Beta
×

Welcome to the Slashdot Beta site -- learn more here. Use the link in the footer or click here to return to the Classic version of Slashdot.

Thank you!

Before you choose to head back to the Classic look of the site, we'd appreciate it if you share your thoughts on the Beta; your feedback is what drives our ongoing development.

Beta is different and we value you taking the time to try it out. Please take a look at the changes we've made in Beta and  learn more about it. Thanks for reading, and for making the site better!

Using Gravity To Tow Asteroids

ScuttleMonkey posted more than 8 years ago | from the and-you-thought-a-snails-pace-was-slow dept.

Space 508

cryptocom writes "Space.com is reporting that two scientists at NASA are proposing using a 20-ton spacecraft to pull asteroids off a possible collision course with Earth, using the spacecraft's own gravity as an attractor. This idea would not only be cheaper, but have a much higher chance of success, due to not having to actually land on the asteroid's surface."

Sorry! There are no comments related to the filter you selected.

The mother of all asteroid deflection devices (4, Insightful)

nizo (81281) | more than 8 years ago | (#13992329)

Assuming:
2000 lbs in a ton
20 ton spacecraft
$10,000/pound to get to geosynchronous transfer orbit


$400,000,000 just to launch this thing into a geosynchronous transfer orbit (not counting construction costs). I assume the fuel to move it isn't included in the 20 ton estimate either (since it will burn off on the way) so that would need to be lifted as well. I wonder if a huge nuke would be cheaper and easier to construct and launch? Then again, with the current U.S. national debt at over 8 trillion (with which we could pay for the launch costs of 20,000 of these things) maybe the launch costs aren't unreasonable.

that's what i was thinking (1, Interesting)

conJunk (779958) | more than 8 years ago | (#13992349)

Right on. While it's really an elegant solution, highly cool, I imagine there is an asteroid-size pile of kinks to work out before this becomes reality though.

Launching the craft. How much fuel would it take to get escape velocity on something this massive? Probably not a small amount.

The crew. The time the crew would be away from earth would be how long? 10 years? 20 years? Managing and provisioning crews for such a long amount of time is probably among the major challenges facing the extension of our space travel abilities.

Coming home. What happens when a ship this large is re-entering Earth's atmosphere? That sucker will have a lot of force coming down.

Would it work? How do you test something like this before sinking billions into the final product and subsequent launch? what if it didn't work? What kind of contingency plans could we have?

Shelf life. So we make a ginormous space tractor. Maybe we don't face an asteroid threat for 15,000 years. That's a lot of upkeep.

who pays for it? This would turn into what, a trillion USD project? Who's footing that bill? What kind of bickering will we get in to breaking up those kinds of costs among dozens of nations?

All in all, I think it's a brilliant solution that just may not be feasable, but it's nice to see creative people are thinking about it.

Re:that's what i was thinking (2, Insightful)

jabelar (913707) | more than 8 years ago | (#13992425)

Maybe it would not have to be launched from Earth. Perhaps another asteroid type object could be maneuvered to do the same job, or perhaps a chunk of the Moon. Or maybe something that was already in orbit -- just collect a bunch of space junk, or dare I say the International Space Station?

Re:that's what i was thinking (2)

peculiarmethod (301094) | more than 8 years ago | (#13992440)

it would be cheaper if we mined heavier rocks to use as primary weight from the moon. the lighter gravitational pull would help tremendously. you'd just have to launch a craft that transformed its parts into a container.

Re:that's what i was thinking (2, Interesting)

Rei (128717) | more than 8 years ago | (#13992557)

No. We're not talking about a big counterweight - we're talking about a functional spacecraft. That weight will be nuclear reactor, engines, fuel, etc; there's no way they'd pack it with dead weight for no good reason.

Lunar and Martian industrialization is not a twenty year job. It's a several hundred year job. I can get more into this if you care. It's questionable whether the moon could ever support a mostly self sufficient industrial base because it is so deficient of many critical elements (nitrogen, hydrogen, etc) - and imports to the moon will cost a fortune, making the concept rather questionable. The moon has an awful lot of light metal oxides, and is mostly barren apart from that. Industry doesn't just require the particular ore that you're interested in - there are always other things needed in the process (strong acids, fluxing agents, sacrificial parts, etc).

Re:that's what i was thinking (4, Insightful)

Rei (128717) | more than 8 years ago | (#13992442)

Crew? Not a chance. There is absolutely no reason to send crew on a mission like this. It would just complicate a mission that computer controls could already do more than well enough, and send the price through the roof. We're already doing completely automated asteroid *landings* (harder than it sounds, because they have very irregular gravity fields). There's no way that the 20 tonnes includes a human payload and all of the associated baggage.

