferred over adequate capability, especially when the result of its application yields an uncertain and potentially dangerous result (the small but real risk of a short term return impact) and that there are many legal and social challenges to its use.

Russell L. Schweickart

[American Patriot]

Megaton nuclear blast can protect Earth against asteroid attack

“To deal with a giant asteroid, the human race will probably have to detonate a nuclear charge with an explosive force equal to that of several hundred A-bombs dropped on Hiroshima,” said Anatoly Zaitsev, head of the Russian Center for Planetary Defense. On the face of it, his idea to use nukes for stopping a space intruder may appear crazy. However, one might as well give it another thought should the threat posed by a giant asteroid look real. Anatoly Zaitsev speaks with MK reporters about his plan to prevent the end of the world:


“There’s a lack of government support for us, that’s the main ingredient still missing. All the remaining components are on hand,” Zaitsev said. The Tsitadel (Russian for “citadel”) program encompasses the best projects developed by the Lavochkin NPO (a production and research company – ed. note), Molniya NPO, and Vympel NPO. The projects aim to detect and intercept dangerous heavenly bodies. Westerns companies have just begun working on the problem, whereas we got plenty of experience and necessary equipment,” Zaitsev added.

A huge nuclear blast may destroy nuclear asteroid (spacearts.info)


Yet the Americans have long built a powerful skyward “scanner” capable of gathering data on every dangerous heavenly body.


It’s true. But the U.S. skyward surveillance system can only detect flying objects at night, whereas our equipment is capable of identifying objects bound for Earth from the Sun. We will be able to build a reliable system for the global anti-asteroid protection of Earth within five years provided that our program is adequately funded. This country could take full advantage of such an opportunity. However, the Russian government seems to be completely aware of a real threat posed by asteroids.


Perhaps the threat has been slightly exaggerated

Well, you can judge for yourself. According to estimates by U.S. sources, there are about 4,000 asteroids flying in space at the moment. Those asteroids pose a potential threat to Earth. Some of them are the size of a fellow that caused the Tunguska Event, others are even larger. A larger asteroid poses the biggest threat. I’m referring to Apophis, a notorious asteroid measuring from 200 to 400 meters in diameter. In 2029, it is expected to fly past Earth at a distance of less than 40,000 kilometers. If the asteroid should get into a small area dubbed a “keyhole” during a fly-by in 2029, it will inevitably collide with Earth while flying past the planet again in 2036.


So what is your plan?


We suggest that a rapid response air-ground force under the Tsitadel program be put in place. The task force will comprise surveillance spacecraft, exploration spacecraft and interceptors.

Once a dangerous heavenly body is sighted by surveillance spacecraft, light-weight exploration spacecraft will be immediately launched into space to gather data for target acquisition. Exploration spacecraft would approach an ‘aggressor’ and take photographs of it; they would also examine its makeup and trajectory. By the way, we are no strangers to this kind of activity. The Soviet Vega unmanned spacecraft designed by the Lavochkin NPO were launched to flyby Comet Halley in the mid-1980s. The spacecraft had a two part mission to investigate Venus and also flyby the comet.

What about the interceptors? Are they available to share in the program?

The Center for Planetary Defense suggests that an interceptor be built using the design of Phobos Ground spacecraft, which should be launched to flyby Mars’ moon in 2009. If we get enough information regarding a collision several years before it actually takes place e.g. the Apophis case, we would be able to deploy an interceptor for dealing a kinetic blow to the asteroid. It will change its speed and direction following the blow, and therefore it will pose no threat to Earth any longer.

What if an object the size of the Tunguska Meteorite should come out of the blue?

Then we’ll have to act according to a contingency interception plan. There is a booster rocket Dnieper, designed on the basis of the ballistic missile Satana (Russian for “Satan”). It can be activated for launching within several minutes. We can also use the method of a kinetic blow if an object is relatively small, some fifty meters or so in diameter. However, a nuclear explosion will be the only solution for taking care of a ‘space stranger’ which measures from 100 to 200 meters. Using a nuclear weapon against asteroids is currently considered the most reliable method.

Is it going to be a big blast?

We will have to use a nuclear charge with an explosive force equal to that of several thousands A-bombs dropped on Hiroshima. In other words, it’s going be a megaton nuclear charge.

What kind of impact will it have on the humankind?

The impact may vary depending on a distance at which the charge will be detonated. In any case, we’ll have to go for the lesser of two evils. We propose that an insurance fund of the humankind be set up so that different nations may join forces to deal with the threat of an asteroid attack; otherwise a nation that builds an anti-asteroid defense system single-handed may be enticed to dictate its terms to other nations or simply keep them in the dark about the impending danger.

Moskovski Komsomolets

Translated by Guerman Grachev
Pravda.ru

[American Patriot]

Yet the Americans have long built a powerful skyward “scanner” capable of gathering data on every dangerous heavenly body.

The above quote from Moskovski Komsomolets in Pravda is a prime example of exactly WHY the Russians ought not be trusted.

The Americans have NOT built any such "scanner". What we HAVE are a whole bunch of astronomers who spend hours taking photos and looking over those photos, and computers that examine the changes in light on images. We don't have a "scanner" that would operate in an autonomous sense of the word, nor is there some simple machine that does this work.

Let's be very CLEAR on this. The funding for this project is limited and Congress hasn't given it a whole lot of money, secondly there are a LOT of volunteer professional and amateur astronomers alike that are working on collecting data on NEOs and PHAs.

