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NASA Outlines Asteroid Deflection Program
Posted by
Zonk
on Sat Mar 17, 2007 06:22 AM
from the please-destroy-ben-affleck-as-a-side-effect dept.
from the please-destroy-ben-affleck-as-a-side-effect dept.
An anonymous reader submitted a link to an International Herald Tribune story about NASA's answer to the movie 'Armageddon'. Specifically, they've outlined a plan to deflect a planet-killer asteroid. "In 1998, Congress gave NASA's Spaceguard Survey program a mandate of 'discovering, tracking, cataloging and characterizing' 90 percent of the near-Earth objects larger than one kilometer (3,200 feet) wide by 2008. An object that size would probably destroy civilization. The consensus at the conference was that the initial survey is doing fairly well although it will probably not quite meet the 2008 goal." With this tracking system in place, scientists are hopeful an intervention could be staged before any grim choices have to be made. Assuming they have the money and manpower needed for the effort, NASA has actually outlined a pair of procedures that dove-tail with each other: "First we would deflect the asteroid with kinetic impact from a missile (that is, running into it); then we would use the slight pull of a 'gravity tractor' -- a satellite that would hover near the asteroid -- to fine-tune its new trajectory to our liking. (In the case of an extremely large object, probably one in 100, the missile might have to contain a nuclear warhead.) To be effective, however, such missions would have to be launched 15 or even 30 years before a calculated impact."
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Interventions (Score:5, Funny)
NASA has announced that they have gathered the mother, father, siblings, and close friends of asteroid YT8OJR in order to confront it about it's continued binge drinking and other self destructive behavior before it leaves more shattered lives in its wake. Unconfirmed reports show that the troubled asteroid could be close to cracking up. Hopefully the intervention will keep it from a collision course with disaster.
Make things worse? (Score:4, Interesting)
Re:Make things worse? (Score:5, Informative)
Parent
Re: (Score:3, Insightful)
By hit you also mean the hit of gravity from a close encounter, right?
Re: (Score:2)
Re: (Score:3, Insightful)
You can imagine Peter Sellars in the War Room on the phone to China explaining that the nuclear deterrent is to deter asteroids, and in no way is trying to arm space.
How would nuclear weapons work in outer space? (Score:5, Interesting)
In the case of an extremely large object, probably one in 100, the missile might have to contain a nuclear warhead.
On earth, a nuclear weapon causes damage via its atmospheric shock wave - it's the motion [kettering.edu] of the air that causes buildings to fall down [or implode, or whatever].
Do we even know how a hunk of rock would react to the introduction of a bunch of alpha particles/gamma rays/x-rays/infrared radiation/etc? How would the the crystalline structure of the rock be affected? What models do we have that indicate the rock would shatter from an internal heat differential, rather than merely glowing very bright red for a while [assuming the rock even chose to absorb the heat energy in the first place, rather than just deflecting it off into the void of outer space]?
By contrast, underground detonations of nuclear devices are very benign events, and release vastly less energy than a small earthquake or a small volcanic event.
It's only the gaseous shock wave of an atmospheric detonation that causes damage to humans & their metropolitan areas - in the vacuum of outer space, with no atmosphere [i.e. with no gas, hence no gaseous shock wave], a nuclear detonation might not be that big of a deal.
Parent
Re:How would nuclear weapons work in outer space? (Score:5, Interesting)
Much of the damage caused by nuclear weapons, particularly hydrogen bombs, is actually from the intense heat released; the thermal energy is capable of causing severe burns miles from the point of explosion even after the air has absorbed most of the radiation (which is why, believe it or not, "duck and cover" isn't such bad advice). My suspicion is that you would want to detonate the bomb some distance above the asteroid; the heat would cause the surface of the asteroid to vaporize, and the gas jetted from the surface would shove the asteroid off course.
Parent
Empty space varies as N-cubed (Score:2, Insightful)
My suspicion is that you would want to detonate the bomb some distance above the asteroid; the heat would cause the surface of the asteroid to vaporize, and the gas jetted from the surface would shove the asteroid off course.
Empty space varies as R-cubed, and the spherical effects tend to degrade as 1 over R-squared.
It doesn't take much of an R to make that asteroid look like a tiny, insignificant needle in the vast, overwhelming haystack of empty space.
