The debris free challenge!

[Sillychris]

I was in my career mode tracking station the other day and I said "Wow, I left a lot of garbage in space"

The challenge is simple: Land on cellestial bodies, then return and don't leave any debris in space. Restated, this means you can only blow stages when you are on sub-orbital trajectories... or close enough that the decoupling lowers the spent stage into a sub-orbital trajectory.

I'm not going to bother with scoring or anything. I think it's a neat idea to try and I'd like to see people's designs with this restriction. I'm going to start with the Mun.

Edit: Mods are allowed, just say which ones you used.

Edited April 17, 2014 by Sillychris

[Taki117]

I don't believe this is a challenge really, you should probably read the guidelines.

[samiamthelaw]

I don't believe this is a challenge really, you should probably read the guidelines.

Seems fine, really. It's possible, not duplicative, easily understood. The leaderboard can just be who's made it to what celestial body & back without leaving debris in space.

It might help to clarify whether mods are allowable.

[Pds314]

The trick with this is to expend your orbit stage just before you get to orbit, and then start your transfer burn. Once you are on a sufficiently close direct intercept, you can drop the transfer stage and let it smash into the world you want to go to. Alternatively, you can use it to brake and then just drop it before landing.

[MarvinKitFox]

Easy enough, although very tedious.

Simply modify each and every piece that will get dropped by adding a tank of xenon + ion engine + probe control pod + solar cells.

(always use decouples, not separators, of course)

After staging, your dropped stages can *fly* themselves to a suitable demise.

Adding a mere 410 Kg package will allow several hundred meters of delta-v.

Even in an extreme case, an orange tank with attached Mainsail engine, remnants of radial decoupler and several RCS ports, can be given 1086m/s of delta-v by adding an ion drive with 4 tanks of xenon(770 kg). Not bad for a 10 ton piece of floating junk.

That's only 770/10110 = 7.61% dry mass penalty. (1.833% launch mass penalty)

This is likely to be MUCH less than the penalty incurred by forcing your staging to be on sub-orbital pathways, always.

For very small packages (<< about 0.5 ton) you might want to use an oscar-b tank and one of those ant engines, for the same purpose. One oscar-b + control + ant engine = 149kg, and give a 600Kg junk some 228 delta-v. This is quite enough to de-orbit from LKO. Personally I rather use the ion engine, and just make sure my discards clump together in suitable chunks, with only one ion engine along with each dropoff. i.e. drop pairs or clusters of boosters together.

ahem. mods: None needed, but I *always* use MJ, and it is needed to show you the delta-v in the VAB.

Edited April 18, 2014 by MarvinKitFox

[SRV Ron]

One should see how far they can go, preferring return, without leaving debris in space. It is even possible to do a Voyager escape mission with Jeb using a 10 part two stage rocket, or a probe SSTE; (These don't count as they are one way trips.) The orange tank booster came up short of a SSTO and lands back on Kerbal. A probe with ant engine should work in place of the manned capsule for returning

It also did one way to Duna, Eve, and Laythe.

Edited April 18, 2014 by SRV Ron

[sdj64]

I think that debris-free is a nice commitment to make, and as far as challenge goes, not too much effort over that required to complete the mission in the first place. Most of my missions are debris-free including my manned Eve return and my Jool-5 Challenge submission. On the Jool-5 I actually left a fuel tank in orbit but went back to get it and de-orbit later because I had more fuel left over and wanted to make the mission debris-free.