Tips for crashing finished stages, or how to reduce debris?

[phemark]

Hi,

So now I have some knowledge about KSP (greatest achievement being Duna-rescue-precision landing-and-return). I decided now to have an extra challenge in my further flights, which is to keep debris 0 or close to it.

(I removed all debris for this (was ~100), and will start from scratch, although will continue the same career).

For now, everything is working ok. My last missions consisted of raising SCANSat satellites above Kerbin, Mun and Minmus. For this I have 2 stage rocket:

a) First stage separates while ascending. And then I use my second stage to reach orbit I want.

Then, I have 6 small SRB facing opposite direction on the 2nd stage. Once I am in the orbit I want, I face prograde (so that SRBs will face retrograde) and launch them while decoupling. This works fine, and 2nd stage loses speed and de-orbits it self. Works as described on Kerbin, and for Mun/Minmus I need to point a bit more to the side than retrograde, because otherwise debris just makes another orbit:).

Question 1) - Does this method sound ok? What could be improved?

If 1) is ok, then this will work for all stages once I am orbiting object. However, if I will need to stage during interplanetary transfers, this wont work.

Question 2) - What are the best means to destroy redundant stages while doing interplanetary transfers? Is it better to not design ships that will stage during the burn? Or maybe somehow aim, and once staged, debris will crash into something? (But again, what if staging is needed earlier..).

So I think that careful rocket design will be the key to the success of this, as if you need to stage while doing burn, nothing will help. But please share your tips if you try to reduce number of debris in your KSP space:D

Thanks

[Vilheim]

Hey phemark,

I have found that one way you can help reduce debris is add some control to each of your stages i.e a probe core with a battery and a few solar panels. When you stage, leave a little fuel in each stage so as to give the piece that is left behind some delta-v. You can then control the discarded stage and ditch it into the nearest surface while your main craft goes on its merry way.

Worst case scenario, where you have garbage stuck in orbit, you could build a garbage collector craft (especially now that we have ARM this is much easier) to take care of debris.

EDIT: And yes your method is actually pretty cool because it is a simple yet elegant way of de-orbiting stages.

[Taki117]

Why stage your interplanetary ships at all? Build them such that you don't have to stage, then just drop your empty tanks (If you can) when aerobraking at you destination (If it has an atmosphere) or put yourself on a collision course just after entering the SoI of your target and then dropping anything unnecessary prior to staging. If you want some ideas you can check This Thread for some ideas. (the only debris I have is the lower stage of my Apollo-style two stage lander.

[EdFred]

I've had success with nuclear engines getting to and from Duna. Build your ascent stage with chutes so they can be recovered (and probes cores if you want to officially recover them). It's easy enough to get 4000+dV with nuclear engines which is more than enough to finish circularizing Kerbal orbit, go to Duna, land and return home.

[phemark]

Thanks for answers. Will try to make ships that dont need staging and/or put command modules if needed.

Is there a way to remove debris from the ground? I have an empty lander on Duna (I rescued Kerbal later), and now it is just there. What would be ways of destroying it? Get a rocket, aim good, and fire?

[Red Iron Crown]

The Alt-F12 cheat menu has Whack-a-kerbal in it, should be able to destroy it with that.

[Claw]

Thanks for answers. Will try to make ships that dont need staging and/or put command modules if needed.

Is there a way to remove debris from the ground? I have an empty lander on Duna (I rescued Kerbal later), and now it is just there. What would be ways of destroying it? Get a rocket, aim good, and fire?

I assume you don't want to just terminate the flight...

You could Claw it with a small rocket and launch it into the air. Wait for gravity to take over. Just make sure to get it high enough.

Edited April 14, 2014 by Claw

[FREEFALL1984]

Fortunately (or unfortunately) for me I don't have to worry about debris because my computer is so slow I have to periodically purge the debris every few days to keep it all running smoothly kinda sucks though because when building big stations I have some terrible framerate issues, for instance I had to build a vessel in orbit at a mighty 3fps.... needless to say it took a long long time

[Jimbimbibble]

Also, it doesn't really matter if you shoot your debris into orbit around the sun. Just design your interplanetary craft so the first stage of the transfer has at least 1000m/s. For use around Kerbin, I do one of three things. Either I design my final stage to have enough dV to circularize and perform any necessary maneuvers, or, if I'm going to Mun or Minimus, I crash my transfer stage into the target, or, if I want a high Kerbin orbit, I launch strait to that altitude and keep my Pe below the surface so my lifter crashes on its way back.

