Or, once you have these engines dropped, you could gradually reduce the asteroid's rate of rotation...
Gravity Tractor discussion ...
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Travis Reed
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Unfortunately, the Gravity Tug cannot be run in Orbiter. Last I knew, Orbiter doesn't simulate 'vessels' as producing any gravity. The only objects that produce gravity are those listed in the sol config file (planets, moons, any addon asteriods, etc).
That said, a good programmer could come up with a workaround. However, such a workaround would likely either be vessel specific or in MFD form.
That said, a good programmer could come up with a workaround. However, such a workaround would likely either be vessel specific or in MFD form.
It is possible with the [ame="http://www.orbithangar.com/searchid.php?ID=3190"]Gravity Tool[/ame] vessel by Artlav. You could spawn one with the orbital elements of Apophis, and another next to it which is the tractor, and set their respective gravity in m/s. I haven't tried it though.
There's already a vessel on OH which simulates a gravitational pull on nearby vessels.
Travis Reed
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I was not aware of it. But then, I don't frequent OH unless it's for something specific. I've found most addon makers rely on Spacecraft and Multistage more than I'd like...
*wants more ships with panels and systems and such simulated, similar to the XR series, DG3, Shuttle A2 ( which was never finished...
), Vespucci D, and the old Helios ( the newest version of it had a panel and some systems simulated, but it only works in Orbiter 2003 )*Unfortunately, significantly altering the asteroid's rate of rotation would require more impulse than the alteration of its orbit--you only need to accelerate the entire asteroid by about 30 cm per second total delta-v to get it to miss Earth if you have one year's lead time. (divide 30 cm by the number of years you have to get a rough estimate of how much delta-v you need)
the.punk
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I think also we must launch different missions if the "Big One" comes. maybe also a nuke.
And for the rotation I said something earlier, but this would require more fuel and that's more payload that must be transported.
And for the rotation I said something earlier, but this would require more fuel and that's more payload that must be transported.
Andy44
owner: Oil Creek Astronautix
Trying to change the asteroid's rotation rate is yet another complicated engineering headache.
For starters, as Ijuin pointed out, the impulse required for this is greater than that needed for changing the rock's velocity. Even if you can deliver it, it would take a very long time, time which is too precious to blow on this.
Supposing you decide to do this anyway, you now need a lander with a gimbaled thruster and a way to anchor your lander to the surface. You know nothing about the composition of the surface, so good luck with that.
You also may not know what the rock's rotation rate and axis is. You really need to figure this out before attempting a landing. If it's too fast, you may have come all this way for nothing. If it's slow enough to allow a landing, you now have to have some star trackers and adequate flight software to determine the attitude of the lander after anchoring, so it can control the thruster gimbal dynamically as the rock rotates.
Someone mentioned turning the thruster off when the rock faces the wrong direction, and turning it back on when the rock's attitude is favorable. Yet another engineering issue here: in addition to the fancy star trackers and software mentioned above, most ion thrusters are designed to be turned on and left on for long periods of time.
For starters, as Ijuin pointed out, the impulse required for this is greater than that needed for changing the rock's velocity. Even if you can deliver it, it would take a very long time, time which is too precious to blow on this.
Supposing you decide to do this anyway, you now need a lander with a gimbaled thruster and a way to anchor your lander to the surface. You know nothing about the composition of the surface, so good luck with that.
You also may not know what the rock's rotation rate and axis is. You really need to figure this out before attempting a landing. If it's too fast, you may have come all this way for nothing. If it's slow enough to allow a landing, you now have to have some star trackers and adequate flight software to determine the attitude of the lander after anchoring, so it can control the thruster gimbal dynamically as the rock rotates.
Someone mentioned turning the thruster off when the rock faces the wrong direction, and turning it back on when the rock's attitude is favorable. Yet another engineering issue here: in addition to the fancy star trackers and software mentioned above, most ion thrusters are designed to be turned on and left on for long periods of time.
One answer might be to find the asteroid's axis of rotation and to land at the pole instead--then your gimballed engine can remain pointing in an inertially static direction if you are at the pole. That at least would address the asteroid rotation issue.