No humans, no coming home. Also, they mention 20 years prep time - i.e., they're not planning to build it until a threat is discovered, and the couple billion dollar cost would be amortized over that time to perhaps 100 mil per year, split around the world's space agencies. I'm sure that's more than enough time and low enough cost. Also, a 200 meter asteroid is hardly a worldwide cataclysmic event if it hits; it's like a single large nuclear weapon hitting a random place on the planet, if you can trust the impact calculator [arizona.edu] .

Humans perhaps.... (1, Funny)

isotope23 (210590) | more than 8 years ago | (#13992600)

Crew? Not a chance. There is absolutely no reason to send crew on a mission like this.

Question, I assume there will only be one of these made at the time, so what happens if it BREAKS?
1.No humans = no fixing it,
2.No fixing it = End of civilization
3. E.O.C. = ????
4. Profit!!!

Re:that's what i was thinking (5, Insightful)

Desert Raven (52125) | more than 8 years ago | (#13992478)

Launching the craft. How much fuel would it take to get escape velocity on something this massive? Probably not a small amount.

Why would you launch it from earth??? It's just weight for weight's sake, so build it from stuff already in space, or at the very least, on the moon. Only the engines, control module, etc would need to be lifted from earth. My personal opinion would be to find a nearby asteroid or similar of the appropriate size, shape it as needed, and slap some thrusters on/in it.

The crew. The time the crew would be away from earth would be how long? 10 years? 20 years? Managing and provisioning crews for such a long amount of time is probably among the major challenges facing the extension of our space travel abilities.

What crew? Why on earth would you crew it? Remote operation should be just fine.

Coming home. What happens when a ship this large is re-entering Earth's atmosphere? That sucker will have a lot of force coming down.

OK, now you're just being stupid. What possible reason would there be for landing this contraption on earth?

Re:that's what i was thinking (1)

conJunk (779958) | more than 8 years ago | (#13992553)

i think you've just identified why *i'm* not in charge of this project!

Re:that's what i was thinking (1)

Hrvat (307784) | more than 8 years ago | (#13992504)

First of all, why in the world would you need to construct the whole thing on the ground? Why would you construct the whole thing at all? Majority of the craft would be mass, probably useless anyway. I'd think that they'd want to build a craft that can either ensnare another asteroid from the belt and tow it to wherever it needs to be to affect the incoming asteroid, or just launch payload (over several launches from Earth. Alternatively you could carve out a piece of the Moon, and use that.

Also why would it have to be crewed? Even if you have to have it crewed part of the time you could build modular, so you have a crew capsule/module detacheable, thus you can have the crew in and out pretty quickly, independently from the main craft.

Why would you need to land it on Earth again? Stick it in orbit (far orbit) or just put it at Earth-moon LG point and let it sit there.

Who's going to pay for it? Well, if you reduce launch mass, you'd have lower cost.

In any case, the main problem I see is detection time. It seems to me that the X amount of time to move an asteroid an appreciable amount and the Y amount of time to fly to the asteroid add up to quite a few years. We'd need to be able to detect this threat far enough in advance to identify it. This is where the problem is, in my opinion.

Re:that's what i was thinking (1)

mtaht (603670) | more than 8 years ago | (#13992510)

Space Tractor - now that's phrasology that must get the Russians all excited

Re:that's what i was thinking (1)

MindStalker (22827) | more than 8 years ago | (#13992517)

Well once its in space a combination of nuclear/solar power fuel would probably be sufficent for moving around and towing.

Crew? Why would this need a crew? a computer could do this job easily and you could provide basic commands remotely abit with a large time delay.

No reason to reenter earths atmosphere, this wouldn't be damaged in anyway by pulling an astroid. You simply need to being it back in orbit if you need to do regular mantainence and this baby would be ready at minimal cost to defend against future astroids.

Salvage one had the right idea (1)

ankarbass (882629) | more than 8 years ago | (#13992520)

There's no need to launch all of it at the same time. In fact, why not just launch a big empty ship that can go around gathering up all the heaviest old satellites, e.g. hubble, that have been all used up and stuff them in the hold.

You could borrow an idea from salvage one [geocities.com] and use the space left over from the spent fuel as the hold.

Re:The mother of all asteroid deflection devices (1)

darth_MALL (657218) | more than 8 years ago | (#13992354)

We could fling it into space with a giant trebuchet...

Re:The mother of all asteroid deflection devices (1)

stecoop (759508) | more than 8 years ago | (#13992401)

Something about the wording in your post made me think of an empty Borg cube being sent into space. Then filling it with rocks dust whatever we could collect around the frame making it a total of 20 tons but the only actual cost would be sending up the frame, fuel and collection/assembly equipment.

Re:The mother of all asteroid deflection devices (4, Funny)

lightyear4 (852813) | more than 8 years ago | (#13992367)

I don't think you should place a price upon the value of saving civilization.

