What is the real use of an SSTO?

[Red Iron Crown]

I could see the appeal of an SSTO with a contract system. If you threw away a 747 every time it flew like you do with a rocket prices would be astronomical. I imagine budgets will make them very attractive.

All depends on how (or if!) reusability is implemented in the game.

[Duke23]

All depends on how (or if!) reusability is implemented in the game.

You can already land and refuel and use docking ports or KAS to reattach payload. In the budget system that equates to not paying for another plane / rocket and I imagine they'd also reimburse a certain amount for recovered parts / ships?

[Red Iron Crown]

Yeah, I realize that, I was just hoping that reusability could be represented in the game without messing around with ground crews (which I know some enjoy, but I find tedious).

[Duke23]

Yeah, I realize that, I was just hoping that reusability could be represented in the game without messing around with ground crews (which I know some enjoy, but I find tedious).

True. I kind of enjoy doing that but of course I would probably change my mind after 20 flights. That's why I'm hoping they will make an option to click a button if you're at KSC that would bring a menu for refuel and add payload, like VAB or spaceplane hangar but without the full cost of relaunch. If that makes any sense. There's really a lot of room to mod that portion of the game. Maybe I'm being a little wishful but it seems like a logical path...

[Hodo]

Try doing SSTO spaceplane in Realism Overhaul. I still cannot do that after a lot of testing

It is possible, but my best one could only haul at most 5 tons to orbit. I was on the cusp of building a better SSTO space plane but had a hard crash and lost everything including KSP, reinstalled KSP but didn't bother with RO.

SSTOs in KSP are useful they are quite useful. I use my SSTO line all the time for a great number of tasks, but my SSTOs actually haul more cargo then any rocket I can build.

[magnemoe]

True. I kind of enjoy doing that but of course I would probably change my mind after 20 flights. That's why I'm hoping they will make an option to click a button if you're at KSC that would bring a menu for refuel and add payload, like VAB or spaceplane hangar but without the full cost of relaunch. If that makes any sense. There's really a lot of room to mod that portion of the game. Maybe I'm being a little wishful but it seems like a logical path...

my guess is that we get an faction of cost back, hopefully high at spaceport. And lower if you land other places

[WeatherMAN]

This may be my own lack of reading into the subject, but as far as re-useability goes what prevents you from putting parachutes and trackers on the stages of a rocket and then recover the spent stages to be reconditioned and used again? I'm sure there is a little more cost with recovery than just having a space plane landing at your doorstep but how much more compared to the ability to get much larger payloads into space?

There is also the turn-around time to be wary of. I'm sure you could turn a space plane around much quicker than a rocket as all you need to do is inspect/replace the heat shielding from reentry so that is one solid advantage of a space plane over rockets.

I guess with 0.24 coming sometime I am just really interested in how much the real-world value of space planes are compared to rockets with re-usability and contracts/budgets in mind?

[rosenkranz]

SSTO's would be great and are pretty easy in KSP. It only takes 4500dV to get to orbit. If you're first stage has 5000dV, it has enough to get up, drop off the payload and land back at KSC in about 30min.

However, IRL, it takes 9500dV to get to orbit. For even small payloads, that would need a huge rocket. Getting something that big back down in one piece is likely going to be trickier than it sounds.

I think SpaceX's solution to the issue is genius. Since it's broken up into separate stages, none are too big to land intact.

[Wooks]

... I'm sure there is a little more cost with recovery than just having a space plane landing at your doorstep but how much more compared to the ability to get much larger payloads into space?

There is a huge difference in costs between launching a rescue / recover mission to bring back parts of the rocket scattered around and having a ship land at your doorstep ready to be used again after maintenance.

Imagine you want to make a trip to the grocery store in your car, but you need first to go out of your house to buy gas, then go back to your home and refuel your car, and then go out to find each tire, go back, put them on and then go out to find the keys that are out there somewhere... I think you see where I´m going, is easier to have a fully functional, always ready vehicle at your doorstep than having to assemble one new every time you need it.

