debris mitigation

[Zephram Kerman]

So the subject has been mentioned briefly in various forum threads since five minutes after persistence was introduced. Perhaps it\'s time now that we actually discuss it in earnest. Debris mitigation, also known as cleaning up after ourselves, eco-friendly orbits, conquering the clutter kraken, and not crashing into last weeks junk.

To get things started, I\'m considering the following protocol for my future designs:

1) launcher stages are discarded before final circularization,

2) trans-Munar Injection stage is discarded while approaching Mun for impact or escape,

3) final Munar orbit circularization by lander stage, to remain on surface,

4) return stage goes from Munar surface to Kerbin atmosphere.

Using this staging setup, the only surviving pieces are the crew return vehicle and a lander monument to mark the spot. No mess, no fess... or something. And some of the explosions will be close enough to look cool. 8)

Now talk amongst yourselves. Thoughts? Anyone?

[Rock-it-man]

I have the same setup going on at the moment with one exception, I leave my TMI stages in munar orbit as \'survey craft\'.

One problem I have encountered only yesterday though, drag is not modelled on ships you aren\'t focussing on. This wasn\'t a problem for munar missions as my launcher stage drops off at around 80km with roughly half the circularization burn done by the TMI stage. But I recently used the same launcher (with the adition of MechJeb) to launch a keostationary satelite. On this ascent path the boosters do orbit, and I thought they would go away as their periapsis is only like 10 km, but unless I actually focus on the boosters individually and follow them enterring atmosphere, they orbit with no degradation.

I propose the following 3 changes to KSP:

1: self destruct systems for unwanted boosters etc, activatable in game and tracking station.

2: an easy way of marking \'wanted\' debris as something other than debris (I use notepad ++ to edit persistence.sfs and change my munar landing stages to 'Odysseus x3 landing site' etc. ). This would hopefully lock them in place too. How many times have you focussed on an old lander only to have its location spaz out and it explodes?

3: More detailed modelling of other ships and debris while not focussed on them. I know this one is hard to do and would cause issues with slower PC\'s, but you could always have an option to swich it off or change its area of effect, just like object fade, we could have physics fade.

Am I a genius or what?

[Mojavi-Viper]

I would like to point out that this is a problem today. NASA tracks all little pieces to other larger item. This is no solution, just a funny observation.

[khyron42]

I normally use your approach for lunar landings. Stage one disconnects on a suborbital trajectory, stage two stays with me until almost landing on the mun and then crashes there.

Another trick is, if you have a launcher where you know one of the stages will be left in orbit - put an extra mechjeb in that stage and make sure it still has some fuel when you jettison it. You can then deorbit it using mechjeb, assuming it has a gimballing engine.

[vexx32]

Usually, I don\'t even have to worry about this. My ship designs are always very simple, and tend to end up with the ascent stage crashing back into the surface, the TMI stage hitting the Mun, and the lander stage being left behind on the Mun, on the rare occasions that I actually manage to land on the Mun.

Minimal debris. Purely by accident. It\'s always been this way O.o

[LaydeeDem]

I tried to deorbit my debris. The only problem now is that they are now orbiting inside the Mun. ???

[DonLorenzo]

Leaving TMI stages on free return trajectories is also a possibility. Will be easier with the actual patched conics system coming up.

[Richy teh space man]

I\'ve been wondering about this too, I could just edit some file somewhere but I think its kinda cheating, I\'m hoping once we get space stations set up we\'ll be able to send out robot drones or something to salvage the wreckage thats floating around..

[DonLorenzo]

I\'ve been wondering about this too, I could just edit some file somewhere but I think its kinda cheating, I\'m hoping once we get space stations set up we\'ll be able to send out robot drones or something to salvage the wreckage thats floating around..

Another nice option would be to not display debris older than X (or exceeding some sequential numbering), but still have them in the game and show up with the grey reticules when you\'re close to them. Get the immersive feel of lots of old clutter without the annoying clutter in map view/tracking station

[Uehen]

I was just coming here to talk about this.

I hate garbage. I know there is a pretty small chance that I will smash into a discarded fuel tank, but it really bothers me seeing it swing around the planet in its ugly misshapen orbit. So far I have only manage to put satellites in orbit cleanly, with out anything left over, but a Mun landing with the current parts is just not possible. As far as I can tell.

What I have been trying to do lately.

1. No junk floating in space or left on the surface of the Mun.

2. Land safely on the Mun, place a probe on the surface.

3. Place a satellite in orbit around the Mun.

4. Return crew home.

Not needing to be done in any order, but all needing to be done in a single flight. So far I can get three out of four of these most of the time, but until we get docking I do not see how I could manage all four with the current parts. My computer isn\'t great, and starts to stall out after adding my 12th-14th booster so I have not been able to build any titans to carry up a LEM type craft with more than than a single engine. Once we can leave a rocket in lunar orbit to fly back to Apollo style re-dock and have it carry us home we will be set.

I keep thinking about flying a whole space station to Mars. or... what would you kall a kerbal Mars? Kars? Are we all going to fly to Kars?

[RedDwarfIV]

what would you kall a kerbal Mars? Kars? Are we all going to fly to Kars?

Cease your speculations, or face the wrath of NovaSilisko the Infuriated By Overuse Of Kerbalisation Of Words.

I tend to leave junk up there to see if I can get close to it occasionally.

[Zephram Kerman]

I propose the following 3 changes to KSP:

1: self destruct systems for unwanted boosters etc, activatable in game and tracking station.

