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NASA's DART spacecraft changed an asteroid's orbit around the sun

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Re: NASA's DART spacecraft changed an asteroid's orbit around the sun

#81

Post by ryandrake »

Ajakks wrote: post #79
wongarsu wrote: post #62

Earlier quoted context omitted.

> That is simply "Assured Destruction" with absolutely no mutual drawbacks Nuclear countries would simply declare that they will launch nukes if any rod comes down on their territory. Even if you had thousands of projectiles in orbit (at considerable cost per projectile) this would not be significantly different from 60s-style MAD: put nukes in bunkers, in the air and in the sea to ensure they can't all be taken out.…

That reaction is not the same tho - a rod isn't even a conventional weapon, I am not certain off hand that an incredibly destructive such weapon would even be banned under current treaties. That matters bc your taking about the end of the world. Only Russia would ever shoot at the US - so, dont drop rods on Russia. Plus - if countries don't do space wars - this will still happen 100%. It will just be a non-state acto…

Heinlein's The Moon Is A Harsh Mistress kind of mapped out what to expect if/when your adversary manages to position themselves significantly above you in the Earth's gravity well.

Re: NASA's DART spacecraft changed an asteroid's orbit around the sun

#82

Post by Ajakks »

anigbrowl wrote: post #53
Ajakks wrote: post #49

Earlier quoted context omitted.

I personally would get whatever metal in space, so weight is not the issue - solving this problem would also create almost immediately chunks of rocks that could also be dropped. In all reality, anything can be "setup" to be a weapon - many ways have been identified here. All required innovations - of which, most are not out of reach in the slightest, all of that tech would be immensely valuable, literally everything…

If this is satire, it's not that funny. If you're serious, it's a good example of 'the ugly American.'

I wish it were satire - we do actually need to have space defenses, asteroids exist 2st off - its just bc we ignore all the craters that we sleep at night.

We feel safe here on earth but it's really a giant graveyard trap - that so effectively exerts control over life on it, that it made all living mammals out of mice - we may actually be safer on almost any other planet.

All life on earth has eventually died out so far, we are the 1st species that could stop the most likely extinction level event - but this DART is the closest we ever got to actually taking up that responsibility - the preservation of our species and whatnot, thats just 1 minor reason.

The most important tho, given how much we have example of people "getting theirs" at all other peoples expense - this is much worse if a non-state actor gets there 1st.

Lastly, I do have to clarify the American position - we run the world, or there will not be one to run. Nobody alive today made that decision - it changes nothing, once that choice was made, we are locked into it. Did you think we are only an economic power? That is the front. We can always pivot to actual power - the kind that can destroy all cities above a certain size - we have never hid this fact, the whole world knows of MAD. That is what power is.

What is American power if someone can destroy the US and we can't destroy them?? That doesn't work for the US - nothing at all changes if the US gets that spaceship first.

You can call this ugly - there were more modern wars before we started running things, from the looks of things - the whole world will go to war the moment we are out of the picture.

Re: NASA's DART spacecraft changed an asteroid's orbit around the sun

#83

Post by alex43578 »

idatum wrote: post #77
alex43578 wrote: post #72

Earlier quoted context omitted.

Two different problems: detection, deflection. Before this, even if we spotted one, we didn’t know if we could prevent impact. Detection honestly feels like an easier problem, especially as networked sensors and space-lift capacity has improved.

Is there really better confidence we could now detect a similar 2013 Chelyabinsk meteor event?

Yes? Rubin is supposed to contribute, and more broadly we have more and better "eyes" on the night's sky than ever before. There's always the opportunity for more tracking, but tracking without being able to do anything about it would've been pointless.

Re: NASA's DART spacecraft changed an asteroid's orbit around the sun

#84

Post by infinitewars »

infinitewars wrote: post #39

> slowed the orbit of a pair of asteroids around the sun by more than 10 micrometers per second Or in other words, 1 meter per day Why not say that?

1 meter per day is something most people can understand. But even more relevant would be 1 Earth diameter in 16,000 years... which makes it very clear this isn't useful for saving the Earth from asteroids yet.

Re: NASA's DART spacecraft changed an asteroid's orbit around the sun

#85

Post by gatreddi »

adriand wrote: post #70
gatreddi wrote: post #16

Wild that we went from "can we even deflect an asteroid" to measurably changing a solar orbit. 150 milliseconds sounds tiny until you realize compounding over decades makes that a meaningful trajectory shift. The engineering confidence this gives for actual planetary defense is massive.

> The engineering confidence this gives for actual planetary defense is massive. Is it? Isn’t it the case that we can’t even detect the vast majority of objects on a potentially problematic intersection path with earth? I feel like the most likely scenario is that by the time we realize we’re about to get slammed by an asteroid, it’s way too late.

Detection is still the weak link, that part is true. But the equation is shifting. Surveys like NASA’s NEOWISE mission and the upcoming NEO Surveyor mission are specifically aimed at finding those missing near-Earth objects earlier.

The point of DART mission wasn’t that we can deflect every asteroid tomorrow. It was to prove that physics and guidance actually work in space. Now the playbook is clearer: detect earlier, then nudge early.

