Where are the rocket SSTOs??!!

[lammatt]

because planes look cooler.

[Spatzimaus]

My own SSTO, as shown many times before, is the Brick-41 (so named because it's 41 stacks of 3.75m rockets, linked together radially):

Launch mass 12000 tons sans payload, with a max delta-V of about 5600m/s and a TWR of about 1.8 fully fueled. It can put a 1000-ton payload into a circular 75km orbit and de-orbit itself afterwards. In the above shot, it's launching a 1.4-ton ion probe (seen in the center), but I use it mainly to lift my 900-ton station. I've got smaller versions for smaller payloads, all with the same basic design; the Brick-21 can easily handle my 300-ton fuel depots, and the Brick-9 can manage pretty much anything under ~200 tons.

Here's the thing. An asparagus design would have a much higher efficiency, no question; the same 12000-ton setup with asparagus could probably lift twice as much payload. But the SSTO Brick design has a few major advantages:

1> No debris at all. No dropped stages on the way up, nothing left in orbit. The whole thing disintegrates upon re-entry, and once we get an economy I'll add parachutes for recovery. Really, the lack of debris is a huge benefit, and is the main reason I chose this path.

2> The effectively "flat" top surface of the stacks makes an excellent platform to hold awkward payloads in place, since you can strut from the side stacks easily. The whole point of the design was to launch things like the aforementioned station, without the need to dock components in orbit to assemble a large station. With asparagus you'd be losing those side stacks on the way up, which'd make it impossible to strut to them for the final maneuvers.

3> It's really, really easy to launch. You just need to slowly tip over as you go, and keep the throttle at terminal velocity (I use the Engineer mod for this, but I used to eyeball it). No screwing around with separating stages, which also means no possibility of disastrous collisions along the way. This also helps if you're launching something with a high part count, as the lag doesn't really hurt much.

4> The part count is surprisingly low given its sheer size (~700 for the Brick-41) since there are no radial separators, fuel lines, etc. in this sort of setup. The smaller versions have much lower counts; the Brick-9 has about 150-200 parts, which keeps lag manageable.

These sorts of SSTO boosters are all I ever use these days, except when I'm playing with my spaceplane (which is just more fun to launch).

Edited June 30, 2014 by Spatzimaus

[hempa2]

My own SSTO, as shown many times before, is the Brick-41 (so named because it's 41 stacks of 3.75m rockets, linked together radially):

http://i.imgur.com/VVWXaI9.png

Launch mass 12000 tons sans payload, with a max delta-V of about 5600m/s and a TWR of about 1.8 fully fueled. It can put a 1000-ton payload into a circular 75km orbit and de-orbit itself afterwards. In the above shot, it's launching a 1.4-ton ion probe (seen in the center), but I use it mainly to lift my 900-ton station. I've got smaller versions for smaller payloads, all with the same basic design; the Brick-21 can easily handle my 300-ton fuel depots, and the Brick-9 can manage pretty much anything under ~200 tons.

Here's the thing. An asparagus design would have a much higher efficiency, no question; the same 12000-ton setup with asparagus could probably lift twice as much payload. But the SSTO Brick design has a few major advantages:

1> No debris at all. No dropped stages on the way up, nothing left in orbit. The whole thing disintegrates upon re-entry, and once we get an economy I'll add parachutes for recovery. Really, the lack of debris is a huge benefit, and is the main reason I chose this path.

2> The effectively "flat" top surface of the stacks makes an excellent platform to hold awkward payloads in place, since you can strut from the side stacks easily. The whole point of the design was to launch things like the aforementioned station, without the need to dock components in orbit to assemble a large station. With asparagus you'd be losing those side stacks on the way up, which'd make it impossible to strut to them for the final maneuvers.

