NASA Says Dart Mission Succeeded In Shifting Asteroid's Orbit (theguardian.com) 77
An anonymous reader quotes a report from the Guardian: A spacecraft that plowed into a small, harmless asteroid millions of miles from Earth succeeded in shifting the orbit of the space rock, Nasa said on Tuesday, announcing the results of its first such test. The US space agency strategically launched the Double Asteroid Redirection Test ("Dart") spacecraft into the path of the asteroid, thereby throwing it off course. Nasa hopes to be able to deflect any asteroid or comet that comes to pose a real threat to Earth.
Dart altered the orbit of the Dimorphos asteroid by 32 minutes. Glaze said the minimum requirement for changing the orbital period was "really only 73 seconds." Last year, in a test that cost $325 million, another Dart spacecraft, roughly the size of a vending machine, was destroyed when it slammed into an asteroid 7m miles away, at 14,000mph.In a tweet, the vice-president, Kamala Harris, said: "Congratulations to the team at Nasa for successfully altering the orbit of an asteroid. The Dart mission marks the first time humans have changed the motion of a celestial body in space, demonstrating technology that could one day be used to protect Earth."
The scientist and educator Bill Nye said: "We're celebrating ... because a mission like this could save the world."
The Nasa administrator, the former astronaut and Democratic Florida senator Bill Nelson, said: "We showed the world that Nasa is serious as a defender of this planet."
Lori Glaze, director of Nasa's planetary division, said: "Let's all just take a moment to soak this in. We're all here this afternoon because for the first time ever, humanity has changed the orbit of a planetary body."
Dart altered the orbit of the Dimorphos asteroid by 32 minutes. Glaze said the minimum requirement for changing the orbital period was "really only 73 seconds." Last year, in a test that cost $325 million, another Dart spacecraft, roughly the size of a vending machine, was destroyed when it slammed into an asteroid 7m miles away, at 14,000mph.In a tweet, the vice-president, Kamala Harris, said: "Congratulations to the team at Nasa for successfully altering the orbit of an asteroid. The Dart mission marks the first time humans have changed the motion of a celestial body in space, demonstrating technology that could one day be used to protect Earth."
The scientist and educator Bill Nye said: "We're celebrating ... because a mission like this could save the world."
The Nasa administrator, the former astronaut and Democratic Florida senator Bill Nelson, said: "We showed the world that Nasa is serious as a defender of this planet."
Lori Glaze, director of Nasa's planetary division, said: "Let's all just take a moment to soak this in. We're all here this afternoon because for the first time ever, humanity has changed the orbit of a planetary body."
Yup (Score:1)
To be pendantic... (Score:1)
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Dimorphos [wikipedia.org] has a mass of 5 million tonnes.
The impactor had a mass of 610 kg and a delta-V of 6.6 km/sec.
E = 1/2 mv^2 = 13 gigajoules
The change in the orbital speed of the asteroid = sqrt(2*E/M) = 2 meters / sec.
If it were on a path to hit Earth, the trajectory would need to be moved about the radius of the Earth. To move 6400 km at 2 m/s would take 3.2 million seconds = 37 days.
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Your numbers are incorrect. The original orbital speed of Dimorphos was 0.174m/s. If it had changed by 2 m/s, the moon would've been thrown out of orbit.. Instead, the orbital period was shortened by 4-5%. I'm too lazy to look up the exact math to convert that to the change in speed, but this is not a dramatic change.
When making estimates of inelastic collisions, it's more useful to calculate momentum. In this case, the basic formula would result in a velocity change around 0.008m/s. A lot of the kinetic en
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The most relevant physical quantity to track here is momentum (mv) not kinetic energy (0.5*mv^2). Momentum is independently conserved and unlike energy cannot change form - there is no momentum version of "heat" where it can disappear for example and momentum is a vector quantity.
We know precisely how much momentum DART had, and thus how much was transferred directly by impact. But what we are learning is how much momentum was imparted on Dimorphos by the rocket-effect of the ejecta thrown out by impact. By
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If you do the correct momentum calculation (not the irrelevant thing you did with kinetic energy, which bears no relation to the actual physical process) you find that since Dimorphos is 8 million times more massive than DART its velocity would be 1/8000000000 as much to conserve momentum, or about 0.8 mm/s.
