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The Asteroid Deflection Gambit

We’ve talked often in these pages about Near Earth Objects (NEOs) and the potential danger posed not just by them but by objects from much further out in the Solar System if they were to take an Earth-crossing trajectory. But it’s also true that NEOs have a certain allure even if they are potentially dangerous. They’re close enough to consider a manned mission, and even a small 2-kilometer sized metallic NEO could contain rich metals and minerals worth trillions of dollars. Of course, what metals markets would do if we suddenly had access to such an object is another matter. And mining an NEO, not a new concept, is still on the impractical side.

But Hexi Baoyin (Tsinghua University, Beijing) and colleagues are proposing a possible solution. The temporary capture into Earth orbit of an NEO by creating a small velocity change could allow a relatively low-cost trajectory to the object that would provide mining opportunities. And indeed, various asteroid deflection schemes from solar radiation to nuclear explosions are available in the literature, most considered in terms of saving our planet from an impact. The authors of this new paper (thanks to Phil Mowatt for the tip) have set about identifying what it would take to capture an NEO to Earth orbit, using as their case in point a periodic comet called 39P/Oterma.

It’s an interesting object, this Oterma, one that sometimes is captured by Jupiter for one to several orbits. Call it a ‘temporary moon.’ In the same way, the authors believe that ‘a small velocity increment’ would be enough if exerted in the right place to cause the temporary capture of a NEO in Earth orbit. They acknowledge that the method would work only for small NEOs, based on our current technology, with the larger ones being too heavy for significant change to their orbital energy.

How to cause the desired effect? The authors look at alternatives from nuclear explosions and kinetic impactors (impulsive) to Yarkovsky effect, focused solar, gravity tractor, mass driver, pulsed laser and space tug (slow push) before settling on one from the first camp:

Considering the required impulsive velocity increment is not so small and the diameter of NEOs is relatively large, there are two impulsive capture methods available, kinetic impactor and nuclear explosion, but they are never tested or applied. Among them, the nuclear explosion method may not be proper one for the mentioned small NEO, because the nuclear explosion can release a very large amount of energy, the result may be a fragmentation of the target NEO. So the kinetic impactor is often considered as a better maneuver means especially for the NEOs smaller than 50 meters in diameter.

So we’re talking about a space probe or projectile that would hit the NEO at high velocity and change its orbit. A possible candidate is the smallish asteroid 2008EA9, but the list of candidates is growing as our surveys continue. The new orbit would be a temporary one but would allow a prolonged period of study and, possibly, exploitation of resources there. All of which jogged my memory of Carl Sagan’s work with JPL’s Steven Ostro on precisely these matters. One paper devoted to the problem was “Cosmic Collisions and the Longevity of Non-Spacefaring Galactic Civilizations” (citation below). Two matters come to mind in relation to it, the first being the need to deal with space debris over the long haul, which Sagan and Ostro handle thusly:

Sooner or later human civilization must confront the asteroid/comet collision hazard or become extinct. Dealing with interplanetary collision hazards over a period of centuries or millennia will naturally take our spacefaring society further out into the solar system — if for nothing else, to improve surveillance of incoming comets. As technology advances and the life-span of our species (and its successors) lengthens, a slow outward transition from interplanetary travel towards cometary source regions and interstellar spaceflight seems conceivable.

That’s a ‘meme’ that Centauri Dreams has been working with for the past seven years, that interstellar flight will grow organically out of the need to extend infrastructure outwards in the Solar System rather than through an interstellar project mounted Apollo-like on its own. The second issue, though, is much more troubling. Sagan and Ostro again:

… altering the trajectories of objects in nearby interplanetary space can introduce perils on timescales much shorter than the average intervals between natural impact catastrophes… Thus, interplanetary collision hazards may act as a kind of sieve, simultaneously requiring civilizations to become spacefaring and to institute stringent controls on the misuse of orbit-engineering technology. These joint constraints may or may not be so severe as to truncate the longevity of spacefaring civilizations below the timescales for civilization-ending impacts themselves. One way or another, interplanetary collisions constitute a unique, exogenous environmental factor in the natural selection of long-lived civilizations.

