Component Reusability

[Kobymaru]

Hello Guys,

so I feel that my career and my space program has now advanced pretty far. With the new ARM parts, my launch capabilities have risen up to about 105 tons to LKO.

There's only one minor problem: on each launch I am dumping one awesome first stage and two awesome liquid boosters with (probably) crazily expensive engines.

And that just doesn't feel right! Real space programs have some reusable stages (if I understand correctly) that reduce the launch costs significantly.

I was trying to get some of my stages to land safely for recovery, but I came upon the following problems:

• Simulation of physics stops for parts fruther away than 2 km. That means they are deleted if they're still in the atmosphere
  
• With a moderate amount of parachutes, the touchdown velocity is still too high for the weak parts at the bottom and they explode
  
• Even with landing struts at the bottom, the spent stages could topple over and partly explod
  
• Dumping them in the ocean is very risky, because even if the lowest part survices the splashdown, the higher parts might still be destroyed due to higher entry speed
  

I use my SSTO spaceplane to get upt to 3 Kerbals in/out of LKO, and I introduced reusable interplanetery tugs but even they need fuel tanks launched into orbit for refueling.

(I am planning on developing a cargo SSTO, but planes are so hard to make and I guess it will only work for small cargos )

So how do you guys handle this "burden"? Do you ignore the (imagined) launch costs or do you take some measures to soothe your conscience?

[EdFred]

Debris gets recovered without your involvement and sent to the Kerbal scrapyard for recycling - most likely as parts with the next release. Problem solved.

[Taki117]

WEll, I use a mod called Kerbal Construction Time which almost forces reusability. (16 Earth hrs to "build" an SSTO vs 4 Earth days for a rocket)

You might also try Mission Controller Extended which adds a money factor, meaning that each thing you recover will cost less.

You should also check out RealChute Parachute System for its configurable parachutes to ensure that your stages will always touch down safely.

(I use the first and last mods and It almost forces re-usability)

[Kobymaru]

Debris gets recovered without your involvement and sent to the Kerbal scrapyard for recycling - most likely as parts with the next release. Problem solved.

That sounds really interesting! Could you please elaborate and/or provide a source?

[LordFjord]

I'd recommend you to check out the entries of the Affordable space program challenge.

It addresses your question and you will get a lot of answers - at least regarding SSTOs, not recovering stages (which is pretty much impossible due to the 2km limitation).

And yes, heavy SSTOs are hard to build and even harder to fly.

That sounds really interesting! Could you please elaborate and/or provide a source?

Irony - don't let him fool you

[EdFred]

That sounds really interesting! Could you please elaborate and/or provide a source?

That's how I justify it in my head. Until money becomes an issue in the game, there's an imaginary Kerbal recovery crew that goes out and picks up all the debris and recycles it without me having to worry about the trash I'm leaving - well - everywhere. (I have debris set to 0)

Irony - don't let him fool you

Well, I thought it was a valid justification. Although in future releases after currency comes into play I could see such an option available. A yearly contract for debris recovery - and you get Kerbucks back in your account for whatever the scrap value is.

[Kobymaru]

I'd recommend you to check out the entries of the Affordable space program challenge.

These guys are crazy. It's incredible how much engineering and flying time went into this! This challange is a bit too steep for me.

But now I'm really motivitated to at least design myself some cargo SSTO. There's just one thing that annoys me about most of the SSTO designs: I consider plastering your plane with air inlets cheating, but without it it gets really, really hard. I am conflicted

[LordFjord]

Its totally worth it A similar step up, satisfaction and personal achievement as with reaching orbit the 1st time, 1st mun landing, 1st docking, ...

If you want to go the SSTO way - and one that can carry some cargo, here is another thread where some experienced folks helped me out a lot to get my design into space.

Long story short (regarding number of intakes):

many intakes, nukes, slow but effective approach or: MOOOOAR BOOSTERS

[O-Doc]

Yep, the amount of cargo you can carry up is directly related to air intakes. Just think about it, once you switch off your jets you then have to carry all that engine + extras weight into orbit. You can't discard it like a rocket stage. So, the higher you can go with turbos the less gravity you have to fight with them as dead weight.

20T of cargo is very viable with only 2-4 intakes per turbo without excessive part counts. I personally don't have a conceptual problem with air-hogging. I exploit where I can to overcome game design limitations that don't exist in real life. And also because that's the type of gamer I am. Sure, I and others spam it pretty hard, sometimes to the absurd but, at the end of the day you get to choose what is realistic and what is fun or you.

I definitely recommend you get into SSTOs. They make you a far better rocket engineer and pilot because of the intimate understanding of the atmospheric physics you develop on the journey.

[KerikBalm]

(I am planning on developing a cargo SSTO, but planes are so hard to make and I guess it will only work for small cargos )

So how do you guys handle this "burden"? Do you ignore the (imagined) launch costs or do you take some measures to soothe your conscience?

Sometimes, I put a set of landing legs and chutes on my spent stages, and just pretend they are recovered (I don't often test if it would be sufficient to allow them to survive), or I go the SSTO route.

My first successful one: 40 tons to orbit, with a cramped payload bay:

Then I went bigger, 80 tons to orbit, larger payload bay:

Then ARM came out, and I took advantage of the stiffer part joints, and liquid boosters, to make a lower part count, heavier lifter.

As I figure, it hauls just about 100 tons to orbit - first test was 53 tons to orbit, with 45 tons of rocketfuel remaining.

Next use of it was to haul 77 tons to orbit, with about 25 tons of other consumables on board at release - although in this case, it was a payload for my laythe mission, and the SSTO laythe lander was contributing two turbojets and some inakes to the SSTO's thrust.

I don't part clip, I don't use nukes in the atmo (the TWR is too low anyway if you don't air hog and get an perapsis before you've even fired rockets), and I don't excessively airhog.

But it takes so long, and the frame rate is so low, and my payload is studded with the strut connectors used to hold it in place... I just launch it on a SLS stack, and pretend it was a reusable SSTO cargo plane - but aint nobody got time for that!

[undercoveryankee]

Mission Controller Extended and Kerbal Construction Time give you credit for recovering any stage that's despawned in the atmosphere with enough parachutes that it would land safely if you were following it.

If I start building reusable, I'll do something similar even if I'm not running the mods that keep score. One or two test flights where I focus on the booster to make sure it comes down, then give myself credit for a reusable booster even if it despawns.

[Amaroq]

Yeah, if you're going to go down this route, I'd recommend the following set of mods:

1. Kerbal Construction Time - as others have said, actually takes recovery of spent stages into consideration; works around the 2.5km limit for dropped boosters if they have a parachute on them.

2. RealChute Parachute Systems - So that you can have in-line parachutes, among many other excellent features.

And for SSTO building:

3. Ferram Aerospace Research - Replace the 'stock' aerodynamics with 'realistic' aerodynamics. Warning: steep learning curve, high reward in "fun factor". Among other things, "intake spam" will cost you, in terms of drag.

4. Procedural Dynamics Procedural Wing - for better control of your wing surfaces (prettier, fewer parts, better control of the CoL). Almost a necessity for FAR, in my mind, but also almost a necessity for SSTO aesthetics.

5. Deadly Reentry Continued - So that your spaceplaces have a chance of burning up, of course. There's nothing more heart-pounding than trying to come down in an all-IVA view with one of the improved interior mods, and seeing all the windows go bright red, and hoping hoping hoping that you aren't coming in too steep / too fast, but knowing that the first sign of trouble is going to be the only one!