The far more massive but slower ejecta plume could have induced an even larger momentum transfer. Since the orbital period is roughly proportional to velocity (the radius will change but not dramatically
And in 2079... (Score:3, Interesting)
"Remember the story of how NASA deflected that very first test asteroid back in 2022? Well, that change put that previously harmless rock on a course to hit the Earth in three years. Nobody knew to check tha..."
"Well shit... I guess we'll hit it with the railguns when it comes into range. It'll be a fun fireworks show."
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Sometimes people make silly jokes just for the hell of it. I suspect you're not much fun at parties.
Re:And in 2079... (Score:5, Informative)
The asteroid they hit was orbiting a larger asteroid. That's why they chose it. They altered its orbit around the larger asteroid.
Harris, Nye .. (Score:1, Insightful)
Kamala Harris said ... ...
Bill Nye said
Only Bill Nelson's comments are relevant.
Otherwise we forgot Neil Degrasse Tyson.
Oh and William Shatner and Bruce Willis.
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Re: Harris, Nye .. (Score:2)
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Such as the chair of the National Space Council?
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Okay, they asked Bill Nye... but what are John Keister's thoughts regarding the test?
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Only [some guy]s comments are relevant.
In ancient times the Greeks discovered that if a statement is true or false does not depend on who the speaker is.
Too bad your understanding of logic is thousands of years out of date.
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Starman (Score:2)
The asteroid is now on track to collide with Starman in 2061.
Now we just need to detect asteroids in time... (Score:5, Insightful)
Being able to shift the orbit of an object in space is one thing, but for this to really work as protection we need to be able to detect objects early enough that an impactor can be launched and intercept an asteroid with enough time for an orbit alteration to prevent collision.
The problem is that, with our current observation capability, we wouldn't know until it is too late to actually do anything.
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How long would we need for an asteroid of this mass, deflected by this much. A month? A year? 200 years (and so we have some work to do?)
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How long would we need for an asteroid of this mass, deflected by this much. A month? A year?
The impact would need to be about a month before the asteroid reached Earth. I posted the calculations in a previous comment.
More time would be needed to prepare for the launch and travel to the asteroid. DART took nearly a year to reach Dimorphos, doing flybys on the way. A real mission to save the planet wouldn't do that.
Re: Now we just need to detect asteroids in time.. (Score:1, Troll)
You do not understand the purpose of this test. America now has the ability to end Earth. DART if used to target our own planet would destroy it. This is what america has just said to every other nation. Let that sink in for a minute
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This post is serious- isn't it?
DART hit an object 170 meters in diamater.
The thing that knocked out the dinosaurs was 10km in diameter.
You'd need to fire a lot of DARTs to alter the orbit of a 10km impactor enough to kill the Earth anytime in the next 30 million years.
So, back to use as a weapon.
The problem with knocking an asteroid into an Earth crossing orbit, is there is precisely no way to be sure it doesn't land on DC at the time of orbital deflection.
If this was a joke, my apologies.
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I'm more than happy to criticize America given a chance but you have to be completely deluded if you think anybody involved in this is thinking DART is a weapon.
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Phew, good thing America doesn't have a giant series of nukes that could be used to destroy the planet. Imagine if they had that much power for the last 50+ years!
Let reality sink in for a minute.
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You do not understand the purpose of this test. America now has the ability to end Earth. DART if used to target our own planet would destroy it. This is what america has just said to every other nation. Let that sink in for a minute
Cannot be further from the truth, I will be polite however and answer with reason:
- the impactor mass is 610kg and it hit Dimorphos with about 7km/s, ergo Ev = mv^2 / 2 =~ 15GJ, which equals about 3.6tTNT, which is about 4200 less than Hiroshima bomb
- recent Chinese 20t first stage reentered Earth uncontrollably with a speed roughly equal to 7km/s and mostly burned in the atmosphere
- former Mir station weighing ~130t (~200 times heavier -> ~100 times more energy) mostly burned in the atmosphere with remn
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It depends on how far away we can find and hit it. If we have a decade it doesn't take much of a change in velocity to change a direct hit to a near miss.