2: an easy way of marking \'wanted\' debris as something other than debris (I use notepad ++ to edit persistence.sfs and change my munar landing stages to 'Odysseus x3 landing site' etc. ). This would hopefully lock them in place too. How many times have you focussed on an old lander only to have its location spaz out and it explodes?

3: More detailed modelling of other ships and debris while not focussed on them. I know this one is hard to do and would cause issues with slower PC\'s, but you could always have an option to swich it off or change its area of effect, just like object fade, we could have physics fade.

Am I a genius or what?

1) Yes.

2) Yes!

3) They look fine to me?

4) Jury is still out, but #2 is definitely evidence in favor of your genius.

I would like to point out that this is a problem today. NASA tracks all little pieces to other larger item. This is no solution, just a funny observation.

Not funny at all. We\'re having the same problem as NASA, except for us it\'s not deadly.

...deorbit it using mechjeb...

Brilliant!

...robot drones or something to salvage the wreckage...

I\'m hoping we get to salvage it ourselves.

...immersive feel of lots of old clutter without the annoying clutter in map view/tracking station

I like it! Perhaps the control would be 'forget objects older than (X).'

[Thiel]

I\'ve found that careful planning can solve most of the debris problem.

For a Mun mission I use the first stage to break out of atmo and raise my Ap to the required altitude, my second stage is then used to circularize, TMI burn, braking burn, Munar orbit circularization (sp) and powered descent to about 100m above the surface.

The third stage is the lander and the return stage.

[sal_vager]

Almost all of my designs have turned out to not leave anything floating around, I drop all the launcher stages before their periapsis goes over 20k and whats left over usually gets me to the Mun and deorbits me there.

The the deorbit stage gets dropped on the Muns surface to crash, and the lander comes back without needing to drop any more parts, all stock btw.

Here\'s my most basic vertical stage mun capable rocket, there\'s a little bit of fuel wasted in the launcher when at Ap 70k and Pe 20k, but as long as I watch for that I don\'t leave any debris at all.

[Rock-it-man]

1) Yes.

2) Yes!

3) They look fine to me?

4) Jury is still out, but #2 is definitely evidence in favor of your genius.

By more accurate moddelling I was talking about the physics. As I said, grag is not moddelled on ships that are outside of visual range, so my boosters that are \'orbiting\' but with a periapsis of 10 km don\'t get slowed down and crash due to the atmosphere unless I fly close to them or focus the camera on them so the game goes 'Oh right, this is flying 3000m/s in dense atmosphere. DRAG FOR YOU!'. So yeah, I have a shirtload of old boosters from keosynch launches that by all rights should crash back to the ground but don\'t.

[Zephram Kerman]

By more accurate moddelling I was talking about the physics. As I said, grag is not moddelled on ships that are outside of visual range, so my boosters that are \'orbiting\' but with a periapsis of 10 km don\'t get slowed down and crash due to the atmosphere unless I fly close to them or focus the camera on them so the game goes 'Oh right, this is flying 3000m/s in dense atmosphere. DRAG FOR YOU!'. So yeah, I have a shirtload of old boosters from keosynch launches that by all rights should crash back to the ground but don\'t.

Ohhhh, then Yes! I suppose it shouldn\'t take much to check a crafts periapsis at load time. If periapsis < 70km, pay attention to drag. Otherwise NO DRAG FOR YOU. TWO WEEKS. Jettisoned parts drag could be modeled 'on rails' once they cross the 2km limit. It seems possible, but I\'m sure there are factors I\'m not aware of.

[sal_vager]

I don\'t think there\'s been a single straight answer from any of the developers about why debris aren\'t handled properly.

From what I remember of other threads though, the extra calculations were considered not worth bothering with, I and a few others had the idea to either precalculate \'best match\' orbits for debris to choose from, or to try to do something when the player was using warp and there were no heavy calculations going on.

At the moment debris that gets around 22k is auto deleted but it still doesn\'t take drag into account, maybe when the new conics thing is introduced it\'ll be possible to do a one time calculation for a piece of debris and save that orbit to a type.

But I was thinking earlier, debris mitigation is good but for a lot of us it\'s too late, so what ideas do people have to deal with already existing debris?

I have a few capsule recovery craft that might be able to push debris into a lower orbit, and I\'m sure someone made a craft that could capture a spent booster.

[karolus10]

Also good will be put a programmable computer inside jettisoned stage (maybe in near future ), so it could be program to attempt retrograde burn after separation (like centaur upper stage) or control it remotely like normal ship - it will be nice to operate unmanned ship\'s from another ( like controlling progress from ISS, when docking ) !

[DonLorenzo]

Also good will be put a programmable computer inside jettisoned stage (maybe in near future ), so it could be program to attempt retrograde burn after separation (like centaur upper stage) or control it remotely like normal ship - it will be nice to operate unmanned ship\'s from another ( like controlling progress from ISS, when docking ) !

mechjeb does this, allowing control at least.

[Mr_Orion]

I think we should be able to change vessel\'s draw distance. I don\'t mean whether or not they are on-rails, just the draw distance; they can disappear rather jarringly.

Another, more elegant and efficient option would be to have 2d imposters that appear after the 3d models are gone (so basically, you just see a sprite), and then even further away, just turn it into a point of light or a glow.

[sal_vager]

Is it possible to make a sprite in game just from the 3d data?

I\'m thinking that rendering the mesh and texture to a backbuffer, then sticking that on a flat polygon facing the camera would not be much faster than mipmapping the texture and just rendering it as is.