Re:The mother of all asteroid deflection devices (1, Insightful)

CyricZ (887944) | more than 8 years ago | (#13992384)

Everything has a price, even that of billions of lives.

Re:The mother of all asteroid deflection devices (2, Funny)

richdun (672214) | more than 8 years ago | (#13992390)

I don't think you should place a price upon the value of saving civilization.

You've obviously never taken a modern finance course - everything has a price!

Re:The mother of all asteroid deflection devices (2, Insightful)

ozydingo (922211) | more than 8 years ago | (#13992472)

I therefore propose we spend all of our efforts placing glasses of water and mounted baseball bats aronud every family's house just in case those aliens from Signs come and hunt us down. Don't discount the possibility that it could happen, we're talking about potentially saving civilization here.

Re:The mother of all asteroid deflection devices (4, Insightful)

tji (74570) | more than 8 years ago | (#13992567)

> I don't think you should place a price upon the value of saving civilization.

That's silly.. The goal is "saving civilization". There are many ways to accomplish this goal, a perfectly valid input into the decision process is "how much does this method cost".

Re:The mother of all asteroid deflection devices (5, Funny)

Gulthek (12570) | more than 8 years ago | (#13992370)

Maybe to stop a huge asteroid from impacting on the Earth's surface the cost would be quite reasonable.

I.e. I don't think that world leaders would look at the figures and go "Hrmmmmm...when you say extinct...how extinct?"

Re:The mother of all asteroid deflection devices (1, Funny)

Anonymous Coward | more than 8 years ago | (#13992376)

But the movie would be so boring... Imagine no last-minute, daring attempts to set off some nuclear warheads at the core of the asteroid, just in time for it to... Just sitting around, waiting for "gravity" to run its course...

Fred: Can I just land on it once?
Captain: No
Fred: But, I just wanna LOOK!
Caption, No, you're not allowed 'cause you'll nuke the whole damn thing, like in that stupid movie. ...
3 weeks later
Fred: How about now?
Captain: Oh, fine, nuke the fucker. It's more fun than this stupid idea.

Re:The mother of all asteroid deflection devices (1)

tradiuz (926664) | more than 8 years ago | (#13992411)

Build the frame here, fill it with mass from the Moon. That way you're only lifting the bare bones out of orbit. Heck, you could ship all the parts to the moon and build it there.

Insert tab A into slot B...

Re:The mother of all asteroid deflection devices (1)

ozydingo (922211) | more than 8 years ago | (#13992540)

I hate to nitpick, but sending the parts to the moon and building it there doesn't save any energy over building it here on earth and sending it into orbit. Plus, you have to launch the parts a second time once it's built on the moon. Not that counters your original suggestion.

Re:The mother of all asteroid deflection devices (1)

onetwentyone (882404) | more than 8 years ago | (#13992545)

Futurama all ready provided the answer. All we need to do is launch all the trash from New York at it. Surely there's 20 tons lying around.

Re:The mother of all asteroid deflection devices (1)

Tatarize (682683) | more than 8 years ago | (#13992574)

Or find a way to find space trash floating around in Earth's orbit (there's a lot of it). Grab it and use it as mass. Or I suppose you could with decades of notice push another rock near where the one rock was going to go at some point in the future and just tweak it to that way. Deflect it with gravity and all, but only use the ship as a thruster to toss a rock that you're sure won't break up into it's path.

Re:The mother of all asteroid deflection devices (1)

daniil (775990) | more than 8 years ago | (#13992420)

Hey, I have an idea. They could first launch a smaller satellite that would attract all kinds of space debris until it's big enough to take out an asteroid. It'd spin around the Earth until an asteroid came about, and then they could just fling it in the direction of the asteroid!

Better yet, they could have several of these things circling up there, just in case.

PS: yeah, I know it's not Tuesday, but I couldn't resist :7

Re:The mother of all asteroid deflection devices (0)

Anonymous Coward | more than 8 years ago | (#13992547)

I'm picturing a stellar game of Katamari Damacy...

Up out of the well? (1)

FlyingOrca (747207) | more than 8 years ago | (#13992424)

Better to build the thing in orbit, using mass from the asteroid belt. Should cost a lot less to get the mass where you need it.

Of course, that's going to require some infrastructure. Which reminds me, why was the ISS built in LEO again? ;-)

Re:The mother of all asteroid deflection devices (2, Interesting)

Daveznet (789744) | more than 8 years ago | (#13992427)

Lets say the asteroid hits New York and whipes out its population and buildings that is going to cost ALOT the country alot more than 8 trillion dollars. You cannot put a price on human life!

Re:The mother of all asteroid deflection devices (5, Insightful)

stienman (51024) | more than 8 years ago | (#13992603)

You cannot put a price on human life!

