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Using Gravity To Tow Asteroids
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."
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.
I Am My Own Worst Enemy
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.
"Rocky Rococo, at your cervix!"
"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.
domain combinatorics
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...
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.
Dealing with the impact of a 20-ton spacecraft on earth.
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?
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.
He's just being nice so my real father won't freeze him in carbonite and sell him for spice.
And put Superman out of a job?
"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!
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?
How about using momentum from an astroid to provide power? Any Ideas?
There is no
Great, the asteroids miss the earth, but damage from falling 20-ton spacecraft becomes an issue.
"Flame away, I wear asbestos underwear"
So, by the same means they can put an asteroid in a direct collision course.
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?
Corruptissima re publica plurimae leges.
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.)
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!
Error: Id10t detected
I am willing to send my in-laws on this earth-saving mission. Thank you thank you ... it is all for the human kind.
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.
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.
mir weighed 135 tons and it burned up just fine on its way down. 20 tons, relatively speaking, isn't really all that much.
Looks like the beginning of a "good news / bad news' scenario to me.
A goal is a dream with a deadline
this isn't a follow-up story to "asteroid on collision coarse with earth" IS IT!?!?
Considering the number of asteroids etc that only get seen on the way out, asking for decades of warning is perhaps unrealistic.
Engineering is the art of compromise.
This just in:
Response from FEMA: "Not good enough. We need more time."
A citizen of America will cross the ocean to fight for democracy, but won't cross the street to vote in an election.
...with women, but I've had mixed success(wrong body part got gravitationally attracted to my face).
"You're everywhere. You're omnivorous."
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.
- In hell, treason is the work of angels.
As suggested over at Intuitor, why not send up a team of bowling experts to create a hole to the center, and then detonate a few nukes?
Simple...
NeoThermic
Use my link above, or to view my server, NeoThermic.com
If we're talking decades here, could this be used to send other asteroids into Mars to introduce the planet with some new water?
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 and use the space left over from the spent fuel as the hold.
Wanted: Clever sig, top $ paid, all offers considered.
$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...
Bruce Willis will save us all!
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.
------ The best brain training is now totally free : )
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.
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
Mimetics Inc. Twitter
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.
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Just send Kristie Alley up there. That should work.
// no
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.
Sounds like the makings of a sequel. Armageddon 2: Nerds Save the World
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!!!
Service guarantees Citizenship! Questions Guarantee GITMO.... Amerika Uber Alles!
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.
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.
The space shuttle has a landing weight of 198,909 lbs, which is almost 100 tons. (source Shuttle press kit). This is not a big deal.
You call this a sig?
I like the big bomb solutions best. But thats just me.
MadOgre.com
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.
....Bruce Willis happy.
This is my opinion. To make sure you don't steal it, it's covered by the DMCA.
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.
TODO create witty sig.
Has anyone else noticed how it used to be NY times who got linked by slashdot twice a week, but now it seems to be space.com that's shelled out for an exclusive slashdot linkage? :p
:/
Perhaps next month slashdot will have exciting news about every new bangbus.com video... Or follow closely the movements of the latest additions to russianladies.com?
God knows...
...this 20 ton vehicle wouldn't you be better off simply sending the engine up without the 20 tons and have it push the asteroid directly? Even if the asteroid rotated, you could fire the engine in bursts, once per revolution. This is hardly 'complicated', it's elementary physics. You (1) wouldn't have to launch 20 tons and (2) you could get the job done much quicker. If you can spot an asteroid 20 years in advance you wouldn't need to use the thrusters for long to push it out of harm's way.
Talking about moving asteroid reminds me of an episode in Star Trek:TNG where they use Jordi's visor technology to send high frequency pulses to move a core fragment that was en route to destroying a society based on controlled genetic breeding.
The shuttle lift off weight is 4,520,235 lbs. thats 2260 tons... WTF is a 20 ton object going to do? do Normal communication satalites fall outa orbet because the come close to the shuttle?? I don't understand...
Ad eundum quo nemo ante iit!
Yes, a lander is risky, but so is a much bigger rocket.
Two wrongs don't make a right, but three lefts do.
Wouldn't that divert the spaceship more than it would divert the asteroid?
Thanks for comin'. Please try again.
Why, oh why, didn't I take the Blue Pill?
" higher chance of success, due to not having to actually land on the asteroid's surface."
ok. didn't we already land a craft on an asteroid? in fact didn't we land a craft that was not designed for that purpose and actually get back info once it was landed? so we know that while not exactly easy it's not impossible.
i forget the name of the craft and am too lazy to search. but i'm sure i'm not the only one that remembers how cool that mission was.
i favor the blow asteroids up option.