I’m thinking that Sagan and Ostro had the matter precisely right. Whether through simple error or the calculated decision to use a small NEO as a weapon, the dangers of asteroid deflection for research and mining seem not to merit the risk. I’ll buy the notion that getting to an asteroid with robotic probes or manned missions makes sense as we continue to assess the potential threat they may pose, but let’s reach them without trying to tug them into new trajectories. As Sagan and Ostro noted some time ago, we’re about at the point where we have the technology to alter an asteroid orbit. And as Sagan wrote in Pale Blue Dot (1994), “If we’re not careful, many nations may have these capabilities in the next few decades. What kind of world will we then have made?”

The paper is Baoyin et al., “Capturing Near Earth Objects,” accepted for publication in Research in Astronomy and Astrophysics (Chinese Journal of Astronomy and Astrophysics). Preprint available. The Sagan and Ostro paper is “Cosmic Collisions and the Longevity of Non-Spacefaring Galactic Civilizations,” JPL TRS 1992+, available online. See also Sagan, “Dangers of Asteroid Deflection,” Nature 368, Issue 6471 (1994), p. 501.


Comments on this entry are closed.

  • Martin J Sallberg September 7, 2011, 10:48

    The unlimited abundance of resources and real estate in space would eliminate all motivation to fight, and thus asteroid-weapons will never be a problem. Mentioning the abundance would be the perfect conflict-solver, there would be no motifs for territoriality at all.

  • Tom Mazanec September 7, 2011, 11:28

    Martin, do you REALLY believe that resources and real estate are the only reason humans fight?

  • Alex Tolley September 7, 2011, 11:30

    Does mining the asteroid in situ vs sending it to earth for LEO mining really change the cost of the project? In situ mining makes more sense if the cost of support is not much larger than at LEO and you want to reduce upfront capital costs.

    IMO, the mining technology issues are the more interesting ones.

  • david lewis September 7, 2011, 12:50

    Any nation able to use asteroids as weapons of mass destruction will have other options available. Take the US for example, it can’t yet use asteroids as weapons yet during the cold war built around 70,000 nuclear weapons. It would also be obvious who deflected any asteroids used in such a way, meaning the nation to retaliate against would be obvious. Plus the amount of time it would take for such a weapon to be used would allow the chance of deflecting it and/or for the nation being attacked to at least launch its own attack.

    The same argument can be used to claim that the moon should not be used as a source of materials for building in space – that materials taken from the moon can be hurled at earth based target.

    Such arguments effectively limits us to materials we can launch out of the earth’s gravity well as well as effectively stopping the development of any serious space based infrastructure.

  • ljk September 7, 2011, 12:58

    But not every nation will have their own access to space and they may resent not being able to get at the wealth. We have seen what happens here in these scenarios when one group wants what the other has and feels there is only one way to get it. Planetoid resources may just enhance this age-old issue.

  • Tom Louden September 7, 2011, 13:26

    Martin, I think you underestimate the human capacity to find things to squabble over…

  • Mike September 7, 2011, 13:30

    One way to reduce the risk would be to only allow asteriods to be placed in Lunar orbit. That would provide some cushion for any possible mistakes in the calculations for altering the orbit of the asteroid. And it would still be parked closeby for mining. To avoid malevolent usage the technology would have to be very tightly controlled. Still, a risky project though.
    Much safer to mine them where they are and send the smaller pieces to Lunar orbiting factories. Real SF this!

  • ljk September 7, 2011, 13:45

    As for China in particular, I can see two reasons why they would be interested in the planetoids: If they want to dominate the Sol system, securing as many of these plentiful and easy-to-access interplanetary resources is a logical step.