Nonsense. In fact, there's a whole work force [soa.org] employed to do exactly that.

-Adam

Re:The mother of all asteroid deflection devices (2, Interesting)

mtaht (603670) | more than 8 years ago | (#13992455)

Nice illustration of the miniscule strength of gravity relevant to tonnage, and how over long periods of time, it's possible to use gravity assists for just about anything. It is important to understand how weak - but persistent - and wonderful - interactions with gravity can be. The Grand Tour that Voyager went on, for example, or the Interplanetary Superhighway [sciencenews.org] , or Lissajous orbits [nasa.gov] ....

The spacecraft design with the angled rockets is wasteful, but if you are getting the fuel from the asteroid, the fuel is effectively unlimited. But: if you are getting fuel from the asteroid, you should be able to keep the spacecraft attached to the asteroid by the "hoover"ing effect of sucking up the raw material you are ejecting to the sides!! - a force far, far more potent than gravity would be.

Alternatives: You could focus mirrors one side of the asteroid and take advantage of the outgassing...

Or you could (my preference) just mine the asteroid down to nothing long before impact [blogspot.com] ...

After all, covering that 400 million dollar launch cost would be a lot easier if we just shipped a few billion dollars worth of materials back to LEO [blogspot.com] !

Re:The mother of all asteroid deflection devices (1)

0xABADC0DA (867955) | more than 8 years ago | (#13992494)

Well you probably want it to come back again too... if it was in two parts you could just eject one part the opposite direction with a giant cord attached to it. After the asteroid course was changed you could just reel the parts back together again. With some kind of 'cord' that could become rigid you could use solar power or nuclear power push/pull the pieces and so deflect any number of asteroids. And if there was some emergency you could also project one half into the path of the asteroid to break it up a bit.

Re:The mother of all asteroid deflection devices (1)

Mahou (873114) | more than 8 years ago | (#13992499)

and why would they need to launch it from Earth? couldn't they just mine 20 tons out of the moon or capture some meteors and throw some rockets on them and then put them in orbit around the sun.
...that just made me think of Invader Zim driving Mars.

Re:The mother of all asteroid deflection devices (1)

geomon (78680) | more than 8 years ago | (#13992558)

mine 20 tons out of the moon

Mine twenty tons of what?

Are you going to use the raw material, or are you going to smelt it into something other than ore? How much would it cost to send a complete mining, smelting, power generation factory to the Moon?

It is probably cheaper to send the truck into space from Earth.

Re:The mother of all asteroid deflection devices (0)

Anonymous Coward | more than 8 years ago | (#13992506)

How much would it cost to launch a bunch of mylar with a shiny metal coating to get that radiation pressure action going.

Space Junk (1)

arrrrg (902404) | more than 8 years ago | (#13992526)

$400,000,000 just to launch this thing into a geosynchronous transfer orbit (not counting construction costs).

I'm sure there's already more than 20 tons of junk in orbit... all we'd need to do is collect it and add a thruster, and we'd be good to go...

Re:The mother of all asteroid deflection devices (1)

drpimp (900837) | more than 8 years ago | (#13992556)

Good math, but does it really matter how much it costs.... hmmm

Lets see, $400,000,000 to total anniolation of Earth. I am sure more than just the US will contribute to these costs.

As far as nukes, single manned JIHADISTS in jets with nukes attached should be a good solution as well, but might not be proven effective. All we need to do is convince the terrorists that the crusaders are invading Earth in asteriods.

Re:The mother of all asteroid deflection devices (1)

Kaenneth (82978) | more than 8 years ago | (#13992591)

Imagine if it was remotely hijacked... hopefully it would be designed to self-destruct/break apart on reentry.

Re:The mother of all asteroid deflection devices (1)

slashdotnickname (882178) | more than 8 years ago | (#13992565)

It would be more efficient to build it in space. Perhaps even on or orbiting the moon, using lunar material. This could then justify creating a permanent lunar base, which could have other uses besides saving the Earth.

Re:The mother of all asteroid deflection devices (1)

adavies42 (746183) | more than 8 years ago | (#13992569)

Why not get the best of both worlds? Make it Orion [wikipedia.org] -powered.

Re:The mother of all asteroid deflection devices (0, Redundant)

GungaDan (195739) | more than 8 years ago | (#13992615)

Why not take the majority of the spacecraft's mass from an object already outside of Earth's atmosphere? Send this asteroid-tractor into space with a big empty cargo (er, ballast?) hold, and pick up a bunch of moon (or maybe chunks of some other asteroid) once it's well beyond Earth's gravity?

Re:The mother of all asteroid deflection devices (1)

vertinox (846076) | more than 8 years ago | (#13992627)

I wonder if a huge nuke would be cheaper and easier to construct and launch?