Cf Derbyshire's critique of Whedon & the "n [nationalreview.com]
Re:Empty space varies as N-cubed (Score:4, Insightful)
Without doing any calculation, I presume there's an optimal distance away which is somewhere around a quarter or a third of the asteroid's diameter. Presumably someone would simulate this properly before launching a nuke all the way to an asteroid.
Parent
Re: (Score:2)
Most of the he
Ladies and Gentlemen, I present to you: CTDF (Score:5, Funny)
1. Fly satellite up there
2. Make satellite paint a big-fat google logo on the asteroid
3. Let Steve Ballmer have a look through telescope
4. Provide him with practically insufficient supply of chairs
5. Wait
6. Danger avoided
Re: (Score:3, Informative)
Re:Ladies and Gentlemen, I present to you: CTDF (Score:5, Funny)
1. Tell Steve Ballmer the asteroid is a threat to Microsoft
2. Disable all space-based anti-ballistic-chair defenses
3. Wait
4. Danger avoided
Parent
http://www.lpl.arizona.edu/impacteffects/ (Score:5, Informative)
Your Inputs:
Distance from Impact: 250.00 km = 155.25 miles
Projectile Diameter: 1000.00 m = 3280.00 ft = 0.62 miles
Projectile Density: 3000 kg/m3
Impact Velocity: 40.00 km/s = 24.84 miles/s
Impact Angle: 80 degrees
Target Density: 2500 kg/m3
Target Type: Sedimentary Rock
Energy:
Energy before atmospheric entry: 1.26 x 1021 Joules = 3.00 x 105 MegaTons TNT
The average interval between impacts of this size somewhere on Earth during the last 4 billion years is 1.8 x 106years
Atmospheric Entry:
The projectile begins to breakup at an altitude of 67700 meters = 222000 ft
The projectile reaches the ground in a broken condition. The mass of projectile strikes the surface at velocity 39.8 km/s = 24.7 miles/s
The impact energy is 1.25 x 1021 Joules = 2.98 x 105MegaTons.
The broken projectile fragments strike the ground in an ellipse of dimension 1.1 km by 1.08 km
Major Global Changes:
The Earth is not strongly disturbed by the impact and loses negligible mass.
The impact does not make a noticeable change in the Earth's rotation period or the tilt of its axis.
The impact does not shift the Earth's orbit noticeably.
Crater Dimensions:
What does this mean?
Crater shape is normal in spite of atmospheric crushing; fragments are not significantly dispersed.
Transient Crater Diameter: 17.2 km = 10.7 miles
Transient Crater Depth: 6.08 km = 3.77 miles
Final Crater Diameter: 25 km = 15.5 miles
Final Crater Depth: 0.78 km = 0.484 miles
The crater formed is a complex crater.
The volume of the target melted or vaporized is 10.9 km3 = 2.62 miles3
Roughly half the melt remains in the crater , where its average thickness is 47.1 meters = 154 feet
Thermal Radiation:
What does this mean?
Time for maximum radiation: 0.54 seconds after impact
Visible fireball radius: 16.6 km = 10.3 miles
The fireball appears 15.1 times larger than the sun
Thermal Exposure: 6.78 x 106 Joules/m2
Duration of Irradiation: 280 seconds
Radiant flux (relative to the sun): 24.2 (Flux from a burner on full at a distance of 10 cm)
Effects of Thermal Radiation:
Much of the body suffers third degree burns
Newspaper ignites
Plywood flames
Deciduous trees ignite
Civilization (Score:2)
At least we'd have spectacular s
Hey (Score:2, Funny)
Why not use it? (Score:2)
Re: (Score:2)
Oh, I have no doubts asteroid mining will one day be a huge driving force for the commercialization of space. Once it's practical and cost effective, we'll do it. But regardless of the value of an asteroid's material composition, it is decidedly *not* useful if it's headed right for us on a collision course. Nudging such an asteroid just enough to be captured into Earth orbit ra
Asteroid Radar System? (Score:2, Interesting)
1. Go into a position above the plane on which the planets rotate around the sun so it looks "down" on the solar system.
2. flash a bright light of a specified color every day at a certain time.
3. read back the ping signature of the solar system's objects with a light sensitive camera.
4. plug the changes into a computer.
5. calculate trajectories of all objects.
6. determine exactly which ones are on a bee-line for earth.
