Space Shuttles, For and Against

[Red Iron Crown]

STS-style Space Shuttles? Against.

There's basically no role for them that isn't better served by something else. A disposable rocket puts more mass into orbit for a given launch mass and at lower cost. A recoverable rocket still beats it on payload fraction and does even better on cost. An airbreathing SSTO beats it on fuel cost and recovery by a wide margin. STS-style is also way more difficult to design and fly.

About the only thing they can do marginally well is recovering things in orbit to bring them back to the surface, but that is an edge case and even then an SSTO or simple pod+cargo bay+claw+heatshield+chutes type craft does the same for less.

Build them if you think they're cool or just for the challenge, but don't kid yourself about them being efficient or cost effective.

[Frozen_Heart]

I enjoy using shuttles a lot in KSP. I even find them to be slightly cheaper if you can land the orbiter (not even remotely guaranteed...)

First one I built was in 0.18 and been using them since then. Had to rebuild when the old Mk-3 was removed though.

 

 

 

[RizzoTheRat]

If you're using the Construction Time mod I can really see the advantage of a shuttle to lift a large cargo bay to orbit with whatever payload you want.  In a standard game though I thing they're probably more of an interesting challenge than a craft I'd ever use out of preference.

I tend to use SSTO spaceplanes for passengers or small satellite launches but have never bothered with Mk3 cargo bays as my bigger stuff never fits in them, hence I've not really bothered with shuttles.

[Pax Kerbana]

Building a shuttle for Laythe. Other than that I don't have a use for them. The constraints of fitting modules into a cargo bay are significant. A vertical launch non-SSTO isn't very cost effective. Small cargo (the only type that can be placed into orbit with a shuttle) are very easy and cheap once you've got the S1 booster. The shuttle itself, if it is to be of any real use, must be large and will be more difficult and costly to maneuver. Total mission time is significant, requires long flight times and the inevitable "trying to hit KSP" on re-entry. There's nothing a shuttle can do that a rocket can't do better, except for crew and payload return.

SSTO crew planes however, with or without external liquid fuel drop tanks, are very efficient and worthwhile. Return for Kerbonauts is usually in a Mk1-2 pod, which is very easy, safe, and my preferred method... but is annoying for crews of more than three. So a 6 Kerbal plane with a Mk2 cockpit and Mk2 cabin is great for LKO. Add some jet fuel drop tanks and now you're talking easy.

A few days ago I was just fooling around with some wings and ended up making an amazing 18 Kerbal hypersonic SSTO in a near perfect V-shape with bottom ram scoops, just like a real one might some day. Now that thing is fun. Too bad I don't have a use for it. Imagine all the great things the world would have if we just had a use for them... someone please open the space market by opening a Moon resort. That's all we need... a decade after the first moon base there will be real plans underway for a Jupiter station. Because what wealthy adventurer wouldn't want to see Jupiter in person?! I wonder if there will be heated towels? Maybe at Spa Europa.

 

Edited May 10, 2016 by Pax Kerbana

[Basto]

38 minutes ago, Whiskybob said:

Wait Engineer can repair solar panels ?? Since when ?

I'm glad I am not the only person who noticed this!  

To the OP Engineers can repair wheels and repack chutes. Unfortunately they cannot repair solar panels. 

[suicidejunkie]

4 hours ago, Basto said:

I'm glad I am not the only person who noticed this!  

To the OP Engineers can repair wheels and repack chutes. Unfortunately they cannot repair solar panels. 

If you have Kerbal Attachment System installed you can at least bolt on replacement solar panels, and deorbit the broken ones.

[Speeding Mullet]

I couldn't very well be Shuttle Program Director and Admin (totally shameless plug alert) of the Shuttle Challenge v3 without putting in my 2 cents here.  Wear the badges be prepared to defend the badges I say

As @Red Iron Crown says they are largely useless from a point of view of efficiency or cost effectiveness when compared to other methods of getting to space.

OK so maybe that's not a good start to my "for" argument but I totally agree - There's many other designs I should pick to fly @inigma's 42t fuel pod to orbit, to lift the modules of my space station for on orbit assembly, heck even to land an asteroid (yes I've done that with my Buran).  But none have been so satisfying for me personally than designing and building a complex working shuttle and proving it with a series of increasingly difficult missions regardless of it's efficiency, limitations and various constraints.  Gliding into KSC from a re-entry in a shuttle, flaring up before touch down and deploying the drag chute to signal a mission well planned and executed is intensely pleasing.

In summary:  Whatever you think about the Shuttle Program(s) IRL, they were unbelievable engineering feats and if you can distil it to just that I think you will enjoy the challenge of refining a shuttle design and working with the limitations they mandate.  I've learnt a lot more about balance, aerodynamics, highly accurate re-entry, and packaging complex modules in confined spaces with designing shuttles than I have with designing rockets, and I've found as a consequence my rocket building has become increasingly refined, as have my plane building capabilities.