    Using a couple of them as a “playing card” in global politics also makes sense: Just as with nuclear weapons, you don’t have to actually use an NEO, you just need to let your enemy know that you can control them. This includes the possibility of dropping one on a rival nation’s capitol, with the added bonus of no messy radiation in the aftermath as with a nuclear bomb.

    To those who wish to explore and utilize space for peaceful purposes “for all mankind”, the above may seem primitive and even repulsive, but we first achieved access to space via rockets originally intended as carriers of weapons of mass destruction. The US military space program still gets more funding than NASA and I bet the Chinese version does too. For both nations’ leaders, despite the platitudes of using space for the betterment of scientific knowledge and improving terrestrial society, it is ultimately about how controls the ultimate high ground, just as it was in the Cold War days with the USSR.

    We may be seeing signs of a new space race, one that is more low-key on the public surface but with much higher stakes than who puts their flag and footprints on another world first. And science will once again take a back seat and be utilized primarily to make sharper spears.

  • Astronist September 7, 2011, 15:48

    Paul: “the dangers of asteroid deflection for research and mining seem not to merit the risk”? I don’t buy it. For one thing, we’ll need asteroid deflection sooner or later anyway. For another, as soon as the technology becomes generally available, moving an asteroid off a collision course will always be easier than moving it onto one. And in my concept of the future, interplanetary transport Earth-Mars will be partly carried on cyclers, inhabited stations in heliocentric orbits which grow to interplanetary cities, and one of those could as easily be used to impact a country on Earth. What we want here is a universal and international system of space traffic control, analogous to air traffic control on Earth, not an aversion to doing anything that has the slightest risk attached to it.

    Oxford, UK

  • Tulse September 7, 2011, 16:32

    I would really like to see some real economic analysis of asteroid mining, as I am far from convinced of the economic feasibility in any reasonable time frame. Mining involves moving a lot of mass a lot of distance, and that is very difficult to do in space.

  • Alex Tolley September 7, 2011, 16:50

    The asteroid material can be used to move pieces around, for example using mass drivers as suggested by O’Neill. If volatiles are present, high Isp electro-thermal engines could be used. Finally you could use solar sails.

    That is not to say that the economic questions are easily solvable. The resources are there, and huge, but the cost of mining even the most expensive elements on earth are still far lower than asteroid mining.

    Another option is to mine the asteroids after they have made the journey to the inner system themselves, such as impact sites on the moon, as the delta v is much lower than from the asteroid belt.

  • andy September 7, 2011, 17:19

    Far as I am aware the cost per kilogram of getting the material down safely is going to be prohibitive. And on Earth many of the valuable minerals are concentrated by the actions of tectonic or hydrological processes that do not operate on asteroids.

    Extracting precious metals from sea water seems much more feasible than asteroid mining, but that is still not economically viable…

  • Rob Henry September 8, 2011, 4:20

    Martin J Sallberg’s sentiments can only be admired, but I would go further than his other critics and say what a wonderful way this would be to wage a covert war. Note how widely held the belief in a hyper-competent government is, and now note that a bug planted in the telemetry software by a foreign agent or terrorist would effectively deflect suspicion from the true culprits. Thinking this couldn’t work if the government presiding over the enterprise is the main victim is equivalent to thinking that no one could be naive enough to believe that George Bush planned September 11.

  • Martin J Sallberg September 8, 2011, 8:09

    I meant that fighting ULTIMATELY boils down to resources and real estate. When people claim to fight over anything else, it is because they have been indoctrinated to think they fight for another reason, are indoctrinating others to dito, or are denying and suppressing their own true motifs. Aggression is a instrumental behavior, rational from a egoistic point of view. The myth of aggression being some “irrational instinct” (absurd term for lack of sensible terms to describe the mainstream idea, because the mainstream idea is absurd) was created because leaders were spreading propaganda that egoism was wrong (in order to make the people sacrifice themselves for them), and that made people deny their true motifs. People who are born sceptic for genetic reasons have very good, nearly eidetic, memory, because they are immune to indoctrination and thus their minds do not split in one conscious and one subconscious part (I am one of the congenital sceptics, otherwise I would have been too indoctrinated with mainstream propaganda to do this research).

