Watch NASA Crash a Spacecraft Into An Asteroid (nytimes.com) 38
If all goes as planned, a SpaceX Falcon 9 rocket carrying the Double Asteroid Redirection Test (DART) will launch early Wednesday morning "to test whether slamming a spacecraft into an asteroid can nudge it into a different trajectory," reports The New York Times. "Results from the test, if successful, will come in handy if NASA and other space agencies ever need to deflect an asteroid to save Earth and avert a catastrophic impact." From the report: The DART spacecraft is scheduled to lift off atop a SpaceX Falcon 9 rocket on Wednesday at 1:20 a.m. Eastern time (or 10:20 p.m. local time) from the Vandenberg Space Force Base in California. NASA plans to host a livestream of the launch on its YouTube channel starting at 12:30 a.m. on Wednesday. If bad weather around the Vandenberg launch site prompts a delay, the next opportunity for liftoff would be about 24 hours later.
After launching to space, the spacecraft will make nearly one full orbit around the sun before it crosses paths with Dimorphos, a football-field-size asteroid that closely orbits a bigger asteroid, called Didymos, every 11 hours and 55 minutes. Astronomers call those two asteroids a binary system, where one is a mini-moon to the other. Together, the two asteroids make one full orbit around the sun every two years. Dimorphos poses no threat to Earth, and the mission is essentially target practice. DART's impact will happen in late September or early October next year, when the binary asteroids are at their closest point to Earth, roughly 6.8 million miles away.
Four hours before impact, the DART spacecraft, formally called a kinetic impactor, will autonomously steer itself straight toward Dimorphos for a head-on collision at 15,000 miles per hour. An onboard camera will capture and send back photos to Earth in real time until 20 seconds before impact. A tiny satellite from the Italian Space Agency, deployed 10 days before the impact, will come as close as 34 miles from the asteroid to snap images every six seconds in the moments before and after DART's impact.
After launching to space, the spacecraft will make nearly one full orbit around the sun before it crosses paths with Dimorphos, a football-field-size asteroid that closely orbits a bigger asteroid, called Didymos, every 11 hours and 55 minutes. Astronomers call those two asteroids a binary system, where one is a mini-moon to the other. Together, the two asteroids make one full orbit around the sun every two years. Dimorphos poses no threat to Earth, and the mission is essentially target practice. DART's impact will happen in late September or early October next year, when the binary asteroids are at their closest point to Earth, roughly 6.8 million miles away.
Four hours before impact, the DART spacecraft, formally called a kinetic impactor, will autonomously steer itself straight toward Dimorphos for a head-on collision at 15,000 miles per hour. An onboard camera will capture and send back photos to Earth in real time until 20 seconds before impact. A tiny satellite from the Italian Space Agency, deployed 10 days before the impact, will come as close as 34 miles from the asteroid to snap images every six seconds in the moments before and after DART's impact.
Best of luck to them (Score:2)
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Um, isn't it just basic math?
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What is not that well understood is the exact behavior of materials involved in the impact. An asteroid can be made of somewhat loosely connected boulders, and we need empirical evidence beyond theory.
We woudn't want to find out too late that we should have had a bigger mass to deflect an incoming asteroid.
Re:Best of luck to them (Score:5, Insightful)
While the orbital physics of this are well understood (after all, we've landed on the Moon and returned successfully several times), there are still a few questions:
-how well can we target that asteroid
-we have made very precise calculations on the results. However, how much our calculations will fit to real life results?
-there are a number of unquantifiable issues:
- with a lateral impact, how much of the energy impacted will go towards _moving_ the asteroid versus just adding more rotation
- with any kind impact, what is the result of the thrown mass? (the asteroid has basically zero gravity, any debris thrown from a 15 km/s collision will escape the asteroids)
- how will the two asteroids system move after the impact (also, compared to NASA's calculations)? Will the energy impacted affect the movement of one satellite, both of them, what is the resulted change in movement in their orbit around each other and around the sun
-will any of them get angry and want revenge?
