Defending Earth From Asteroids With MADMEN 499
jolomo writes "A partner of Atlanta-based NASA Institute of Advanced Concepts is working on a concept they call MADMEN (Modular Asteroid Deflection Mission Ejector Nodes), which would launch a distributed attack against large Earth-bound objects. Thousands of MADMEN could be built by many nations and when launched, each would land on the object, drill into its surface and remove enough material to change its course."
LUNATIC?? (Score:3, Informative)
Why so much negativity? (Score:5, Informative)
If you had RTFA, they address those odds pretty well. The odds of getting another Tunguska sized impact are roughly 1 per 1000 years. That's an *average* people. To break it down, it could theoretically happen tomorrow. Further, if you had RTFA, you would note that an object of roughly the same size as the estimated Tunguska object (150 meters across) which was first discovered this year just passed within 3.8 million miles of our planet. That's roughly 16 times (two bytes) the distance from us to the moon....or pretty damn close.
These are ideas. If they sit around and come up with 1000 bad ideas for every good one, I still don't care. That one good idea might save my ass...or my family's collective ass.
There's always people who won't believe it can happen to them, though. Look at all the folks who insisted that, because of the SF quake in 1906, that they would be safe 'for their lifetime' since it couldn't happen again. Whoops. Tell that to the folks smashed in their cars when the elevated roadway collapsed. Or, 'Well, we know Mt. St. Helens is a Volcano, but it hasn't erupted since we've been keeping track...so it'll be safe as long as I'm alive.' Tell that to those folks who chose to stay and whose bodies will never be found underneath 100's of feet of mud.
Hell, the odds of being struck by lightning are VERY slim...but plenty of research goes into preventing that, and no one complains. The odds of being shot and killed are miniscule...but look how much money we spend on prevention. But as soon as you begin researching something that could, quite literally, kill millions of people in an instant, you're branded a 'waste of time and money'.
Tell you what. Give me back the taxes I spent that went to teaching your children, and I'll gladly redirect them to fund this type of research.
Re:Alternative methods (Score:3, Informative)
Even so, the considerable problem of detecting a small, dark object at a very great distance with enough time left to be able to deploy countermeasures is not solved. This might require deploying a network of passive sensors across the solar system...
Re:Experiment (Score:2, Informative)
if you have an object made of two parts (e.g 'gun and bullet' or 'rocket and exhaust gas') which is initially stationary, then if one part moves forwards, the other part MUST move backwards to conserve linear momentum.
Re:All nations, huh? (Score:3, Informative)
So really the only way you could get it to hit the "other" side of the earth, would be to delay it AND deflect it to be into the new spot in earth's orbit. If you can deflect it, just deflect it the OTHER WAY.
In addition, an asteroid of any significance hitting the earth (singificant enough that we would try and deflect it) would be pretty much cataclysmic regardless of where it it. Tidal waves, and dust plumes, and fires would do the damage no matter where they started from.
Re:Experiment (Score:2, Informative)
The A-10 is somewhere between air-cavalry (which would be the army's business) and fighter (which of course the air force would command).
Since it's got fixed wings, and requires (a relatively long runway), and all the support equipment and personel related to fixed wing aircraft, it's the Air Force's.
But you're right about the gun.
Search for A-10 test clips on the 'net. It's insanely powerful.
Re:Experiment (Score:3, Informative)
Re:Experiment (Score:2, Informative)
Re:Alternative methods (Score:5, Informative)
I'm not sure why people seem to think that you only need to paint half. I'm also not sure why other people think that because asteroids rotate this doesn't work - it is actually *because* the rock rotates that it does work.
This relies on a phenomenon called the Yarkovsky effect. It can be thought of this way: Imagine you're standing on the asteroid where it's "asteroid high noon". Light is being absorbed throughout the "asteroid day" and heats the surface, particularly if the asteroid is darkly colored (e.g. a carbonaceous asteroid). After a while, the asteroid rotates and the sun sets. The asteroid then reradiates this heat in the direction of "asteroid evening". As it rotates more, by the time "asteroid morning" rolls around, the area your standing on has cooled down enough to radiate much less. Ergo, there is a differential radiation pressure on either side of the asteroid, which results in a net force over time. If it rotates with the same spin orientation as its orbit, its orbit will get wider. If it rotates with the opposite spin as its orbit, its orbit will get smaller.
By painting the rock, you change this force - the brighter the paint, the more light is reflected, the less thrust, thereby changing the path.