By the time you recovered all the parts and assembled your vehicle, your neighbor with a fully functional car has gone to work, to the grocery store, visited some friends, the movies, out on a date and back home.

I think SpaceX's solution to the issue is genius. Since it's broken up into separate stages, none are too big to land intact.

I couldn´t agree more, for a first step into a fully reusable space program I think SpaceX is in the right track.

Edited June 2, 2014 by Wooks

[LethalDose]

I hope 0.24 doesn't provide an extreme price advantage to spaceplane SSTOs. I've tried them, and I hate them. I keep trying them, hoping I'll "get it", and I never do. I just feel like I wasted hours trying to make them work. They would almost be tolerable to use if landing them wasn't such a disaster. But it is, so they're not.

IMO, if spaceplanes do have any economic benefit, then the parts to build space planes (intakes, RAPIERs, Turbojet, etc) should be extremely expensive compared to rocket hardware, so the advantage of SSTOs is only gained after the initial cost of the space plane is amortized over a handful of launches.

It's probably not a popular opinion, but it's mine. I can do without the "well, I guess some people just don't like difficult games" responses.

[WeatherMAN]

There is a huge difference in costs between launching a rescue / recover mission to bring back parts of the rocket scattered around and having a ship land at your doorstep ready to be used again after maintenance.

I guess I meant difference relative to the cost of the project itself. The turnaround time I can understand, but it seems like you are giving up a lot of utility for a very niche vehicle.

Using your car example it seems like space planes are like vespa scooters - they can get you from point A to point B if you are alone and not needing to haul anything whereas rockets are more like trucks - they can haul you, your friend, your, all your stuff, and still have room for more. You give up MPG to gain a ton of utility. Yes the Vespa has a place but it seems much more niche. Maybe I am completely misunderstanding the utility of one in real life as well as KSP, and I'd love to hear more if you have information counter to my intuition

[Wooks]

I guess I meant difference relative to the cost of the project itself. The turnaround time I can understand, but it seems like you are giving up a lot of utility for a very niche vehicle.

Using your car example it seems like space planes are like vespa scooters - they can get you from point A to point B if you are alone and not needing to haul anything whereas rockets are more like trucks - they can haul you, your friend, your, all your stuff, and still have room for more. You give up MPG to gain a ton of utility. Yes the Vespa has a place but it seems much more niche. Maybe I am completely misunderstanding the utility of one in real life as well as KSP, and I'd love to hear more if you have information counter to my intuition

Think of commercial flights then, imagine you have to take a trip from New York to San Francisco, you board the plane with the other passengers, reach destination, and then the plane is put into a shredder by the airline, then they proceed to recover the fuel tanks and some other scattered pieces and then prodeed to reassemble the whole ship for its next flight. Imagine how much a plane ticket would cost. How much time between flights.

Here´s another analogy: Using a staged rocket to deliver crew and cargo to the ISS is like renting a semi truck to use it as a passenger taxi. Overkill all the way up to orbit.

Now speaking of a niche market, imagine a company that offers suborbital flights (lets call it, I don´t know, Virgin Galactic), and those flights can get to one side of the globe to another in less than 3 hours instead of 12 or 14. How many people would be interested in that kind of advantage?

The first company (or government, ha!) able to achieve a kind of reusable ship (spaceplane or rocket, or a combination of both) is going to kickstart the new era of spaceflight and exploration. It´s a complex idea to wrap ones mind around because we are accustomed to see rockets as the paragon of the space industry, and the Space Shuttle really wasn´t that great as a reusable program, I can understand that.

On a side note this thread is about SSTO (single stage to orbit) and not spaceplanes "per se", but the terms can be more or less swapped.

Edited June 3, 2014 by Wooks

[Red Iron Crown]

Now speaking of a niche market, imagine a company that offers suborbital flights (lets call it, I don´t know, Virgin Galactic), and those flights can get to one side of the globe to another in less than 3 hours instead of 12 or 14. How many people would be interested in that kind of advantage?

Judging by the track record of the Concorde, very, very few. People don't seem to be willing to pay much more for reduced travel times. As long as they can get to their destination in a day it's "good enough". Suborbital flight just takes too much energy, it will likely never be price competitive with conventional aircraft even if the maintenance and turnaround costs are similar.