...duct tape. Prevents exposure to biological weapons, makes fashionable wallets and clothing, and movies dangerous asteroids. Why do you think MacGyver liked it so much?
Correct me if I'm wrong, but wouldn't pulling it with gravity use even MORE fuel, since you're basically expending the same amount of fuel to move the target, plus additional fuel to move the 20-ton gravity "tug"?
We should just start blasting nukes at all the tracked asteroid in our solar system. Eventually we'd have them all destroyed. Well, either that or set them on a crash course with earth...
Hmmmm, well either way we should do it! YEEEEHAAAAWW!
So what do we do in a few centuries when we start to notice that these 20-ton spacecraft are on a collision course for earth? Send up more spacecraft to deflect them? But then we'll have kazillions of these things up there, hovering around the solar system, just waiting for their chance to crash into us .... shriek!
This isn't meant to be a swipe at the astronauts in any respect, but why does the summary say "scientists" when the actual article only ever says "astronauts"? You don't have to have any real scientific expertise to be an astronaut, although quite a few do. Still, without knowing their backgrounds, why should we take the word of two astronauts that such a plan would even work? And if they do really think that this is a good plan, why didn't they run it past more of NASA before telling the media?
This may be a false impression, but I can't help but feel like this sounds as if a couple of astronauts were talking out of their asses to the media, and the latter decided to write a report on it rather than fact-check and do their jobs.
I was watching a presentation by MIT Lincoln Labs because I was considering doing a co-op with them. Aparently they detect NEA's. http://www.ll.mit.edu/LINEAR/
Aparently there are 1622 objects that need to be towed.
Ooo man the floppy drive is broken. No wait. The computer is just upside down.
This seems backward to me... If we have an asteroid that's big enough to do major damage, that's unmanageable. Breaking it apart into pieces, even if some of the pieces hit the earth, is far better. First, most of the pieces won't hit us (if the asteroid is broken up reasonably far away), and second, the ones that do will be a lot smaller. So they'll do a lot less damage, and the damage that they do will be spread out, rather than packed in one killer punch. What's so bad about that scenario?
So what is Bruce Willis supposed to do in this scenario?
Personally, I wouldn't rely on the mother. That is like buying version 1.0 software. I'd go with the over-achieving child of the mother of all asteroid deflection devices. But I guess that is just me.
-matthew
"THERE IS NO JUSTICE, THERE IS ONLY ME." -Death
Why does the mass have to come from earth? Wouldn't lifting the equivalent of 20 earth tons of mass from the moon be easier?
This may not be the best solution, but his point was that we shouldn't right it off just because it's expensive. Its feasibility must be studied and if it works, we should put ourselves in a position to implement it on short notice if the more cost effective methods fail.
Halelujah, do you know what this means? We can deflect any and all asteroids with only a gumball now... all we need a few millenia of advance warning on the strike! We're all saved! I mean, our distant progeny, anyway.
Gumball saves!
It has the benefit of having many popular science fiction references.
Where law ends, tyranny begins -- William Pitt
--dave
davecb@spamcop.net
From TFA:
"An asteroid the size of two football fields..."
'Nuff said.
How is this flamebait?
+++ATH0
Personaly, i think they should send out two or three 'guard posts' around earth with like 2 nukes each. whenever we have a problem we fire a couple at whatever it is. like i said, its probably way far out there, but it sounds awesome in theory, right?
The Saturn V was capable of sending around 50 tons to the moon (over 120 tons to LEO), and the planned STS Heavy Lift Vehicle will be slightly more powerfull. Even with existing rockets, the Titan IVB/Centaur and the Delta IV are each capable of sending over 6 tons to geosyncronous orbit.
For recent comparison, the shuttle orbiter is over 100 tons and capable of carrying about 30 tons of payload to LEO Cassini was about 6 tons, and we sent it all the way to Saturn.
If we could afford to launch all these things, then we can afford to launch something to prevent a cataclysmic astroid strike.
That's no moon, it's a space station!
Well, technically...
-Styopa
Instead of one big asteroid we now have 20 smaller ones,
and they all want to have a word with you.
The key point is control. Intercept the asteroid long enough in advance,
then nudge it slowly and gently to a new orbit , keeping it in one piece.
When you start to rough it up, you don't know exactly what will happen.
Nuclear weapons certainly aren't useful, they're heat pulse generators.
A big disadvantage about the gravity towing mechanism that doesn't land,
is they'll have to bring the mass that they want to throw away.