One last comment - the effect is subtle, so it would need to be applied early. It also preferentially favors diversion for small asteroids, since the Yarkovsky effect is a surface phenomena. The larger the asteroid, the smaller the surface-area-to-volume ratio, and the less deflection this thrust will do.
Re:Experiment (Action - Reaction) (Score:0, Informative)
When you fire a bullet, a certain force is required to launch that bullet.
This force can be represented by a vector, with a certain length, and heading.
In complex notation it could be 500 mark 90
The law of action/reaction says that for every vector 500 mark 90 there will be a vector 500 mark 270
and it is that vector that moves your boat or whatever.
Re:Serious Problems (Score:5, Informative)
That's physically impossible. In the absence of torque, a rotating object will rotate about precisely one axis. It is possible for objects to "tumble," i.e., continually change the direction of their angular momentum vector, but this only occurs if there is a similarly complex external torque. If the external torque is constant, the resulting effect is called "nutation" or "precession," but it is not tumbling.
For an example, consider the Saturnian moon Hyperion, which is irregularly shaped and thus tumbles chaotically under the influence of the gravity of Saturn and the nearby moon Titan. However, if we removed Hyperion from the vicinity of Saturn and put it out in space far from any external forces, it would rotate quite simply around one axis only.
Asteroids do not "tumble" unless they are A) very irregularly shaped and B) extremely close to a massive body, which can supply a tidal torque.
Re:Appropriate acronym (Score:3, Informative)
This is finally some good use of taxpayer money. Science and technology like this is rarely applied directly as intended, but the spinoffs are what give us MRIs, integrated circuits, etc. </preach target="choir">
Re:Not the greatest threat... (Score:2, Informative)
CFC stands for Chlorofluorocarbons, which are manmade organic molecules produced at petroleum refineries for various uses. They do not exist naturally in any significant amount, and most definitely do not come from volcanos.
Disclaimer: I am a geologist
Re:Experiment (Score:5, Informative)
Re:Experiment (Score:2, Informative)
Scientifically/mathematically, the gun expels a small amount of mass accelerated to a given velocity by the propellant in the cartridge. This generates a back push (the bullet leaving the barrel - not the exploding powder). Simple action/reaction -- because the bullet is moving freely down the barrel (what energy lost is heat in the rifling, which is dissipated off the barrel), the gun is not accelerated by the "explosion" - the bullet is accelerating, not the gun.
Proof that the burning powder does not push against the gun, is that the barrel does not flip up (torque the gun), until the moment the bullet has exited the barrel, otherwise no bullet would ever hit a target it was directly aimed at.
Furthermore to correct most people on the thread, the bullet is accelerating all the way down the barrel --- the powder is burning through the entire path of the bullet down the barrel (not exploding at the cartridge --- though the initial pressure surge of the burned powder that separates the bullet from the cart is extremely important), enhancing the bullet's performance down the barrel. This is also why magnums or other high powered bullets have a lot of muzzle flash, these cartridges are stuffed with excess powder to give the bullet an extreme kick in the pants all the way down the barrel. Usually this results in an excess heated gas wave carrying burning burning powder and exiting the barrel of the gun, with burning completed outside of the gun barrel (and to no effect on the bullet). The excess is not a big deal -- unless you are firing somewhere close to a combustible object or liquid/gas. It's better to have more powder (since its cheap), to guarantee the effectiveness of the accelerator (as long as the accelerator can hold up to the pressures involved), with the accelerator being the barrel....
There is little to no push on the gun from the gases exiting the barrel... until the burning powder exits the gun barrel, all of the energy being released by the burn should be transferred to the bullet (save for the heat loss and frictional losses to the barrel).
TurboD
Re:Serious Problems (Score:3, Informative)
Re:Proliferation was great for the USA (Score:2, Informative)
Planes: The Russian counter part (Su-27) to the F-22 has been in production longer than the F-22.
Helicopters: The Apache helicopters are much less robust then the Hind. The apache is expensive and requires a lot of maintainence and can be shot down by co-ordinated rifle fire or unguided rpgs. The hind is more durable.
Generally: The US tries a lot of advanced technology but a lot of tiems a lower tech solutions is better. For instance the A10 warthog is a flying ofrtress that is very successful at it'a goals. IT's effective, cheap, druable, and low maintainence. The Army wants to scrap it in favor of a higher tech solution. The Colt carbides the army uses are expensive to make and not much mroe effective than the Ak lines that the russians make. The AK's are cheaper, more durable and essentially provide the same performance.
Right now, the russian military has been sinking into decay, but before the end of the cold war, their war machine was more cost-effective and more effective.