Ever had troubles with Kessler syndrome? a.k.a 'Gravity'

[Wampa842]

I recently collided a personnell and resource transport with my space station in LKO. It created a nice big cloud of debris. It's staying together as of yet. I know the pieces will drift away eventually, but it got me to think: has anyone ever had troubles with Kessler syndrome? A.k.a has anyone re-enacted the movie 'Gravity'?

[Galileo Kerbonaut]

I have no actual science to back this up, but in my opinion Gravity is wrong. The debris should be on a eccentric orbit from the space station.

I have tons of debris in orbit, but never suffered from the Kessler syndrome. It must be a lottery win to actually experience that.

[FlamedSteak]

A debris cloud should drift apart eventually due to the nature of orbital mechanics. Even two screws a millimetre apart will eventually drift as they are at different altitudes and therefore rotating their body of influence slightly out of synch.

Plus an explosive cloud of debris should scatter off into very different orbital trajectories. Hopefully most of it will be intercepting the atmosphere at some point.

I'd actually be really surprised if a Kessler syndrome would be possible to create in KSP, you'd need an awful lot of crap up there and I'm not even sure if ksp models collisions that are out of your field of view.

Edited November 26, 2013 by FlamedSteak

[doggie015]

A debris cloud should drift apart eventually due to the nature of orbital mechanics. Even two screws a millimetre apart will eventually drift as they are at different altitudes and therefore rotating their body of influence slightly out of synch.

Plus an explosive cloud of debris should scatter off into very different orbital trajectories. Hopefully most of it will be intercepting the atmosphere at some point.

I'd actually be really surprised if a Kessler syndrome would be possible to create in KSP, you'd need an awful lot of crap up there and I'm not even sure if ksp models collisions that are out of your field of view.

It doesn't even simulate them in your field of view if you time accelerate...

[Requiem762]

I have no actual science to back this up, but in my opinion Gravity is wrong. The debris should be on a eccentric orbit from the space station.

I have tons of debris in orbit, but never suffered from the Kessler syndrome. It must be a lottery win to actually experience that.

There's a lot wrong with the movie.

[Bacterius]

An integral part of Kessler syndrome is that debris collide with one another and multiply at an exponential rate. KSP doesn't model that, so it's hard to get those really high debris densities where low orbit is basically permeated with tiny debris that erode your station over time, and the occasional paint fleck that drives a hole through the cockpit and kills everyone on board. In KSP it's just a big decoupler-sized debris that passes by at orbital speeds taking half your station with it if you are unlucky enough to collide with it (which is very rare, as you need near perfect orbit matching for the debris to intercept your station, so unless you are doing it deliberately or have somehow entered resonance with a debris, it almost never happens).

And Gravity is nothing like real life. There aren't "killer debris clouds" in space that come back every orbit with perfect coherence, they average out to evenly permeate their orbits rather quickly, and the debris certainly were not thrown in near identical orbits to begin with.

Edited November 26, 2013 by Bacterius

[vexx32]

Trouble with it? Well, not really, at least so far. I'm actually off to do some experiments in Sandbox as to how much junk can be floating around before it starts to become common enough to run into it... I think I'll build a ship designed to turn into a million pieces (a big bunch of stack separators and other assorted bits and bobs should do the trick).

[Travisfv]

I purposefully make sure that my launches never leave anything in orbit. Even if I have a large amount of fuel in a stage, if I see that staging will leave it in a persistant orbit, I use what I can but always drop in into the atmosphere. And the new way I've been doing my launches kinda ensures I don't need more than 200 m/s to circularize at my apogee.

[RickRastardly]

I've often been tempted to build two large ships and put them in opposite orbits, just to see what would happen, I'd imagine it would be an excellent technical feat to get them to connect at a closing speed of over 4200m/s

[rosenkranz]

I did something like that as well. Built a payload (mostly separators and small trusses) specifically to simultate a large debris field (about 500+ parts).

Unfortunately, after getting 3 of these into orbit (about 60 deg apart) the debris caused the map view to stutter horribly. FPS dropped to about 10 or less.

