Automatic delete of space debris that have orbit perapsis lower than 30 km

[Pawelk198604]

Now i'm not playing ksp but when i play in my free time is one thing that annoy me.

Namely the fact that when i decouple used wasted stage of my rocket is leftover on orbit despite fact it is about 20 or 30 km.

In real life such debris would burn-up and crashed on surface.

[SilverWarior]

Which version of KSP are you playing?

I belive that 0.17 introduced this functionality. Any object which is more than 2.5 km away from your active craft and inside athmoshpere (below 30 km) gets automatically destroyed.

[Pawelk198604]

Which version of KSP are you playing?

I belive that 0.17 introduced this functionality. Any object which is more than 2.5 km away from your active craft and inside athmoshpere (below 30 km) gets automatically destroyed.

I have .22

[Sirrobert]

I'm pritty sure that already happends

[vexx32]

Yeah, I'm pretty certain that any debris around that altitude is already coded to be destroyed. If it's not, perhaps one of your mods has altered this behaviour?

The exact altitude it gets destroyed at, though, I can't remember. I'm fairly sure it's not far off 30km, though.

[Tommygun]

I have seen old boosters stay in permanent orbit with an orbital shape of Pe=38 and Ap=80.

I don't think I have ever seen any with a periapsis in the twenties though.

[maltesh]

The kill line is at about 21-22km over Kerbin. One of the things I used to do in every save was to edit an Impossisat into a stable 25 km altitude circular orbit, just to see its icon dart by KSC at 2.3 km/s every thirty minutes or so.

[Sirrobert]

The kill line is at about 21-22km over Kerbin. One of the things I used to do in every save was to edit an Impossisat into a stable 25 km altitude circular orbit, just to see its icon dart by KSC at 2.3 km/s every thirty minutes or so.

That's awesome

[Dunbaratu]

Yeah, I'm pretty certain that any debris around that altitude is already coded to be destroyed. If it's not, perhaps one of your mods has altered this behaviour?

The exact altitude it gets destroyed at, though, I can't remember. I'm fairly sure it's not far off 30km, though.

Perhaps the suggestion should be changed to "the altitude at which this happens is too low".

Because a piece of debris that's dipping into the atmosphere *at all* would eventually decay and fall in if you were willing to perform the tedious task of having to watch it the whole time so it doesn't go on-rails. It might take more than one orbit to eventually decay that far but it would eventually do it, as it slows down each time it dips into the atmosphere.

[Superfluous J]

Just any reasonable model of atmospheric breaking would work for me. It doesn't even have to be accurate, so long as that debris that's skimming the upper atmosphere will EVENTUALLY come down and crash.

And don't delete it. Let it crash. Or even better land if it has parachutes.

[Kerbart]

Perhaps the suggestion should be changed to "the altitude at which this happens is too low".

Because a piece of debris that's dipping into the atmosphere *at all* would eventually decay and fall in if you were willing to perform the tedious task of having to watch it the whole time so it doesn't go on-rails. It might take more than one orbit to eventually decay that far but it would eventually do it, as it slows down each time it dips into the atmosphere.

That's why I have no problems manually removing them. I agree that the 20km limit is very conservative, and that the OP mislabeled his post. I haven't seen anything that makes it out of the atmosphere once it dips below 30 km but I'm sure Whackjob or Chuck Manley can prove me wrong.

[Sirrobert]

That's why I have no problems manually removing them. I agree that the 20km limit is very conservative, and that the OP mislabeled his post. I haven't seen anything that makes it out of the atmosphere once it dips below 30 km but I'm sure Whackjob or Chuck Manley can prove me wrong.

You mean Scott, right?

[Faark]

And don't delete it. Let it crash. Or even better land if it has parachutes.

Deleting it is kinda the only way to do it that will not burn a common computer. Simulating your current vessel + a 2.5km bubble around it is hard enough in a lot of cases... but potentially loading multiple planets & location to simulate a bunch of derbies would be either most likely impossible or at least lots of wasted resources.

[PDCWolf]

Deleting it is kinda the only way to do it that will not burn a common computer. Simulating your current vessel + a 2.5km bubble around it is hard enough in a lot of cases... but potentially loading multiple planets & location to simulate a bunch of derbies would be either most likely impossible or at least lots of wasted resources.

You do not have to fully simulate everything, just make it a protovessel (uni-part) and add some simple calculations for how atmosphere drag will affect it, hell, they don't even have to be dynamic calculations that are remade every second or so, just input the velocity and angle at which the atmosphere is hit and add drag to it, once the path is calculated it falls to the ground. It has parachutes? safe. Doesn't have them? destroy. It isn't the most complex thing in the world but would solve a lot of problems.

This would be a good way to eliminate the 2.5 km auto-delete limit when doing multiple stuff inside the atmosphere. We'd finally be able to make drop-probes and let them fall from great heights without having to worry for them being deleted if we go further than 2.5km.

[Sirrobert]

You do not have to fully simulate everything, just make it a protovessel (uni-part) and add some simple calculations for how atmosphere drag will affect it, hell, they don't even have to be dynamic calculations that are remade every second or so, just input the velocity and angle at which the atmosphere is hit and add drag to it, once the path is calculated it falls to the ground. It has parachutes? safe. Doesn't have them? destroy. It isn't the most complex thing in the world but would solve a lot of problems.

This would be a good way to eliminate the 2.5 km auto-delete limit when doing multiple stuff inside the atmosphere. We'd finally be able to make drop-probes and let them fall from great heights without having to worry for them being deleted if we go further than 2.5km.

