SSTO's in 0.24

[LexDavis]

Do you think there will finally be a need to develop and use SSTO's in .24 career mode? or is there still some things that need to be done before they're useful.

[Tortoise]

Ive seen this discussrf in many other threads, bht yes. Since the business-economy-thingy is being added, it'd most likely be better to build a cheap rocket with not many stages. But with safety as your first priority aswell.

[sumrex]

I would imagine so. Space planes are defined by economics so I imagine they would feature in the new system somehow. I could see something along the following lines. Crew X needs a shift change fly x number of Kerbals in to replace them......

[Pecan]

Rather than single-stage rockets I think concentrating on recoverable stages will be most popular. Single-stage just isn't able to lift as much as an efficiently staged rocket.

[qromodynmc]

I dont think so,There is no parts to put cargo in it,Or wings to lift it..

[Karriz]

If you get more funds for recovering the entire craft after the mission instead of just a small capsule, then it certainly would make sense to use SSTO's.

It was probably mentioned in some thread, maybe I can find it.

[RidingTheFlow]

It does not have to be SSTO... Actually it will remain to be seen will SSTO actually save much with 0.24, considering it relatively inefficient comparing to staged design, and you won't be able to recover the full cost of parts even if you land everything back.

But it will make sense to save at least the top lifter stage (esp. if its using very expensive engines like NTR) - and you don't really need cargo bays or wings for - just to add enough chutes and landing legs.

[Urban_K]

SSTO in itself will probably only be useful if you can build and launch one cheaper than a TSTO. Possibly there might be an advantage in recovering as much hardware as possible and in that case SSTO is advantageous if you can recover it.

Me, I'm thinking perhaps reusable SSTO will be useful: https://plus.google.com/u/0/b/102471323450679812923/photos/102471323450679812923/albums/6024429621134236993

(But that makes the fuel trucks disposable, so...?)

[rkman]

Space planes are defined by economics

In ksp space planes are also defined by buggy and over-powered jet engines.

That's a major reason why currently for small payloads rockets are no competition to space planes/winged ssto's.

[LethalDose]

As pointed out before, yes, there will be more of a a point SSTOs in the new version.

HarvesteR has said that you will get back a fraction of the cost of the parts and resources (LF, Ox, MP, etc), so you'll be able to recover more funds if you're able to recover the entire vessel.

Another option, which I don't see mentioned often, is to not recover the SSTO and refuel it by spawning a tanker on the tarmac.

I currently use SSTOs to move Kerbals, Science and resources to and from my space stations. Getting structural parts into space, though, is still tricky without a cargo bay.

I dont think so,There is no parts to put cargo in it,Or wings to lift it..

Uhm, there are wings in the game.

(But that makes the fuel trucks disposable, so...?)

Well, the cost of the fuel truck is probably less than the cost of the space plane, so it's still a gain. And you can refuel the trucks by just spawning a fuel tank with a docking port on it.

Edited July 1, 2014 by LethalDose

[RidingTheFlow]

As pointed out before, yes, there will be more of a a point SSTOs in the new version.

HarvesteR has said that you will get back a fraction of the cost of the parts and resources (LF, Ox, MP, etc), so you'll be able to recover more funds if you're able to recover the entire vessel.

But, to get same weight to orbit, you will have to make heavier SSTO, which will cost significantly more in total than staged design. Which is possible to make it a loss from financial standpoint if "loss fraction" from landed SSTO is actually higher than the cost of lost stages for non-SSTO.

[Alshain]

Rather than single-stage rockets I think concentrating on recoverable stages will be most popular. Single-stage just isn't able to lift as much as an efficiently staged rocket.

Only if the fix the problem of despawning parts as they go low. You can't recover stages that aren't there.

But, to get same weight to orbit, you will have to make heavier SSTO, which will cost significantly more in total than staged design. Which is possible to make it a loss from financial standpoint if "loss fraction" from landed SSTO is actually higher than the cost of lost stages for non-SSTO.

Well it's going to be a case by case basis. If your launching 5 tonnes in the air, you have to decide... SSTO or Rocket, which is more cost effective. I see that as part of the game, there will not be a 1 size fits all.

(But that makes the fuel trucks disposable, so...?)