They'll have to throw the little they have much harder than they otherwise would.
The nice thing about installing a mass driver on an asteroid, is that the asteroid can be mined for mass.
Maybe in the end they will have to use the gravity towing design for extremely brittle asteroids.
What makes them think we're going to have that much warning? A few years ago we had a fairly near miss and only had a few days warning. There wasn't a whole lot of warning about the comet that hit Jupiter either. Remember asteroids don't emit any light of their own, they are small compared to a planet or even our moon, and they are are coming in from quite far away from the Sun so they aren't exactly the easiest things to see.
cat /dev/tongue
Rather than launching all that weight from the earth, which is way too expensive, why not launch a "driver" that would attach to an existing a big ol' existing asteroid, and use the now "friendly" asteroid to pull asteroids on a collision or near-collision course off to a safer trajectory?
The driver could use one or more navigation/propulsion systems (solar sails, ion drive, etc.) and it would still be cheaper than lifting a satellite with that much weight out of our gravity well.
Hell, you could probably setup a matrix of these out a certain distance from the sun, providing greater coverage and depending on how close they all are, you could even have two or more "friendly" asteroids deflect an incoming one with greater efficiency.
that, or get all the robots to vent their exhausts upwards at the same time all from same place. ;)
Once it's up there, it can chill out somewhere waiting for another asteroid from which to save civilization.
F = ma
There is a certain force acceleration needed to move the asteroid. That multiplied by the mass of the asteroid gives the force needed. It doesn't matter whether the force comes from a thruster, gravity or a long rope hooked to earth. Multiple the force by the time needed to get the total energy needed.
Appling the force with gravity uses
f = (G * m1 * m2) / d^2
The force needed is determined by the orbit of the asteroid and Earth and the time available--it can't be changed. The mass of the asteroid is constant and it is unlikely that G will change. That leaves the mass of the spaceship and distance between the objects as variables. You can send a less massive spaceship if you keep it closer to the asteroid.
Note that you must keep the spaceship at a constant distance from the asteroid. If you fire the thrusters too fast, the spaceship moves away and the force is reduced. If you fire them too slow, the spaceship crashes. As the equation shows, you need just enough force to counteract the asteroid's gravity on the spaceship. A less massive spaceship would need a higher thrust because it was closer to the planet--the same as saying that the closer the spaceship is to the asteroid, the more force it can apply.
In the end, this is the same as putting a thruster on the planet. The only difference is that a thruster on the planet would rotate and so not be usable at all times. Also there are probably differences in the efficiency of the methods.
Another good reason to stay awake in Physics class. That lecture on Newton's laws just might same your life!
Disclaimer: I wrote this off the top of my head. Before sending an actual spacecraft, I suggest you double check my physics. If you don't and there is a problem, I won't be held liable for any damages caused by the extinction of life as we know it.
What if you detonate a nuke surrounded by say, cement, close to the asteroid. That way the small bits of cement would nudge the asteroid off the course, without breaking it appart?
If you don't know what AltaVista is (was), get off my lawn.
Instead of deflecting the object, why can't we dodge it? Like putting up huge engines that stick to the ground in various strategic locations and fire them up at the right time. By then we should be able to increase the rotation speed or maybe even push earth outta orbit. Oh yeah, pushing a bit further outward will solve the global warming problem too :)
So $400 million looks downright cheap to me. Or quadruple it for other costs - $1.6 billion. No big.
These boffins always want to complicate things
Some of us enjoy the action of both watching paint dry and watching the grass grow.
I don't think you should place a price upon the value of saving civilization.
You think that its possible to sufficiently deflect an asteroid of civilization-endangering proportions with ONLY the gravity of a 20-ton satellite?
I'd hate to be living here when they try it....
"Those who think they know everything are of great annoyance to those of us who do." - Isaac Asimov
I think what a lot of people are missing is that if you actually mount a rocket on the asteroid (or set off a nuke on it) you have to worry about all sorts of problems due to the potential fragility of it. What if you shatter it into pieces? Knock a chunk off? You could easily cause something unpredictable to happen which could force you back to the drawing board with not enough time.
The advantage this has is that you can move it without physically touching it, so you greatly reduce the chance that you are going to affect it in a way that causes you problems.
The cake is a pie
There were no signs of the world getting hit by a killer asteroid in any of the star trek movies so between now and then we should be safe.
Having to work for a living is the root of all evil.