Most likley, but you might end up making the world's largest shotgun out of a asteriod made of iron.

Re:The mother of all asteroid deflection devices (1)

nihilogos (87025) | more than 8 years ago | (#13992632)

Since most of it only needs to be mass, they could just start tacking moon rocks onto it or into it. Or defunct satellites, there are plenty of those around.

Bad math? (0, Troll)

Loether (769074) | more than 8 years ago | (#13992640)

I didn't RTFA. But if your figures are right...

US debt 8 trillion = $8,000,000,000
Cost to launch = $ 400,000,000

So you'd be able to launch 20 of these things not 20,000.

20 Ton Tractor (2, Interesting)

geomon (78680) | more than 8 years ago | (#13992331)

That would make the rig smaller than an 18-weeler. Their gross weight capacity is 40 tons.

That would place it safely in the realm of 'Cube Truck' capacity.

Hell, they wouldn't even have to stop at the scales in some states.

First Post (-1, Troll)

CRCulver (715279) | more than 8 years ago | (#13992335)

How about a 20-ton FIRST POST?

How exciting, sort of (4, Funny)

phpm0nkey (768038) | more than 8 years ago | (#13992336)

"The kind of spacecraft we've talked about could move an asteroid 650 feet (200 meters) across provided we have decades of advanced warning,"

Neat... although, if this works, it will totally kill the Hollywood "asteroid catastrophe" genre. The concept of sitting a giant hunk of metal next to an asteroid for 20 years to gradually shift its path doesn't exactly make for fast-paced, high-tension action movie fare.

Re:How exciting, sort of (1)

FooAtWFU (699187) | more than 8 years ago | (#13992360)

You're right. We need a psychopathic homocidal AI computer running this ship, who tries to kill off the crew. We could call it something like HAL as a joke, since that's one-letter-before IBM.

Re:How exciting, sort of (1)

Mahou (873114) | more than 8 years ago | (#13992598)

he wasn't a psychopathic homicidal(nor was he homocidal) AI. did you even read the books? he was just ensuring the completion of a higher priority mission. he made a choice the best he could(which he wasn't designed to make) on how to deal with the crew.

Re:How exciting, sort of (1)

Joe the Lesser (533425) | more than 8 years ago | (#13992439)

Kinda like Speed III?

'If this glacier moves faster than one inch a year we're all gonna die!!'

Until the 20 ton hunk of metal pulls a "Skylab" (1)

StressGuy (472374) | more than 8 years ago | (#13992460)

Looks like the beginning of a "good news / bad news' scenario to me.

Advanced warning (4, Insightful)

EmbeddedJanitor (597831) | more than 8 years ago | (#13992466)

Considering the number of asteroids etc that only get seen on the way out, asking for decades of warning is perhaps unrealistic.

Re:How exciting, sort of (1)

blake3737 (839993) | more than 8 years ago | (#13992468)

The concept of sitting a giant hunk of metal next to an asteroid for 20 years to gradually shift its path doesn't exactly make for fast-paced, high-tension action movie fare.

You've not been paying attention to hollywood have you?? do you know what ACTUALLY PASSES for a high tension movie these days? [yahoo.com]

Re:How exciting, sort of (2, Funny)

Toxicgonzo (904975) | more than 8 years ago | (#13992521)

Yes, it can. It would be perfect for Speed:3. Just imagine a tense scene where Keanu Reeves, head of NASA, yells "If that spaececraft doesn't move the asteroid more than .000000000000000005 miles per hour we're all dead!"

This has a higher chance of being moderated (0)

Anonymous Coward | more than 8 years ago | (#13992340)

This idea would not only be cheaper, but have a much higher chance of success, due to not having to actually land on the asteroid's surface

Cheaper than what? Sending Bruce Willis up to take care of business? Drinking forties of Olde E?

Come on guys, at least make an attempt...

They only have one small problem to solve (2, Funny)

Anonymous Coward | more than 8 years ago | (#13992352)

Dealing with the impact of a 20-ton spacecraft on earth.

Re:They only have one small problem to solve (0)

Anonymous Coward | more than 8 years ago | (#13992393)

mir weighed 135 tons when they deorbited it... too bad they don't still have that up there ready to be retasked.

It's all relative (1)

BigDawgES (821410) | more than 8 years ago | (#13992353)

a much higher chance of success

A higher chance of success than, say, a rag-tag bunch of all-american guys from an oil rig?

Re:It's all relative (1)

Seiruu (808321) | more than 8 years ago | (#13992404)

Considering that Bruce Willis hasn't been doing too well financially, that's not such a bad idea.

I mean, how many people can go "I got experience when it comes to blowing up space rocks"?