So, regardless of what Pravda says, there are some holes in their story.

As to whether the Russian government is "unaware" of the threat, I think they, like most other governments on this planet are subject to the whims and wherefores of their leaders and peoples thus they pay less attention to the sky, something that has NOT screwed with us in Eons, and more attention to people who might revolt around them at any moment.

If it came down to keeping myself in power and alive as a communist "dictator", like Putin, I think I wouldn't be very worried about asteroids either.

But, unlike Putin, myself and others believe in the future of the human race as a whole and while I'm as nationalistic as anyone else, and stand firm as an American fighting a war against terrorists, I think we still need to concern ourselves about the other threats to the human race, and ADDRESS them.

[American Patriot]

Lightweight lasers can eliminate Earth-striking asteroids
From our Correspondent

Washington, Mar.20: Researchers at the University of Alabama in Huntsville have claimed that a lightweight, space-based laser has the potential to eliminate dangerous asteroids posing a threat to Earth.


According to says Richard Fork, the head of the Laser Science and Engineering Group at the university, the technique could detect and deflect space rock away.

"Though the technology may take two decades or so to mature, this is something that is doable," Fork is quoted, as saying.

One of the great advantages of using lasers is that their beams remain relatively tightly focused over long distances, allowing them to study asteroids from farther away than is currently possible.

Previously, researchers had proposed several methods to save Earth from an asteroid impact. These included blowing it up with a nuclear bomb or putting a spacecraft beside it so the craft's gravity could tug the asteroid off course.

But these solutions had their drawbacks.

A laser, on the other hand, could give researchers an advance warning of the asteroid's likely composition and exact shape, which would help them figure out how to move it.

In fact, the laser itself could also do the moving. If its short pulses were focused on a centimetre-sized spot on the asteroid, they would repeatedly pulverise material, ejecting tiny bits of space rock at 10 kilometres per second. This would function as the asteroid's propellant, pushing it into a different orbit - and safely away rom Earth.

"It really doesn't take much of a push provided you do that early," Fork told New Scientist.

"The key thing is to act early on," Fork added.

According to Fork, several major technical hurdles need to be overcome before such a system could be put in place.

For instance, if the spacecraft is used to characterise asteroids, it would require an antenna about 30 metres across to transmit the laser's light.

If on the other hand, the spacecraft is simply intended to deflect asteroids, it would not need such a large antenna, but ngineers would still have to find a way to make existing laboratory lasers - which are heavy - more lightweight to launch them on a spacecraft about the size of a truck.

At the moment, Fork and his team are developing a titanium-sapphire laser capable of pulverising materials with its pulses. They hope their laser could be the grandfather' of a laser that might one day come to the aid of humanity.

There is a small chance such a life-saving laser would be needed in 2029, when the asteroid Apophis will make a close swing by Earth. If it passes through a specific region of space just 600 metres across at that time, there is a 1 in 45,000 chance it could hit Earth - perhaps slamming into the Pacific Ocean - on 13 April 2036.

If a laser spacecraft were going to be ready to deflect Apophis before it could reach the 600-metre-wide keyhole' in 2029, the government would have to start funding the mission now, says Fork.(ANI)


Copyright Dailyindia.com/ANI

[American Patriot]

Dueling over asteroids

Posted: Wednesday, March 21, 2007 5:50 PM by Alan Boyle





http://cosmiclog.msnbc.msn.com/archi.../21/97410.aspx

Former astronaut Rusty Schweickart is to asteroids what Al Gore is to global warming, and Schweickart is none too pleased with NASA’s latest strategy for coping with potential threats from the sky.


Those plans came out this month in the form of a report to Congress, laying out an analysis of the various methods for detecting and dealing with potentially hazardous asteroids and comets. It's all part of NASA's legislative mandate to find 90 percent of such near-Earth objects, or NEOs, wider than 460 feet (140 meters) by the year 2020. An asteroid that big could devastate a city-sized region if it were to hit Earth.


Schweickart, who flew on Apollo 9 in 1969, set up the B612 Foundation to raise awareness about NEO threats - and he's organizing a series of workshops under the aegis of the Association of Space Explorers to develop an international plan for dealing with them.


"Not to make it sound overly dramatic, but you're not dealing with just science, you're dealing with public safety issues," he told me today. "You're dealing with the survival of life."


That's why he's taking the new report so seriously. NASA's official view is that the most efficient way to divert a potentially threatening NEO is by setting off a nuclear bomb nearby, to nudge it into a safe orbit. "The implication is that it is the preferred way to go to deflect essentially any near-Earth object," Schweickart complained.


In contrast, Schweickart argues that the so-called "nuclear standoff" option should be used only as a last resort. He contends that 98 percent of the potential threats can be mitigated by using less extreme measures. For example, he favors the development of a "gravity tractor" - a spacecraft that would hover near an asteroid for years at a time, using subtle gravitational attraction to draw the space rock out of a worrisome path.
To kick it up a notch, Schweickart said a threatening NEO could first be hit with a kinetic impactor - say, a scaled-up version of the Deep Impact bullet that hit Comet Tempel 1 back in 2005 - and then the orbital track could be fine-tuned using the tractor. Navigational sensors aboard the tractor would check to make sure the NEO was on a completely safe path.


"This combination is obviously the way to go," he said.


NASA sees it a different way, however. The report said the gravity tractor concept and similar techniques would be the "most expensive" ways to divert an asteroid: "In general, the slow push systems were found to be at a very low technology readiness level and would require significant development methods," it said.


