What is the real use of an SSTO?

[Laie]

Well then they'll have to change the current system of deleting an object that is in atmosphere and more that 2,5km away from the focus point. I tried to have parts splash down safely for roleplay purposes, but they always just get deleted.

There has to be a way, and it's already in the game: the king-size boosters from ARM last until ~10km, so they definitely fall out of the physics bubble after detachment. Yet they're recoverable, even without me adding any parachutes.

[r4pt0r]

how about anything outside of 2.5 and in atmosphere the game checks the weight of . say a falling stage weighs 8 tonnes. then the game can check to see if it has deployed chutes. say an 8 ton stage would need 1 chute, and a 16 ton stage would need 2 chutes and so on.

provided you deploy the chutes on ejection, and if the numbers add up then it is "recovered" automatically. if not then its deleted with no return benefit.

also the 8 ton, 16 ton weights thing is a example. how many tons can a single chute safely land? use that number.

[qromodynmc]

I only use ssto for carrying kerbals to my space station,or recovering them manually,you know,sstos are best way to travel on kerbin.

[hempa2]

OK, this thread is kinda done!

Conclusion: SSTOs are only good for Kerbals to LKO, while rockets are good for launching a station, interplanetary craft or a simple satellite!

[rosenkranz]

Don't underestimate the maintenance.

On passanger airplanes you have a lot of redundancy: if one system fails, you have a backup system to take over; if one engine fails, the remaining thrust still gets you to some landing site and so on. That concept has a name which escapes me; the basic idea is that any single failure should be no more than "an issue" or at worst "a problem". If you browse the last few decades of airline catastrophies, you'll notice that it usually took a chain of events, each of which, in and of itself, would not have been that bad .

Spacecraft have much less redundancy, because weight. You've got a host of possible failures that would each lead to instant catastrophy; to make up for that, everything is double- and triple checked before launch. Accordingly, maintenance has to be more thorough in shorter intervals. Your "little bit of refurbishing" may well amount to a complete disassembly after every flight, checking every piece for hairline fractures &c.

Maintenance also requires facilities and a workforce. Not sure of the proper terminology, is that overhead or running cost or what? Anyway, the whole setup is designed for a certain number of launches/year; not meeting (or exceeding) that figure will drive up the cost per mission.

Very much this. This is what plagued the shuttle program. They thought they'd be able to relaunch this much much more often than they ended up doing because the maintenance ended up being way more than expected. Honestly, as much as I loved the shuttle program as a kid, if you look at the actual performance vs. the advertised performance, it's a wonder the program wasn't killed off in favor of a better design a long time ago.

This is also very likely why NASA is going back to the capsule designs as cheaper and more reliable than a new shuttle design.

[jfull]

OK, this thread is kinda done!

Conclusion: SSTOs are only good for Kerbals to LKO, while rockets are good for launching a station, interplanetary craft or a simple satellite!

One major thing you're forgetting.

They're the best way to land on Laythe, period.

[Greenfire32]

as it stands, there's real no benefit to going SSTO over MSTO (multiple stage to orbit). Once contracts and funding come into the game, SSTO's primary benefit will be saving piles and piles of money.

[Red Iron Crown]

Maybe. We have no idea how or if reusability will be implemented in game. Or how much spaceplane parts will cost.

[Aghanim]

SSTO simply means that you put the entire vehicle into orbit. It doesn't mean it's reusable or any cheaper. You are confusing reusability, single-stage to orbit, spaceplanes, and rockets.

SSTO is quite easy (The old Mercury-Atlas was SSTO, and the Titan I first stage could also orbit itself if they wanted to). You can have multi-stage reusable rocket-powered spaceplaces and you can have single-stage expendable ramjet-powered missiles, and just about any combination of the above.

No way. I thought that no one successfully created SSTO in real world yet

[magnemoe]

No way. I thought that no one successfully created SSTO in real world yet

Because nobody has bothered to send a atlas first stage into orbit, you don't get any useful payload and you can't land it again.

You also need upper stage stuff on it to like restartable engines and rcs.

