The trick with planetary defense is that the delta-v required is tiny if applied early.
Change an asteroid’s velocity by millimeters per second decades ahead of time and you’ve moved the intersection point with Earth by thousands of kilometers.
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.
>> The engineering confidence this gives for actual planetary defense is massive.
I've been waiting for this a long time. They initially reported significant changes to the orbit of the smaller rock around the larger one which was cool and all, but I kept wanting to hear how much it affected the whole system. I suspect it's taken several years to answer that because it's such a tiny change in velocity. Dimorphos we can deflect, Didymos not so much.
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 got through, only due to shitload of decoys and overall numbers.
A dumb rock would totally get vaporized without the plot armor in a safe distance.
Why exactly? I think the US ought to spend a few trillion on an actual space battleship - one that never comes down to the surface, just sits in orbit. There was a project regarding dropping telephone pole sized pieces of metal from space as an offensive weapon - put something like that on the space battleship and...
That is simply "Assured Destruction" with absolutely no mutual drawbacks or lingering consequences like radioactive wasteland. Just craters.
This is also something where the 1st country to achieve the "Space Battleship" could effectively prevent any other from also doing so...
In theory, Bezos or Musk could do it.
I don't understand why any country would bother with ground based military assets at this point.
> 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. We might see the return of strategic bombers that stays in the air for weeks at a time.
Alternatively they can just shoot down your battleship with anti-satellite weapons. The risk of retaliation might be worth preventing the disadvantaged position in the long term
You've described a space station, which three countries have already done independently (Mir, SkyLab, Tiangong).
But dropping rods from an orbiting platform makes no sense. There's a reason that "Rods from God" didn't pan out, and it has to do with orbital dynamics. Neither Bezos nor Musk can do it, because it actually doesn't work.
I doubt it was seriously considered at the time it was discussed. Space Stations are in orbit - the space battleship doesn't have to be, that is very significant.
Earth is spinning in a giant circle around the sun. Thats facts. "aiming an asteroid" is less of making a rock a missile - and a lot more of tug-boating it into the exact right spot, in the way of earth, so that earth hits the asteroid - not anything complicated like the asteroid hitting earth.
Any realistic space warship design will need propellant - sure you can avoid ground based interceptors and kill sats but it will eat into your propellant reserves over time.
You will need to replenish from somewhere & that somewhere might as well get nuked instead of the ship, rendering it useless.
> 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 - not anything complicated like the asteroid hitting earth.
From an orbital mechanics standpoint I don't think there's actually a difference. You're changing an orbit either way.
> There's a reason that "Rods from God" didn't pan out, and it has to do with orbital dynamics. Neither Bezos nor Musk can do it, because it actually doesn't work.
The technology doesn't exist and it would be a huge waste of money.
How heavy would a telephone pole sized tungsten rod be?
What happens when China, Russia, India or Pakistan find out you are building this (cause you can't hide it if it's in near earth orbit)? They would either knock it out of the sky or hit you with everything they have. We would do the exact same if anyone else was developing such a weapon.
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 we do to secure space superiority will be actual gains - not smaller microchips equivalent innovations - entirely new machines, entirely new economies of scale - there is no equivalent military tech that we can develop on earth.
Not only is there really no conceivable way to ignore the strategic advantage once considered, the long-term economic payoff is actually reason enough alone to pursue the radical idea of a "space battleship" - I can think of about 20 ways to cause significant global issues with one measly space battleship.
As a hypothetical alone, it has reason enough to warrant a substantial amount of the 1.5 trillion defense budget the Pentagon plays with.
That totally depends on the type of super villain organization we're discussing. Some are willing to watch the Earth burn making the colonization step unnecessary. Others think humans are the problem and again would be willing to skip that step.
Slight changes can cause such impacts? Now imagine how many other meteors and comets also will be adjusting because of this. Will one of them once on a course to never hit earth suddenly shift to hit earth in a thousand years time? The confidence i get is the opposite
Oh no. I was not talking about the other objects that float through space influenced by such a small object so far away.