Schweickart said NASA must have "misunderstood or mischaracterized" the gravity tractor concept. And he worried that the report may make things tougher for researchers working on kinder, gentler ways to head off killer asteroids.


"It may be harder to continue with that research," he said. "The irony is that NASA ought to be doing that research.


"But beyond that, there is also the issue that people are beginning to wrestle with this question on a much larger basis internationally," he said. "The idea that the only way you can protect Earth from these things is to compromise all your principles about nonproliferation would be shocking to anybody else. Almost anytime the United States is going to say anything about this, eyebrows are going to go up."


Schweickart already has written a 13-page retort to the report, as well as a letter to NASA Administrator Michael Griffin asking him to reconsider the agency's policy. Both are available from the B612 Foundation press page as Word documents. Schweickart is also calling on NASA to release more of the background analysis that went into the final report.
"I just felt that it was inappropriate that this stand unchallenged - not only unchallenged, but unsupported," he said.


He feared that his anti-nuclear stand might make him "persona non grata" in NASA circles - but astronomer Donald Yeomans, the head of NASA's Near Earth Object Program Office at the Jet Propulsion Laboratory, said Schweickart's idea of combining kinetic impactors with gravity tractors had merit.


"That's an interesting concept if you wanted to do non-nuclear," Yeomans told me.


He pointed out that the NASA report was merely aimed at outlining the viable options for dealing with potentially threatening NEOs, and that the nuclear standoff explosion would be a "viable option for almost anything."
(NASA isn't crazy about planting a nuke right on a NEO, a la "Armageddon," because of the risk of breaking the object into hazardous pieces.)


The kinetic impactor, perhaps combined with a gravity tractor or monitoring device, would be the most straightforward way to head off a NEO threat - and would probably be preferred for the smaller-scale threats.


"You really don't have one technique that fits all - except for this standoff blast, perhaps - but I don't think anyone is comfortable with this nuclear option," Yeomans said. "I think nuclear is there and available, but it's sort of a last resort. That's my own opinion. ... It's politically a tough sell, and it gives most people the willies."


One thing that nearly everyone agrees on is the need to devote more resources to hunting NEOs in the 460-foot-and-up range. The NASA report suggested two options for complying with Congress' requirements: either building a new ground-based telescope facility dedicated to the asteroid search, or putting a new infrared telescope into a Venus-like orbit. Unfortunately, NASA says it can't afford either option for the time being.



"The decision of the agency is we just can't do anything about it right now," Lindley Johnson, program scientist for near-Earth object observations at NASA Headquarters, told The Associated Press.


The Venus-orbit telescope may sound expensive (with a price tag in the range of $1 billion to $1.2 billion, compared with $800 million to $1 billion for the ground-based facility), but Schweickart said he'd put a "very big plus sign" on that option. Yeomans noted that a similar mission called NEOCam had been proposed in the past, with the L1 gravitational balance point between Earth and the sun serving as the telescope's vantage point.


"If what you're interested in is just the letter of the law, then there are a number of options," Schweickart said. "But if what you're really interested in is being prepared to deal with the threat, then that infrared telescope in Venus orbit is much more valuable - because without it, you're relegated to looking at things from the surface of the Earth. And it's very difficult to pick up things that are largely inside Earth's orbit."


For example, the asteroid Apophis spends nearly all its time inside Earth's orbit, and that location is what's making it hard for astronomers to figure out whether or not it will hit Earth in 2036. Yeomans said that, for now, the odds of collision are still set at 1 in 45,000 - but that may change once additional analysis from the University of Hawaii's Institute for Astronomy is added to the mix.


Astronomer Dave Tholen is reportedly still working on the analysis, which should become available soon. "He's so good that it's well worth waiting for," Yeomans said.


Will Apophis be crossed off the list of threatening asteroids? Or will we have to wait until 2013 to get the final answer? Stay tuned, and keep an eye on NASA's list of cosmic threats.

[American Patriot]

Scientists fear asteroid is heading ‘uncomfortably close’ to Earth.

http://www.justsixdays.co.uk/isblog/?p=1531

http://abclocal.go.com/ktrk/story?se...ech&id=5133261

Circle your calendar. April 13th, 2036 could be a really, really bad day on planet Earth.

A group of astronauts and engineers warns that an asteroid may pass uncomfortably close to Earth that day.

The chances it will actually hit are just one in 45,000, but even at those odds, the scientists warn, the United Nations should consider a response.

Potential Threat

The scientists met this past weekend in San Francisco to discuss the potential threats asteroids pose to the Earth and what can be done to prevent a possible collision.

Most feared is Apophis, a large asteroid that will pass within 10,000 miles of Earth around 2029 and even closer in 2036.

Dr. Dan Barry, a retired astronaut, told ABC News, “Even if the probability is low of an asteroid hitting Earth, if it has the potential to have a significant impact, then it has to be looked at. It is the absolutely responsible thing to do. In fact, it would be irresponsible not to do so.”

Barry said more research is needed so that when a potentially dangerous asteroid is found, there is a plan in place. He said it is therefore important to start the search for asteroids now, to allow enough time to effectively deal with them.

Scientists believe that if advance warnings of dangerous asteroids like Apophis can be made decades in advance, there will be enough time to try and knock them off course.

Suddenly, Bruce Willis on a mission to stop a devastating asteroid from destroying Earth, as he did in the movie “Armageddon,” does not seem as far-fetched.

What Are The Solutions?