Wishbone
Clueless developer
Save the Earth, launch your Gravity tractor NOW!
Am reviving this thread because there was an article by Olympio in the June issue of AIAA J. of Guidance..., and the new Orbiter is out, with designer-definable forces. If an asteroid is pictured as a very large vessel that responds to other vessels flying nearby, this kind of deflection may become feasible. Who wouldn't like to be the person saving the Earth from wholesale destruction?
(the slight problem is that some of the ways to do that would require hundreds of days sitting at the screen, but it takes some sacrifice to become a hero...)
Am reviving this thread because there was an article by Olympio in the June issue of AIAA J. of Guidance..., and the new Orbiter is out, with designer-definable forces. If an asteroid is pictured as a very large vessel that responds to other vessels flying nearby, this kind of deflection may become feasible. Who wouldn't like to be the person saving the Earth from wholesale destruction?
(the slight problem is that some of the ways to do that would require hundreds of days sitting at the screen, but it takes some sacrifice to become a hero...)I think we've got to look at it a bit more carefully; nuking the asteroid isn't about blowing it up, or blowing chunks off of it, or even pushing it with the detonation products of the nuke.
Nukes in space act kind of like very powerful flashbulbs; a very brief, very high power release of energy. And that basically tends to ablate/vaporise stuff. So you impart momentum from the asteroid, by ablating a certain part of the surface. The asteroid doesn't fly apart, it doesn't explode, and rocks the size of houses don't come flying off of it.
Nukes are very politically problematic, for obvious reasons. Their use in space is outlawed by treaty. But I doubt launching one into space, in a collaborative, international effort, would cause a war. Unless you're Kim Jong Il you're not going to go off putting resources and human lives down the drain, because, I dunno you don't like the idea of nuke-based asteroid deflection.
My problem with a mass tractor is chiefly the mass, and the time it would take to have an effect. Yeah, an Ares V might be able to launch the thing, but Ares V doesn't exist, and it probably won't by the year 2029 either. Apophis is a good candidate for a mass tractor mission (or any asteroid deflection stratagy, really) because we know of it's position (more or less) decades in advance, and if we get it right the first time, we only need to nudge it out of a relatively small "keyhole".
Yes, we've seen asteroids with strikingly large craters. Yes, that also means they can have a weakened structure. But it also means that asteroids can, to an extent, survive striking impacts and survive (relatively) intact. And even if relatively large fragments spall off the object, they are small enough to cause limited damage (Tunguska sized), and it is important to note that Earth is mostly uninhabited, with large oceans etc.
Apophis won't cause a mass extinction; not nearly. The last NASA impact energy estimate was 510 megatons; while that is a lot in say, nuclear weapons terms, it isn't a world ending event in terms of natural disasters (Krakatoa was maybe 200 megatons). It's a small enough impact, that if it occured in Houston, Texas, and you were situated in Dallas, you would be practically unscathed from the immediate effects, apart from a bit of shaking and a light dusting of fine ejecta.
But it is by no means a small event- estimates state that an impact in central america could kill tens of millions, and it has the potential to cause a tsunami event as well.
The question is: if the governments of the world could avert the deaths of ten million people, by spending several billion dollars, would they do so?
Nukes in space act kind of like very powerful flashbulbs; a very brief, very high power release of energy. And that basically tends to ablate/vaporise stuff. So you impart momentum from the asteroid, by ablating a certain part of the surface. The asteroid doesn't fly apart, it doesn't explode, and rocks the size of houses don't come flying off of it.
Nukes are very politically problematic, for obvious reasons. Their use in space is outlawed by treaty. But I doubt launching one into space, in a collaborative, international effort, would cause a war. Unless you're Kim Jong Il you're not going to go off putting resources and human lives down the drain, because, I dunno you don't like the idea of nuke-based asteroid deflection.