7. continue to mo
Re: (Score:2, Informative)
The real question (Score:2)
Funding? (Score:2)
Bruce Willis (Score:3, Funny)
Re:Bruce Willis (Score:5, Informative)
Parent
stupid idea from NASA (Score:2)
a plausable idea would be to use a nuclear bomb, not to destroy the asteroid or meteor but to detonate the bomb before it gets too close leaving the asteroid or meteor mostly intact, the blast wave from the bomb can be strong enough to push it out of the way...
Re: (Score:2)
And what exactly does this blast wave consist of? The ether? Phlogiston? Cowboy Neal?
SteveM
Launch vehicle? (Score:2)
What's the hurry? (Score:2)
Why bomb the asteroid when you could keep ion engines running for decades instead? Or maybe find some point in its orbit where it's going between two heavy bodies and a small change will tip it one way or the other and make a big difference?
Re: (Score:2)
Funding? (Score:2)
Was that just a build up to make them look more important when this got released or did they find funding from their Doom and Gloom apropriations aproach?
OR maybe all the discusion NASA not being able to fund [slashdot.org] this exact program was sparked because someone didn't know what was going on? The government doesn't work this fast in approving funding so how could it be possible for them to all the sudden have it now? Especial
Re:Get a life (Score:5, Insightful)
Well, unless you've seen any dinosaurs lately, an extinction event has happened in the Earth's past at least once. Yeah, the chances of it happening again in our lifetime are infinitesimally small, but the consequences of *not* deflecting an asteroid if it comes our way are especially dire. I, for one, am all for the "just in case" planning in this regard.
Parent
Re:Get a life (Score:4, Funny)
Parent
Re: (Score:3, Funny)
Re: (Score:2, Insightful)
True, there are other, more pressing issues in the world, and so the asteroid thing should be on the back burner, but that does not mean that we should turn the back burner off. People can multi task, so lets do it.
Re:Get a life (Score:4, Insightful)
Considering how well money has been spent on projects like "the war to end all wars" and the "war on terrorism", I would say that a project to deflect asteroids looks very wise in comparison. Whereas, I agree, the research on diseases is an important and underfunded domain (yes, I'll consider it underfunded as long as I have a life expectancy inferior to two centuries). Anyway, it's "just" a few millions dollars spent on watching pebbles in the sky, an activity that could be useful and do no harm, and it goes back into the economy anyway...
Parent
Re: (Score:2)
The elite of the Renaissance spent the wealth of nations funding alchemists who promised to discover the Elixer of Life; throwing money at a problem will not cause a 300% increase in our adult lifespan.
Re: (Score:2)
Maybe not, but I wish I could write grant proposals like that.
Insurance (Score:2)
Re: (Score:3, Insightful)
You have to be crazy enough to realize that civilization is more fragile than the species is, and crazy enough to realize that if an explosion the size of Tunguska or even smaller goes off near the India-Pakistan border the world will be breathing radioactive fallout for years.
You also have to be crazy enough to do basic math and work out the odds of intolerable damage on a time scale of hundreds or thousa
Riffing off Tunguska (Score:2)
You bring up a valid point, but it actually raises more questions than answers, IMO.
Re:Get a life (Score:4, Funny)
Parent
Re: (Score:2)
Are you doing crack?
Re: (Score:3, Insightful)
So now I don't know exactly what to think.
Bringing Them *Closer* (Score:2)
This is an interesting case. Naturally, your first response to OP's allegation that some people in the government would intentionally risk causing the end of humanity is: Nobody is crazy enough to do that. But then it hits you: Obviously this bozo is.
So now I don't know exactly what to think.
Well, unfortunately, I think the GP is not the only crazy that would think like this. There are a lot of extremists out there that think the Earth needs a good cleansing and are not afraid to die themselves. Whether they could ever get their hands on an asteroid steering system is another question.
Crazies aside, there is a good reason to steer an NEO closer to Earth. It would make a great resource if it could be coaxed into orbit, especially if it contained smeltable metals or was big enough to serve as
Re: (Score:2)
the United States has detonated exactly two WMDs in anger. This was done so because the projected loss of life from the war it averted was significantly higher than that of the WMD attack. And the gov't took immediate claim for it, just as they've taken immediate claim for any major militar
Off Topic (Score:4, Interesting)
Parent
Re: (Score:2)
Re: (Score:2)
Since they're continuous thrusters, gravity tug doctrine should be to put the tug in halo orbit, and put more than one. Many relatively small launches are easier than one big launch after all, and they can be replaced as they fail without losing 100% thrust. The orbit would also mean that the exhaust would be less obscured by the payload.
Re: (Score:2)