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An impactor large enough to do real damage is going to take a lot more than a DART to move it in a way that can even be measured.
So ya, if you use that decade to throw a few hundred DARTs are it, you could effect a hit from a significantly sized impactor.
There's a reason we launched it at something under 200 meters in diameter.
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That's why you want a **LOT** of time. To simplify, think of two straight lines a meter long that intersect at a point a centimeter wide. If you bend the line 10 cm from the point you need to move it 18 degrees to just miss the point. On the other hand if you bend it just after the starting point you only have to move it 1.8 degrees (just made up the angles, too lazy to look it up now.)
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You're not wrong about that part.
I was just helping you get an idea of the scale.
DART hitting the asteroid it was a bullet hitting an elephant.
DART hitting the thing that took out the dinosaurs is a bullet hitting a baseball stadium.
The actual change in velocity is going to be millionths of a meter per second.
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The problem is that, with our current observation capability, we wouldn't know until it is too late to actually do anything.
How do you know this -is it hunch, or does it come from awareness of the data?
As I understand it, many of the images coming from observatories today are run through an image processing pipeline that identifies objects and adds them to an inverted index: supply the x, y coordinates within an indexed image, and the framework returns the identity of any known object(s) at that pixel point.
With that, I would think that there's a good chance that a transiting object having been recorded would become tracked, eve
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How do you know this -is it hunch, or does it come from awareness of the data?
Absolutely not a hunch. DART was launched 21 November 2021 and impacted 26th September 2022 (ie. it took 309 days). The vast majority of close calls (asteroids passing Earth at less than 1 Lunar Distance) have either been detected with less than one week's notice or (more alarmingly) have not been detected at all until after the fact. [wikipedia.org]
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What if it turns out that larger objects are easier to see at a distance than smaller objects? Would you still consider that wikipedia list to be important for understanding the problem?
Because it sounds idiotic to me.
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It's not a hunch. This report [nasa.gov] estimates we have found only 1/3 of the potentially civilization-ending asteroids (near Earth asteroids larger tan 140 m). More worryingly, NASA is planning a mission to improve this (NEO Surveyor), but recommended putting it on hold in next year's budget, indicating they don't see it as the high priority it should be.
Re: Now we just need to detect asteroids in time.. (Score:2)
That is a shame, it's got to be a priority. Don't these people watch Hollywood blockbusters?!! Surely Don't Look Up was popular viewing among NASA and planetary defense staff.. lol.
Hopefully the budget won't get deleted by a future U.S. administration or Congress that decides to deprioritize science.
Butterfly Effect ... in the year 2343 CE (Score:1)
Well, they also altered an orbit of some random asteroid orbiting another, and now our Sun is going super nova and 5 billion years early.
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Small effects can't really turn into anything of consequence in the future of its solar evolution.
Does this prove anything? (Score:2)
Is this anything but a basic proof of concept, though? Like, if the asteroid was big enough to be a serious danger to Earth, wouldn't we need to hit it with a sufficiently larger mass to deflect it? And that could pose problems if we couldn't get that amount of mass into space...
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Or lots of smaller ones, and it all depends on how much its orbit needs altering.
Newton's Physics theory confirmed! (Score:2)
Scientists drunkenly celebrate worldwide!
Details at 11.
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Like, if the asteroid was big enough to be a serious danger to Earth, wouldn't we need to hit it with a sufficiently larger mass to deflect it?
We would need to hit it either harder or earlier.
"Harder" can mean either more mass or more velocity.
Or the "mass" could be a thermonuclear warhead with a proximity detonator.
And that could pose problems if we couldn't get that amount of mass into space...
It doesn't need to be a single launch. We could hit it multiple times with small masses.
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They proved targeting capability, not Newtonian physics. Bill Nye is a dope.
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That is correct. Obviously if we are going to try doing something new we need to start small.
A big asteroid could be deflected with a smaller force if done while it was far enough away, where a tiny change could make a big difference. Deflecting one that is closer would require a bigger mass.