I was talking about the sun shaking in its orbit because high velocity objects are now pulling at it differently causing other objects to be influenced by the new position of the sun.
I read the parent comment as “solar orbit change” meaning the sub was changing position.
Okay but they didn't give it in meters per second, they gave it in micrometers per second. Converting to micrometers per second is exactly as much arithmetic as converting to meters per day.
I'm genuinely curious whether there are a substantial number of people out there who deal on a regular basis with dV's on such a minute scale. Who would that be, outside an asteriod-redirect program such as this? Satellite operators doing precision trajectory correction?
I found the meter per day conversion helpful. Through another lens, it's about 0.000036 km/hour (or about 1.5 inches per hour).
That's interesting news. I wonder how much kinetic energy it had. This accumulation of information might be useful if an asteroid were to hit the Earth someday. At the very least, it's more realistic than sending oil drilling experts to an asteroid.
Interesting. I'd not considered the loss of mass as a means of propulsion.
Obviously there was the kinetic energy transfer but the impact ejacted some of the asteroids mass opposite to it's trajectory further increasing it's trajectory change.
When the impact happened the news articles seemed to imply some surprise about that as well which seemed strange to me. I just wrote it off to the journalist just not being up to speed on the subject matter. The size of the debris field trailing also seemed to be a surprising result.
It's the butterfly effect. After the momentum exchange (the rocket slamming, stuff being ejected in the impact, etc), the entire system was left with different properties. From now on, the equation F=Gm1m2/r^2 will have a different m1, and you can sum the equation over all m2 (literally every other massive object in the universe).
Yeah, I sort of meant in the context of an object losing its mass, it's seldom used on earth as the effects are small but on the timescale/distance/speeds of an asteroid it could have noticeable effects.
Rockets are using mass loss but there's more going on with the rapidly expanding gas causing the increased impulse.
Rockets are able to optimize due to dealing with a gas. It's still just pushing off of a disconnected mass. You go one way the lost mass goes the other.
If you think about it that's how a cannon works. The projectile gets pushed forwards and the barrel gets pushed in the opposite direction. Some of the larger ones can push their launcher back quite a bit more than you might expect.
My point is that this is actually a common failure of intuition. We tend to think of larger objects on earth as fixed and in our day to day life on dry land they often are (at least more or less) due to static friction.
A slightly more interesting observation (I think) is that if the bodies don't achieve escape velocity relative to one another then the forces all cancel out in the end. It just might take an arbitrarily long time in the case of similarly sized masses.
A lot of asteroids are much less solid than we used to think. Some of them are big rocks, but many of them are just piles of sand- and gravel-sized material loosely held together by gravity. Clamps work great on the solid rock type, but many of the alternative methods - including smashing into it - work on asteroids of any composition
That's valuable not only for versatility, but also because it would really suck to send a spacecraft on a redirect mission only to find out that our assumptions about the asteroid's composition were wrong
Some have suggested attaching a solar shield to objects to add drag to alter the course. However, that would require a much more precise landing and some sort of drilling/anchoring effort. A kinetic impact like this is always going to be more efficient.
Instead of pointing out that exact measurements finally came in (of long term movement change), journalist instead focused on the obvious outcome that everyone expects and knows
However, the most efficient method would be actually land (I know - maybe even impossible?) on it, and use propellers to change its trajectory. We don't have too much throwaway high-tech to crash it on asteroids...
I'm not sure this is actually a necessary explanation...but while propellers technically COULD function in space (not a perfect vacuum, right?)...they're basically going to be useless.
He probably misuses "propeller" which is strangely restrictive to "rotative blade propulsion" in English whereas "to propel" is generic in its meaning.
Inflammable made me so angry as a child/teen when I found out. I read it in our encyclopedia set but we didn't have a dictionary, and this was pre-internet.
It was in the context of hydrogen and I could have sworn it was flammable. But here is this encyclopedia telling me it's INflammable. It's... not flammable? Looked it up in the school library.