I think that's going to add much more to the game for modders. It gives you 2 things:

1. A reason to mine resources such as Kethane ON Kerbin.

2. A reason to have atmospheric vehicles (Firespitter, et al.).

Edited July 1, 2014 by Alshain

[Pecan]

Only if the fix the problem of despawning parts as they go low. You can't recover stages that aren't there.

Which is why you stage in such a way that they are recoverable ^^. Exo-atmospheric, pre-circularisation being favourite, obviously. NeverUnload or equivalent for low-staging if you like it, etc.

SSTO or Rocket, which is more cost effective.

Huh? Why choose SSTO or rocket? SSTO rocket and don't waste mass on silly wings.

[Alshain]

Which is why you stage in such a way that they are recoverable ^^. Exo-atmospheric, pre-circularisation being favourite, obviously. NeverUnload or equivalent for low-staging if you like it, etc.

I don't believe Squad will make it that difficult. If they plan on having you recover parts like that then they will find a way to get them onto the ground without flip-flopping between craft and stages, or they just won't do it at all. I'm not saying it's impossible to do, just that I don't think they will force that kind of mechanic. It's more likely they will just implement a version of NeverUnload in stock.

[Random Tank]

Huh? Why choose SSTO or rocket? SSTO rocket and don't waste mass on silly wings.

Wings weigh hardly anything, and they save you fuel; they're awesome!

[Javster]

I'd assume it would be more expensive to start with, but if you did, say, 5, 10, or 20 flights, you would save a lot of kash.

[RocketPilot573]

The problem may be the lack of proper parts to build it with. Making a HUGE wing and cargo bay out of a hundred wing connectors be probably be bad for pricing. This is hard to explain, but 5 cargo bay parts will probably cost wayyyy less than 100 wings, even if the resulting ship is the same size.

But an SSTO that you can reuse for real (without recovering), should defiantly work. Since they don't actually get any damage from reentry and stuff.

Edited July 1, 2014 by RocketPilot573

[Random Tank]

They should just use that idea where there is a giant fuel tank by the hanger that allows you to refil nearby crafts via docking or pipe connector. Planes would just roll up next to it to refil, and any rockets would just land nearby and a truck could bring the fuel to them! (WIP idea)

[malkuth]

Started toying around with Adding A fuel Tank that can be used on Ground only to buy fuel and refill tanks. The only thing you need to buy is the fuel. The truck can stay on ground. Right now Its part of Mission Controller, but when .24 comes out I plan on separating this part of plugin and having it all on its own. That way people that don't like MCE can still use the Refuel Tanks and get charged in game via the new economy in KSP .24. I also added a Sell Tank that can sell resources too.. Like kethane.

makes planes really fun. I had a small fleet of Space Planes in my last game. Some went on 10 + missions, unless they took damage and had to be scrapped.

Edited July 1, 2014 by malkuth

[Pecan]

Wings weigh hardly anything, and they save you fuel; they're awesome!

Nope, never seen wings save fuel on the way to orbit. Single. Stage. To. Orbit.

What may happen later is a whole different game.

@Alshain - yes, I think that's the way it'll go too, eventually at least. Point is, I think recoverable stages will become more practical and therefore more common.

[magnemoe]

But, to get same weight to orbit, you will have to make heavier SSTO, which will cost significantly more in total than staged design. Which is possible to make it a loss from financial standpoint if "loss fraction" from landed SSTO is actually higher than the cost of lost stages for non-SSTO.

True, an KR-1x2 with two orange tanks can put 10 ton into LKO with two orange tanks and land back on pad.

You also need probe, landing legs and power.

However an far smaller and cheaper rocket can also do this, so it depend on how much we bet back, for small launchers and crew transport is might make sense to refuel.

Refueling is practical for crew transport and smaller rockets not so much for large payloads even the fuel handling will be hard, same with adding payload to large rockets, planes has an benefit here.

[LethalDose]

But, to get same weight to orbit, you will have to make heavier SSTO, which will cost significantly more in total than staged design. Which is possible to make it a loss from financial standpoint if "loss fraction" from landed SSTO is actually higher than the cost of lost stages for non-SSTO.

Yes, your comment about the financial loss is true if that's where the balance lies. Thats on the devs, or any mods that change the balance.

