Career Mode: Closed Cycle

[DocMoriarty]

When i started career mode i developed quite a few rockets before i had the science points to really dig into the space plane stuff. While developing rockets especially for heavier payloads i thought it would be cool if i could get the test rockets back to KSC later. Yet the parachutes are too small to really land large main stages and even if you get them down at reasonable speeds they usually still disassemble as they slow dive into water (splashdown should give you a merciful crash tolerance 1.5x the normal one). So i decided to slap probe cores on my main stages and to leave them in orbit. Probably i would find a better method at a later time to 'reposses' them.

A Typical main stage worth recovering looks like this for example. I usually launched them without payload to determine their payload capacity (not using any mods but chatter and alarm clock).

Slowly time went on and orbit filled with expensive rocket trash and i started to suffer from Kessler syndrome (lots of trash) despite it sometimes being remedied when launching KSP.

Space plane stuff got researched and i started to create space planes to transport a lot of stuff into LKO but also always with the option in mind, to get some of that stuff back. So i constructed ever bigger space planes until i got to create REPOMAN! Constructing a big plane like this was quite a challenge, getting it quite correct aligned and balanced and stuff. Unlike other space planes and transporters this one also features 4 nuclear engines for extended operations at least in the Kerbin system. Other than that it also has 12 rapier engines and can be refitted and used as a space transporter for roughly 156 max TOW too (payload with nukes installed 45t, without around 57).

Repomans main purpose though is to reposses and return stuff to KSC. So Repomans basic fitting is a claw. In this special version it's balanced to connect to rockomax sized trash. Once basic tests were done, Repoman started for the first repo-mission in space.

Thanks to repomans nukes it's very fuel efficient to do the final insert into orbit. And of course all other space borne operations are quite a lot more efficient than with the rapiers.

After the usual approach procedure Repoman got ready to attach to one of the old Zeus experimental main stages.

Attaching a payload like this must be as precise as possible. Had to take care that CoM doesn't move too far forward or backward. The height alignment of the claw is already perfect for rockomax diameter. Although not seeing CoM while flying i guessed pretty well where CoM is. Also supporting my guess a bit with pumping fuel around. Good thing repoman has these big sidetanks since Zeus main stages were designed to arrive with as much fuel in orbit as possible. This one had 1.5 orange cans worth of fuel on board.

Now the reposses process had to begin, de-orbit burn went well. Intentionally overshooting KSC a bit. While turning back to KSC i started to burn the excess fuel using the rapiers in closed cycle mode. This got landing weight from 145t down to around 100t which seemed a bit safer than keeping the fuel. Also flying in atmosphere it turned out that balance was hit pretty well. Would still have had the option to pump fuel forward or backward to modify balance if needed.

The approach went well. Got the plane perfectly aligned with runway. Kept SAS on to keep the inherently wobbly construction a little less wobbly.

Knock Knock! Take your crap back! (It would really be cool if, when taxiing close to the hangar doors, the doors would open and you could drive inside. After driving inside you should get recovered automatically)

That was worth it! Although, Repoman is worth around 360k too.

Well in any case it was an interesting challenge. Cycle Closed.

The first repo mission went so well, that i actually only moved a few structs a bit and added 2 more to make the clawed stuff more stable.

Here's the link to the craft file:

http://www.docmoriarty.com/ksp/mods/SPT Repoman LC1 1_01.craft

Edited August 6, 2014 by DocMoriarty

[lunait]

That's a cool and unconventional way to recover launch stages! I just put a pair of parachutes and some landing legs on mine, and did a semi-powered landing.

Javascript is disabled. View full album

[Blue]

Neat idea. I probably would've just figured out a way to use parachutes.

By the by, "closed cycle" in rocketry usually refers to cycling exhaust gases directly into the combustion chamber, which produces more thrust at the expense of design complexity and weight, over "open cycle", which vents fuel pump turbine exhaust. Open cycle is less efficient and usually 15% less powerful, but is much easier to design and build (cheaper) and they weigh less.

The word you're probably meaning is 'fully reusable'.

[DocMoriarty]

Yes closed cycle here is actually meant in terms of recycling yet a bit refferring to rapiers 'closed cycle' mode, was just intentionally playing with words here. I experimented with the parachute stuff too but it's unsafe since the chutes get cut off as soon as you ascend only 1 millimeter during powered landing. If splashdowns would be more merciful as in allowing lets say 1.5x the crash tolerance and if there would be bigger chutes it would make more sense. Yet i completely went away from rockets since it's simply inefficient compared to space planes. Recovering the main stage is also only part of the launch vehicle, usually you loose boosters or asparagus stages too.

So meanwhile my space program is centered around space plane transporters. Repoman is just the biggest of them for now. Flying like a charm. I might use it to catch asteroids with a special fitting.

Other examples are Paperman here with a 27t space station core as payload ...

... or a 47t tugboat payload that is mainly used to haul KR2L engines for part test missions.

Another big transporter is milkman. Here are 2 milkman docked to a space station core like the one transported by paperman.

And finally a small 11t max payload 3-engine transporter i named dove which just delivered an experimental payload for 2 missions to the tugboat mentioned above. The tug will get it on the fancy trajectory needed and bring it back.

[problemecium]

wow...

my version of "Repoman" is just a little nuclear tug with a blob of extra parachutes stuck all over it.