  • Martin J Sallberg September 8, 2011, 8:12

    Just one more thing: without competition over resources and real estate, the motifs for deception and thus the very practice of “making up excuses for squabbling” will disappear.

  • Doug M. September 8, 2011, 10:03

    1) Getting metals from an orbiting asteroid is not a simple thing. You need to use aerobraking (otherwise your delta-V costs devour your profit), which means you need to build aerobraking shells. And you’ll be sending megatons of metal out of the sky, and they’ll be hitting Earth at terminal velocity (at least), so you’d better have seriously redundant navigation systems. I have yet to see a discussion of this topic that doesn’t handwave this away, but it’s arguably the technically trickiest part.

    2) Can we just stop using the DANGER OF ASTEROID IMPACT! ! meme? Pretty please?

    The current best guess is that we get potentially civilization-destroying impacts on the order of every million years or less. That’s geologic time, dude. And we’ll see it coming decades to centuries in advance. (Unless civilization has already fallen. In which case, you know, civilization has already fallen.)

    We already know where most NEOs over a couple of hundred meters are. Within a decade or two, we’ll have catalogued everything that size within the orbit of Jupiter, and we’ll have found every NEO down to a few tens of meters. At that point it will be impossible — repeat, *impossible* — for us to be surprised by a major asteroid impact.

    (There are still comets. But cometary impacts are around 2 orders of magnitude less common — and a large long-term comet is going to make itself obvious well before crossing Earth’s orbit.)

    3) “many nations may have these capabilities in the next few decades” — As opposed to the ten or so nations that can build fission bombs, or the five or so that can build fusion bombs, I guess.

    If you’re trying to smash another nation, grabbing an asteroid seems like a really, really inefficient way to do it.

    Doug M.

  • Bob September 8, 2011, 11:57

    I believe religious and ideological differences are very real and can and do lead to aggression and they are not always ultimately about resources but about ideas. If resources were no issue at all some would still try to force their culture and ideas on others.

  • Denver September 8, 2011, 13:13

    Humanity will reach a point where individuals will have access to technology capable of dropping rocks from great heights. Unless you believe we won’t colonize the asteroid belt and that colonization won’t lead to criminal and megalomaniacal individuals living, working and pro-creating, in that environment.

    We think too small when we believe responsible government will control this, or any, technology forever.

  • ljk September 8, 2011, 13:17

    Doug M., who said the planetoid resources would all be heading to Earth? Most of them will be utilized for building an interplanetary infrastructure such as O’Neil colonies and interstellar space arks. Some minerals will be shipped to Earth on an as-needed basis, but it will always be expensive and dangerous, so there will not be a huge market for that aspect.

    Attacking another nation with a planetoid has one big factor in its favor: The psychological one. How possible this will actually be and how much damage it can cause will be secondary to the fear it will instill in a government and populace that barely know anything about them besides having seen Armageddon a few times.

    Putting humans on the Moon in the 1960s was not the most efficient way to
    get lunar science, but it had a tremendous impact in all sorts of ways that reverberate to this days, whereas the few Soviet robotic Luna missions and the American Surveyor landers are barely remembered by anyone but the space buffs. Plus the Luna probes returned mere grams of lunar regolith compared to the 840 pounds of rocks by Apollo, along with the scientific instruments left there.

    Please reread my post in this thread on how China and other space powers can and likely will utilize the psychological threat of NEOs in what may become a new space race. That is my interpretation as to why China is suddenly so interested in these celestial objects and why NASA is suddenly being told to start sending manned missions to them.