Problem is different parts have different impact tolerance. Those things are pritty big factors when deceiding if your craft stays in 1 piece or not on touchdown. And a chute isn't a failsafe. If you land a long rocket on it's tail on a mountain at 0,5m/s it's still going to fall over and die

Edited November 13, 2013 by Sirrobert

[PDCWolf]

Probably is different parts have different impact tolerance. Those things are pritty big factors when deceiding if your craft stays in 1 piece or not on touchdown. And a chute isn't a failsafe. If you land a long rocket on it's tail on a mountain at 0,5m/s it's still going to fall over and die

It's a start. I'm going to use the excuse you all throw. IT'S AN ALPHA.

Now that I think about it, and it's still just a single calculation, we could just input more values. Enough of them to remain a single calculation but to provide a fairly good result.

Anyways, I don't see why would you want to land something huge with parachutes while having it uncontrolled or why you would throw important equipment that can be damaged if tipped over into the mountains.

Edited November 13, 2013 by PDCWolf

[Kerbart]

You mean Scott, right?

Well he's the Chuck Norris of KSP.

Or is Chuck Norris the Scott Manley of earth?

[Sirrobert]

Well he's the Chuck Norris of KSP.

Or is Chuck Norris the Scott Manley of earth?

That joke is WAAYYYYY

[astropapi1]

Well, a solution to this might be to detect if a craft is in the atmosphere, and activate it's "physics" so the atmosphere has a real effect in it. Just like selective rendering of crafts.

[Superfluous J]

Deleting it is kinda the only way to do it that will not burn a common computer. Simulating your current vessel + a 2.5km bubble around it is hard enough in a lot of cases... but potentially loading multiple planets & location to simulate a bunch of derbies would be either most likely impossible or at least lots of wasted resources.

It doesn't need full simulation, just "does the craft have a deployed parachute?" and if so "can the parachute(s) that is(are) deployed slow the craft sufficiently before impact?" and if so place the craft on the ground in its flight path. None of this needs to be incredibly accurate, even. Just a couple quick calculations.

I'm not saying it'd be easy to code (though compared to the current actual physics they calculate this is pretty simple), but unless 100 pieces of debris hit atmo all at the same time a computer that can otherwise run the game won't really notice.

[boomerdog2000]

It doesn't need full simulation, just "does the craft have a deployed parachute?" and if so "can the parachute(s) that is(are) deployed slow the craft sufficiently before impact?" and if so place the craft on the ground in its flight path. None of this needs to be incredibly accurate, even. Just a couple quick calculations.

I'm not saying it'd be easy to code (though compared to the current actual physics they calculate this is pretty simple), but unless 100 pieces of debris hit atmo all at the same time a computer that can otherwise run the game won't really notice.

What about if the parachute would actually just shear off? It may theoretically have the drag to slow the craft down but if you flew the craft itself it would fail.

[JoCRaM]

It doesn't need full simulation, just "does the craft have a deployed parachute?" and if so "can the parachute(s) that is(are) deployed slow the craft sufficiently before impact?" and if so place the craft on the ground in its flight path. None of this needs to be incredibly accurate, even. Just a couple quick calculations.

I'm not saying it'd be easy to code (though compared to the current actual physics they calculate this is pretty simple), but unless 100 pieces of debris hit atmo all at the same time a computer that can otherwise run the game won't really notice.

what iof it has lifting surfaces? it gets much much harder.

BUT I think the decsion was made early on , when simulating the dropped stages seemed wasteful.

as for difficult - no it's not, you have a list of objects that need simulating, you jump from one to the next. 5 objects take 5 times as much state information (memory) and slightly longer than five times as long to calculate.

but don't speculate - test:

• https://github.com/m4v/DontUnload
  
• TT NeverUnload: http://forum.kerbalspaceprogram.com/threads/48720-TT-NeverUnload-Vessel-Unloading-Preventer?p=632071&viewfull=1#post632071
  
• and the Lazor system all manipulate the atmospheric unloading
  

- but strictly speaking Krakenbane needs appyling as you switch beteween vessels, and that can only be done (I could be wrong) by Squad

[JoCRaM]

I'm sort of happy with the decision to not simulate multiple vessels at once, but I'm not happy with the choice to simply delete. I would rather they applied extra-special relativity, and qunatum ultra-uncertainty, and froze an object in place (relative to the surface of the SOI) until it became eligable for simulation. Unrealistic? certainly, but so is deleting my plane launch system - however it is a lot less agravating.

[Dunbaratu]

The parachute is irrelevant to the calculation of whether or not the debris should be removed.

The craft dipping into the atmosphere WILL decay and fall in at some point. The parachute just means it will happen in fewer orbits.

[Superfluous J]

What about if the parachute would actually just shear off? It may theoretically have the drag to slow the craft down but if you flew the craft itself it would fail.

That question is taken care of in the "can the parachute(s) that is(are) deployed slow the craft sufficiently before impact?" question. Generally chutes can land you safely, or they (or something else on the ship) fall off. Those could all be considered failure cases and I bet the bulk of them would be found with a simple equation comparing mass to braking power of the chutes, based on velocity.

what iof it has lifting surfaces? it gets much much harder.

No it doesn't. If an unmanned space plane re-entered Earth's atmosphere, the fact that it had wings wouldn't matter. I propose they simply ignore everything except mass and number of deployed parachutes.

I'm not asking for the things to be modeled with full - or any - physics. I'm suggesting maybe you could do a quick parachute check on an item that physics is NOT being modeled for. Does it have one? Sweet. Is it deployed? Cool. Would the amount of parachutes be able to bring down this mass safely? Great. Instead of deleting that thing, set it down on the ground where it would have crashed.

Done and done.

The parachute is irrelevant to the calculation of whether or not the debris should be removed.

Yes, it is. But it doesn't have to be.