SM

[Choctofliatrio2.0]

Cons: Expensive, time consuming, tough to build, represents NASA's decline from the Apollo-era...

Pros: You built a space shuttle

[Enorats]

As others have said, they're just not that useful. They can do a lot of things.. but they can't do anything very well or efficiently. We never should have built them in the real world, and while the game is a bit different many of the same reasons still apply. In general it comes down to this.. why would you ever launch what amounts to a space station up to orbit just so you can launch a satellite? Just put the satellite on a vastly smaller rocket and launch it directly. It'll be far cheaper and easier.

Even if the shuttle (or even its boosters) are reusable, it just doesn't make sense. While KSP doesn't factor in vehicles aging and maintenance costs, it does still take vastly more fuel to get a shuttle and payload into orbit as opposed to just the payload. This is even more true if the payload alone is being delivered via a SpaceX style reusable system.

Space shuttles just don't make a lick of sense no matter how you look at them.

[G'th]

I don't particularly care for the system the real Space Shuttle used, mainly because its a pain to get it working properly and ultimately its finicky without countless amounds of tweaking.

 

What I do like, however, is a Dreamchaser style of shuttle, where the Orbiter is mounted on top of the rocket rather than bolted to the side of it. That much can be seen below in my short lived STS series. 

[MatttheCzar]

On 5/10/2016 at 8:03 AM, Basto said:

I'm glad I am not the only person who noticed this!  

To the OP Engineers can repair wheels and repack chutes. Unfortunately they cannot repair solar panels. 

Really?  I just assumed they could.

[KerikBalm]

Before the vecotr was introduced, I built a shuttle using the KR-2L as a main engine... the best I got with it was about 700 funds per ton to orbit... this required recovering the external tank, and landing the orbiter on the runway.

I then made a bigger version and crammed more payload in the mk3bay (and didn't place any components inside of it like my previous one which used some of the space in there for vital components. It came out to 576 fund/ton assuming 75% ET recovery... this barely beats disposable launchers which have been clocking in at 595/ funds/ton... although a mk3 cargobay is more versatile than those... the funds per ton goes way up if you don't fill the payload to capacity because the net costs don't come down proportionately with a payload reduction.

Then I made a flyback booster, using a little bit of airbreathing (afterburning panthers, mainly for landing)

That has some time critical switching between craft, but came in at 490 funds/ton to orbit, both sections land at KSC.... except I found I could have more fuel left over in orbit by skipping the seperation event and using the fuel that was reserved for the booster flyback.... it performed better as a SSTO rocket.

The best SSTO non-airbreathing rocket that I've seen comes in at 360 per ton.

My heavy cargo SSTOs, including the cost of a disposable fairing (that often seems to amount to 1/3 of total costs) comes in at about 200-250 per ton depending on payload (and significantly under 200 if the payload is streamlined and needs no fairing.

My smaller cargo SSTOs are all in the 100-200 funds per ton range

For bulk transport of material (ore/fuel) that needs no fairing/cargobay, and can be stored inline in the craft (although certain inline payload can be made ot work by releasing them and redocking craft sections), sub 100 funds/ton is possible.

Recoverable staged vehicles to orbit simply don't seem "economically" viable given the parameters in KSP.

They are harder to make than pure SSTOs or disposable rockets, they are harder to use.

They are however *fun* to try and make work. I make and test them in sandbox, but not in career mode.

[AeroGav]

The game is a tech grind not a money grind, in any case the costs of upgrading buildings vastly outweighs what you will spend on vehicles, so if you were power playing,  just spam satellite contracts for money and never land anything.  Then there's the fact that there are no other airports to land on,  the fact you can't recover stages or air-launch to orbit.  I could go on.

Back on topic,  recreating the STS is fun but makes no sense in career mode, because it requires  high tech level mark 3 fuselages, giant tanks and boosters, even vector engines.

This SSTO has 2200dv in orbit and can take you past minmus, it's only tech level 7.

That said, if you are going to build a shuttle, maybe it's easier to incorporate the LF tanks in the body and not have to worry about external tanks messing with your CG / symmetry.  These things are only vaguely economic in game because the SRB cost has been set so low.

TBH in career games, when i want to build a partially re-usable spaceplane, i tend to use this design - 

Those engines get dropped when they flame out, boo hoo.

In orbit, we can leave the airplane stuff behind while we fly the core fuselage to Minmus (had Kerbalism mod installed at the time, so was encumbered with a lot of life support).   We can dock with it again for re-entry.

[AeroGav]

Just going back to first principles to make sure i'm not missing any tricks, or potential other ways of doing re-usability -

SSTO  

Wings used for lift below 70km.  Become dead weight for deep space missions.