  • Martin J Sallberg September 8, 2011, 14:01

    The whole concept of forcible introduction of ideas is a result of competition over resources. There is concrete evidence for this. Before Earth was overpopulated, identical cave paintings and sculptures were spread across vast areas, and human bones from that time show no evidence of violence. That means that pre-overpopulation humans were not xenophobic at all, they did not even feel any need to demarcate “we or them”. Considering that transportation was slow back then, far too slow to fulfil Hitlers criterium “the people needs a visible enemy, not an invisible one” (and of course the impostor effect, that it is possible that someone can hoax their own identity which means that rivalry between groups is bound to spill over into suspiciousness within the group, which would rule out the evolution of modern human naivity if rivalry existed between groups), it cannot have been any kind of “vast military alliance” either. Extant hunter-gatherers are not an accurate model for early humans because the former are subject to exterior threats the latter did not face, and as mentioned above there is concrete evidence of such differences too. Furthermore, modern ethology shows that aggression in clever animals such as monkeys is rational and instrumental (Konrad Lorenz only studied dimwitted animals like fish and songbirds), which makes sense because advanced brains can discriminate between many different situations.

  • andy September 8, 2011, 14:39

    Please reread my post in this thread on how China and other space powers can and likely will utilize the psychological threat of NEOs in what may become a new space race.

    It’s about time we adapted Godwin’s law to a form appropriate to discussions of spaceflight. How about:

    As the length of a discussion of space travel on the internet increases, the probability of posts containing anti-Chinese xenophobia approaches 1…

  • ljk September 8, 2011, 16:08

    Martin J – How do you explain Native American populations in pre-Columbian times with all of their fighting and artificial borders? While perhaps our prehistoric ancestors were not into organized warfare, I find it hard to believe that everyone lived in an Edenic harmony with each other. Chimpanzees sure don’t.

    Andy – If you have evidence that the Chinese government has only peaceful scientific intentions for their space program, please present it. They have five space centers, which I find incredibly generous for their government to spend money like that just on altruistic research, and in 2007 they demonstrated their ability to take out satellites in orbit, which the US promptly responded in kind under the pretense of getting rid of a potentially dangerous old satellite.

    Dominating space does not have to be a hot war, nor would any government with any sense make their ultimate intentions obvious. Perhaps I am wrong, but why wouldn’t China look ahead far down the road, knowing where human destiny may reside as Earth becomes more crowded with fewer resources. I would be staking claims to valuable property out there had I such abilities in my posession.

    The nice thing about this is that I hope I am wrong, that this is just paranoia left over from growing up during the high years of the Cold War and being both surprised and disappointed when I figured out that the USA and USSR were really using space to plan geopolitical strategy and not just for science and adventure. I don’t really see the Chinese government behaving any differently based on a combination of political logic and history, but maybe this time I will be surprised in a different way. Of course if what I predict does turn out to be true, then at least I will be glad I was not intimidated into keeping my thoughts to myself.

    And here is my next “paranoid” space prediction for China: They have a lot of room in their relatively barren western desert regions to test and launch an Orion nuclear fission vessel. They have had nuclear capabilities since 1964, a space program just about as long, and Orion is the most probable of all interstellar vehicle concepts to become a reality in our lifetimes. Of course Orion is also quite suitable as an interplanetary vessel, too. After all the American developers of Orion used to chant “Saturn by 1970.”

    If I am wrong, then I am wrong and in certain ways that will be sad for those of us who do want to see the Sol system colonized some day and probes heading off to Alpha Centauri soon after that. But if I am right, then perhaps some healthy competition in the Final Frontier again will be what it takes to get us back up there, this time to stay.

    Once we are established up there, THAT is when private industry can really do its thing. Otherwise right now space is much too expensive for most businesses to risk investing real money, except for those companies that want to take a few rich people on suborbital joyrides.