Note, you could probably get some useful payload if you made the fuel tanks larger as the first stage alone has high TWR, to be useful you need a heat shield for the huge stage, legs and fuel for landing.

[Hodo]

Maybe. It all comes down to how cheap they can make it and what people are willing to pay.

People once said that no one would pay to fly in a plane across the Atlantic they would rather take the cheaper more luxurious route of the boat. Well how many people do you know now days who takes a boat across the ocean to go anywhere? Most people I know fly, why? Because it is cheaper now. It is cheaper because of mass production and the reduction in cost on aircraft parts and labor. This has carried over to the mail industry. Most freight under a certain weight is usually sent by air now, why because it is faster and cheaper then by sea.

[Dangerous_Beans]

in my experience, the point of SSTOs is when you need to stick a 3.75/5m stage under a payload fairing to stop it flipping over, and the only way to make it fly is to stick enough fuel into it to make it reach space in one stage. the point of space planes it to kill <s>kerbals</s> time while waiting for your current mission to reach where ever it's going.

[Hodo]

in my experience, the point of SSTOs is when you need to stick a 3.75/5m stage under a payload fairing to stop it flipping over, and the only way to make it fly is to stick enough fuel into it to make it reach space in one stage. the point of space planes it to kill <s>kerbals</s> time while waiting for your current mission to reach where ever it's going.

In the stock KSP they have no use. But once you start adding more realism to your game then they start finding a use. Especially with Mission Controller and dealing with costs. While rockets are cheap, they can add up in cost, a SSTO is cheaper in the long run, more so if it is recoverable and reusable.

I know in the Reusable space program challenge, I used a SSTO space plane that built a space station in 4 launches. It was only loaded once from the SPH, after that it stayed in the game world, never recovered. It was loaded with the new module after every mission from a loading crane. The cost savings was quite a chunk. Went from over 500mil to launch this station to under 300mil. That is a HUGE chunk.

But in the stock KSP SSTOs are pointless, but so is anything that flies.

[OgreMagi]

SSTO space planes fill a niche in the space program to easily and simply ferry personell between the ground and orbit in a planet with a thick atmosphere.

Around Kerbin, you can easily launch a rocket to orbit and aerobrake a return capsule but it is very inefficient, effectively throwing away 95% of its mass to do the job.

A SSTO rocket can do the job but usually has multiple stages with throwaway solid rockets, and throwaway sections to get into orbit. The Main bus uses a ballistic return with parachutes to slow it so it can land. A slightly more efficient design but still your throwing away more then 50% of the rocket to do so.

The SSTO space plane is a single stage that uses turbo jets to get it to near orbit and a much smaller rocket to take it into orbit, I seen several designs that can carry 4 or more kerbals only using stock parts and it is reusable. However around kerbin rockets are much easier but on Laythe where you cannot build rockets nor throwaway boosters, it is the only way to move people from the ground to orbit.

that's how I see it.

Moreover, I would like to see a airbreathing engine that can be used on other planets with atmospheres, Duna, and Eve come to mind. I have tried the kethane engine mod but it has a lot of limitations and several bugs. but just my thoughts.

[DivisionByZero]

SSTO space planes fill a niche in the space program to easily and simply ferry personell between the ground and orbit in a planet with a thick atmosphere.

...

Moreover, I would like to see a airbreathing engine that can be used on other planets with atmospheres, Duna, and Eve come to mind. I have tried the kethane engine mod but it has a lot of limitations and several bugs. but just my thoughts.

Two things:

If you have a station in orbit and need to frequently replenish supplies like food to the Kerbals, then spaceplane SSTOs make sense as well. In addition, it's a good personnel transport, as you said, and avoids debris for those of us that aren't quite good enough to leave all of our debris in decaying orbits. There is also an ability to place small satellites into basically any orbit without needing to put any fuel/engines on the satellites themselves, which saves weight.

