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(No Longer Possible) Satellite Collision thread (April 9, 2021 17:18 UTC; DMSP 5D-1/F3 & Kosmos-3M Spent 2nd Stage)


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Will say that I initially wanted to re-use this thread, but I guess better to start a new one. (Not really willing to maintain it, though ? I'm not really up to satellite news.)

Apparently it's going to be a DMSP sat + Russian upper stage collision. Since the satellite is launched 43 years ago I'll assume that it is dead (upper stage is definitely dead, like most upper stages do after launch is complete).

Spoiler

 

Sorry for mostly relying on Twitter. Really just knew this.

Edited by YNM
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This relative velocity looks extremely high to me. Considering that both are moving in the same general direction, a velocity above escape velocity sounds strange... I mean I don't say it is wrong. I am just surprised. 

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They can not travel to same direction. Otherwise at least one of them should be on hyperbolic orbit, i.e. not bound on Earth. They must have quite large inclination difference, I would say at least tens of degrees without calculations.

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Posted (edited)
2 hours ago, hms_warrior said:

Considering that both are moving in the same general direction

Not necessarily, esp. remembering that this is a polar orbit and there are many orbital planes used for it (unlike GEO where there's only one plane possible). Orbital planes can intersect at almost any angle imaginable, both due to inclination and ascending node position. The collision back in 2009 was a bit more than perpendicular (102.2 degrees), and that made for 11.7 km/s of relative velocity at collision, so I presume that this time it's even more than that. Early last year a close approach at head-on had happened before as well.

Edited by YNM
my bad, corrected things.
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What's the NORAD or designation of that booster? I can find 18 SL-8 R/Bs from 1981... 

NORAD for the booster is 12443. Here it is:

http://www.satflare.com/track.asp?q=12443#TOP

And here is the satellite.

http://www.satflare.com/track.asp?q=10820#TOP

They are indeed in the prime positions to smack each other face on at orbital velocity.

29j0WOs.png

Edited by cubinator
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Posted (edited)
40 minutes ago, cubinator said:

They are indeed in the prime positions to smack each other face on at orbital velocity.

Thanks for the plots !

But yeah this seems really serious if it does collide and breakup. Okay maybe not yet ?

Welp, fingers crossed I guess...

Edited by YNM
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Posted (edited)

From LeoLabs, their results seems to indicate lower probability :

Still no update on whether it hit though.

Edited by YNM
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I love space. Absolutely nothing happened, but there is enough tension and buildup for a novel in this thread alone.

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6 minutes ago, K^2 said:

Absolutely nothing happened, but there is enough tension and buildup for a novel in this thread alone.

Maybe more like a short essay...

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3 minutes ago, YNM said:

Maybe more like a short essay...

Nonsense. Just add a romantic subplot within the radar office or something and maybe move the satellites down in the way of some space telescope. That's enough for a full novel.

Edited by cubinator
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1 hour ago, cubinator said:

Nonsense. Just add a romantic subplot within the radar office or something and maybe move the satellites down in the way of some space telescope. That's enough for a full novel.

Don't forget that the hero, a slightly past middle age former space jock is the only person in the world trained for this, his love interest is half his age and a total knock-out, and they build the spacecraft in 17 hours - launch it and he saves the day using nothing more than a pistol shot to deflect it... sadly he's lost in space never to be seen again!

 

 

I smell an OSCAR!!!!!

Edited by JoeSchmuckatelli
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19 hours ago, JoeSchmuckatelli said:

sadly he's lost in space never to be seen again!

But if it’s Dirk Pitttm  it would only appear that way. But he miraculously found a way to ride the crippled craft down to the ground, half suffocated, half frozen, and half toasted

Edited by StrandedonEarth
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5 hours ago, JoeSchmuckatelli said:

Don't forget that the hero, a slightly past middle age former space jock is the only person in the world trained for this, his love interest is half his age and a total knock-out, and they build the spacecraft in 17 hours - launch it and he saves the day using nothing more than a pistol shot to deflect it... sadly he's lost in space never to be seen again!

 

 

I smell an OSCAR!!!!!

Where do the sharks get on screen?

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3 minutes ago, mikegarrison said:

Where do the sharks get on screen?

After he lands, nearly dead, he has to fend off vicious, bloodthirsty sharks while awaiting extraction from the depths of the Pacific. But can they get there before the volcano erupts???

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A plot of the encounter (was over Alaska) :

And yep, we're absolutely clear of this particular close encounter.

 

4 hours ago, NFUN said:

But can they get there before the volcano erupts???

Unless if it's a Bond villain lair... oh wait wrong genre.

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One thing I've been wondering: If you were, somehow, sitting on one of the satellites headed for near-collision, would you even notice the other one as it flew past? At 14 km/s it would whizz past you in a fraction of a blink of an eye, and in a vacuum it wouldn't even make a whooshing sound. Even if you knew which direction it was coming from and you were actively looking for it, I don't think you would be able to perceive it unless it happened to reflect a lot of sunlight in your direction. It could pass within ten centimeters of you and you'd be none the wiser.

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1 hour ago, Codraroll said:

One thing I've been wondering: If you were, somehow, sitting on one of the satellites headed for near-collision, would you even notice the other one as it flew past? At 14 km/s it would whizz past you in a fraction of a blink of an eye, and in a vacuum it wouldn't even make a whooshing sound. Even if you knew which direction it was coming from and you were actively looking for it, I don't think you would be able to perceive it unless it happened to reflect a lot of sunlight in your direction. It could pass within ten centimeters of you and you'd be none the wiser.

You'd see it.

In 1 second it travels 14 km, which means in 1 millisecond it travels 14 m. In 1/100 second it travels 140 m. So, by 1/100 second before you'd be able to make out the object, and the whole encounter would last about 2/100 second. You'd probably only be able to watch half of that, but people can see things that happen that quickly, even if not react or understand.

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