Nobody knows for sure what it would take to push a massive asteroid off its course, but the theoretical possibilities include detonating weapons on an asteroid’s surface or using gravitational pull to alter a possible collision course.

But it could also break an asteroid into many pieces, all still headed toward Earth.

Some scientists say a better option could be to launch a large satellite to rendezvous with an asteroid. The mass of the satellite alone could produce enough gravitational pull to change the asteroid’s course.

Another suggestion is to crash a spacecraft into an asteroid in the hopes of changing its direction.

“Done far enough away, only a small deflection would be needed and it is kept in one piece,” said Barry.

In 1996, NEAR became the first spacecraft launched by NASA to orbit and land on an asteroid. The purpose of the mission was to determine the asteroid’s mass, structure, gravity and magnetic field. Scientists hoped this important information would help them understand asteroids.

So, while astronauts blowing up an asteroid may be movie fiction for now, scientists are already thinking about how to save Earth from a massive asteroid possibly on its way.

[American Patriot]

SNAPP SHOTS: MARTIN SNAPP
Giant deadly asteroids too close for comfort

WE'RE OBSERVING a scary anniversary today. On this date in 1989, a mountain-size asteroid named 4581 Asclepius passed within 500,000 miles of Earth.

By cosmic standards, it was a very close shave. The asteroid passed directly through a spot we had occupied just six hours before. A little sooner, and it would have smashed into us with the force of 40,000 hydrogen bombs.

If it had hit land, it would have made a crater the size of Washington, D.C., and flattened everything beyond that for 100 miles in all directions.

If it had splashed down in the ocean, the result would have been a tidal wave that would make the Indian Ocean tsunami of 2004, which killed a quarter of a million people, look like a gentle ripple.

Now, here's the really scary part: There are hundreds of thousands of other asteroids in our immediate neighborhood.

Astronomers call them Near Earth Asteroids, or NEAs, and they estimate that 1,000 to 1,200 NEAs are 1 kilometer or larger in diameter. One monster called 1866 Sisyphus is 100 kilometers.

"Anything over a couple of hundred meters is bad news," says Ryan Turner of the Chabot Space & Science Center in Oakland. "But 1 kilometer or larger is a disaster."

It was an asteroid that killed the dinosaurs -- and 75 percent of all other life on the planet -- 65 million years ago.

The good news is that NASA started tracking NEAs larger than 1 kilometer in 1998. It has pinpointed about 65 percent, and determined that none of them will be a threat to us within the next 100 years.

The bad news is the 35 percent still undiscovered -- not to mention the 100,000 or so smaller, but still very dangerous, NEAs larger than 100 meters.

And even bodies smaller than 100 meters can do serious damage.

Meteor Crater in Arizona, which is three-fourths of a mile across, was created by an asteroid only 50 meters in diameter.

So what can we do about it? In the movies, the solution is simple: Send Bruce Willis up there with a nuke and smash the thing into a million pieces.

"That's a great idea if you want a million pieces raining down on Earth," says Turner. "The consequences would probably be worse than if you did nothing at all."

Fortunately, somebody has been doing some serious thinking about this -- the Association of Space Explorers, an organization of astronauts and cosmonauts from 29 countries.

They've created the B612 Foundation -- named after The Little Prince's asteroid in the Saint-Exupery story -- to push for another solution: a space tugboat to gently nudge the intruder into a different orbit, away from us.

But the trick is to have everything ready to go as soon as the asteroid is spotted. If we deflect it when it's still relatively distant, we'll need only a small change in direction to send it far away from us by the time it reaches our neighborhood.

"But if we wait until it's almost on top of us, it'll be too late," says Turner.

Make no mistake, we're living in a cosmic shooting gallery. Sooner or later, a rock with our name on it is going to arrive.

The goal of the B612 Foundation is to have a space tugboat ready by 2015.

The foundation's chairman is astronaut Rusty Schweickart, the lunar module pilot on Apollo 9. His motto, which he repeats everywhere he goes, is "Are we dinosaurs?"

"He means that the dinosaurs couldn't do anything to protect themselves, but we can," says Turner. "The question is: Do we have the will to do it?"

Reach Martin Snapp at 510-262-2768 or e-mail msnapp@cctimes.com.

[American Patriot]

Astronomy Cast - Good Podcast

Filed under: Survival, Astronomy, The Asteroid Threat
Astronomy Cast
Recommend you listen to this podcast if you’re interested in Asteroids. I’m concerned about “Apophis”, also known as 2004MN4 coming close enough to hit a “gravity keyhole” on 13 April 2029.


Should this asteroid hit the “sweetspot” the chances of it actually coming back around and hitting the Earth a few years later increases drastically.


Listen to the podcast which they talk about how these things are discovered, the chances we’ll get hit and so forth. About 1/2 hour show.


Update: I have one small issue with this podcast and Dr. Pamela. She sounds smart, but she also states the following:

We recently had a scare with the asteroid Apophus. It’s not going to hit the Earth. It’s not going to hit us any time. So, we know that it’s not a worry, but we thought it was for a while. The Planetary Society put out this call for proposals on how could you go out and put a radio transponder on an asteroid so that we can track it and get accurate positions over time. One of the first steps to diverting an asteroid is actually just radio tagging it, like you might radio tag an endangered species, so we can keep track of it as it migrates through the solar system.

