The DART mission to nudge an asteroid

cvanc

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I've been looking for the actual trajectory DART is taking to get to the destination. If any of you have found it please share the link.

I read the booster change basically made the ion thruster unnecessary, but I can't find if it's now a direct trajectory or there's an Earth flyby or something like that? Thanks...
 

Funkworks

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I've been looking for the actual trajectory DART is taking to get to the destination. If any of you have found it please share the link.

I read the booster change basically made the ion thruster unnecessary, but I can't find if it's now a direct trajectory or there's an Earth flyby or something like that? Thanks...

These 2 links go into it a little deeper but I haven't gone through them yet.
https://www.nasa.gov/specials/pdco/index.html#dart
 

Blast it Tom!

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I love Lucy. I hope they can fix her. She's in the sky, at least... any diamonds? (ok, I'll stop now...thumbs up to any Olde Codgers that gets the first of those two cultural references...)
I was unaware (until you more informed folks pointed it out) that the nudge is to a small asteroid orbiting a larger one. That makes a lot more sense, as the measurements can be made relative to the two of them.
 

Funkworks

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Not to spoil the fun but the word plays have all been done already.

"The Lucy mission is named after the fossilized skeleton of an early hominid found in Ethiopia on Nov 24, 1974 by Donald Johanson and Tom Gray. That Lucy in turn was named by expedition member Pamela Alderman after a celebratory evening dancing and singing to the Beatles’ song “Lucy in the Sky With Diamonds.” Just as that Lucy fossil provided unique insights into humanity’s evolution, the Lucy mission promises to revolutionize our knowledge of planetary origins and the formation of the Solar System."


"L’TES is Lucy’s Thermal Emission Spectrometer, which detects far infrared radiation emitted by the asteroids."
...
"Like its predecessor, inside L’TES is a large diamond that serves as a beamsplitter. (Perhaps a reference to a certain Beatles song is appropriate here.)"

 

Blast it Tom!

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Not to spoil the fun but the word plays have all been done already.

"The Lucy mission is named after the fossilized skeleton of an early hominid found in Ethiopia on Nov 24, 1974 by Donald Johanson and Tom Gray. That Lucy in turn was named by expedition member Pamela Alderman after a celebratory evening dancing and singing to the Beatles’ song “Lucy in the Sky With Diamonds.” Just as that Lucy fossil provided unique insights into humanity’s evolution, the Lucy mission promises to revolutionize our knowledge of planetary origins and the formation of the Solar System."


"L’TES is Lucy’s Thermal Emission Spectrometer, which detects far infrared radiation emitted by the asteroids."
...
"Like its predecessor, inside L’TES is a large diamond that serves as a beamsplitter. (Perhaps a reference to a certain Beatles song is appropriate here.)"

<sigh> That's me, a day late and a dollar short every time. I should've known a bunch of nerds couldn't resist that one! Carry on, please.
 

Funkworks

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I learned about LUCY from browsing these forums, so if I’m a nerd, I blame on TRF 😄
 

Funkworks

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Amazing! 🛰️ 🌑 Here's a size comparison chart:

2.68950535.jpg

And what the impact shoud be doing, just about:

dart-infographic.jpg
 
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OverTheTop

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There is an interesting effect that comes into play at impact. The impact gets an expected 2.5 to 3 times the energy of the kinetic thump alone. The gas and ejecta from the impact contribute very significantly to the perturbing force on the asteroid.

There are definitely some intriguing physics in many aspects of asteroid redirection and planetary protection.
 

Mushtang

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I still can't understand the reason behind this mission. I know they said it was to show what might be possible with changing the trajectory of an asteroid. But my question is: how does this really help?

In order to get the DART to the asteroid's moon in the first place the engineers had to understand orbital mechanics *very* well. They got this very tiny spacecraft to hit a very tiny moon from a very long ways away.

They know the maths, they understand what the change in direction and velocity will be.

So what was the purpose? Was there a chance they'd hit the moon, they'd make measurements, and then say, "Well dang, I did NOT expect that to happen?"

When learning about new things, sure, these kinds of tests are very valuable and great sources of information. But this is well established stuff already or else they'd never have been able to do the test to begin with.
 

KennB

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I still can't understand the reason behind this mission. I know they said it was to show what might be possible with changing the trajectory of an asteroid. But my question is: how does this really help?

In order to get the DART to the asteroid's moon in the first place the engineers had to understand orbital mechanics *very* well. They got this very tiny spacecraft to hit a very tiny moon from a very long ways away.

They know the maths, they understand what the change in direction and velocity will be.

So what was the purpose? Was there a chance they'd hit the moon, they'd make measurements, and then say, "Well dang, I did NOT expect that to happen?"