[iStickyDuck]

I put probes and SAS on my launchers so that I can turn them around and de-orbit them once payload is in orbit. For interstellar tugs, I put more fuel on them than I need and repeat what I do for launchers

[Technical Ben]

I also use stages/drop tanks up to and before 20km orbit (note I can be above 100km or so ap, but my pe is kept below 20km for drop tanks). Then after that I keep the tanks on until I get to the destination, or sometimes if it's a small Dv penalty, I drop my pe again, drop tanks, then circularise.

[cantab]

For launching to LKO, the two main approaches are to put a probe core on the upper stage and leave it with a bit of fuel to deorbit itself, or to stop the circularisation burn with the periapsis below 69 km and preferably below 23 km, separate from the upper stage, and finish the circularisation with the payload's engine.

(If you have any ship or debris orbiting Kerbin with a periapsis between 23 and 69 km you'll have to "fly" it in order for drag to affect it and bring it down. Same idea, but with different numbers, for anywhere with atmosphere.)

For trans-Munar injection, you can make the previous stage hit the Mun, fly past into a wide Kerbin or even solar orbit where it won't hit anything, or fly past on a free-return trajectory and hit Kerbin. Same options for Minmus. For interplanetary transfers you can try for an impact but you'll need to either be precise or have control over the stage, otherwise just leave it in solar orbit.

For discarding spent stuff from orbits around bodies other than Kerbin, your best bet is to have a probe core and a little fuel in them for a deorbiting. Next best is to use your active stuff dock/claw and do the deorbit, but I'd only do that if your spent part lacks an engine, otherwise it's more efficient to dock/claw and give it a little fuel.

You can deorbit something with a manned pod too, should it lack a probe core. Have a Kerbal do the deorbiting, bail out, and reorbit himself with his jetpack then rendezvous with his craft. EVA rendezvous takes a bit of practice but isn't too hard, you can bring up the map view with M to get near then use the target marker to judge lateral and radial speed and distance to get close.

[Skorpychan]

Generally, I find that once I'm in orbit and have dropped the ascent engines, there is no such thing as 'garbage'. My fuel tanks are little craft in and of themselves, so they can be recovered and refilled. I'm even starting to design lifters so that the bulk of tankage has docking ports on for recovery.

Cruise stages are reused as space tugs. Just add more fuel to them.

[psyper]

my final stage has around 60 rcs and thrusters along with a probe body and solar panels - just gotta get it below 21 km for kerbin and it'll disappear (you know you're there when your view switches). My final stage is used to get my orbit to match with my space station or ship I'm constructing in space - it unloads any remaining fuel and just leaves enough rcs to deorbit

[Vanamonde]

I have to periodically purge the debris every few days to keep it all running smoothly

You know you can set debris to zero and it all just goes away, right? It's a slider on the settings screen.

[michaelhester07]

The garbage collector ship (could be a probe even) sounds like the most realistic solution to the Kessler syndrome that you're trying to prevent. We may have to actually do this IRL. Take a big kevlar net up, spread it wide, attach some rockets so you can de-orbit the garbage.

In KSP, this would be a probe with a LV-909 or nuke engine with the grappler on it. Latch on the debris then de orbit it just enough that it hits kerbin's atmosphere, then release and speed back up to collect more garbage.

[Pecan]

Is there a way to remove debris from the ground?

The easiest way is to go to the tracking centre, make sure debris is displayed then the piece you want to remove and 'terminate' it.

[phemark]

The easiest way is to go to the tracking centre, make sure debris is displayed then the piece you want to remove and 'terminate' it.