Thank you, that memory came up from the depths of time. Probably haven't thought about that in 30 years. Funny how we sometimes just didn't know stuff, and couldn't find out back then.
It's just a parsing error. "in-" is also a prefix to create verbs from a name or another verb like inhume, inflame, induce, incite, inject, infiltrate. Inflammable is (inflame)-able and not in-(flammable)
There are many counter-examples to your examples, such as “direct” and “indirect”, “humane” and “inhumane”.
The words used should be clear in their meaning. “Inflammable” is ambiguous, and it makes a great deal of difference which meaning is intended.
Flammable is unambiguous, as is non-inflammable. I’m forced to use these. Personally, I’m more in favour of flammable (able to catch fire) and inflammable (not able to catch fire).
There's an inconsistency but no ambiguity, only ignorance. Inflammable only ever means one thing regardless of how ridiculous english might be.
The historically correct term would be non-inflammable. The modern variant is non-flammable.
Similarly, inflammable is the historic term and flammable is the modern variant.
The confusion arises when people are exposed to the word flammable and then attempt to apply the usual rules to construct a word they've never actually used before.
This isn't the usual sort of inconsistency introduced by our fusing multiple incompatible languages. It's from the original Latin and I'm unclear what led to it. For example consider inflammable versus inhumane. It seems Latin itself used the prefix to mean different things - here on(fire) versus not(human). But confusingly it's ex to indicate location, despite ex also being the antonym of in. So ex equo means you are on horseback, not off it as I would have guessed.
Change an asteroid’s velocity by millimeters per second decades ahead of time and you’ve moved the intersection point with Earth by thousands of kilometers.
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.
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.
I've been waiting for this a long time. They initially reported significant changes to the orbit of the smaller rock around the larger one which was cool and all, but I kept wanting to hear how much it affected the whole system. I suspect it's taken several years to answer that because it's such a tiny change in velocity. Dimorphos we can deflect, Didymos not so much.
It's also the best planetary terrorism, going by the plot of The Expanse
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 got through, only due to shitload of decoys and overall numbers.
A dumb rock would totally get vaporized without the plot armor in a safe distance.
That is simply "Assured Destruction" with absolutely no mutual drawbacks or lingering consequences like radioactive wasteland. Just craters.
This is also something where the 1st country to achieve the "Space Battleship" could effectively prevent any other from also doing so...
In theory, Bezos or Musk could do it.
I don't understand why any country would bother with ground based military assets at this point.
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. We might see the return of strategic bombers that stays in the air for weeks at a time.
Alternatively they can just shoot down your battleship with anti-satellite weapons. The risk of retaliation might be worth preventing the disadvantaged position in the long term
But dropping rods from an orbiting platform makes no sense. There's a reason that "Rods from God" didn't pan out, and it has to do with orbital dynamics. Neither Bezos nor Musk can do it, because it actually doesn't work.
Earth is spinning in a giant circle around the sun. Thats facts. "aiming an asteroid" is less of making a rock a missile - and a lot more of tug-boating it into the exact right spot, in the way of earth, so that earth hits the asteroid - not anything complicated like the asteroid hitting earth.
There are a lot of little things like that...
You will need to replenish from somewhere & that somewhere might as well get nuked instead of the ship, rendering it useless.
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 - not anything complicated like the asteroid hitting earth.
From an orbital mechanics standpoint I don't think there's actually a difference. You're changing an orbit either way.
Can you say more on this? Thanks!
There are ways to battle that - balistic missile submarines for one and then "Project Michael" which would be a massive spoiler to elaborate on. ;-)
I remember it was nicknamed "Rods From God". Kinetic energy weapon using 9 ton tungsten rods dropped from an orbiting platform. https://en.wikipedia.org/wiki/Kinetic_bombardment
How heavy would a telephone pole sized tungsten rod be?
What happens when China, Russia, India or Pakistan find out you are building this (cause you can't hide it if it's in near earth orbit)? They would either knock it out of the sky or hit you with everything they have. We would do the exact same if anyone else was developing such a weapon.