So we gotta put a 20 Ton hunk of metal in space, find a astroid that could possible hit Earth, fly the hunk of metal to the astroid, basically stop it and then fly it in the direction of the astroid to move it out of our way? Hope NASA doesn't mix up feet and meters again. And also was the decade just to move it out of our way and not the travel time to get to the astroid? I think I'd rather take my chances of NASA screwing up again and the astroid missing earth. I have enough to worry about just trying to dodge traffic in the morning.
If we could get rid of 20 tons worth of evil bears, it might be worth the price.
Sally Struthers' Tiberian Junker using the Positronic Tractor Beam?
http://home.arcor.de/pla-scripts/scripts-311.htm
What *would* make a great movie is having the asteroid mover not do its job correctly sending the asteroid into NYC instead of into the desert of Arizona. If only they had left the asteroid alone...
$400,000,000?
:-P
Geez! That's government spending for ya....
If it was up to me, I'd just pay the $80/yr for a AAA membership and have them tow it..
DEAD DEAD DEAD DELETE ME
If you are willing to accept the small size and long lead time, there are better solutions. How about a solar sail? How about giving it a static charge (perhaps spraying from an ion drive, but cathode rays would do the job, too) and using big-ass magnets? If it's icy you can just focus lots of heat (big-ass mirrors) on one side and make its eruptions change its course. Hell, if it's that small, just fire lots of small, fast projectiles (magnetic acceleration of moon-mined iron, perhaps). There are innumerable ways of providing the energy for the dV needed to alter the asteroid's course that do not involve that much mass, that much expense, that much Earth-provided energy, that much fine control, or even that lack of reusability. What a godawful idea.
Okay, it's not "as large as Texas" but really, why go with such an unrealistic example? Assume something comparable to what has hit the earth in the past. Call it an asteroid 8km across, maybe 100-400 billion tons depending upon composition. That's still a lot of mass but you only need a modest amount of deflection.
For every complex problem there is an answer that is clear, simple, and wrong. -- H L Mencken
You remember all those left over copies of Windows ME?
Ira
This is just to get around the cost of launching from the "deeper" gravity well of Earth - see "The Moon is a Harsh Mistress".
Whether this is actually feasible or not is an interesting thought experiment - I'm not sure I buy into it. We could get the asteroid towing the tug-craft in for a crash as well ;-)
.. paranoid crackpot leftover from the days of Amiga.
We should capture Apophis at the next opportunity and interrogate it for information on the plans of other NEOs. And, yes, this is exactly the type of situation in which torture is justifiable.
Proposal: 20 ton object
Current shuttle: 100 ton object
So, this would be about 1/5th of the current launch weight of the shuttle and probably about the same cost.
Read the best of all of Slash: seenonslash.com
We stick a 20-ton craft near an asteroid many times its size. The 20-ton craft immediately "falls" to the surface of the asteroid, because hey, gravity. Now what? Propel away, right? Problem is, at close distances (necessary for the craft's gravity to matter), propelling away from the asteroid PUSHES it away as well. One possible solution is to have the 20-ton thing tethered to another craft that is far enough away, although that seems sort of elaborate. Maybe they suggest that in TFA. I wouldn't know. Articles about outer space are boorrrinngg.
If we can make them change course at all, we should be sending them into an orbit relatively close to our own, so we have less far to go to harvest the minerals.
Let's face it, we _are_ a virus and we _have_ to get off this planet sometime, or we _will_ face extinction (queue Casablanca theme) maybe not today, maybe not tomorrow, but soon.
So, let's start using the freely available resources that the cosmos is kindly sending our way.
If it can be deflected the same system could be used to aim the asteroid at a target on earth. 20 tons is nothing really the hubble is 12.75 tons, so 2 hubbles and your there.
"It's so convenient to have a system where everyone is a criminal" - A. Hitler
"Korean uses giant rubber band to slingshot asteroids"
FTFA- "You can think of it like a big elastic band between the two pulling them together," said Edward Lu...
It's a heavy payload, it's size will depend on density.
I suggest not using styrofoam.
The Kruger Dunning explains most post on
Finally, a useful purpose for the space station. Just hook up the rockets and blast-off to the asteroid.
Also, spin. You can't just mount an ion drive on something that spins 50 times a day and expect it to work.
--LWM
Just maker it manned, and add an alien monster. An Alien monster released from the astroid that is actually an Alien prison ship!
Lets see:
Bruce willis as the action star.
Winona Ryder as the 'nerdy' science officer/love interest.
Monster tries to take over the ship and crash the astroid into the earth while imprenating Bruce Willis(plot twist!) with it's 'children' that will burst from his body infecting the earth. Bruce Willis tries to destroy the ship, but fails. Leaving the action star partially naked as she blows up the ship!