3> It's really, really easy to launch. You just need to slowly tip over as you go, and keep the throttle at terminal velocity (I use the Engineer mod for this, but I used to eyeball it). No screwing around with separating stages, which also means no possibility of disastrous collisions along the way. This also helps if you're launching something with a high part count, as the lag doesn't really hurt much.

4> The part count is surprisingly low given its sheer size (~700 for the Brick-41) since there are no radial separators, fuel lines, etc. in this sort of setup. The smaller versions have much lower counts; the Brick-9 has about 150-200 parts, which keeps lag manageable.

These sorts of SSTO boosters are all I ever use these days, except when I'm playing with my spaceplane (which is just more fun to launch).

That rocket... Just asking to myself, where are the krakens!

[Raven.]

People do make them. They are just uncommon.... probably from the modest payload compared to a staged craft.

Some people have jet-assisted SSTO rockets too. Which I think are underappreciated.

I've played around with both. The jet-assisted SSTO rockets, in my personal experience, have their biggest value in delivering small payloads, such as Kethane probes and RemoteTech 2 comm sats. I've had very little success with jet-assisted rockets on a larger scale, especially since my shuttle fleet can lift a much heavier payload faster and higher. I got one shuttle that's been lifting 40-50 ton, 2.5 m payloads to 500 km orbits with fuel left to spare. And everything except the SRBs is reusable. So it's extremely difficult for to justify a jet-assisted SSTO rocket unless it's a very small payload. Especially when budgets is about to be introduced and when my shuttles can outperform it.

Now, what I've had very promising success with, is the reusable first stage similar to what SpaceX is doing, both on a small scale and a large scale. This last weekend I played around with a reusable first stage using the new 3.75 m stock parts, and was able to perform a deorbit burn, reentry, a safe landing, and a full recovery. This has the advantage of having some re-usability, like what you would have with a SSTO, but it still has the payload capacity of a staged rocket.

I am personally not a big fan of spaceplane SSTOs for multiple reasons. The biggest reason is that a NASA style shuttle that's designed correctly and designed well will outperform most (but not all) spaceplane SSTOs.

[SofusRud]

Single-Stage-to-Laythe rocket y'all!

[iClarion]

I'm brand new to this forum, and I saw this thread and decided to make a ship I've been thinking about for a while

It's a rocket-style SSTO crew transporter. I call it the "TransKerb". It uses 4 Rapier engines, 1440 units of jet fuel (the tanks are split like that to make oxidizer levels more precise), and 8 radial air intakes. I can just barely get it into a 75k orbit, so it's fun to fly! 70k is pretty guaranteed, but my station is at 75k.

[Whackjob]

At last I can reveal my contribution. It's the rocket from the Kerbal Cup challenge #3:

From ground to orbit in a single stage. Would need refueling to get elsewhere.

[Tortoise]

Almost all my rockets are SSTOs xD.

But I don't use too many plane sstos

[Jouni]

I think a major difference is that I use FAR & DER. I probably should have said "In my experience, landing rockets like that is a nightmare." I've tried landing these with RAPIERs and 'chutes, it just never seems to go well. And the efficiency issue remains with vertical thrust. It took me quite a while to figure out how to land aircraft with FAR, but it goes much easier now that I figured it out, at least on the KSC runway. I still can't land on that d@mned island.

I haven't really tried jet engines with FAR and DRE, because I don't like the way they currently work.

That said, I just rebuilt my crew shuttle from 0.23 and tried it with FAR and DRE installed. I needed a steeper ascent profile and a shallower reentry, but otherwise the thing worked fine. Two parachutes almost burned during the ascent, because I had to maintain a high angle of attack, and the landing struts heated to almost dangerous levels during the reentry, but the shuttle survived in one piece.

