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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

#22
post #4

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. Cool demonstration, hopefully not needed one day.

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).

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

#23

Earlier quoted context omitted.

Be careful about how you store those inflammable propellers.

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…

Exactly!

The only logical way out of the flammable/inflammable mess is to use 'flammable' and 'non-inflammable', which makes me so mad.

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

#24

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.

Or offense.

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

#25

I'm annoyed at these nothing-burger titles... 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 top comment in this thread calls this "wild" and expresses amazement that this is possible; clearly it's not what "everyone expects and knows".

The nitty-gritty details are what the article is for, not the title.

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

#26

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.

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.

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

#28
post #24

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.

Or offense.

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

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

#29
post #21

Is debris a problem? I think the ideal would be to embed or clamp a rocket on the target.

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

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

#30

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.

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
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