All required innovations - of which, most are not out of reach in the slightest, all of that tech would be immensely valuable, literally everything we do to secure space superiority will be actual gains - not smaller microchips equivalent innovations - entirely new machines, entirely new economies of scale - there is no equivalent military tech that we can develop on earth.
Not only is there really no conceivable way to ignore the strategic advantage once considered, the long-term economic payoff is actually reason enough alone to pursue the radical idea of a "space battleship" - I can think of about 20 ways to cause significant global issues with one measly space battleship.
As a hypothetical alone, it has reason enough to warrant a substantial amount of the 1.5 trillion defense budget the Pentagon plays with.
Before?! We're already doing a great job at it!
I was talking about the sun shaking in its orbit because high velocity objects are now pulling at it differently causing other objects to be influenced by the new position of the sun.
I read the parent comment as “solar orbit change” meaning the sub was changing position.
Or in other words, 1 meter per day
Why not say that?
I found the meter per day conversion helpful. Through another lens, it's about 0.000036 km/hour (or about 1.5 inches per hour).
Mandatory sharing of Ben Afleck commentary speaking for all of us.
https://youtu.be/-ahtp0sjA5U
Since kinetic energy is proportional to v squared, that highly depends on how you measure v...
Obviously there was the kinetic energy transfer but the impact ejacted some of the asteroids mass opposite to it's trajectory further increasing it's trajectory change.
Cool demonstration, hopefully not needed one day.
Rockets are using mass loss but there's more going on with the rapidly expanding gas causing the increased impulse.
If you think about it that's how a cannon works. The projectile gets pushed forwards and the barrel gets pushed in the opposite direction. Some of the larger ones can push their launcher back quite a bit more than you might expect.
My point is that this is actually a common failure of intuition. We tend to think of larger objects on earth as fixed and in our day to day life on dry land they often are (at least more or less) due to static friction.
A slightly more interesting observation (I think) is that if the bodies don't achieve escape velocity relative to one another then the forces all cancel out in the end. It just might take an arbitrarily long time in the case of similarly sized masses.
That's valuable not only for versatility, but also because it would really suck to send a spacecraft on a redirect mission only to find out that our assumptions about the asteroid's composition were wrong
You build a little factory and use chunks of the asteroid itself as thrust.
Instead of pointing out that exact measurements finally came in (of long term movement change), journalist instead focused on the obvious outcome that everyone expects and knows
The nitty-gritty details are what the article is for, not the title.
However, the most efficient method would be actually land (I know - maybe even impossible?) on it, and use propellers to change its trajectory. We don't have too much throwaway high-tech to crash it on asteroids...
It was in the context of hydrogen and I could have sworn it was flammable. But here is this encyclopedia telling me it's INflammable. It's... not flammable? Looked it up in the school library.
Thank you, that memory came up from the depths of time. Probably haven't thought about that in 30 years. Funny how we sometimes just didn't know stuff, and couldn't find out back then.
The only logical way out of the flammable/inflammable mess is to use 'flammable' and 'non-inflammable', which makes me so mad.
There are many counter-examples to your examples, such as “direct” and “indirect”, “humane” and “inhumane”.
The words used should be clear in their meaning. “Inflammable” is ambiguous, and it makes a great deal of difference which meaning is intended.
Flammable is unambiguous, as is non-inflammable. I’m forced to use these. Personally, I’m more in favour of flammable (able to catch fire) and inflammable (not able to catch fire).
The historically correct term would be non-inflammable. The modern variant is non-flammable.
Similarly, inflammable is the historic term and flammable is the modern variant.
The confusion arises when people are exposed to the word flammable and then attempt to apply the usual rules to construct a word they've never actually used before.
This isn't the usual sort of inconsistency introduced by our fusing multiple incompatible languages. It's from the original Latin and I'm unclear what led to it. For example consider inflammable versus inhumane. It seems Latin itself used the prefix to mean different things - here on(fire) versus not(human). But confusingly it's ex to indicate location, despite ex also being the antonym of in. So ex equo means you are on horseback, not off it as I would have guessed.