The Kruger Dunning explains most post on
...if I simply ask you what you think your life is worth, you may be tempted to exaggerate, so economists judge people based on their actions. Dangerous jobs tend to earn higher pay, while activities such as buying smoke alarms or buckling seat belts carry their own costs as well as bringing safety benefits.
a lue-of-iraqi-life.html
A typical calculation: you might pay up to $6,000 on a safer car that reduced your risk of dying by one in a thousand. Six thousand divided by one in a thousand is six million, so you are valuing your own life at about $6m. This is a typical result for residents of the US.
http://www.timharford.com/deareconomist/2005/10/v
Launching massive spacecraft is quite feasable with the Orion drive. While the usual objection is the fallout from the nuclear explosions, this pales in comparison with a large asteroid hit. Plus, fallout can be limited and launched in a less sensitive area.
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Comment removed based on user account deletion
20 to 200 thousand tons. Killer asteroid size. We're not even going to talk about Chicxulub size asteriods, 150 - 300 km in diameter. That's extinction size.
What's the size of that pea shooter again? 20 tons? KYAGB...
MSBPodcast.com The opinions expressed here are my own. If you don't like 'em... Think up your own stuff.
Getting heavy things into space is expensive. Why not use nanotube material (since we're talking at least two decades out) to make a giant bag with a very long cable attached? At the end of the cable is a much smaller bag. The big bag goes around the asteroid, and the little one is filled with a chunk that's knocked off of it. When the entire contraption gets near a planet or moon (other than Earth, obviously), it tosses the smaller bag into the gravity well. It acts like a sea anchor, and slingshots the asteroid onto a different trajectory. The bag would probably come apart, but not before changing the course enough for the asteroid to miss the Earth.
If the asteroid were known to be very solid, you could even forego the bag and tie the cable around like a gift bow.
If you REALLY built it well, maybe you could put the asteroid into orbit around the moon/other planet and hollow it out to use as a space station, a solid platform to build communications relay gear or robotic probe staging equipment on, or even a space elevator for a body other than Earth.
"...always new atoms but always doing the same dance, remembering what the dance was yesterday." -Richard Feynman
Never mind moving the objects, just move the earth out of the way. Just mount an engine on the north and south poles. No need for any space travel. This can be done at ground level. A pair of coal fired steam jets should do it.
Oh well, what the hell...
Why's everybody so worried about an impact anyways? Heating the atmosphere instantly above 300 C may have hidden advantages. Liberals will constantly bitch, and whine, and claim that this kind of instant heating trend is going to be catastrophic. It can be seen, however, in the fossil record that such "catastrophic" events probably have occured before in the past on multiple occasions.
Seems like it would make more sense to manuver a smaller asteriod to accomplish the same task. The asteroid would end up a moon of the larger rock and be availible if further coarse corrections were they needed. Launching something of that mass, obviously a series of launchings, makes little sense.
We can eventually modify what equipment and what kind of equpment is carried but we can achieve economies of scale right now and cover Mars with tracks...
We don't need no stinkin' people.
MSBPodcast.com The opinions expressed here are my own. If you don't like 'em... Think up your own stuff.
surely putting a few overweight people on the thing will help increase its gavitational pull :)
Find a job you like and you will never work a day in your life.
Might it not be easier to eg: launch the "tractor" (small rocket, big motor) and hook up to the "trailer" (some small rocky asteroid) once already out there? Then shunt that tame asteroid (whose metaphoric role changes to that of a "carrot") in order to attract the rogue "donkey" into a safer orbit.
...every action has an equal and opposite reaction... ...so asteroid pulls the spacecraft... ...for 20 years... ...so the spacecraft needs some sort of fuel that will allow it to fight this pull for 20 years... ...so... ...can this be done?
sorry, its a genuine question from a layman. what is the answer?
Find a job you like and you will never work a day in your life.
Wow, I just read the headline as "Using Gravy As Astroglide"
I'm not sure where my mind is right now but I think it should leave there immediately.
bring this up, but yes, a first-world life is worth $5-10 million dollars, depending on how you do your figures. This is how much we value our own lives, as expressed by our willingness to take risks for money (which we all do, every day, if we are brave enough to drive to work or undertake other similar trivial daily events)
This has a lot of implications for the legal field. Many of the whacko verdicts you hear are patently absurd. If my whole life is at the outside worth ~$10 million, how can something which is obviously a small fraction of my life's happiness be worth as much or more?