The other question you asked is solved in KSP-Interstellar. There are thermal-turbojets that operate on whatever atmosphere is around allowing them to operate in turbo-jet mode on any planet with sufficient atmosphere. Once they are upgraded (or "regular" in sandbox mode), they can automatically switch to a thermal rocket and then function just like a RAPIER/SABRE engine. In thermal rocket mode, though, they need an internal fuel source, but that can be anything you can shove in a tank.

I totally agree with your scheme for Laythe and Eve - seems natural to me to use spaceplanes to get up and down.

For me, I enjoyed the challenge of figuring out FAR and what it actually takes to get a sizable spaceplane up into orbit and beyond. If there's a payoff in 0.24 then I'll be ready. if not, I'll still have a cool spaceplane.

[Red Iron Crown]

People once said that no one would pay to fly in a plane across the Atlantic they would rather take the cheaper more luxurious route of the boat. Well how many people do you know now days who takes a boat across the ocean to go anywhere? Most people I know fly, why? Because it is cheaper now. It is cheaper because of mass production and the reduction in cost on aircraft parts and labor. This has carried over to the mail industry. Most freight under a certain weight is usually sent by air now, why because it is faster and cheaper then by sea.

That's a bigger difference in time commitment, though. Travelling by sea meant several days to cross the Atlantic, while planes were able to do it in a matter of hours. The jump from atmospheric aircraft to suborbital spaceplanes is smaller and less significant, and I don't think the pricing can ever be brought as low as atmospherics. Even if fuel is the only cost, it takes a lot less fuel to fly atmospherically. That's not to say that suborbital commercial transportation will never be viable for the higher end travelers, but I don't think it will ever replace atmospherics for the general population. Getting somewhere in a single day is "good enough" for most commercial travelers that additional costs to reduce the time is likely not worth it.

[Nibb31]

A SSTO rocket can do the job but usually has multiple stages with throwaway solid rockets, and throwaway sections to get into orbit. The Main bus uses a ballistic return with parachutes to slow it so it can land. A slightly more efficient design but still your throwing away more then 50% of the rocket to do so.

If it has multiple stages, then it is not an SSTO rocket.

In addition, SpaceX plans to do a multiple stage rocket where all stages are reusable. SSTO != reusable.

People once said that no one would pay to fly in a plane across the Atlantic they would rather take the cheaper more luxurious route of the boat. Well how many people do you know now days who takes a boat across the ocean to go anywhere? Most people I know fly, why? Because it is cheaper now. It is cheaper because of mass production and the reduction in cost on aircraft parts and labor. This has carried over to the mail industry. Most freight under a certain weight is usually sent by air now, why because it is faster and cheaper then by sea.

The difference is that there was actual demand for fast transatlantic transportation before it existed. There was a destination on the other end of the journey, with stuff to see, things to do, people to meet, business trips, trade, tourism, friends, relatives, business contacts... For public transportation to exist, people need to have a reason to travel.

The demand for transportation to LEO is low because it is not an actual destination. There is nothing there. For most people, there isn't anything to do except float around in zero-g and stare out of a porthole. Us space geeks might find that fascinating, but for most people, that gets old after a day or two and is not worth the ticket.

Edited June 4, 2014 by Nibb31

[magnemoe]

That's a bigger difference in time commitment, though. Travelling by sea meant several days to cross the Atlantic, while planes were able to do it in a matter of hours. The jump from atmospheric aircraft to suborbital spaceplanes is smaller and less significant, and I don't think the pricing can ever be brought as low as atmospherics. Even if fuel is the only cost, it takes a lot less fuel to fly atmospherically. That's not to say that suborbital commercial transportation will never be viable for the higher end travelers, but I don't think it will ever replace atmospherics for the general population. Getting somewhere in a single day is "good enough" for most commercial travelers that additional costs to reduce the time is likely not worth it.

High chance for this, no current supersonic passenger jets, problem is that your marked is the few first class passengers, yes they are willing to pay a lot for tickets however its few of them and if you only have few routes its faster to fly direct than flying from Madrid to London then supersonic too New York then too Miami rater than flying direct.

It might be an private jet marked, some is working on a supersonic private jet.

An suborbital system has obvious military use.