Interesting, but slow (4, Interesting)

Rei (128717) | more than 8 years ago | (#13992363)

Interesting proposal, although the rate of towing still seems a concern if it takes a year to tow a 200 meter asteroid the small amount needed to make it miss Earth, with 20 years prep time required. Hopefully there aren't too many asteroids much larger than that which aren't currently tracked, but you never know.

If they're concerned about the amount of impulse delivered by a direct nuclear weapon impact, why not a series of projectile impacts (or at-a-distance, low impulse nuclear detonations)? While you'd have to launch more payload into space, the prep time would certainly seem to be far lower.

What? (1)

voice_of_all_reason (926702) | more than 8 years ago | (#13992368)

And put Superman out of a job?

I'd say so! (1)

pegr (46683) | more than 8 years ago | (#13992377)

"This idea would not only be cheaper, but have a much higher chance of success, due to not having to actually land on the asteroid's surface."
 
... and blow it up!

It's been awhile since I've taken physics... (4, Interesting)

jkauzlar (596349) | more than 8 years ago | (#13992381)

but since it seemed strange to me that a 20 ton object could possess any considerable gravitational force I did a quick calculation, with a lot of rounding, to determine the force between the 20-ton object (~18150 kg) and the fourth largest asteroid Hygiea [aas.org] which has a mass of about 9x10^19 kg. My result, for a distance of 1 kilometer between the spacecraft and the asteriod, was 10^8 Newtons of force.

So comes the hard part of determining how far out the spacecraft would have to meet the asteriod and glide along beside it so as to veer the asteroid to a safe range of R kilometers from Earth. Any ideas?

Re:It's been awhile since I've taken physics... (0)

Anonymous Coward | more than 8 years ago | (#13992503)

Any ideas?

Er, no - that's why we have scientists. Now if you want a server prepped I'm your man!

Re:It's been awhile since I've taken physics... (2, Interesting)

Xentor (600436) | more than 8 years ago | (#13992543)

Well let's see... That would apply an acceleration of 1.11x10^-12 m/s^2 to the 'roid...

On the other hand, the same gravitational force would be acting on the spacecraft, and F=ma gives us 5509 m/s^2 there...

Am I calculating this wrong? Because it seems it would take a hell of a lot of fuel to keep that spacecraft from just crashing into the asteroid... And they plan to keep this spacecraft sitting next to the roid for years?

Nuke it.

Interesting Concept (1)

MontyP (26575) | more than 8 years ago | (#13992398)

How about using momentum from an astroid to provide power? Any Ideas?

Re:Interesting Concept (3, Funny)

Quaoar (614366) | more than 8 years ago | (#13992481)

Having it slam into the Earth would be one way.

20-ton spacecraft collisions (3, Funny)

Spectre (1685) | more than 8 years ago | (#13992400)

Great, the asteroids miss the earth, but damage from falling 20-ton spacecraft becomes an issue.

mir (3, Informative)

elinden (155827) | more than 8 years ago | (#13992452)

mir weighed 135 tons and it burned up just fine on its way down. 20 tons, relatively speaking, isn't really all that much.

I for one welcome... (2, Interesting)

xv4n (639231) | more than 8 years ago | (#13992402)

... our new asteroid-deflector overlords.

So, by the same means they can put an asteroid in a direct collision course.

Two questions (1)

Trevin (570491) | more than 8 years ago | (#13992429)

20 tons doesn't seem like very much. So I'd like to know:

1. How much does an asteroid weigh? (That is, the average size that this 'tractor' is intended for.)

2. How early would the asteroid have to be pulled from its trajectory in order to sufficiently deflect it from the earth? Could we detect such an asteroid headed our way in time? (Okay, so that may be three questions.)

astronomical engineering (1)

ricochet81 (707864) | more than 8 years ago | (#13992432)

I remember a NASA article about this, but it was in relation to using asteroids to engineer a change in earths orbit to compensate for global warming. Amusing!

Astronomical Engineering: A Strategy For Modifying (1)

ricochet81 (707864) | more than 8 years ago | (#13992568)

A bit OT, but... Here's the article abstract to which I was referring: Astronomical Engineering: A Strategy For Modifying Planetary Orbits The Sun's gradual brightening will seriously compromise the Earth'sbiosphere within sim 109 years. If Earth's orbit migrates outward,however, the biosphere could remain intact over the entiremain-sequence lifetime of the Sun. In this paper, we explore thefeasibility of engineering such a migration over a long timeperiod. The basic mechanism uses gravitational assists to (in effect)transfer orbital energy from Jupiter to the Earth, and therebyenlarges the orbital radius of Earth. This transfer is accomplishedby a suitable intermediate body, either a Kuiper Belt object or a mainbelt asteroid. The object first encounters Earth during an inward passon its initial highly elliptical orbit of large (sim 300 AU)semimajor axis. The encounter transfers energy from the object to theEarth in standard gravity-assist fashion by passing close to theleading limb of the planet. The resulting outbound trajectory of theobject must cross the orbit of Jupiter; with proper timing, theoutbound object encounters Jupiter and picks up the energy it lost toEarth. With small corrections to the trajectory, or additionalplanetary encounters (e.g., with Saturn), the object can repeat this process over many encounters. To maintain its present flux of solarenergy, the Earth must experience roughly one encounter every 6000years (for an object mass of 1022 g). We develop the details ofthis scheme and discuss its ramifications.