What was interesting was watching what happened to the debris fields over time. Over a period of a few days the 3 fields had spread out into a crescent with 3 knots where the payloads have been 'detonated'. After a few weeks game time they had become a fairly distributed ring of debris with only slight concentrations where the initial payload popped.

If I had watched for longer, I'd bet it would oscillate, clumping up, thinning out and so on. I had planned on putting up more and seeing how much of a danger it posed my space program. However, I hadn't anticipated the effect it would have on the map view.

Of course since Kerbin is so small the orbit is pretty tight. In Earth orbit I imagine this process would take quite a bit longer. But the results would indeed be the same.

[purpletarget]

If you want to see a real life example of an incident that give Gravity it's semi-plausible premise, check this out:

The ISS crew has been sent to their shelters on occasion for close debris encounters such as this.

[radonek]

I don't think its possible in KSP. First, you can't really smash your rockets to pieces, collisions only tear parts apart. There is no "piece of metal from larg orange tank" part. Second, number of objects involved in true kessler syndrome is HUGE and required calculations would sooner blow your computer to pieces. Not like physics calulactions are not trying to fry CPU even with just small number of parts, right? Which is why KSP actually have a limit on number of debris, look around settings panel.

[Moar Boosters]

The whole point of a kessler cascade is that it keeps spreading out due to micro-collisions within the debris cloud, so what happened in the movie could happen...... but they'd never see the same pieces of debris twice. Each time they'd hit a different part of the debris field. Each time it hits them it gains more debris from the stuff it smashes up.

Sure you can't simulate the micro-collisions, but if you search youtube for "ksp kessler bomb", you can see the stuff spreads out in the game, just due to the fact when you explode the spaceship. stuff flies in different directions, and eventually moves apart due to each part being given a different velocity by the initial explosion.

[rosenkranz]

True, but it would never happen like they depicted. They depicted it as if once the satellite blew up the debris stopped and the shuttle and what not would pass through it every orbit.

In reality it would take quite a while that debris to be an issue. Plus, considering such satellites are in different orbits entirely, it would likely be a non-starter for such a drama. However reading some of the reviews, the director did acknowledge that they understood all that and tried to sacrifice as little as possible to keep the realism at max while still having a story to tell. Otherwise, like I said, there wouldn't be a story.

[Richy teh space man]

In my opinion, the focus of Gravity was on the people and the situation they were in as opposed to scientific accuracy. They could have done the film on a remote ship in the Atlantic and still not lost much. (Well, besides cool visual effects of Earth).

As others have mentioned though, the debris just explodes as opposed to shrapnelling into thousands of pieces, and even if it did, space is mostly empty so the chances of a collision are pretty low.

[Traches]

In my opinion, the focus of Gravity was on the people and the situation they were in as opposed to scientific accuracy.

The thing that drives me insane is that the two goals are not mutually exclusive; frequently it's just laziness that makes movies completely implausable. If you need one or two "magic" technologies or impossibilities to make the plot work that's fine, but if the entire movie is just WRONG then I can't enjoy it at all.

[TheBadAstronomer]

There's a lot wrong with the movie.

Come on guys, does it matter if every little detail is right? The movie is for your entertainment, and it doesn't matter if they got some minuscule detail wrong.

I've never had that problem with debris, as I deorbit most of it.

[Kerbart]

Come on guys, does it matter if every little detail is right? The movie is for your entertainment, and it doesn't matter if they got some minuscule detail wrong.

I wouldn't classify is as a "miniscule" detail, but you are right in the fact that it's a movie, not a documentary and that it doesn't matter as long as the movie is enjoyable to watch. Most movies have their facts wrong. Sometimes out of ignorance of the movie makers (directors, script writers, producers), sometimes because... well, it makes a better movie.

Even within the frame of reference you'll find inaccuracies everywhere. Consider Terminator Two, where at one point the friendly T800 is repairing a car and asking for a torque wrench. He's a friggin' robot. He knows what force he's extorting! Why would he be asking for a torque wrench?

See? Movies are full of BS. Even when you're not looking for it. But what counts is that they're entertainable.