[Bishop149]

My main uses of SSTO's are also focused around Laythe, for the simple reason that I want to be able to get to and from Low Laythe Orbit by adding (as little as possible) fuel alone . . . rocket launch systems than ditch most of their mass along the way are fine for messing around in Kerbins SOI. . . for long term use anywhere else they are totally impractical.

Due to the relative lack of solid land based Kethane deposits on Laythe I am currently designing as system to ship it from Pol if needed, plan involves:

- Reusable rocket / miner for the actual mining and shuttling between Pol and Laythe orbit.

- Large capacity storage / transfer / refinery station in Laythe Orbit.

- SSTO that can launch to the station fill up with 8000 units of Kethane and land it safely on Laythe's surface . . . all whilst using as little fuel as possible, exercise would be pointless if the SSTO required more Kethane to refuel than it could ship down from Laythe orbit.

[rosenkranz]

Actually, time commitment is kind of reversed in KSP.

On a rocket the trip to orbit is less than 10 minutes (SSTO or not). Landing a capsule or whatever that is ballistic won't take more than 10 minutes either. Done it countless times now, both with and without mechjeb. However, getting a space plane up is a trick and it takes time. Getting one down seems to be even trickier and takes a lot of time as well. I've watched vids of this and it seems tedious to me but that's just me.

I'll admit, I'm a noob as spaceplanes go. I've done it a few times, but only proof of concept craft. Nothing big enough to be worth the effort. And I've yet to be able to land one intact, let alone land one at KSC.

Of course I realize this has nothing to do with SSTO's but my preference for an SSTO is likely always going to be a rocket for these reasons. If I'm throwing away 90% of my mass, that is okay. It's just fuel. In real rocketry, the fuel isn't even 10% of the cost of the rocket. Well, since I can land the orbit stage(s) back at KSC then I'm recovering 90% of my investment. Would be cheaper to refurb rocket parts in real life vs. the maintenance on a spaceplane, now there is a good question.

[Hodo]

An suborbital system has obvious military use.

This right here.

Currently the US Army's 82nd Airborne has a 24hour deployment ability. That means ANYWHERE in the world in 24hours. Imagine being able to cut that down to 12, or even 4 hours. Things like the attack on the Isreali Olympic team back in the 70s near impossible, or the ability to capture a high profile target without them having time to evade. Or the projection of force that would give you as a nation. This is what would fuel the SSTO market, more than the civilian market. While they would help they would not be the primary supporters. They would benefit from the technological gains but at first it would be for only the wealthy jet setters. I can imagine some major mega corp CEO would use this for no other reason then to better micro manage their assets.

[Red Iron Crown]

I'm thinking smaller payloads for the military, too. Imagine being able to deliver a MIRV-like payload of armed drones anywhere in the world within a couple of hours.

[Frederf]

I find Falcon-style reusable rockets much more interesting than SSTOs. The SSTO is essentially the age-old idea that a free man rides his own horse wherever he wants. It's a nice idea, but it doesn't seem to be that much in touch with reality.

SpaceX also tries to achieve cheap spaceflight, but instead of listening to sci-fi authors and test pilots, it's listening to engineers. Reaching orbit is a demanding and highly specialized task that requires a lot of expensive hardware. After reaching orbit, that hardware becomes dead weight, making the ship much worse in everything else. It makes much more sense to drop that hardware before reaching orbit, and to reuse it in the next launch.

About the aero gear being "dead weight" upon reaching LKO. I've been toying with the idea of a spaceplane capable of shedding its aero gear in LKO, flying beyond LKO, and then rendezvousing with it and recoupling to land. This avoids the penalty of lugging the aero gear any farther than absolutely necessary.

[dreamsofspace]

There have been a few SSTO's constructed, not lifting from Earth but lifting from the moon, as the LEV attained lunar orbit in a single stage

[Carey]

SSTO's have no inherent advantage other than minimizing debris or the number of parts that must be retrieved individually. The best staging design is dependent on the specific mission and the parts available. Sometimes the most efficient design is an SSTO sometimes its not.