Redundant question (1)

karvind (833059) | more than 8 years ago | (#13992438)

Isn't 20 ton a huuuuuuuuuuuge payload ?

I am willing to send my in-laws on this earth-saving mission. Thank you thank you ... it is all for the human kind.

Re:Redundant question (1)

JustNiz (692889) | more than 8 years ago | (#13992513)

I guess you could launch an empty (i.e. relatively lightweight) container which once in orbit could fill up with 'space debris' to increase its mass.

They are wrong (0, Troll)

suso (153703) | more than 8 years ago | (#13992449)

By my calculations, you'd need a 21-ton spacecraft to move an asteroid off course and save the earth from disaster. So they better start collecting enough metal to make one because 21-tons is a lot and will take quite a bit of power to put into orbit. ;-)

And yes, I RTFA'd and understand that everything has gravity and in space it has more effect, etc.

Re:They are wrong (1)

wpiman (739077) | more than 8 years ago | (#13992539)

$10,000 a pound I've heard through around.

So that would be 2000 x 21 x 10,000-- or $420,000,000.

Let' sell some more IOUs to the Japanese and Chinese.

Re:They are wrong (1)

suso (153703) | more than 8 years ago | (#13992578)

I figured I'd get marked as a troll. Compare $420,000,000 with the $60,000,000,000 amount being quoted as damages from Hurricane Katrina. Now it doesn't sound like much does it. Its amazing how people don't take things seriously until its too late. I guess false alarms reduce readyness.

Tow cable? (1)

erroneus (253617) | more than 8 years ago | (#13992451)

Uhm... if we can send something so large that its gravity will affect an otherwise Life-on-Earth-as-we-know-it-ending asteroid's course, then how about an enormous tow cable in addition to that and slinging that puppy in another direction...say... the sun or something.

i've been away for a few days.... (3, Funny)

shrewd (830067) | more than 8 years ago | (#13992461)

this isn't a follow-up story to "asteroid on collision coarse with earth" IS IT!?!?

Not good enough (3, Funny)

TreeHugger04 (739276) | more than 8 years ago | (#13992476)

"...provided we have decades of advanced warning," Lu said. "That's not out of line with what you'd expect - we can predict the orbit of an asteroid decades in advance."

This just in:

Response from FEMA: "Not good enough. We need more time."

I tried this... (4, Funny)

novus ordo (843883) | more than 8 years ago | (#13992477)

...with women, but I've had mixed success(wrong body part got gravitationally attracted to my face).

From Jack Handy... (2, Funny)

Astin (177479) | more than 8 years ago | (#13992482)

The big, huge meteor headed toward Earth. Could nothing stop it? Maybe Bob could. He was suddenly on top of the meteor--through some kind of a space warp or something. "Go, Bob, go " yelled one of the generals. "Give me that" said the big-guy general as he took the microphone away. "Listen, Bob," he said. "you've got to steer that meteor away from Earth." "Yes, but how?" thought Bob. Then he got an idea. Right next to him there was a steering wheel sticking out of the the meteor.

Why not launch a ship to bowl at it? (1)

NeoThermic (732100) | more than 8 years ago | (#13992493)

As suggested over at Intuitor [intuitor.com] , why not send up a team of bowling experts to create a hole to the center, and then detonate a few nukes?

Simple...

NeoThermic

Terraforming? (4, Interesting)

NelsonM (906317) | more than 8 years ago | (#13992507)

If we're talking decades here, could this be used to send other asteroids [space.com] into Mars to introduce the planet with some new water?

We don't need that thing at all. (0)

Anonymous Coward | more than 8 years ago | (#13992537)

Bruce Willis will save us all!

Isn't the problem here... (4, Interesting)

popo (107611) | more than 8 years ago | (#13992541)


Isn't the problem here the 20 ton spacecraft?

Which

a) is difficult to move all by itself.

b) doesn't do much to a 6800 ton asteroid travelling at 1600 miles per hour.

Re:Isn't the problem here... (0)

Anonymous Coward | more than 8 years ago | (#13992577)

It's it's only going 1600 mph, you could practically catch it with your bare hands. Most of these things move at 20-30 Mi/sec.