In particular, “It’s not going to hit us any time.”
That’s a definite statement of fact, coming from her. Unless she has extremely accurate course information on that particular asteroid, then she can not say this definitively. As a matter of fact, at this point no one can say for sure it will hit, or it won’t hit ever, just that it is highly unlikely to hit us on the dates we’re expecting it to come close. There is a possibility it will hit this gravity keyhole and then all bets are off, but. There is a HIGH probability it can hit us.
1-in-10,000 in 2039 if I understood what I was reading correctly. This is not something you can take and say, “No it won’t hit”. So, basically, I disagree with the Doctor on this one point.
My take on this whole thing is that this is a pretty big chunk of rock. It’s about 1050 feet across. That’s a pretty good sized rock.


According to the research I’ve done over the past few days, this asteroid was removed from being very high on the Torino scale around August 5th, 2006 (That’s my birthday, must have been a present, huh?) and is now considered a zero on the scale. As such, it is no threat. Fine and dandy, since I personally do not have enough data to calculate the orbit out several more years, I can only go by what NASA says. Here is their link if you need to see it yourselves.

[American Patriot]

China, U.S. among most at risk from killer asteroid

Tue, 2007-03-27 06:43 — BJS

Researchers at the University of Southampton have developed a software package for modelling asteroid impacts that enables them to assess the potential human and economic consequences across the globe.

The software, called NEOimpactor, has been specifically developed for measuring the impact of 'small' asteroids under one kilometre in diameter, and early results indicate that the ten countries most at risk are China, Indonesia, India, Japan, the United States, the Philippines, Italy, the United Kingdom, Brazil and Nigeria.

'The threat of the Earth being hit by an asteroid is increasingly being accepted as the single greatest natural disaster hazard faced by humanity,' comments Nick Bailey of the University of Southampton's School of Engineering Sciences, who developed the software with University colleague Dr Graham Swinerd, and Dr Richard Crowther of the Rutherford Appleton Laboratory .

'Since 1998 the international Spaceguard survey has been cataloguing all near earth asteroids (NEA) larger than one kilometre in diameter. However, small asteroids, under one kilometre in diameter, remain predominantly undetected. While the direct consequences might not be quite as extreme, these small objects exist in far greater numbers and therefore will impact more frequently. It is on these sub-kilometre asteroid impacts that we have been focusing to assess the consequences for both humans and for infrastructure across the globe.'

Initial investigations have examined how the consequences of an impact change with increasing impact energy. Taking a spherical stony asteroid travelling at 12,000 miles per second and varying the diameter to increase kinetic energy, the results indicate that a 100 metre diameter asteroid will predominantly cause localised casualties and damage across a few countries when impacting on either land or ocean. However, the consequences of a 200 metre diameter asteroid hitting the ocean increase significantly, with the generated tsunamis reaching a global scale. At 500 metres in diameter, almost any ocean impact will generate significant casualties and economic cost across the world.

The team used the raw data from the multiple impact simulations to rank each country based on the number of times and how severely they would be affected by each impact. Early results show that in terms of population lost, China, Indonesia, India, Japan and the United States face the greatest overall threat; while the United States, China, Sweden, Canada and Japan face the most severe economic effects due to the infrastructure destroyed.

In both rankings, the United Kingdom appears eighth in the list of countries most affected. Of the top twenty for each ranking, over half the countries appear in both lists.

'The consequences for human populations and infrastructure as a result of an impact are enormous,' continues Nick Bailey. 'Nearly one hundred years ago a remote region near the Tunguska River witnessed the largest asteroid impact event in living memory when a relatively small object (approximately 50 metres in diameter) exploded in mid-air. While it only flattened unpopulated forest, had it exploded over London it could have devastated everything within the M25.

'Our results highlight those countries that face the greatest risk from this most global of natural hazards and thus indicate which nations need to be involved in mitigating the threat.'

Source University of Southampton

[American Patriot]

China and US at highest risk of damage from asteroids

* 14:01 27 March 2007
* NewScientist.com news service
* David Shiga



China and the US are the countries most vulnerable to damage from future asteroid impacts, according to preliminary new research. Sweden also ranks surprisingly high in this first attempt at quantifying the risks of impact effects, such as tsunamis, on individual nations.

Scientists have been able to simulate the propagation of tsunamis, earthquakes, and debris from virtual asteroid impacts for years. But previously, there has been no software to quantify the human toll on particular countries.

Now, researchers have combined impact effects with data on population density and infrastructure location in a computer model to produce the first global ranking of countries based on their vulnerability to impact damage.

Nick Bailey of the University of Southampton, UK, led the development of the new software. The team used the model to simulate thousands of impacts at points all over the Earth, building up statistics on which countries tended to be the worst affected the most often.

They considered a range of impact energies corresponding to asteroids between 100 and 500 metres across, striking with typical solar system speeds of about 20,000 kilometres per second.
Earth at night

The team focused on smaller asteroids because they hit the Earth more frequently. An asteroid a few hundred metres across hits the planet about once every 10,000 years, on average, while those larger than 1 kilometre hit only every 100,000 years or so. Small asteroids are also harder to spot. "We're more likely to be hit by one without much warning," Bailey told New Scientist.

Using maps of population density, the researchers charted the places likely to suffer the most casualties. As might be expected, countries with large coastal populations turned out to be most vulnerable, with China, Indonesia, India, Japan and the US in the top five spots.

Determining the economic damage to different countries was more difficult. The researchers made this part of their assessment based on estimates of the amount of infrastructure located in different parts of the world.