  • Eniac September 8, 2011, 20:58

    This excellent post, and the mention of kinetic impactors, has made me think of a possible way to move any size asteroids around practically at will, with very little energy expense: A sort of interplanetary Billiards.

    You would start with a VERY large catalog of objects of all sizes orbiting the sun. You would then pick a chain of increasing size, each within a small delta-v of the next. You would launch a small pebble to start the cascade: the pebble would collide with a rock, and put it into collision course with a boulder, which in turn would hit a house sized asteroid, and so on until you reach the desired size. Sure, the calculations would be very complicated, but that’s why we have computers. Adjustments would probably be needed every step of the way, perhaps aided by starting multiple converging cascades. The ratio of delta-V achieved vs. delta-V invested could be astronomical.

  • Rob Henry September 8, 2011, 21:10

    Ljk, I have no problem with hypothesising that the Chinese have plans for global hegemony, but surely their space ambitions works best if it is undertaken in lieu of war, and very cost ineffective if it is just meant to augment it? Thus I put it to you that there is great reason to believe their plans are peaceful, but they might be dastardly.

  • Martin J Sallberg September 9, 2011, 2:41

    The Native Americans were actually what modern researchers term “quasi-agrarian”, that is, they exterminated or decreased the numbers of unwanted plant species to favor wanted plant species, they practiced much of their hunting just for balancing animal populations, and other work-demanding environmental modification. The myth of hunter-gatherers in general working all day long comes from studying such quasi-agrarian societies and then falsely believing it to be typical of hunter-gatherers. And it is obvious that the same type of breeding workforce applies to quasi-agrarian families as to “true” agrarian ones. Quasi-agriculture gave less returns than “true” agriculture, meaning that overpopulation caused competition for resources earlier, which I think explains why stratification happened earlier in the New World than in the Old World (a 7800 year old chieftain grave has been found in the New World, while no evidence of stratification in the Old World is older than 7000 years, barring only the temporary hierarchies that some neanderthal groups formed during starvation disasters). I never claimed that China has only peaceful space intentions, but I think their warlike space intentions is all either instrumental for Earth interests or the result of ignorance of the unlimited abundance in space. The unlimited abundance of resources and real estate in space makes claiming exclusive property pointless (there is always equally good places just around the corner), it is quite unlike on present-day Earth where there is lots of claimers and limited resources. And I have already explained that our ancestors transcended chimplike competitiveness when the first hominins migrated from Africa. Indeed, the theory of recent replacement is debunked in the study “Heterogenous variation patterns among multiple human x-linked loci”, which shows that while most loci shows the greatest diversity in Africa, some loci do show the greatest diversity in Europe or Asia, and even among the afrocentric majority there is much heterogenity from loci to loci in how afrocentric they are, which means that the neutralist bottleneck model is wrong and the real reason why africans are most individually diverse is that diversity-reducing selection has done the most work outside Africa. Much of the difference between human and ape biology is about the life cycle (long childhood, living past menopause, and so on), which is obviously an adaptation to storytelling. Perhaps diversity-reducing selection has done the most work outside Africa because the “leavers” successfully avoided competition slightly earlier than the “stayers” and thus got a slight head start in the “no motifs for deception”-trust required for the origin of storytelling. Early modern humans everywhere show more individual diversity than currently living humans, and much of what is considered “multiple species” or “sexual dimorphism” in early Homo may instead be truly extreme individual diversity. Protein analysis also show much biomolecular continuity between neanderthals and the earliest cro-magnons, far more than 1-4%. The last neanderthals differ a bit too much to be in a perfect biomolecular bell curve with contemporary cro-magnons, but such late neanderthals may just be descended from the starvation-struck populations mentioned above (competition for food halting storytelling evolution), while early neanderthals who were spared from rivalry all along evoved into cro-magnons. Early anatomically modern humans did not posess fully modern senescence either.