Whats the point of using gravity? (1)

Kookus (653170) | more than 8 years ago | (#13992548)

If we flew a 20 ton object past another object to change it's course, it would have to be an incredibly far distance away so the miniscule trajectory change would have time to make a difference. Point being, are we trying to retrieve the 20 ton object after it flys by? How about give in and just assume it as a loss and fly the 20 ton object right into the comet/meteor. I would think that would have more of a dramatic effect, thus cutting down on the time needed to find the object comming at us.

Should this be addressed first? (1)

mykepredko (40154) | more than 8 years ago | (#13992550)

The article indicates that there is an issue of the asteroid/comet being broken apart by the shock of the thrust, but I have a hard time believing that this is the case if the amount of thrust is on the order of 1 lb. I would have to believe that a small thruster with a large plate to spread out the force of the thrust could be placed on the object.

Of course, dragging the object by gravity would avoid the issue of having to despin the object or coming up with a thruster or multiple thrusters placed on the spin equator and firing at specific intervals.

Regardless, I would have thought that the most important work item would be to come up with a method to find and plot the orbits of all objects which could be a threat to the earth.

This will require the proverbial Beowolf cluster of insert computer here to sorth through millions of pictures looking for moving points relative to stable points and then plotting their orbits and trajectories.

With this information, it should be possible to determine what is the best way to change the objects tractory in the most cost (which translates to energy).

myke

Save Money (2, Funny)

jatemack (870255) | more than 8 years ago | (#13992589)

Just send Kristie Alley up there. That should work.

"That's no moon!" (3, Interesting)

skelly33 (891182) | more than 8 years ago | (#13992597)

Here's a thought: how about launching a far smaller, more capable space craft which is able to gain mass on its way out of Earth orbit by collecting up whatever tonnage of free-floating space junk it needs from Earth's orbit?

If it employed some sort of lightwight truss-style, perhaps geodesic framework with cable "netting", it could form a lightwieght, but voluminous enclosure that could be used to capture orbiting space junk before heading off for its mission.

Overall, the idea of gravity-towing sounds pretty neat to me.

Armageddon 2 (1)

dividedsky319 (907852) | more than 8 years ago | (#13992599)

This idea would not only be cheaper, but have a much higher chance of success, due to not having to actually land on the asteroid's surface."

Sounds like the makings of a sequel. Armageddon 2: Nerds Save the World

How to eliminate asteroids (0)

Anonymous Coward | more than 8 years ago | (#13992608)

Everyone knows the proper way to eliminate asteroids is to shoot little white dots at them, thus breaking them into smaller and smaller pieces, until they disappear.
Also works on 'asteriods'. By breaking up enough chunks, you could 'earn' enough energy to do a hyperspace jump, thus avoiding the costly trip back home to Earth.

won't happen (1)

theheff (894014) | more than 8 years ago | (#13992610)

An asteroid of large enough proportion will never hit Earth. No way. Now before you ridicule me for such a proposal, just think about it. Sure, small meteors may slip through into Earth's atmoshphere; it happens all the time (constantly, actually). But do you know how large Jupiter is? Or take Saturn or Uranus... Earth is a spec of dust compared these planets, yet they orbit much further away from the sun, meaning that an asteroid of mass proportion will never make it to earth... gravity from larger planets in orbit will not permit it. The volume of Jupiter is 1300 times Earth's. I'm sorry, but this is just another instance of the media abusing science to make $$, blowing things out of proportion.

20 tons is not that much (1)

fallungus (810282) | more than 8 years ago | (#13992611)

The space shuttle has a landing weight of 198,909 lbs, which is almost 100 tons. (source Shuttle press kit [shuttlepresskit.com] ). This is not a big deal.

Weak solution (1)

Mad Ogre (564694) | more than 8 years ago | (#13992612)

I like the big bomb solutions best. But thats just me.

Why can't we simply use an Ion engine. (4, Interesting)

orichter (60340) | more than 8 years ago | (#13992622)

I know that people have already discussed the possibility of mounting a rocket on an asteroid, and it has many problems (namely that the asteroid rotates, and it would be difficult to mount the rocket) But if we are talking about parking a spacecraft next to an asteroid, why couldn't you simply mount an ion engine on opposite sides of a space craft, and point one beam at the asteroid, and one beam in the opposite direction. Wouldn't this beam impact the asteroid, and thus impart a thrust. I realize this would theoretically cost twice the energy of mounting the same ion beam on the asteriod, but it could fire continuously. Does the ion beam spread out too fast, because if it could stay collumated, I would think it could be quite effective.

This should make...... (2, Funny)

8127972 (73495) | more than 8 years ago | (#13992639)

....Bruce Willis happy.
Load More Comments
Slashdot Login

Need an Account?

Forgot your password?