Using images of the Earth from space showing the distribution of light from artificial sources, they assumed the brighter places were more built up. Then they simulated the propagation of tsunamis, earthquakes and debris from a wide variety of impact locations to rank countries on the vulnerability of their infrastructure.

The US faced the worst potential losses, perhaps not surprisingly, since it has a lot of infrastructure on coastlines facing two different oceans. China was second, followed by Sweden, Canada, and Japan.
Smaller impacts

Sweden’s third highest rank is somewhat of a surprise. Bailey notes that its well developed infrastructure is more vulnerable to tsunamis than that of other European countries like Germany, since it has a long coastline.

The researchers also produced maps showing the worst possible places on Earth for an impact to occur. The Pacific coast of Asia shows up as an especially bad place in terms of producing casualties. Impacts in the north Atlantic Ocean, which can send tsunamis to both Europe and North America, tend to produce particularly high infrastructure losses.

The biggest source of uncertainty for the results is the possibility that a single incoming asteroid might not make it to the ground intact, fragmenting in the atmosphere instead to produce multiple, smaller impacts – a scenario not considered in the model, Bailey says.

Clark Chapman of the Southwest Research Institute in Boulder, Colorado, says more research along these lines is needed to better understand the nature of the asteroid hazard. "We need to understand the potential risks on a country-by-country basis, since individual countries may have different vulnerabilities to this hazard as well as different capabilities to deal with it," he told New Scientist.

[American Patriot]

Enlarge image
The worst places for an asteroid to strike in terms of infrastructure damage are shown here in red, with the north Atlantic appearing prominently (Illustration: Nick Bailey et al/University of Southampton)

[American Patriot]

[American Patriot]

Scientists investigate path of asteroid
By Chris Mader
Publication Date: 03/19/07
Staff Writer Print View

Experts say an asteroid 300 meters in diameter could hit Earth in less than 30 years.

There has been recent talk in the scientific community about Apophis, an asteroid discovered in June 2004. Initially, it was believed it could hit the Earth in 2029, but it's path was later recalculated.

Further investigation shows that it will enter a "gravitational keyhole" and renew it's chance of hitting the Earth by 2036.

Matthew Lister, assistant professor of physics, said that based on past records, an asteroid this size hits Earth about once every 10,000 years.

"As far as asteroids go, Apophis is a rather small one," he said.

The last encounter with an asteroid happened in the Tunguska region of Siberia in 1908 when it exploded in the atmosphere and caused a 15 megaton explosion and felled about 80 million trees.

Lister says the explosive yield of Apophis could be the equivalent of 1,000 megatons of TNT. The largest thermonuclear bomb ever detonated by the United States was 15 megatons.

He said if Apophis landed in a populated area, it could easily wipe out a large city. Since the Earth's surface is 70 percent water, a tidal wave is a more likely prediction, however.

The majority of asteroids do not cross into Earth's orbit, but it is the few others that pose a threat.

"So far, about 4,000 have been catalogued," he said.

Experts said Apophis has a one in 45,000 chance of hitting Earth in 2036. But Lister says there are more asteroids waiting to be discovered.

High-powered telescopes are being used to find asteroids, and in 2013, the birth of the Large Synoptic Survey Telescope will make an enormous impact in tracking these objects.

Project coordinator Suzanne Jacoby said the telescope will operate in survey mode, scanning the visible sky every few nights. It will be able to address the NASA mandate to catalog Near Earth Objects larger than 140 km in diameter.

In January, Google announced they will join the effort. Jacoby said "Individuals at Google are working with our data management team as processing pipelines and file retrieval techniques are being designed to handle the 30 terabytes per night data rate of (the telescope)."

The device will be located on top of Cerro Pach'n in Chile to maximize its viewing capacity without the disturbance of light.

"Ironically, light pollution from cities on Earth is making it more and more difficult to spot these objects with telescopes," said Lister. "Many of the closest close calls we've had with asteroids have actually been spotted after they've passed by the Earth, which is a sobering thought."

[American Patriot]

[American Patriot]

Real video of 1950DA

[American Patriot]

Posted on Wed, Mar. 21, 2007

The threat of asteroids isn't just NASA's problem

McClatchy-Tribune News Service
(MCT)


The following editorial appeared in the Orlando Sentinel on Monday, March 19:


X X X


Talk about your budget crunches. Too little funding of NASA's program tracking asteroids has the space agency behind schedule in its important mission to monitor space rocks that could devastate or extinguish life on Earth.


The problem's hardly academic: If planetary defenders knew of an asteroid's approach, one day they could potentially launch spacecraft with the potential to divert it. The alternative is getting caught unaware. Think, for example, of the strike above the Siberian landscape in 1908 that leveled 830 square miles of forest, or the impact 65 million years ago that likely killed the dinosaurs.


This hardly is NASA's problem alone, however. It's the world's. More of its nations need to pitch in the resources to help all concerned survive it.
---
© 2007, The Orlando Sentinel (Fla.).
Visit the Sentinel on the World Wide Web at http://www.orlandosentinel.com. On America Online, use keyword: OSO.
Distributed by McClatchy-Tribune Information Services.

[American Patriot]

Circumstances Beyond Our Control

by

Rick Donaldson, NØNJY, CET

Night falls quietly on a tiny Midwestern town, the residents of which are quietly watching television, cooking their supper or relaxing from the day's hard work in the fields. In the large city nearby where several factories produce goods for the region, folks have settled into their evening/night shifts for work. The day shift has gone home for the night. Tomorrow is Saturday. For many it will be a day off of work. A few enterprising folks are preparing their small bass boats for a long day of fishing, starting very early tomorrow morning. A group of Boy Scouts left four hours ago for a trip into the mountains, a couple of hundred miles away, prepared for the weekend camping trip - they should be all set up at their camp site shortly. As silently as the night fell, so too falls the twilight of mankind.