Why don't we kill two birds with one stone. Build a spacecraft that collects space junk. It would be cheaper to get it off the ground at it's original weight. Then it would hang out in low orbit collecting space junk. Then when the time comes, our careless littering will be what saves us from certain doom. In 1999, they estimated that there's 4 million pounds of space junk in low-Earth orbit. 20 tons, as in 40,000 pounds, doesn't seem too hard to amass. We can just keep welding, or use some sort of concrete like substance to hold it together.
No need for explosions or anything. If you just attached a mass of stuff to the asteroid, wouldn't that change its course over time because the gravitational effects from all the heavenly bodies would then be different?
So would it not be a question of merely figuring out WHEN to attach the mass to the asteroid and how much to attach, given that it could be done securely enough?
Find a job you like and you will never work a day in your life.
Remember, it's easier to train drillers to be astronauts than to train astronauts to drill. :)
can the 20-ton spacecraft run linux?
The FA states that this method is meant to deflect small asteroids. Not huge ones. It states it is meant to take decades, yet people post that the engines/fuel won't last that long.
The method is pretty obvious: put the big frozen fuel tank in a 'synchronous' orbit, and drag the (medium-sized, identified) asteroid up every time the tank gets pulled too close, or continuously, very slowly. Apparently the calculations may work; it is beneficial for the tank to be bulky, after all.
The whole point is that the risk is not from the massive, known asteroids, with known trajectories, nor the tiny ones too small to be a danger. It is from the small-medium ones which may be detected well in advance, i.e. on a previous incoming close visit, but which do need deflecting.
The science fiction version of this is a space shield with a number of these devices somehow ready to tag on to the orbit of an asteroid. And catching the orbit (in time) is the hardest part.
I'd go for the large array of telescope/x-ray laser hybrid sats
think of the global earth defense array they had in one of those star trek generations movies
a spherical array of thousands of satellites, each equiped with a telescope and an x-ray laser
we get a much better view of the sky, namely a 360, unlike our current 1 percent we'll see it all
and many of the satellites could aim at the same target or targets if the main one breaks up
I think it would work better than the nuclear blast idea some folks have, with one big blast, omni-directional, which wouldn't do diddly, you instead have hundreds or thousands of individual directed blasts focusing on a single area, or several areas depending on the shape of the object, to intentionally fracture a single large object into hundreds of smaller ones, which each can be targeted depending on size, if they are under a certain size simply ignore them as the atmosphere will likely burn them up, otherwise blast em.
Nope. All gravitational force exerted on an asteroid is directly proportional to its mass. Since Force=Mass*acceleration, the mass cancels out of the equation - the acceleration (and hence the trajectory) is independent of its mass. This is the exact same reason why objects of different weights fall at the same rate - both acceleration AND gravitational force are proportional to mass, so mass cancels out of the equation.
Of course, I'm assuming that gravitational interactions with objects of comparable size (i.e. other asteroids) are negligible. My argument only holds if everything the asteroid interacts with is much more massive than it (and thus not affected much by the asteroid's gravitational pull). But I would bet that's a pretty good assumption.
Archimedes said, "Give me a place to stand and a lever long enough and I can move
the world."
Damn ACs don't even know what a fulcrum is.
Required reading for internet skeptics
Assuming a spherical iron asteroid with a 100m radius (the article mentions two football fields across) and a 20 ton ship you can provide a maximum gravitational force of about 1 pound. This is find and dandy and could provide a deflection of nearly the diameter of the earth over a decade period.
But...
The problem is how to produce that required force on your ship without impacting the asteroid. Conventional rockets or ion thrusters would necessarily be directed in the direction of the asteroid which would nullify any net force on the system (ship+asteroid). If you get enough distance between the asteroid and the ship so yout thrust can miss the asteroid and provide a net force, the force you can provide on the asteroid due to gravity drops as the square of the distance and becomes unusably low. You'd need litterally centuries or millenia of advance warning!
If anyone has ideas how to avoid this problem, I'm all ears. :)
I'm disappointed in you, Slashdot nerds. For shame!
Next: Nasa patents "A Method and Process for Using Gravity To Tow Asteroids"
God loses his appeal based on prior art, ends civilization in retaliation.
Returned Peace Corps IT Volunteer
Wasn't this a ST:TNG episode? I believe that the answer lies in extending the warp field around the object in question, or something like that.
The scientist quoted in the article says: "The kind of spacecraft we've talked about could move an asteroid 650 feet (200 meters) across provided we have decades of advanced warning". 650 feet?
I'm posting this here for attribution, just in case in 20 (or 50 or 200) years from now someone rediscovers this idea. Then they'll use the archives to discover that the idea used to save the world was originally conceived by me! (and boost my Karma score into the ionosphere!).