My problem with a mass tractor is chiefly the mass, and the time it would take to have an effect. Yeah, an Ares V might be able to launch the thing, but Ares V doesn't exist, and it probably won't by the year 2029 either. Apophis is a good candidate for a mass tractor mission (or any asteroid deflection stratagy, really) because we know of it's position (more or less) decades in advance, and if we get it right the first time, we only need to nudge it out of a relatively small "keyhole".
Yes, we've seen asteroids with strikingly large craters. Yes, that also means they can have a weakened structure. But it also means that asteroids can, to an extent, survive striking impacts and survive (relatively) intact. And even if relatively large fragments spall off the object, they are small enough to cause limited damage (Tunguska sized), and it is important to note that Earth is mostly uninhabited, with large oceans etc.
Apophis won't cause a mass extinction; not nearly. The last NASA impact energy estimate was 510 megatons; while that is a lot in say, nuclear weapons terms, it isn't a world ending event in terms of natural disasters (Krakatoa was maybe 200 megatons). It's a small enough impact, that if it occured in Houston, Texas, and you were situated in Dallas, you would be practically unscathed from the immediate effects, apart from a bit of shaking and a light dusting of fine ejecta.
But it is by no means a small event- estimates state that an impact in central america could kill tens of millions, and it has the potential to cause a tsunami event as well.
The question is: if the governments of the world could avert the deaths of ten million people, by spending several billion dollars, would they do so?
Grover
Saturn V Misfire
hang on, we already have a huge gravity source protecting us from asteroids: its called jupiter (and i suppose saturn does it as well, but i dont know this for sure), this has already made life on earth possible and then stopped it being destroyed on a few occasions, why would we need a spaceship if we have a huge giant out there.
but seriously, a single nuke would cripple it, and if it didnt change its course, it would certainly make it smaller, maybe too small to make it to the earth's surface. and if that fails LAUNCH EVEN MORE NUKES *evil laugh*
but seriously, a single nuke would cripple it, and if it didnt change its course, it would certainly make it smaller, maybe too small to make it to the earth's surface. and if that fails LAUNCH EVEN MORE NUKES *evil laugh*
Uh... no. It isn't like Jupiter stops offending asteroids with a planet-sized tennis racket; the giant planets can actually, by peturbing bolides, cause more impacts on the Earth. And they obviously will not prevent an impact on a timescale of a few decades when a body is already on a dangerous trajectory.
A single nuke could do a lot of things, and if we do it wrong, or do it with insufficient or incorrect data, it could have an unsatisfactory or even problematic result. My whole point is not to blunder forth and NUKE THE ROCK NOW!!!!111, but instead to consider the use of such devices in a controlled and thought-out manner to achieve the desired effect.
A single nuke could do a lot of things, and if we do it wrong, or do it with insufficient or incorrect data, it could have an unsatisfactory or even problematic result. My whole point is not to blunder forth and NUKE THE ROCK NOW!!!!111, but instead to consider the use of such devices in a controlled and thought-out manner to achieve the desired effect.
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Grover
Saturn V Misfire
ok, well why not launch a one way rocket to the 'roid, drill it in place (robotically obviously) then fire it with enough delta-v to push it well out or harms way, its far more pracital than trying to "make gravity", and safer than nuking the rock, imagine a saturn V rocket on a rock, its gotta budge somehow
(yes, i know getting a rocket this big is hard, but with enough boosters its possible, even if its HUGELY problematic, and dont give the "thats a stupid idea" posts, i know, but we dont really have anything better
(yes, i know getting a rocket this big is hard, but with enough boosters its possible, even if its HUGELY problematic, and dont give the "thats a stupid idea" posts, i know, but we dont really have anything better
Urwumpe
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Why not just land a car sized asteroid lawn mover on it, that slowly mills the asteroid into dust? if you have enough time, you can turn any asteroid into fine dust in a few years. Like, for example, produce a 100m long, 1 m wide and 10 cm deep trench on the asteroid every day...thats 50 tons of asteroid less...every day. A single such mill would just need 1000 years to turn an Apophis sized asteroid into dust... 1000 of them could do the same stunt in 1 year. or use more capable devices...