In the end, the results might make us prepare different experiments:
-how much could we move an asteroid using a small ion drive?
-how much could we move an asteroid by stopping its rotation movement and changing its albedo? (i.e. painted in red with "Coca Cola" written on its side) - that's solar pressure at work over some years
-also related to moving asteroids away from the Earth, how much would we be able to move "precious" asteroids into Earth gravitational field? (one could use an asteroid as protection against solar radiation for a space station, even if actually mining its content or tunneling into it might not be feasible).
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Who's assessing what's going to happen if we hit this test subject and in 200 years it comes back hurling directly towards the Earth? Hopefully by then we'll have this figured out :-)
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Who's assessing what's going to happen if we hit this test subject and in 200 years it comes back hurling directly towards the Earth? Hopefully by then we'll have this figured out :-)
Not only that, imagine the asteroid then changes its trajectory and then goes crashing on some planet populated by and advanced alien civilization who thinks that we started a war with them and retaliates.
At least I hope they change its trajectory so it goes crashing into the Sun. This should reduce the risk of any adverse consequences, at least I think so...
Re: Best of luck to them (Score:2)
That would require a very large retrograde delta-v to eliminate almost all of its orbital velocity component around the sun. I don't know the orbit details of the asteroid/moon pair around the sun, but it is likely tens of kilometres per second. (Earth's is 30km/s)
The impulse needed for this delta-v is therefore millions of times larger than they can achieve in this mission
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While the orbital physics of this are well understood
-how well can we target that asteroid
Not taking away anything from the points you've made, I think the point that jimtheowl is making is about the asteroid *being* targeted. That being, if it is not a solid ball of rock and instead a conglomerate that has the same mass broken up into pieces and hits us as multiple impacts as damaging as a single large impact.
I think the answer to that question is if it is an ice and rock slushy it has to be hit far enough out so that it is still a solid chuck of ice. If it is a conglomerate rock that brea
Re: Best of luck to them (Score:2)
Re: Best of luck to them (Score:2)
For some reason brings strong memories of that futurama episode where they had to diflect one asteroid made up of garbage with another giant ball of garbage. :)
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Um, isn't it just basic math?
The math describing the behavior of billiard balls is even simpler. Doesn't mean I make every shot.
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Um, isn't it just basic math?
Yes, basically it is. What this is, is junk science so privileged kids can enjoy a free ride on the government's dime all while feeling important. What we really need is a real rotating space station, a real moonbase and real astronuats, not a mountain of overpaid earthbound beaurocrats. NASA is completely corrupt and ineffective from what I can see. Just saying.
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I've nothing to hide, and notice I'm not an anonymous coward. On the other hand, you have nothing to say because there is nothing to say. If you had an effective counter-argument, you'd have used it. No wonder you chose to remain anonymous given your cowardly unsubstantiated attack.
Funny how critical reasoning is so resented by the fans.
Is anybody else worried... (Score:3, Interesting)
That this will set off a chain of events. The altered orbit of Dimorphos will cause a domino effect, which 50 years from now will cause an entirely separate asteroid altered by a complex cosmic Rube Golderberg-esque interactions to head toward earth?
The proverbial butterfly, so to speak.
NASA is good, but not *that* good, right?
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It will hit Newark instead of Long Island.
3D Billiards
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So then, it's a net positive?
Re:Is anybody else worried... (Score:5, Informative)
It is not like everything is in a stable orbit and we are not supposed to touch anything. Something will eventually come this way, but not because we caused it.
We are better off being ready.
Re:Is anybody else worried... (Score:5, Informative)
Not in 50 years. Asteroids are small enough that even if two asteroids come within 1 meter of each other, the change in their orbits would be tiny. It'll take a long time (as in, add a few zeroes to that '50 years') for that to have enough of a cumulative effect to make a collision with Earth measurably more likely.
Also, because they're altering the orbit of Didymos' moon only, the CoG of the asteroid+moon doesn't change. You'd have to make a very close pass (within a few km) to notice a difference. Dimorphos' orbital speed will be reduced by something on the order of 1 mm/s.