The "heavier SSTO" argument isn't neccessarily true though. As pointed out above, spaceplanes that can fly perpendicular to the gravity, kept aloft by aerodynamic lift instead of thrust (like a rocket) can require less fuel to get into orbit. They can also use efficient air-breathing engines that can be almost 10 times as efficient than rockets by reaction mass (they have ISPs 3 - 5 times greater than rockets and don't require Ox, which is more than half of the reaction mass required for rockets) for more than half their flight. These properties of spaceplane SSTOs can actually allow them to be lighter than comparable rockets.

I think this is going to remain true for small SSTO payloads vs small rocket payloads. I expect that lifting medium or heavy payloads into LKO is probably always going to be the job of single-use rockets. And until we get stock cargo bays, or I download a mod that includes them, I'll probably continue to use rockets to lift anything structural into LKO.

The bigger issue is that you cut-out the part of my post you quoted that makes the SSTO's even more cost efficient, which is not choosing to not recover them and refuel them instead. Then, on subsequent missions, you're sending resources up basically for only the cost of fuel. Other posters are also discussing this:

They should just use that idea where there is a giant fuel tank by the hanger that allows you to refil nearby crafts via docking or pipe connector. Planes would just roll up next to it to refil, and any rockets would just land nearby and a truck could bring the fuel to them! (WIP idea)

Started toying around with Adding A fuel Tank that can be used on Ground only to buy fuel and refill tanks. The only thing you need to buy is the fuel. The truck can stay on ground. Right now Its part of Mission Controller, but when .24 comes out I plan on separating this part of plugin and having it all on its own. That way people that don't like MCE can still use the Refuel Tanks and get charged in game via the new economy in KSP .24. I also added a Sell Tank that can sell resources too.. Like kethane.

makes planes really fun. I had a small fleet of Space Planes in my last game. Some went on 10 + missions, unless they took damage and had to be scrapped.

Just as an example, my current primary SSTO uses ~ 600LF + 550 oxidizer to deliver ~ 360 LF + 440 Ox (An FL-T800) + 400 monoprop + 3 passenger kerbals to a station at 125 km altitude (using FAR). Now, the volume of the fuel delivery is pretty small. It's really more of a "bonus" when I deliver monoprop and kerbals or recover kerbals and science, but I think the cost efficiency, especially on the later missions, is going to be exemplary. It also weighs only ~22 t fully fueled, which I think would rival any rocket capable of a similar lift.

Edited July 1, 2014 by LethalDose

[RidingTheFlow]

Just as an example, my current primary SSTO uses ~ 600LF + 550 oxidizer to deliver ~ 360 LF + 440 Ox (An FL-T800) + 400 monoprop + 3 passenger kerbals to a station at 125 km altitude (using FAR). Now, the volume of the fuel delivery is pretty small. It's really more of a "bonus" when I deliver monoprop and kerbals or recover kerbals and science, but I think the cost efficiency, especially on the later missions, is going to be exemplary. It also weighs only ~22 t fully fueled, which I think would rival any rocket capable of a similar lift.

Well, no doubt FAR makes it easier. Still, your spaceplane will cost quite a lot - these arerospace parts are among most expensive (and you will lose fraction of that each launch even if recover it). So its not necessary will be more cost effective than just do a small two-stage rocket launch for comparable weight.

Spaceplanes were never really efficient in mass fraction, since they have to haul all of these airbreathing parts and wings in space (where they just dead weight).

Anyway, we will have to wait and see what exact cost values, recover fractions, etc 0.24 will have after release. Probably they will strike some semi-balance for stock, but mods like FAR could skew it quite a lot.

[Sokar408]

I think this patch calls for the addition of letting "on-rails" parts actually land, if the vessel passes some sort of "deployed parachutes onboard in sufficient amounts". This would allow more staged rockets to be economical, as you could attach chutes and save them, even though physics might not be loaded for that staged part. Arguably it all depends on the recovery amounts, and the balance of the economics, but if this whole system shouldn't be completely trivial, then SSTO's as it right now, will be the "go to" lifters, even if it does require more launches. To strike a balance will be hard, but I think staged rockets should be allowed to at least in some capacity, save their staged parts if effort to do so is put in by the player.

[Wallace]

Only if the fix the problem of despawning parts as they go low. You can't recover stages that aren't there.

They just need to replace auto delete with auto recover for any object with adequate parachutes deployed or adequate fuel and TWR to land itself.

If I recall, that's what the mission control mod does.