When learning about new things, sure, these kinds of tests are very valuable and great sources of information. But this is well established stuff already or else they'd never have been able to do the test to begin with.
This gives them some empirical data to compare with their theoretical calculations. They can now revisit the theory and tweak as necessary (of course, they would need many more strikes to have enough data to make significant adjustments). It's like using a simulation program for your rockets; you put in all the data that is easily measured - mass, size, motor impulse, etc. - but your coefficient of drag is a guess at best. With enough flights, you can better define the coefficient for a better simulation.

Let's just say it's a start.
 

Mushtang

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This gives them some empirical data to compare with their theoretical calculations.
No, my point is they have TONS of empirical data about orbital mechanics and have decades of data they've collected. They wouldn't have been able to hit the moon at all unless they knew it very very well already. I still don't understand what they were able to gain from this.

I'm not suggesting that it therefore was a useless experiment, I'm only saying the reason's behind it don't make sense to me yet.
 

Funkworks

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There is an interesting effect that comes into play at impact. The impact gets an expected 2.5 to 3 times the energy of the kinetic thump alone. The gas and ejecta from the impact contribute very significantly to the perturbing force on the asteroid.

There are definitely some intriguing physics in many aspects of asteroid redirection and planetary protection.
I wonder how closely the amount of material ejected will match simulations.

I still can't understand the reason behind this mission. I know they said it was to show what might be possible with changing the trajectory of an asteroid. But my question is: how does this really help?

...

So what was the purpose? Was there a chance they'd hit the moon, they'd make measurements, and then say, "Well dang, I did NOT expect that to happen?"

Some people may be satisfied with simulations, but others will not be satisfied until it has been demonstrated in reality. It's about increasing confidence and reducing the risk of errors (in the math, and in the build). Whether it's a model rocket, car, aircraft, chemical reaction or dinner, people imagine things and then do it, or they do it, and then try to explain it. And they keep going back and forth to keep increasing confidence and to keep reducing the risk of errors. That's what physicists try to do anyway. And engineers, and other scientists.
 

ThirstyBarbarian

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I still can't understand the reason behind this mission. I know they said it was to show what might be possible with changing the trajectory of an asteroid. But my question is: how does this really help?

In order to get the DART to the asteroid's moon in the first place the engineers had to understand orbital mechanics *very* well. They got this very tiny spacecraft to hit a very tiny moon from a very long ways away.

They know the maths, they understand what the change in direction and velocity will be.

So what was the purpose? Was there a chance they'd hit the moon, they'd make measurements, and then say, "Well dang, I did NOT expect that to happen?"

When learning about new things, sure, these kinds of tests are very valuable and great sources of information. But this is well established stuff already or else they'd never have been able to do the test to begin with.

I think a lot depends on the composition of the asteroid. As @OverTheTop said, a lot of the effect of the impact comes from gas and ejecta. And how much of that is generated would depend on the composition of the asteroid. So I think there really is a large range of possibilities.

Think of how many kinds of possibilities there are when you shoot different things with a bullet. Maybe the bullet passes all the way through and doesn’t transfer any energy or momentum to the target. Maybe the target shatters into a million pieces and goes in every direction. Maybe the target just absorbs the bullet. Maybe the bullet ricochets off the target. There is more involved than just the masses and relative velocity.
 

Marc_G

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I still can't understand the reason behind this mission. I know they said it was to show what might be possible with changing the trajectory of an asteroid. But my question is: how does this really help?

In order to get the DART to the asteroid's moon in the first place the engineers had to understand orbital mechanics *very* well. They got this very tiny spacecraft to hit a very tiny moon from a very long ways away.

They know the maths, they understand what the change in direction and velocity will be.

So what was the purpose? Was there a chance they'd hit the moon, they'd make measurements, and then say, "Well dang, I did NOT expect that to happen?"

When learning about new things, sure, these kinds of tests are very valuable and great sources of information. But this is well established stuff already or else they'd never have been able to do the test to begin with.
What others said in other replies above, for sure. But also: we have now developed and tested a working model of how to track an asteroid's movement and control an onrushing spacecraft to impact dead center. The data learned developing the nav/control programming, and from the telemetry of the DART actually executing its program, is HUGE.

There's a BIG chance that they would hit the moon and have the orbital deviation be different than calculated. That's the other point of this experiment: how close would this instance of reality match the theory? I think some of them are HOPING for a deviation from calculations because that would imply a new learning to better model things in the future.
 

techrat

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They are doing this to PROVE THE THEORY. While all the math says they will change the orbit of the smaller rock, there's also a very good possibility that the impact of the craft will not change the orbit in the slightest. We've never done this before. Humans have never changed the orbit of a celestial body. While it's all theoretically possible, it's simply never been done, and we need to prove that it can be done. Because once you do it, doing it again becomes a bit easier. And one day, we may need to do it in order to survive.
 
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