[ame="http://en.wikipedia.org/wiki/Bagger_288"]Bagger 288[/ame] can remove 240,000 tons every day, the question is just to bring this kind of machine in a spacecraft.
[ame="http://en.wikipedia.org/wiki/Bagger_288"]Bagger 288[/ame] can remove 240,000 tons every day, the question is just to bring this kind of machine in a spacecraft.
Wishbone
Clueless developer
Folks, nukes are off for the reason of launch failures. Mass tractor works during 6 years, with the craft hovering over one point of the NEO (not you T.Neo, but the near earth object), and the reason to do this is to avoid both the direct impact and entry of the asteroid into a "keyhole" near earth that guarantees a future resonance return and direct impact. Drilling and pushing is not safe if the asteroid is a loose pile of rubble.
EDIT: The same goes for the miller/lawnmower. You'd have to supply it with plenty of energy to work, which means a nuclear reactor, not a RTG, and disrupting the pile of rubble and losing the lawnmower would mean mission failure as well.
EDIT: The same goes for the miller/lawnmower. You'd have to supply it with plenty of energy to work, which means a nuclear reactor, not a RTG, and disrupting the pile of rubble and losing the lawnmower would mean mission failure as well.
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Urwumpe
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There you would need to explain a lot of stuff. Since you make essentially the goal of the mission a problem for the mission.
And using a nuclear reactor in space is not new technology.
Of course you can loose it. But that can happen to ANY space mission. You can also have at a much higher chance mission extensions.
Wishbone, nukes are often kept in entry vessels anyway. They're built to deliver a payload quickly, not contain radioactive material, but still... So are RTGs, (I mean, the vessels that contain the radioactive materials, not delivery devices specifically :shifty that are launched into space often, and might contain a comparable radioactive payload. Nuclear weapons also do not easily undergo sympathetic detonation.
And a the fallout from a few kilograms of uranium or plutonium is not as bad as a natural disaster that could kill 10 million people. Or do far, far worse, in the case of a really large bolide.
Landing a thruster on an asteroid is possible, but you then encounter problems with the composition (it could be a rubble pile, etc) and rotation of the asteroid (you can't burn all the time on a rotating object, because you then achieve little). And obviously landing something like a launch vehicle stack onto an asteroid is plain nonsense, you'd want to go for something more efficient, like an ion drive.
Urwumpe, that is a brilliant idea... but there is only the tiny problem of having to launch 13 500 tons into space and land it on an asteroid.
that are launched into space often, and might contain a comparable radioactive payload. Nuclear weapons also do not easily undergo sympathetic detonation.And a the fallout from a few kilograms of uranium or plutonium is not as bad as a natural disaster that could kill 10 million people. Or do far, far worse, in the case of a really large bolide.
Landing a thruster on an asteroid is possible, but you then encounter problems with the composition (it could be a rubble pile, etc) and rotation of the asteroid (you can't burn all the time on a rotating object, because you then achieve little). And obviously landing something like a launch vehicle stack onto an asteroid is plain nonsense, you'd want to go for something more efficient, like an ion drive.
Urwumpe, that is a brilliant idea... but there is only the tiny problem of having to launch 13 500 tons into space and land it on an asteroid.
Urwumpe
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Urwumpe, that is a brilliant idea... but there is only the tiny problem of having to launch 13 500 tons into space and land it on an asteroid.
I did not say that my idea is completely thought to the end, but give me a few liters of Cola and I will sure get something that is less visionary. :lol:
Most of the 13500 tons are not needed anyway, that is just solid cheap steel structure for getting the material on a conveyor belt. Since we have a lack of gravity anyway, unless you want to fill containers with asteroid ore, making something that looks and works like a classic military mine sweeper tank would work.
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Wishbone
Clueless developer
Are you sure you want dispersed plutonium floating in the upper atmosphere? Please check its LD50 to see what it can do. Disruption vs. deflection is an age-old dilemma, can't say which is better since there is uncertainty about the geology of the asteroid. What makes the tractor attractive (a bad pun, I know) is Xe ion thrusters, there are other technologies, but they have higher risk of drifting off with a small lump of the asteroid.