There are some unknowns here: we haven't found all asteroids large enough to pose a threat. But we can be certain there's no threat from this collision for a long enough time that asteroid redirection will be routine by the time it could become a problem.
[insert HHGTG Space is Big quote here]
Re: Is anybody else worried... (Score:5, Informative)
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It's interesting that they are using just one vehicle in this attempt. The Chinese are planning a missing using a dozen or more vehicles. I suppose if the intent is just to demonstrate the ability to hit the asteroid at significant velocity then sending more than one probably isn't worth it. Once you have proven you can do that, diverting any asteroid is just a case of sending enough vehicles.
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What the Chinese did was investigate how they could divert asteroid Bennu [sciencedirect.com], they found that the impact of 23 Long March 5 upper stages with payload would be enough, given a lead time of 10 years.
They're not currently planning to launch 23 LM5s to Bennu.
DART is very much a proof of concept. So they're using one vehicle, plus a cubesat to observe the impact. And they're not deflecting the asteroid's orbit, they're impacting on its moon to make a change to its orbit that's small but measurable.
There will be ESA
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"There are some unknowns here: we haven't found all asteroids large enough to pose a threat"
The detection threshold depends (mostly) on asteroid mass, so the bigger they are the farther we can detect them. On the other hand, the farther they are the lower the risk of them "crossing" Earth orbit at an inopportune moment.
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Also, because they're altering the orbit of Didymos' moon only, the CoG of the asteroid+moon doesn't change.
That is wrong.
You'd have to make a very close pass (within a few km) to notice a difference. Dimorphos' orbital speed will be reduced by something on the order of 1 mm/s.
Depends from which side they hit. As far as I remember they hit him from "behind" and increase its speed. Increase into the direction the probe is flying, no idea if that is in the plane of orbit of the "mini moon".
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That this will set off a chain of events. The altered orbit of Dimorphos will cause a domino effect, which 50 years from now will cause an entirely separate asteroid altered by a complex cosmic Rube Golderberg-esque interactions to head toward earth?
The proverbial butterfly, so to speak.
NASA is good, but not *that* good, right?
That is exactly as likely as the domino effect causing an asteroid that would've smashed into Earth otherwise to go somewhere else.
And a realistic timescale for both would be closer to 50 million years than 50 years. I hope that we will have asteroid deflection sorted by then.
Premature (Score:5, Informative)
Today's just the launch, the actual impact will happen in about a year, so if you want to 'Watch NASA Crash a Spacecraft Into An Asteroid' you'll have to wait a while.
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Incorrect headline (Score:5, Informative)
The mission launches today, but it won't be crashing into any asteroids until late September 2022.
So (Score:2)
Will this count as rapid scheduled disassembly?
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Amazing that Falcon 9 is leaving Earth's Orbit (Score:2)
Another flawless launch - very impressive.
I think that this is the first time the Falcon 9 (not Falcon Heavy) has launched a spacecraft out of Earth's orbit. That's quite an accomplishment, especially considering they also recovered the first stage.
Bad weather prompts a delay? (Score:2)
So, if we were to be lucky enough to actually see an asteroid hurtling towards our planet, we may be able to alter its course, given it doesn't currently happen to be raining? That's... reassuring?
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It's called 'risk assessment'. For this test, there's no hurry, so we can afford to wait a day rather than do anything that makes a successful launch less likely, like a lightning strike [nasa.gov].
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Earth orbital velocity is about 30 km/s, and has a diameter of some 12800 km.
It means it "clears" its current position in some 430 seconds, so delaying a glancing "into the bow" shot by 430 seconds would transform into a glancing "into the stern" shot.
Ignoring other possible ways to change an asteroid movement, if it will hit, by delaying it 430 seconds it will miss.
430 seconds in a day (86400 seconds) are 1 in 200. 430 seconds in a year are 15 parts per million
If you can detect the asteroid 1 year in advan
Conspiracy Theory (Score:2)