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A larger mass, or considerably earlier, the latter being preferable. If we need to change the orbital path of the asteroid we can either do it a decade in advance and redirect it 0.00001 degrees, or we can wait and use a very much larger mass/more impactors to change it 1 degree. A secondary problem with the latter approach is that asteroids have a **LOT** of loose objects of various sizes strewn about their surface and only lightly bound by gravity. Move the main body 1 degree and a lot of that shit is
Are we officially the bugs now? (Score:1)
Obligatory (Score:2)
The bugs send another meteor our way... but this time we're ready.
Planetary defences are better than ever.
Would you like to know more?
Is he really? (Score:2)
"The scientist and educator Bill Nye"
Is he really a SCIENTIST?
I mean, I know you can just go out and buy a white lab coat but that doesn't really make him a scientist.
Emily Deschanel also wore a white lab coat for many years, and spouted some very cogent scientific dialogue (and, arguably, more factual than a lot of Mr Nye's comments). Is she a "scientist" as well now?
What if she self-identifies as one?
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Second paragraph of his Wikipedia bio [wikipedia.org].
Now if you want to argue about whether an engineer is the same thing as a scientist, that's a debatable, but it's close enough in my view. He's not just an actor.
Re:Is he really? (Score:4, Insightful)
He constructed 100 episodes of Emmy-winning educational content for his show. In each episode, he performed real science experiments and taught the scientific method to generations of kids.
Fuck yes, Bill Nye is a scientist.
Afterward, Bill has continued to teach science, advocate for science, advise on science education, and advocate for humanity's environmental future.
Bill Nye doesn't play a scientist on TV. He is one. Act like you don't see the difference.
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So he's a successful science show writer and producer = scientist?
Does that make all the writers for, say, NOVA "scientists" even though all they did was write? (Not to disparage the writers who actually were scientists and writers...although if you were going to go that way you'd be acknowledging there is a distinction between the two...)
Bill's CERTAINLY an activist - does that make him a scientist?
Bill Nye plays a scientist on TV (or used to). He's parlayed that into a lot of credibility with the gullibl
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Do you define scientist as someone who does science, or a professional full time researcher? Because Nye might be one and not the other.
Pale Blue Dot (Score:2)
Am I the only one who responds to this development with both hope and terrible dread?
Carl Sagan discussed the idea of moving asteroids in a Pale Blue Dot, chapter Marsh of Camarina.
Given enough time (not civilization time, or species time but geological time or possibly astronomical time), the prospect of us getting hit by another asteroid capable of causing extinctions is not a matter of if, but of when. So we must develop this kind of technology to save our species from extinction.
But the same kinds of t
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None of that is any worse for the humans that if we're dead from nuclear armageddon.
If we're not here to see the cockroaches, is their loss worse from our perspective? No, we don't even have a perspective anymore.
So it is no worse. It is merely equally bad.
And we must not develop this technology or we'll be destroyed
If you believe this, then you can just shut up already because you'd be required to also believe that since we already have nuclear weapons, we're already doomed, and so it doesn't do any good to blather on about anything at all. Lots of people felt that
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I think that the idea of nuclear armageddon is a bit overrated. I read a book years ago called The Medical Consequences of Thermonuclear Warfare, and I'll admit that some of it was beyond me (like forecasting which kinds of cancer to expect from fallout), but my takeaway was that if humanity detonated all of it's existing nuclear in a full on nuclear exchange, we would nuke ourselves back to the dark ages. The human race would survive. Don't get me wrong, that's terrible and I don't want to live in the d
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If we do develop this technology, and we allow the same kinds of geological timeframes, then there will be another psychopathic leader like hitler who would be willing to use a weapon like that in the course of total war
Then it doesn't matter, and nothing else does either. Given enough time, there will be technologies that a madman could use to end civilization, whether it be a gray goo event, or a bioweapon, or something we haven't even imagined yet.
In other news, water is wet! (Score:2)
Hello....excuse me but.... (Score:2)
knocking about stuff in space into unpredictable orbits is probably a bad idea.
Now that the orbit is changed, it could hit something else leading to other problems.
I think experiments like this are stupid and reckless.
Just like putting CO2 into the ground for storage or other human induced climate change woke nonsense.
Is it me (Score:1)
So... (Score:2)
So what? (Score:2)
Just PR. Newton's laws confirmed.