[Tortoise]

In my experience, jet-boosted rockets are the easiest choice for precision landings. The lack of wings makes atmospheric reentry safe and easy with stock aerodynamics. Jet engines allow you to reach the intended landing zone. In the final landing sequence, parachutes are used to kill the horizontal speed and to keep the vertical speed below 20 m/s, while jet engines slow the rocket down to a safe landing speed.

http://www.cs.helsinki.fi/u/jltsiren/stuff/ssto_tanker_2.jpeg

Pure rocket SSTOs are a bit harder, because you can't fly around looking for a good landing zone.

http://www.cs.helsinki.fi/u/jltsiren/ksp/ssto_lifter_8.jpeg

But an SSTO is doesn't mean it has to be reusable, it simply means that it only uses one stage until it gets into orbit.

[hempa2]

But an SSTO is doesn't mean it has to be reusable, it simply means that it only uses one stage until it gets into orbit.

Your right Tortoise

[GoSlash27]

It works! My new Tylo rover can can reach 80km orbit in a single stage, deorbit burn, land without parachutes, and drive home.

I put a link to the download in the stock vehicle section.

-Slashy

[magnemoe]

But an SSTO is doesn't mean it has to be reusable, it simply means that it only uses one stage until it gets into orbit.

Granted it would be pretty pointless if it can not land, yes its exceptions, I once made an kethane miner who could reach orbit but not land, this was on purpose as I would refill it before going to Minmus.

objective was something who could land and take off on Laythe and could land on a kethane deposit on Tylo, mine and take off again.

[CptRichardson]

I see a ton of SSTOs on the forums, and almost none of them are rockets!

Whats wrong with rocket SSTOs, why use plane 100t to orbit when you can rocket 100t into orbit?

Rockets will be more expensive. Putting a plane on a rocket shuttle-style SUCKS and is a hyper-pain to do. Sticking a plane on the very tippy-top of a rocket involves lots of 'augh!'-isms.

[SciMan]

Putting a plane on a rocket is actually harder than putting two planes on one rocket, because of the unbalanced aerodynamic loads. Of course, you need a bigger rocket to get the same dV with two planes, but in KSP that seems to be a lot easier to deal with than unbalanced aerodynamic loads.

[RoboRay]

It's been posted here before, but here's my latest heavy-cargo rocket SSTO:

Javascript is disabled. View full album

Do runway landings count?

If not, I also did a Delta-Clipper inspired passenger-hauler last year...

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[Vindelle_Sunveam]

Snip/

-Slashy

What kind of dark magic is that ? I have no idea of what you may have done, let alone how it works D:

[Tortoise]

Granted it would be pretty pointless if it can not land, yes its exceptions, I once made an kethane miner who could reach orbit but not land, this was on purpose as I would refill it before going to Minmus.

objective was something who could land and take off on Laythe and could land on a kethane deposit on Tylo, mine and take off again.

If you can get your rocket into LKO on one stagr instead of dropping multiple, why not?

And there isn't any current benefit on ksp to make rockets be able to land back at ksc. All you're gonna do is recover it (but you could still fly the rocket again if you never recovered it)

[LethalDose]

But an SSTO is doesn't mean it has to be reusable, it simply means that it only uses one stage until it gets into orbit.

Right, but SSTO's are typically reusable. If you aren't designing them to be reusable, you're sacrificing the efficiency gained by staging for nothing.

[Tortoise]

Right, but SSTO's are typically reusable. If you aren't designing them to be reusable, you're sacrificing the efficiency gained by staging for nothing.

That's true.

[Pecan]

SSTOs have several advantages over multi-stage designs: lower part-count, simpler build, usually cheaper because of those two and, possibly, easier reusability.

[Spatzimaus]

If you aren't designing them to be reusable, you're sacrificing the efficiency gained by staging for nothing.

Not true at all. We've already discussed this many, many times; even a throwaway SSTO has several advantages over multistage designs. No debris. Easy to launch (no staging, just tilt over and tweak the throttle). Much better at holding awkward payloads since you can strut to any part of it, instead of having to work around the parts that'll be discarded. Lower part counts. Less chance of critical failure during a launch, where a booster doesn't separate far enough and knocks your engines off. The list goes on; there have been many threads about this.