At midnight, Central Daylight Time, a meteor the size of several city blocks hurtles into the atmosphere. Traveling at over twenty-five thousand miles an hour, the giant chunk of rock tears a hole into the atmosphere as it hits. The meteor slows quickly, but not before the massive friction causes the rock to glow, then to boil. The resultant ionized trail of gaseous material can be seen for hundreds of miles and thousands look up at the sudden, unexpected brilliant flash and trail. Two seconds after impacting the atmosphere, the meteor becomes a meteorite, striking the surface of the planet.

In a mere matter of seconds, tomorrow is suddenly upon us, disaster has struck and the hopes, fears and dreams of the entire planet are dashed into oblivion by a random, chance encounter with a rock a few miles across. The twilight of the human race has begun. The rock strikes in the United States, someplace in the south. Perhaps it is Texas, or Oklahoma. It might be along the Mexican border. No matter though, for the ensuing explosion is equivalent to over 5000 megatons... 5,000,000,000 or 5 billion tons of TNT. This is five hundred thousand times larger than the bomb that was dropped on Hiroshima in World War II. The ground for several miles vaporizes. The atmosphere, already ripped through once by the massive shock wave of the passing asteroid now is ripped for a second time. Aircraft within one thousand miles will be thrown from the sky by the second shock wave. For hundreds of miles in all directions the shock wave will radiate outward destroying everything in its path. Buildings, trains, airplanes, people, animals are pummeled to death by the overpressure of the explosion. Almost all man-made structures will be destroyed for hundreds of miles in all directions.

About 3-5 seconds after impact this shockwave will push a large quantity of the atmosphere upward and away from the planet. Vast amounts of the atmosphere will be shoved violently into space, forever lost to the planet. Huge, billowing clouds will form near, above and in all directions around the impact site. Life - as they knew it - within 500 miles will cease to exist in less than ten seconds. Massive lightning storms will develop around the explosion within a few minutes. Anyone caught above ground in this shockwave will be killed by the shock wave, by the ensuing heat wave that follows it, or by flying debris if they are some distance away. None will be alive to see the lightning storms. Within a few seconds of impact, the secondary shock wave on the ground and within the planet will be radiating outward through the entire world. It will be felt almost every place on the planet within moments. The exact numerical rating on the Richter scale will be unreadable in Boulder Colorado, because they haven't calibrated their equipment high enough. The readings will show Boulder's own quakes to be around 9 or 10. This will level homes and buildings throughout Colorado, Kansas, Nebraska, Utah, Oklahoma and Texas.

The tiny little Midwestern town, the city nearby and numerous cities, towns and rural areas become, quite suddenly devoid of life forms of any sort. The combination of the two shockwaves, then the heat wave and finally the earthquakes will pretty much kill any creatures in one or the other of the effects. The amount of debris and smoke thrown into the atmosphere block out the sunlight the next day... and for the next many months. No bright sun shine will be seen for a long time to come. Day and night are difficult to distinguish around the globe. The northern and southern latitudes are spared some of the effects of the smoke and dirt in the air, but everything is hazy and dim for months to come. Plants that survived the hit, due to their distance from the impact point begin to die for lack of sunlight. Animals that depend on plants begin to perish a few days, perhaps as long as a few weeks later. Human beings the world over are overwhelmed by the dust in the air. Many begin to die from respiratory dysfunction of all sorts. Food becomes scarce as the remaining grocery stores are emptied, trucks, trains and ships are stripped of food products. Factories are emptied. Electricity failed in many areas the first couple of days. As the weeks go by, more and more power plants drop off the grid.

Famine, thirst, starvation and death is everywhere. Packs of dogs roam the cities, attacking their once-masters, killing and eating humans as if they were simple prey in the forest of their wolf ancestors. Rats are everywhere. So are bugs, especially roaches around the urban areas. Wild animals that have so far survived the wilderness will begin making their way out of those areas in search of food themselves. Finding little to eat except a few pitiful humans, they will fight the dog packs for the choice pieces of meat. Some will fall to the dogs, some will win. Either way, the humans lose.

The Human Race is losing all the way around. This scenario is but one of the possibilities that might befall the frail ecosystem of this world, or the even frailer society of the human race. Although humans have taken over the planet as the dominate species of the world, we have technology, we think-therefore we are. In truth, we are nothing more than another species of mammals on this world, when it comes to Mother Nature. A disaster such as described above may have been the downfall of the dinosaurs that lived millions of years ago on this world. Their kind survived, according to science for many millennia. The human race has only been here a mere few thousands of years. A tiny moment in geological time.

In the movie above you see a meteor that flies across half the United States before finally coming to rest in the backside of a car located in New York City. The piece that landed was larger than a grapefruit, but certainly started out larger than a basketball. Perhaps even larger. From the movie you can see that it broke up into several pieces and had a very firery entry into our atmosphere. Rocks of a larger size, hundreds of yards or even miles across would perhaps break up, but would likely remain intact. The force of impact would be like a large nuclear explosion for those close enough to observe the effects.