[DivisionByZero]

One KSP-based benefit for SSTO and spaceplanes is that they don´t leave debris everywhere.

[The Error]

SSTOs, especially spaceplane SSTO, are _the_ single most stylin' way to get to orbit.

[Nibb31]

The efficiency of an SSTO plane comes from reusability. Every time you launch a rocket you lose the entire ship to deliver a payload into orbit, meanwhile an SSTO can deliver the payload and get back safely, and after being refueled and refitted it can launch again for a fraction of the time it takes to assemble a new rocket.

Picture this: How much an airplane ticket would cost if you had to throw away the plane after delivering the passangers? That is what happens with our current real life space programs, and that is why the private space programs are aiming for fully reusable ships.

KSP right now (remember we are still in Beta testing) has no "real" use of SSTO ships because contracts and costs are not implemented (as allmhuran pointed out), but when it happens the we´ll see how SSTOs fare against rockets.

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.

[R0cketC0der]

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, the mercury-atlas was 1.5 stage to orbit(it dropped some engines on the way up).

[Wooks]

SSTO simply means that you put the entire vehicle into orbit. It doesn't mean it's reusable or any cheaper.

I know, my first words were "The efficiency of an SSTO plane comes from reusability.", answering to a previous argument about spaceplanes on this thread.

SSTO and spaceplanes tend to get swapped around talking about this and is a normal occurrence, google "SSTO" and you´ll find spaceplanes abound in the top results... even some from KSP

[Wooks]

Judging by the track record of the Concorde, very, very few. People don't seem to be willing to pay much more for reduced travel times. As long as they can get to their destination in a day it's "good enough". Suborbital flight just takes too much energy, it will likely never be price competitive with conventional aircraft even if the maintenance and turnaround costs are similar.

Concorde belongs to a different time with different needs, a begone era. When it was retired the fleet had 30 years of service under it´s belt. Virgin Atlantic founder Sir Richard Branson (remember he is also CEO of Virgin Galactic) was interested in purchasing the Concorde from British Airways, but BA refused.

Let´s think a little bit further: FedEx and DHL (and many other global curriers) pride themselves in fast delivery around the world, the fastest, the better... hmmm.

Edited June 3, 2014 by Wooks

[Red Iron Crown]

Concorde belongs to a different time with different needs, a begone era. When it was retired the fleet had 30 years of service under it´s belt. Virgin Atlantic founder Sir Richard Branson (remember he is also CEO of Virgin Galactic) was interested in purchasing British Airways, but BA refused.

Let´s think a little bit further: FedEx and DHL (and many other global curriers) pride themselves in fast delivery around the world, the fastest, the better... hmmm.

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

[kidolvski]

When 0.24 comes out with contracts and costs, you will probably find that SSTO craft that can also land in one piece have the advantage of being cheaper, since throwing away spent engines and fuel tanks every launch is expensive.

I think you will be able to use parachutes to safely "land" spent stages, after which you can recover them.

[Cirocco]

I think you will be able to use parachutes to safely "land" spent stages, after which you can recover them.

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.

[WeatherMAN]

Here´s another analogy: Using a staged rocket to deliver crew and cargo to the ISS is like renting a semi truck to use it as a passenger taxi. Overkill all the way up to orbit.

Gotcha, so space planes are essentially useful for ferrying people out of atmo and into LKO/LEO on the cheap. That is their place, the niche they fill. Transplanetary trips or lifting a lot of weight is where the space planes lose out on their advantage over rockets. Correct?

[Jouni]

Let´s think a little bit further: FedEx and DHL (and many other global curriers) pride themselves in fast delivery around the world, the fastest, the better... hmmm.

Faster planes wouldn't make sense for the couriers with the current volume of shipments. There's almost never a plane departing at the right time for the right destination. International shipments often end up visiting several facilities on different continents, before finally reaching the destination.

[Laie]

With an SSTO you can land it back at the space center and the only cost is a little bit of refurbishing and refueling.

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.