  • andy September 9, 2011, 14:50

    Andy – If you have evidence that the Chinese government has only peaceful scientific intentions for their space program, please present it.

    This is a strawman argument and I am sure you know it. The majority (if not all) of the extant space powers all have their military satellites up there, spying on the rest of the world but we direct all our anxiety against the Chinese. After all, if the criterion for xenophobia and racism being acceptable was that the other party had an army, we could pretty much justify any given example of these.

    I do find it quite sad that once the rationale for space travel gets beyond the flowery rhetoric about leaving the cradle and destiny and all that, it just descends into “well if we don’t do it [foreign bogeyman of the decade] will do it first”. Sad but ultimately not surprising: after all spaceflight’s towering achievement, the Apollo moon landings, was basically a military escapade to make a monument to American nationalism motivated by anti-Soviet paranoia.

  • ljk September 9, 2011, 17:30

    I am more concerned about the intentions of the Chinese government as it currently exists over anything else. Russia likely still has its same national ambitions, but they do not have the budget and resources they once did during the Cold War. No other space-faring nation or group even comes close to might of the Big Three for the next few decades.

    Of course as things get more dire on Earth and the various governments really start to realize how much space (no pardon of the pun) and resources are out there beyond our one little planet, I expect things to get very competitive if not ugly from all sides if we do not try to establish some binding guidelines and infrastructure in the Sol system NOW.

    When I see humanity truly acting as declared on the Apollo 11 plaque attached to the descent stage of its LM in the Sea of Tranquility, then I will relax my guard. Of course that is when an alien fleet shows up and notices all the riches of our Sol system.

  • Eniac September 11, 2011, 11:58

    Let us not forget that the Chinese along with all the others are minnows compared with the shark that is the US military, in space as in all other fields. At this time, nobody can touch us, and it will remain so for the foreseeable future. It will indeed be interesting times if or when this absolute hegemony ever gets challenged, but it is way to early to guess by whom, current conventional wisdom that it be China notwithstanding. On thing is clear, though, to me: space is going to play an important role in this process.

  • Eniac September 11, 2011, 12:04


    Getting metals from an orbiting asteroid is not a simple thing. You need to use aerobraking (otherwise your delta-V costs devour your profit), which means you need to build aerobraking shells.

    You are absolutely correct, except I think that it may be possible to simply drop hunks of metal, without any shells around them. When entering at the right angle, the material should survive intact. Perhaps the heat of reentry can even supplement and simplify the smelting process.

  • Martin J Sallberg September 12, 2011, 9:16

    The sheer abundance of resources and real estate in space makes competition over it futile (why fight to keep something when something equally good is always just around the corner?), and aliens would, for precisely the same reason, have no motivation to attack the Sol system at all. “Binding guidelines” in space is futile because it is always possible to get away (literally, get away from the place) but that will not be a problem in the absence of motivation to do bad things.

  • ljk September 12, 2011, 10:03

    You do not always need fancy technology to fight battles in Earth orbit. Just send up a bucket of sand or pebbles going 18,000 MPH and let physics do the rest. Even beginner space nations can do that.

  • Eniac September 12, 2011, 20:19

    Yes, but that would be considered very bad behavior and the upside for the perpetrator would be extremely limited. And, as I understand, small objects clear LEO relatively quickly due to atmospheric drag.

  • ljk September 13, 2011, 10:03

    Taking out an enemy’s “eyes” in space may be all one needs to do to harm their military capabilities, which for all nations is still largely on the ground or in the air and rely on satellites to communicate with each other as well. Conducting actions considered bad behavior has hardly ever stopped any group or nation before bent on war. Just ask the Taliban who attacked the US Embassy in Afghanistan this morning.