Air breathing engines used half way to space and carried as dead weight the rest of the way.

Space Plane  , staged

Wings used for lift below 70km.  Become dead weight for deep space missions.

Air breathing engines discarded when they flame out.

Air Launch to orbit 

Wings used for lift below 70km.  Become dead weight for deep space missions.

Air breathing engines are on the mother craft, so do not burden the orbiter.  Mother craft lands and is fully re-used, but difficult or impossible in KSC due to objects being deleted outside of physics range.

STS

Wings used for lift below 70km.  Become dead weight for deep space missions.

Gargantuan, disposable, but very low cost solid rocket boosters do the job of air breathing engines.

Rocket fuel tank is external and disposed of when empty in strictest recreation of the NASA Shuttle.

The liquid fuel engines however, are carried home.

 

Am i missing any other ways of bringing partial re-usability - with wings - to a space program?

[Renegrade]

Once I was inspired (or rather, de-inspired) by the painstaking NASA-like engineering hells that were showing up in twitch streams, so I built a rocket-plane of my own.  It was vaguely like one with two tanks for balance mentioned earlier in the thread, only mine had three tanks.  I placed 'em in three-way radial symmetry, with one centered on the bottom.  That placed the other two above the fuselage to the left and right of the vertical stabilizer.

I also combined the drop tanks with SRBs for hybrid-y action (with some careful fuel flow calculations quick data-entry into a tiny script so that the solid fuel and liquid fuel in the boosters would run out at roughly the same time).

I'm not sure which install it was in (it was in a FAR-based one for sure though), so no pictures - but it flew quite well.

Since I can't find a picture of it, here's another wacky plane just for giggles from roughly the same era:

(it was used for some sort of test, I forget what.  I wanted a long, one-piece fuselage, so I drained an SRB of fuel ...)

[Sereneti]

10 hours ago, AeroGav said:

Just going back to first principles to make sure i'm not missing any tricks, or potential other ways of doing re-usability -

SSTO  

Wings used for lift below 70km.  Become dead weight for deep space missions.

Air breathing engines used half way to space and carried as dead weight the rest of the way.

Space Plane  , staged

Wings used for lift below 70km.  Become dead weight for deep space missions.

Air breathing engines discarded when they flame out.

Air Launch to orbit 

Wings used for lift below 70km.  Become dead weight for deep space missions.

Air breathing engines are on the mother craft, so do not burden the orbiter.  Mother craft lands and is fully re-used, but difficult or impossible in KSC due to objects being deleted outside of physics range.

STS

Wings used for lift below 70km.  Become dead weight for deep space missions.

Gargantuan, disposable, but very low cost solid rocket boosters do the job of air breathing engines.

Rocket fuel tank is external and disposed of when empty in strictest recreation of the NASA Shuttle.

The liquid fuel engines however, are carried home.

 

Am i missing any other ways of bringing partial re-usability - with wings - to a space program?

Yes,
Spaceplanes with drop-tanks
-> compact desing
-> drop the cheap (empty) fuel tanks, save the expensive engines
-> less weight to aerobreaking.


Orbit-Launch:
The Spaceplane had the wings and the Air-breathing-Engines, bring the stuff to orbit, and land at the end ...
+ no dead weight on the deep-space-mission
+ Air breathing engines, do a lot of the work
-> possible in KSP , because things in orbit (>70km) wouldn't be deleted

Spaceplanes with JATO...
To small wing area to takeoff at low speed, and a to less Ttwr to get enough speed during the runaway (tldr - too short runaway) ,
+ Small wing area (less drag)
+ a small trust to weight ratio (less engines)






 

Edited May 16, 2016 by Sereneti

[AeroGav]

Quote

 

Orbit-Launch:
The Spaceplane had the wings and the Air-breathing-Engines, bring the stuff to orbit, and land at the end ...
+ no dead weight on the deep-space-mission
+ Air breathing engines, do a lot of the work
-> possible in KSP , because things in orbit (>70km) wouldn't be deleted

 

If I understand you correctly, that's what I was doing here.  Leave the wings etc behind in low orbit, separate the terrier engine, pod, and one small fuel tank big enough to hold the ship's remaining fuel, and lift only that part up to Minmus.

 

 

13 hours ago, Sereneti said:

Yes,
Spaceplanes with drop-tanks
-> compact desing
-> drop the cheap (empty) fuel tanks, save the expensive engines
-> less weight to aerobreaking.



Spaceplanes with JATO...
To small wing area to takeoff at low speed, and a to less Ttwr to get enough speed during the runaway (tldr - too short runaway) ,
+ Small wing area (less drag)
+ a small trust to weight ratio (less engines)



 

 

Drop tanks - I may revisit this concept, however you need to understand that the weight savings won't be spectacular because an empty mk1 fuselage tank only weighs 0.25 ton.  Full with 400 units of LF it weighs 2.25 ton.  A RAPIER engine weighs 2 tons exactly, a whiplash 1.8 and a panther 1.2 tons.