Yes, I know this, but I want to make it harder for my self, hence this thread (or anything in KSP I suppose )

[Taki117]

Yes, I know this, but I want to make it harder for my self, hence this thread (or anything in KSP I suppose )

There is also a mod that adds an EVA Place-able explosive charge for getting rid of unwanted debris

[mellojoe]

I put probe cores and tiny solar panels on every stage. Is this the most effecient? Not hardly. But it allows me to stage my crafts with a tiny bit of fuel left. I use this fuel to rotate and burn to crash the empty stage.

Honestly, your main lifter should be able to get the craft just to the edge of orbit, but still suborbital. You stage here, and let the lifter stage crash back to the planet. Then your transfer stage can push you to where you need to go, and ensure you are on a crashing trajectory with your destination (planet or moon), stage and let the transfer stage crash into that object. Your insertion stage will then do the minor corrections to keep your craft from actually crashing, putting you into its sphere of influence, and put you in orbit or landing for the celestial body you are visiting.

Some debris will be hard to eliminate entirely. For example, a massive mission to Moho will probably require drop-tanks for your interplanetary push. Those are probably going to end up in solar orbit forever. You might consider sticking a small docking port on them somewhere and try to send a debris-clean-up craft after them when they come around again, but that might just be wishful thinking.

In the real world, stuff heading to Geostationary orbit just leaves the insertion stage floating off in no-man's land. Called something like a "garbage-orbit", it drops its payload in geostationary orbit, then pushes itself just a smidge higher. There is a ring of garbage just outside of geostationary just full of spent stages.

[Claw]

Hmm, I see lots of solutions so I'll post part of my own role-play.

For stages dropped low during ascent, I've started attaching radial chutes for recovery. Mostly role play since they often auto-delete due to physics range. Although it's fun to watch them peel away and I can sort of pretend they get recovered.

I've also been experimenting with parachutes during return on otherwise expendable parts. It's a little less realistic to me because tanks/engines would likely experience a lot of damage during reentry. Not that KSP simulates this... (yet)

For orbital insertion stages I will burn but keep the PE below 50 to 60 km. Those parts don't auto-delete, but I basically assume their orbit would decay over time. Periodically I go in and delete those parts as if they decayed and burned up. This yields a little more usable dV but requires some user input.

For parts where I can't do this, or need the extra kick, I also do the small probe/solar panel thing and keep a little fuel in the tank. Then you can burn when this piece is at AP to get an atmospheric reentry.

Munar/Minmus stuff I try to aim at the moon's surface when I can just to keep debris minimal.

Interplanetary stuff and landers, I tend to just let it go. Crash it or aerobrake it if I can, but otherwise oh well...

[Boomerang]

There is also a mod that adds an EVA Place-able explosive charge for getting rid of unwanted debris

I second this!

While it may seem like a particularly Kerbal solution to the problem (PUT EXPLOSIVES ON EVERYTHING!), I find that it works nicely when I've got a third stage that boosts me clear of the atmosphere and takes care of my circularization. The first two stages crash/burn up, but rather than tack on a probe core, batteries/panels/an RTG, and an antenna (playing with RT2) onto the third stage so that I can come back to deorbit it later (and having to remember to leave fuel enough for that), I can just set the explosive charge to detonate after it's been staged and clear of the craft.

Alternatively, though it ups the part count and weight slightly, just use rear-facing sepratrons, if that isn't what you meant by the small SRBs already. I hope that's what you meant, but I can't shake the image of someone mounting a handful of the stock 1.25 SRBs upside down on their launch stages

[Claw]

but I can't shake the image of someone mounting a handful of the stock 1.25 SRBs upside down on their launch stages

That seems like a very kerbal thing!

[Tinyboss]

There is also a mod that adds an EVA Place-able explosive charge for getting rid of unwanted debris

For those who care about realism (and I do understand that's just a fraction of KSP players!) this is kind of silly. All it would do is create hundreds or thousands of little bits of garbage polluting hundreds or thousands of nearby orbits.

[Claw]

For those who care about realism (and I do understand that's just a fraction of KSP players!) this is kind of silly. All it would do is create hundreds or thousands of little bits of garbage polluting hundreds or thousands of nearby orbits.

I was thinking the same thing. But then again my little green guys, who sometimes spend years in a space suit, seem less concerned about this.