Basically one of the big problems of moving an asteroid is its rotation. Trying to move a big spinning object, is really hard. There is a tremendous amount of energy contained in the spin so fighting it will be very expensive.
So don't fight it, USE it. Lower a long rope to the surface of the asteroid letting the spin of the asteroid keep it taught. (same idea as a space elevator). Now ferry rocks way beyond the "Geosync" point, if the rotation is anything substantial it shouldn't be too far from the surface (a few tens of kilometers, no need for carbon nanotubes). Release the rocks into space, timing the release so that they shoot off in the same general direction.
What you're doing is converting the enormous rotational energy of the asteroid into kinetic energy of the rocks. Depending on how long your rope is (and thus how fast your rocks are released) you are going to get a substantial thrust in the opposite direction. (for every action there is a reaction). You are also making the asteroid smaller. As for the released rocks, while they may someday in the distant future hit the earth they'll be small and won't make it past the upper atmosphere.
Of course in addition to the long time frame (given) that this will take; this assumes that the asteroid is rotating (probably won't have to be too fast) and that you can attach the cable to some point on the asteroid. I believe most asteroids we've discovered have a substantial rotation, this is probably due to the violent manner in which they were formed and subsequently battered. As for the cable attachment, some nets and cables stretching around the asteroid should handle this just fine.
So there you have it. Instead of launching a huge expensive power hungry spacecraft that'll provide an absolutely tiny acceleration, you could send a relatively tiny spacecraft consisting of a few solar powered low mass robots (to move the rocks to the cable) and some sort of conveyor mechanism. While this'll take some engineering, it certainly is less than trying to have a 20 ton spacecraft do precision (because gravity is inverse squared you need to be close) station keeping off a tumbling (maybe chaotically!) asteroid for decades. If the rotation rate is high enough, you could even use the asteroid to generate energy (microwave beaming?).
wisebabo
We all know that best way to deal with an asteriod is to get some oil drillers on it and stick a nuke in. Oh, and a ROBUST remote trigger.
I wonder if that lady russian astrologer would sue NASA again for changing the orbits of celestial objects.
This only fixes smaller asteroids, which would burn in the atmosphere anyway.
What about the city size asteroids? All those cold war nuke stockpiles have to go somewhere.
"Give orange me give eat orange me eat orange give me eat orange give me you." -Nim Chimpsky
Send out 1 big ass nuke and blow it on the side to knock it off course. They're talking about using this gravity thing decades before it impacts, so I say just blow it off course a fraction of a degree and by the time it gets here it will be way the hell off course.
... what happens if Rosie O'Donnell doesn't want to go? =P
Look, the thing is that a 200 meter asteroid is puny by comparison to something that could destroy civilization. Something of that size would break up mostly in the atmosphere, and cause little to no damage to the earth. And besides, something that small we can just blow up.
What we should be worried about is one that is a few MILES in diameter. Those are the asteroids that threaten extinction.
So the only question should be which way is the most likely to succeed, cost be damned.
We know that nuking an asteroid doesn't work very well unless you can get the nuke inside it.
But what about anti-matter? If you throw anti-matter at an asteroid, the asteroid's own matter would be converted to energy, so in addition to the explosion blowing it peices, it's own matter would be obliterated.
So just for the sake of argument, let's say a secret government labratory has already solved the problem of how to create large quantites of anti-matter and contain it.
How much anti-matter would you need to adequately destroy an asteroid of a certain size?
It occurs to me though that to hit a rock with antimatter, you'd have to be able to hit it with another rock as well, so maybe just hitting it with another rock would be a solution. What would be the best mass/speed ratio to pulverise a 1 ton asteroid into dust with another asteroid?
1) Planned spacecraft is UNMANNED
2) Requires only about 1 pound of thrust
3) That thrust would push off to the sides, so as not to disturb the asteroid, because...
4) Asteroids are mostly loosley-packed, and might break up if disturbed.
5) They're expecting a close pass sometime in 2035 or 2036
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
Some idiots hijacking the craft and using it to steer a near-miss asteroid directly at earth: Priceless .
This is not a dream, not a dream...we are transmitting from the year 1-9-9-9.
20 tons just isn't that big.
The space shuttle masses over 10 metric tons at liftoff itself with its tanks (and for our purposes, metric tons and 2000 pound tons are interchangeable). The shuttle itself is 2 tons and is capable of delivering payloads of up to 25 metric tons.
So a loaded shuttle with enough fuel to take it out of LEO would be good enough - and this spacecraft would be a lot less sophisticated than the shuttle.