Drag -  I was under the impression that fuselage sections of the same diameter add very little drag when connected in line, it is the nose and tail of this stack that account for most of the drag.   So if you put stuff on drop tanks you are increasing the amount of noses and tails , or frontal area, that your craft has, at least until the drop tank is gone.   But I need to get some verification this is still true after the latest patch.  F12 menu, physics, aero debug, there's an option to show drag data on right click menus.  When i get some time i'll take FAR off and have a look at this.

Cost - the decoupler, nose cone, tail cone and possibly fuel duct that your drop tank is gonna need will bump up the cost a lot - to not far off the cost of a Panther engine.  Better tell the USAF quick, you've got a great money saving idea for them.   

JATO - my spaceplanes tend to have huge wings actually,  it helps hold all the liquid fuel they need for NERV engines.  They also allow me to keep angle of attack to  7 degrees or less above 25km and still get enough lift, i feel this improves drag/efficiency.

Spoiler

Jeb,  this thing had 5 engines on it when you took off !

 

That said, i can think of 2 cases for JATO.   The first is a marginal gain, the second might have a decent payoff, if it works.

First - launch vertically and save the weight of landing gear, and a tiny bit of fuel for t/o.   Put parachutes on the boosters, so long as they land on the runway before the plane flies too far away, they will be recovered.  On return from orbit, ditch in the sea next to KSC.

 

Second -  FLEA jump through the sound barrier !  My giant wings create a lot of drag if you try to go fast and low.    If you climb to 10km first, that's no longer the case.    But, RAPIER engines are very weak below mach 1.   At high altitude, they are even weaker if you're not going supersonic.   Also, they weigh 2 tons each, so i don't want the plane to have a lot of them as it's a lot of extra deadweight to be lifted to orbit.      Bring a flea, light it at 10km, go supersonic and suddenly we're in warp mode.    Of course, getting up to 10km will take forever and suck down a lot of fuel on the least efficient airbreather in game.  So,  put a drop tank on the front of the flea?   Subsonic, the drag won't matter.  Supersonic, it'll be gone anyway.

 

 

 

 

 

 

[nosirrbro]

Vertically stacked shuttles FTW!

Dreamchaser style

alot easier to build and fly, just as useful

[The_Rocketeer]

I see a lot of people talking about efficiency in KSP, and I'm left wondering how they ever have any fun in this game working on such a tight budget...

Shuttles. Are. AWESOME.

I am done.

[PointySideUp]

I love my SRB assisted shuttles!  Cheap, quick to orbit, and they can land or drift down with emergency 'chutes if necessary  

 

[Sereneti]

3 hours ago, PointySideUp said:

I love my SRB assisted shuttles!  Cheap, quick to orbit, and they can land or drift down with emergency 'chutes if necessary 

 

how did you manage to drop the MK2-parts?

 

Quote

Drop tanks - I may revisit this concept, however you need to understand that the weight savings won't be spectacular because an empty mk1 fuselage tank only weighs 0.25 ton.  Full with 400 units of LF it weighs 2.25 ton.  A RAPIER engine weighs 2 tons exactly, a whiplash 1.8 and a panther 1.2 tons.

That was the concept for the space-shuttles:
Drop the cheap tank, save the expensive engines...
A SSTO had a lot mor costs as a shuttle with drop tanks..

4 hours ago, The_Rocketeer said:

I see a lot of people talking about efficiency in KSP, and I'm left wondering how they ever have any fun in this game working on such a tight budget...

Shuttles. Are. AWESOME.

I am done.

With a spaceplane its mor easy to make an equatoreal orbit

thats the reason i prefer spaceplanes

 

 

 

Edited May 17, 2016 by Sereneti

[PointySideUp]

18 minutes ago, Sereneti said:

how did you manage to drop the MK2-parts

Two small blue decouplers and a few struts hold the crew cabin/drone core to the rest of the ship on each end.  Disable staging/Enable crossfeed and bind the decouplers to the "Abort" action group.  Then just offset everything back together smooth 

[STS Fallacy]

They're a whole lotta fun. Although you might call me a shuttle cheater, since I only use the Buran configuration - tried the STS one too, but found it too damn hard to balance properly - and the results were vastly inferior.

Here's one for illustration: 

Unfortunately, they're still vastly inferior to most rockets I've built to date, and SSTOs blow them out of the water. They're bad at everything - payload-to-orbit, cost, safety and manoeuvrability. But I'm having a blast launching them, so I use them anyway.

[Sereneti]

funn part:
I had made a shuttle with a drop-tank, that looks like a fish "<=><", so its a dubstep spaceplane...
.... it drops the bass...