If you get even a few years of warning, a tiny velocity change compounds into a huge miss distance. That’s the real takeaway.

Re: NASA's DART spacecraft changed an asteroid's orbit around the sun

#86

Post by littlestymaar »

alex43578 wrote: post #73
ivanjermakov wrote: post #45

Earlier quoted context omitted.

I find it mesmerizing how predictable orbital mechanics are. We can tell where celestial body will be years ahead with meter accuracy.

I think that’s what makes the 3 body problem unintuitive, given how we can predict 2 easily.

There's no “two body problem” here, the solar system is an n-body problem.

And the “three-body problem” is overblown in pop culture: even n-body problems are fairly predictable in the short-ish term, it's just that you cannot predict things over a long period because measurement imprecisions have a snowball effect, but it's not particularly unintuitive (I'd say it's more intuitive than the idea that we could predict things with perfect precision over billions of years).

Re: NASA's DART spacecraft changed an asteroid's orbit around the sun

#87

Post by Ajakks »

ryandrake wrote: post #81
Ajakks wrote: post #79

Earlier quoted context omitted.

That reaction is not the same tho - a rod isn't even a conventional weapon, I am not certain off hand that an incredibly destructive such weapon would even be banned under current treaties. That matters bc your taking about the end of the world. Only Russia would ever shoot at the US - so, dont drop rods on Russia. Plus - if countries don't do space wars - this will still happen 100%. It will just be a non-state acto…

Heinlein's The Moon Is A Harsh Mistress kind of mapped out what to expect if/when your adversary manages to position themselves significantly above you in the Earth's gravity well.

What an incredibly foresightful work - I have not read that, I will tho. Thanks!

And yeah, it is perhaps the most extremely imbalanced strategic advantage that can be attained.

Re: NASA's DART spacecraft changed an asteroid's orbit around the sun

#89

Post by Ajakks »

m4rtink wrote: post #68
wongarsu wrote: post #28

Earlier quoted context omitted.

You know what they say: the best planetary offense is a good asteroid redirect program It's also the best planetary terrorism, going by the plot of The Expanse

It only worked in the Expanse because they expertly choose a special trajectory that made the rocks hard to detect and some questionable (but plot necessary) "stealth coating". By this point UN and MCR have been in cold war for 100+ years staring each other down with region killer nuke arsenals and an absurd amount of interceptors always ready. See than one time Mars actually fired a barrage - only like two warheads…

Ok. The Expanse is a show/book - that doesn't actually portray any of this very well, but its very important to note - there are no satellites in orbit, with nukes or any kind of missiles - if you want to pretend they are, they are most definitely pointed at the earth.

I'd love to buy into that plot armor but there is too much to take seriously by S6. The reality is, the first time a colony decided to it was independent enough, to use an asteroid - they would pick one, or many, so as to to render earth uninhabitable, there is no doing what they did in the show - thats how you lose a war AFTER having already used a weapon of last resort.

Once Inoki or w/e his name decided to use an asteroid, and one hits, the ONLY choice open to Earth is an immediate unconditional surrender. The only correct choice for asteroid #2 is one that will end all life on the planet without any doubt.

What's her name? The President would have killed us all and attained nothing doing so.

Re: NASA's DART spacecraft changed an asteroid's orbit around the sun

#90

Post by aw1621107 »

Ajakks wrote: post #80
aw1621107 wrote: post #59

Earlier quoted context omitted.

> Space Stations are in orbit - the space battleship doesn't have to be I mean, you did say: > space battleship - one that never comes down to the surface, just sits in orbit. So I think it's understandable for people to take that at face value. Furthermore, if it isn't in orbit, then where would it be? > and a lot more of tug-boating it into the exact right spot, in the way of earth, so that earth hits the asteroid…

If I were holding earth hostage with my Space Battleship - I would sit in a lunar orbit. Also, I am not kidding about tug-boating - if I fly up, match an asteroids speed and velocity, why cant I just throw a tow strap on that, accelerate, and park it an area that only has to be accurate enough for a planet to hit it - I dont need to stop it, or have it flying at the earth, it only needs to be in the way, moving a lit…

> I would sit in a lunar orbit

Ah, so by "orbit" you were talking about orbit around Earth specifically?

> why cant I just throw a tow strap on that, accelerate, and park it an area that only has to be accurate enough for a planet to hit it - I dont need to stop it, or have it flying at the earth, it only needs to be in the way, moving a little slower than the earth.

Again, from a high-level orbital mechanics perspective there is little difference between the two. You start with two non-intersecting orbits and you're changing one orbit to intersect the other at the same time and place. How you go about doing so is just a question of how much time/fuel you're willing to expend, for various values of "just".

That being said, assuming I'm interpreting you correctly what you propose is probably technically possible (e.g., change an asteroid's orbit to a slightly-larger-than-Earth-sized one), but it's also very fuel-intensive compared to skipping the "parking"/"in the way" part.

If you haven't tried it already I can't recommend Kerbal Space Program enough for experimenting with this kind of thing, especially if you are alright with playing with mods. Real Solar System (changes the in-game solar system to match the our real-life one) and Principia (replaces the simplified patched conics system KSP uses for orbits with n-body gravity) would be particularly relevant here.

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