Also, given the low thrust requirements for "towing," this could be a good application for the ion drive, which is high efficiency / ultra low thrust.
"It is our blasphemy which has made us great, and will sustain us, and which the gods secretly admire in us." - Zelazny
What's wrong with blowing an asteroid to smithreens?
Break it up small enough, the pieces will burn in Earth's atmosphere, wouldn't they?
Plus, wouldn't the Moon pull in some pieces away from us, or perhaps also absorb some of the projectiles?
Okay, so we've spent a gazillion dollars launching this thing into space... then we use it to lure an asteroid off course so it doesn't hit Earth... THEN WHAT??? Our spaceship now has a gigantic asteroid following it around!
$nice = $webHosting + $domainNames + $sslCerts
old world saving thread thingy:& cid=4709365
http://science.slashdot.org/comments.pl?sid=45499
mass drivers are coming
mass drivers are coming
the sky is falling
(Babylon5 fans will know what I mean)
Why don't they build the boosters on an asteroid?
They should put only the boosters/fuel on orbit, the rest of the mass would be already out of Earth.
They could slowly build larger and larger attractors as the asteroid gathers mass.
Heck, they could eventually build a new planet!
Unfortunately my work PC wont let me view the link so forgive me if this is irrelavent but....
exactly what effect is a mear 20 ton craft going to have on an asteroid that is 1/2 mile across? The earths gravity acts with a force of 9.81 and weighs 5.9742 × 10^24, the tractor drone weighs 2.0 x 10^7 so exactly how small a pull will it have?
In the not too distant future, next Sunday A.D.
we might always consider ways of altering earth's trajectory.
Although the earth would be a much harder thing to move around, it's far easier to access
and the amount of resources to do so far exceed those of a tiny spacecraft.
In certain scenarios this might be a viable approach, that warrants some thought in any case.
I can recall someone discussing the possibility of hauling black holes around at will using a similar technique (like a carrot in front of a donkey). Is my memory decieving me, or was it Stephen Hawking?
No kidding!!! What do you say at this point?
Just pick a 20 ton asteroid (or larger) that is following near the same orbit as the big bad one. It could even be just crossing the orbit once and a while. This will allow a much cheaper and longer term mission with much observation of the dangerous object (including possibly cutting part of it out for storage elsewhere) and Martin Lo's work on the interplanetary superhighway may in fact find both the dinosaur killers and the civilization savers at the same time. Put an ion drive on that and wait a year! Now if we can find an asteroid with the xeon or whatever it uses and plaster solar panels all over it that will be sweet. Hey let's try it with a non-dangerous asteroid and get some practice!
We could easily get a 20-ton payload from all of our landfills. It would at least solve the issue of where the heck to put all of the waste we create as a species. Of course, in a thousand years, we'll need to worry about it coming back as an asteroid heading for New New York.
In order to maintain a fixed height from the asteroid, the ship will have to fire its thrusters towards the asteroid...which will impact the surface and push the asteroid back towards its original course! Hmmm...
Did the mine field scene come to anbyodies mind besides me? Smacking some bristling alien baddy in the face with a gravity towed asteroid....WHACK!! hehe m
Instead of elaborate explosions, propulsion or hulking great ships up would it be at all feasible to anchor the offending asteroid to another one so as to alter its trajectory? You might connect the rogue to another object upcoming in its path and as it comes past it gets the kind of jolt it was quite good fun experiencing when you catch a lampost with an outstretched arm running at full tilt.
Of course there would seem to be the possibilty of creating a bilobed rotating asteroid complex of doom - then you can start pelting rockets at it for what its worth.
It's just weight for weight's sake, so build it from stuff already in space... find a nearby asteroid or similar of the appropriate size, shape it as needed, and slap some thrusters on/in it.
If it was practical to shape an asteroid and put thrusters on it, you'd do exactly that to the threatening asteroid. The point of using a gravity tug is to avoid having to manually manipulate the asteroid, which is too difficult. From the article: "An asteroid is likely to be loosely packed material, so tugging on it too hard could break it into unmanageable pieces. Or, the force from the spacecraft's thrusters could break up the asteroid."
What happens if we lose control over this massive spacecraft - would it not orbit the sun, thus creating *another* thing that could smash into us?
Just use another astroid to smack into the problem one, just like playing pool. We can place decent rockets/nuke engines on a number of astroids that already have a decent kinetic enrgy and just steer them into the offending one.
just be sure you don't snooker yourself.
{ Pillar candles great for when the power fails and you cant see the keyboard..