[Boris_T_Roach]

I've often been tempted to build two large ships and put them in opposite orbits, just to see what would happen, I'd imagine it would be an excellent technical feat to get them to connect at a closing speed of over 4200m/s

I've tried it with 2 big stations with impressive solar arrays sticking out as something extra to aim at

What you have to do is to get 1 into a perfect circular orbit and then match the other one to it

The trouble is.... at 4300m/s closing speed and the 2.5km 'bubble' around your current ship, they will only be approching for something like 0.5 of a second... maybe 10 or 15 frames and you have to hope that the PC does the frame with the distance at 0'is meters, if it calculates the frame at 150 meters apart, the next frame with be with the target receding at 4.3km/sec...

Not to say it wont happen but its damned hard

[Tank Buddy]

Yes, that was my biggest pet peeve about the movie. The ISS does have a 90 minute orbital period, but if the debris was traveling at a higher relative velocity than the station, as it was, the debris would have to be in an elliptical orbit. This means the debris would take more than 90 minutes to reach the ISS's altitude, and the ISS would not be in the same place at that time either. But imagine how boring the movie would be if the debris only came around once.

[lajoswinkler]

No, it's impossible to experience this in KSP.

Yes, that was my biggest pet peeve about the movie. The ISS does have a 90 minute orbital period, but if the debris was traveling at a higher relative velocity than the station, as it was, the debris would have to be in an elliptical orbit. This means the debris would take more than 90 minutes to reach the ISS's altitude, and the ISS would not be in the same place at that time either. But imagine how boring the movie would be if the debris only came around once.

Debris was probably in polar orbit (Russian satellite, spying). Then the only thing you need to forget is that it wouldn't impact the station every time because there's no reason everything is matched up perfectly. But it's a part of the plot

Edited November 26, 2013 by lajoswinkler

[tntristan12]

I've tried *very* hard to take down one of my space stations with debris. I built an orbital "debris cannon" which is basically just a bunch of tiny fuel tanks (I needed the mass, in order for them to do any damage), and managed to fit one hundred or so onto a big orange tank. Any more than that and it would have been unplayable due to lag. Anyway I put it on a rendezvous orbit with my space station and let the debris fly. No matter how close I got to my space station though, the debris seemed to just fly right past it. It wasn't until I flew within 100m and fired that I actually hit anything. The results were pretty spectacular:

However, given the difficulty of using Kessler syndrome in even a controlled environment, I'd say it's impossible to have it become a problem in-game. This may be due to the fact that if the debris is that thick then it will either be removed from the game, or (if unlimited debris is on) cause the game to lag to the point of being unplayable.

[vetrox]

As has been said already. KSP does not simulate any collisions when you are not controlling things.

As for the movie gravity. Its just one of those things. Although its innacurate its only us mad science nerds that actually notice it, for a member of joe public it seems like an extremely plausible movie. Heck everyone likes star wars and that couldnt be further from reality.

Its like any move. Those who are experts in the movies "field" are going to notice all the innacuracies. Does this mean they wont enjoy it? Im an automotive engineer and the fast and furious franchise (even the early ones) are still an enjoyable watch even with the hordes of stuff that is just "wrong" (manifold overheats so the passenger footwell falls out?)

I haevnt seen gravity yet (As i really dont see sandra bullock pulling off that role along with the fact that i cant stand her!) but it looks to be a good'en. The only sci-fi movie i have seen that tries to be as accurate as possible was the europa report and even that has stuff that could be pointed out as wrong due to it still trying to be a movie.

EDIT: I've started a new save and have built a station in retrograde direction around kerbin. The rest of the save will be as normal but with an emphasis on taking as much debris up with you (procedural fairings is talented at this as this gives me a minimum of 4 debris with every mission)

Edited November 26, 2013 by vetrox

[User Unrelated]

actual kesseler syndrome in KSP?

be prepared for 0.25 fps.

I almost collided with some debris the other day... when I say "almost", I mean 8km away

but that's still the closest I've ever come to debris.

it got much closer, but I was busy concentrating on my LKO exit burn.

[Halo_003]

I had a piece of a launched launched in an orbit opposite to the orbit of my space station. It flew by today when I was docking a module to the station, and came within 1km actually. It was also moving 4300m/s relative to my station, so it would have been spectacular if it had impacted.