The key is that with rockets, there's no downside to going bigger. The only advantage multistage designs have is efficiency, where they can lift a higher payload fraction into orbit. But all you have to do to get around this is use a bigger booster, and the VAB is big enough that it can hold an SSTO capable of lifting thousands of tons along with a large, complex payload, so there's just no point in making complex multistage designs when you can just attach a simple SSTO setup with ease. These days, I almost never use multistage boosters, because it's just not worth the headaches; I've got a stable of a half-dozen SSTO rockets I use instead, with the largest being the one I posted a couple pages back.

Now, once they put an economy in this'll change, since there'll be a downside to just going bigger, but at that point I'll put the effort into making them recoverable. But at present, there's little reason to NOT use SSTOs.

[problemecium]

I agree with this thread. I'm actually getting ready to publish a launcher pack, but in the meantime here's my crew shuttle:

[Geschosskopf]

The key is that with rockets, there's no downside to going bigger. The only advantage multistage designs have is efficiency, where they can lift a higher payload fraction into orbit. But all you have to do to get around this is use a bigger booster, and the VAB is big enough that it can hold an SSTO capable of lifting thousands of tons along with a large, complex payload, so there's just no point in making complex multistage designs when you can just attach a simple SSTO setup with ease.

I myself very frequently use SSTO rockets, especially when using FAR. It likes long, tall rockets, it really doesn't appreciate having radial boosters mounted low, etc. And FAR lets you get to orbit with less delta-v than stock so the efficiency issue is less of a thing. However, there are 2 things to keep in mind with rocket SSTOs.

1. Turning to Circularize.

The longer the rocket, the bigger its moment of inertia in pitch and yaw. With an SSTO rocket where you've still got the whole thing up in space, and with aerodynamic control surfaces now useless, it can sometimes be difficult to get the rocket reoriented for the circularization burn before you pass Ap. Torque simply ain't up to the job, you also need RCS. And the bigger the rocket, the more RCS you need. For big SSTOs lifting big payloads, I frequently have to put like 3 sets (of 4 each) RCS blocks on each end to get the thing to turn in a reasonable time.

2. Burning to Circularize

For really massive payloads, SSTO rockets need an UNGODLY amount of thrust to lift the weight of the ocean of fuel they need. But when you get up to Ap and want to do the circularization burn, the rocket weighs much less due to having burned most of its fuel. But its thrust is still the same, so its TWR is now off the scale. The TWR is so great, in fact, that often if you just slam the throttle all the way on for this burn, the sudden G force will break something. So you have to ease into the circularization burn.

[LethalDose]

Not true at all. We've already discussed this many, many times;

I don't recall discussing this with you, ever, but okay.

even a throwaway SSTO has several advantages over multistage designs. No debris. Easy to launch (no staging, just tilt over and tweak the throttle). Much better at holding awkward payloads since you can strut to any part of it, instead of having to work around the parts that'll be discarded. Lower part counts. Less chance of critical failure during a launch, where a booster doesn't separate far enough and knocks your engines off.

SSTOs have several advantages over multi-stage designs: lower part-count, simpler build, usually cheaper because of those two and, possibly, easier reusability.

Alright, you both make good points about advantages I had not considered, mainly lower part counts and simpler builds. I find handling massive stages in orbit a chore and work to really build "down" my orbital stages instead of building "up" my launch stages. Therefore I tend to choose efficient designs that push smaller payloads instead of bigger designs that push payloads harder. different play-styles.

I don't see how using larger engines and more fuel is somehow cheaper. That arguement doesn't seem to hold water.

I very rarely have boosters damage the parent vessel, but since it is possible I suppose it's an advantage.

I put "awkward payloads" under fairings, so that's less of an issue for me.

Debris is much less of an issue if you reduce the amount of derbis allowed in settings.