It is most arrogant of human beings to sit and watch disaster movies at the theater and then wander off home to the security of their homes saying, "That is impossible because... ". The base truth here, is that we live on a tiny rock in a vast universe. Just imagining the size of the solar system is difficult. Trying to imagine the size of the galaxy is almost impossible for us. To try to see, in our minds the vast, enormous distance the universe covers becomes a mind-bending proposition, driving even the most ardent, logical scientist to God Himself in an attempt to describe that vastness. Looking at it from a purely scientific point of view, not even taking into account the religious implications of thinking and souls and consciousness, one has to consider that this tiny rock is space is nothing more than a sand particle on the beach of the universe.

Living on a grain sand, tends to remind one that along the geological stretch of time, billions of years pass unnoticed in this galaxy of ours. Stars die, stars and planets are born. The distances to the next nearest stars would take humans hundreds of years at current technology and speeds to reach that star. Although it is only about four light years away, as light travels, we would die long before the trip there was over. An asteroid hitting this planet is not as far-fetched as some people want to make it sound. In fact, we are bombarded by particles daily, from space. Some are small as a grain of sand. Others are large as basketballs. There are craters all over the planet that are proof positive that giant rocks have struck this world in it's distant past. The distant past as far as WE humans are concerned. Moments ago, geologically speaking. The following photos show actual craters on the face of the world, that have been created in times past by asteroids and huge meteorites just like in our scenario before. The smallest one (2nd from left) is in Arizona and is 1KM across. The others are all MUCH LARGER.

Because our own lifespan is less than one hundred years, we do not understand the concept of time, except as a moment to moment concept. Our idea of "A few thousand years" is diluted by our own penchant to rewrite our history. Even in the past twenty years, we have gone from teaching about the Revolutionary War as a concept that happened in "recent history" to a concept of "that was a LONG time AGO" in our schools. As far as my own memories go, I remember the first Moon landing, Neil Armstrong and Buzz Aldrin. I remember watching Alan Sheppard go up into space for 15 minutes. I remember John Glen orbiting the world several times and splashing down in the ocean. I was a tiny little kid then. My own children don't remember the moon shots. They barely even notice the Space Shuttle these days. Science and technology are routine. Movies show terrible disasters and people live through them. It is very difficult in our day of technological advancement to comprehend the fact that we can not stop an errant piece of space debris from hitting us. We see nuclear weapons, and massive amounts of the Earth's surface changed by ourselves and believe that it is nothing to move a rock in space.

What we fail to realize is the kinetic energy involved as well as the laws of physics. We've heard it said, and in fact it has been shown in a recent movie that it would be possible to stop an incoming comet. But in essence this would be akin to you standing two hundred yards from someone with a gun. He fires a high-powered rifle at you. You THEN get to reach down, pick up your own high powered rifle and fire back. Only thing is, you don't get to shoot the shooter, you must knock his BULLET out of the air. Not an easy feat, huh? Our own technology has us over-confident that our self-same technology will always pull us out of a fix we're in. People that you talk to will say, "Oh, the government will take care of us", or "Heck, we'll just nuke that rock right out of the sky!" While it isn't impossible for us to move, slow down or stop a big chunk of rock from falling on our heads, it is almost as unlikely that in the time we would have from its discovery that we could even mount such an attack.

Science is good. Calculations, nuclear weapons and asteroid trajectories CAN be handled in this day and age. But hese things rely on a couple of important factors. The first factor is that we see the offending piece of rock before it hits us, and that means in plenty of time to actually do something to change its course. The second factor is that we have to be ABLE to do something to change its course, have a space craft, or missiles sitting in various parts of world READY TO GO. If the rock is big enough and time is short, nothing on this world we can do will move an incoming asteroid enough off course to make it miss us. Currently, there are projects working, privately funded, that are attempting to locate Near Earth Objects. But the government does not have funded projects at this point in time. Congress recently listened to authorities on Near Earth Objects, and the hazards they pose. There are several internet sites that will give you some more information regarding objects in space that pass close enough, and are large enough to be serious hazards to the planet, the ecosystem and mankind itself.

One main point throughout this article comes to the forefront. If this ever happens, there is little hope for escape for us living here, in this time. But, depending on the size of the rock, the location of impact, time of day of the hit and the warning we get some people will probably survive. It is toward that survival that we all should think. Regardless of the time-space continuum, Star Trek-like technological achievements or man-made answers to the cosmos we should be worried about such things happening, and most of all that worry should be put into action. Preparing, teaching and training for the day when circumstances are beyond our control.

Asteroid Impact and Rogue Rock Information Sources

Asteroid 1997 XF11 (Earth Close-Approach) - Jet Propulsion Labs' own information regarding the close approach of 2028
Asteroid Orbital Elements Database - A place to get tracking information and other helpful data.
Astronomical Headlines - International Astronomical Union news.
Comet Impact Simulations - Sandia Labs
Minor Planet Center - Responsible for collecting information, checking calculations, and dissemination of astrometric observations.
List Of The Potentially Hazardous Asteroids (PHAs) - IAU informational page - Updated almost daily.
Solar System Collision Calculator - Calculate approximate effects of a collision with a body from space. (Sky & Telescope).
Spaceguard Australia - The search for Near Earth Objects (NEO) - comets, asteroids and meteoroids (Excellect site with archived News stories).
The K-T Event - The probable extinction of the dinosaurs. Cretaceous-Tertiary Mass Extinction event .

credits:
Don Davis Author of Meteor Strike Image
All other images were from NASA web sites.
Article Copyright © 1998-2004 by Rick Donaldson. All rights reserved.
Revised: 21 Aug 2004