    Though there may be some hidden battlefleet on the lunar farside, I believe the military extent for most spacefaring nations are spysats. I know the DoD has a few weather satellites for their own purposes and no doubt a bunch of comsats, too. As I said, a bucketfull of sand moving at orbital speeds could take them all out. I can even see a nation deliberately fragment a satellite or rocket booster as an “accident” to use the fragments to damage or destroy an enemy nation’s satellites. Of course if LEO keeps getting polluted with space debris as it has no one may need to do anything intentional.

  • Eniac September 13, 2011, 21:04

    I have an idea about who is going to do harm to who’s military if tried to pull a stunt like this.

    There hasn’t really been a war that the US was involved in since Vietnam. What there was were quick routs met with negligible resistance, followed by long drawn out periods of nation-building accompanied by tedious and expensive police action against insurgent activity and terrorism. You can call that “war” to feel better about it, but the good old fashioned idea of two armies clashing surely does not apply.

    I do not think taking out all satellites would change that. Rather, it would likely provoke another one of these “wars” against the perceived perpetrator, with similar results.

  • Rob Henry September 13, 2011, 23:12

    I think this discussion illustrates how important it is that every first world country does its bit any pays its way in space and exploration. The rest of us should not rely on the continuing dominance of an insular country that is prone to sudden bouts of isolationism.

  • Avatar2.0 September 22, 2011, 8:18

    I find using NEO as weapons to be grossly inefficient.

    A simple comparison between NEOs and nuclear warheads reveals the nuclear warheads to be the better weapons under every relevant criterion you would care to consider:

    A nuclear warhead will reach its target within seconds, leaving very little time to the attacked country for interception.
    A NEO would reach its target in, at the very least, weeks, leaving ample time to be diverted again by the attacked country. It’s worth mentioning that, even today, we know the major – and not so major – NEOs. In the future, every single NEO could be easily – and relatively cheaply – monitored.

    A nuclear warhead clandestinely imported in a country and then detonated will hide the identity of the aggressors far better than a NEO.
    Because, in order to reach a NEO and deflect it, one would need a means of interplanetary transportation and the deflection technology – all FAR easier to keep track of and trace than a nuclear warhead.

    As for using pebble-sized NEOs – there’s no need for fancy deflection tech in order to do that. Even today, we’re more than able to do it – if we had interplanetary transport – which, again, IS far easier to keep track of and trace than nuclear warheads, especially if one monitors Earth’s vicinity with a minimal amount of diligence.
    There’s a very good chance of intercepting/deflecting such NEOs.
    In case this fails – any forensic analysis will reveal that those pebble-sized NEOs appeared out of nowhere, aka they were launched/deflected by a ship/probe/etc, and that this ship/probe/etc belongs to X.
    And, of course, anyone who has the means to divert small-sized NEOs has, most likely, nuclear weapons – meaning it won’t resort to such inefficient weapons, but simply use rockets to destroy the enemy country’s satellites and then declare war (seeing as in no scenario can it hide its culpability).

    In conclusion, I find all this fear of using NEOs as weapons baseless.

  • ljk February 16, 2012, 9:49

    NEOShield: a Preemptive Strike Against Asteroids

    by Amy Shira Teitel on February 15, 2012

    Scientists aren’t entirely sure when the last major asteroid hit the Earth, but it’s certain to happen again. Alan Harris, asteroid researcher at the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR), is hoping to head the next one off.

    Last month, Harris established an international collaboration of 13 researchers to investigate methods of shielding the Earth from near Earth objects (NEOs). The project is, appropriately, called NEOShield.

    Asteroids approaching the planet typically travel between 5 and 30 kilometres (about 5 to 19 miles) per second. As that speed, a moderate sized body can have major consequences. The Barringer Crater in Arizona, often referred to as Meteor Crater, is a 1,200 metre crater (about 3,950 feet or 0.7 miles) that scientists hypothesize was caused by a 50 metre (164 feet) meteor.

    The bad news is that there are thousands of known NEOs just like the one that made Meteor Crater, leading experts to posit that a dangerous collision could occur as often as every two hundred years.

    Full article here: