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Shuttle on a plane?


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How hard / silly is the following concept in KSP? Anyone did such before?

shuttle-plane_2195519i.jpg

I'm not really sure what are the real-life benefits of this setup (while we are at it, I don't even know how it's called, so I could google it). I'm pretty sure that launching method has no ingame benefit, but looks fun enough to try. The weighting and the generally setting the plane so it could get high and fast enough would be a nightmare in itself. But my main question is if it's possible to set MJ to handle one craft long enough until I put the other to orbit (or a stable cruise). How would you do it?

Edited by Evanitis
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It is not possible. The moment the distance between the crafts passes 22km your craft in atmosphere will disappear. This will happen even if you have mechjeb or an ai controll unit. If you are asking if it is possible to do it by sacrificing the main craft sure it is actually quite easy to carry another plane. You can always add ejectable extra lift and aerodynamic surfaces for balance untill the crafts are separated.

There is one way to do it tho. And that requires the spacecraft to get out of atmosphere before the distance between crafts reaches 22km. You can switch to the airplane land it and switch back to the spacecraft to complete the orbit.

Edited by n0xiety
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As far as I know, that setup was only for glide testing, and possibly transportation between sites - never a powered launch

That kinda' explains why this solution looks so unviable in KSP. Though good to know that there is a mod for making it possible. I'll totally get that shuttle to orbit from a jumbo-jet... one day, on a very boring weekend. :D

EDIT:

Found a related image, thought I share it here. It feels Kerbals aren't the only silly people doing space-stuff.

20090524_shuttle_mounting_point-620x516.jpg

Edited by Evanitis
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For the IRL details:

The aircraft a modified 747-100 and was officially called the "Shuttle Carrier Aircraft". As mentioned above, it was used for glide testing the "Enterprise" orbiter (A STS prototype that never flew into orbit) and transporting shuttles from Edwards to Kennedy/Canaveral.

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(while we are at it, I don't even know how it's called, so I could google it)

"Composite aircraft." There have been some interesting attempts over the years, some more successful than others. One involved turning an entire bomber into one massive cruise missile, steered from a fighter-bomber strapped to the top.

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I did something like that when I couldn't yet get my space plane to orbit. I'd get into space, then get the satellite into orbit asap and then switch back to the plane in time. I usually needed several save/load tries for that. It is a pain in the ass.

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It is certainly possible to do, but as mentioned, it will eventually unload one of the two craft.

But if you have Netflix and want to watch some cool stuff with that setup, there is a great short documentary called Shuttle Discovery's Last Mission where they show how they get in on the plane and also how to get it back off in a place that wasn't designed to do that.

hgNbASv.jpg

Edited by Alshain
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Doable but difficult.

First, you'd need to separate at some 22km; that's a difficult altitude for a plane to fly. Then you need to accelerate the shuttle enough to enter orbit (or at least take a long time to re-entry) and quickly switch to the plane before it dips below 22km. Glide the plane to safety, then switch to the shuttle and finalize your orbit.

It's much easier if you consider the airplane disposable. A ramjet-powered first stage is a very good idea. (just yesterday I made my first orbit with such a setup; very cheap and simple. Three RamJet engines on a tricoupler + 6 circular air intakes as the first stage, Nuclear engine as the second stage, payload/lander as third. The optimal trajectory is vastly different from common rockets. Instead of a parabolic path, you make an "S"-turn.

gZJTtEt.png

You rise to some 10-15km, then turn the path horizontal. The ramjet gradually increases speed; at certain point its speed starts to grow exponentially and if you stay so low it will burn you up. So, if you reach some 800m/s (point 1) start turning upwards. By the time you reach point 2 (altitude nearing 30km), your speed will reach some 1200m/s or more and you'll have quite a few overheat bars all over. That's also about when your ramjets will sputter out, and you'll need to switch to rockets (and you may dump the ramjet stage or separate the airplane). From then on, continue ascent and circularizing the orbit. Also, at that altitude the nuclear rocket already has the best ISp of all (maybe save ion), and unlike on ground level, it is a superior means of acceleration.

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As people already said, this is the Shuttle Carrier Aircraft, and it was never used for orbital launches. However, the concept has been explored over time - the X-15 was launched from the wing of a B-52, and there is a rocket called Pegasus- basically a giant three stage cruise missile with wings that launches to orbit from the cargo bay of a jet plane. Neither of those are exactly this concept, but Meh, close enough :P

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As people already said, this is the Shuttle Carrier Aircraft, and it was never used for orbital launches. However, the concept has been explored over time - the X-15 was launched from the wing of a B-52, and there is a rocket called Pegasus- basically a giant three stage cruise missile with wings that launches to orbit from the cargo bay of a jet plane. Neither of those are exactly this concept, but Meh, close enough :P

A better example would be Spaceship One, which was almost exactly this.

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I'm more interested in the end cap of the shuttle. :rolleyes:

Anyway, I've tried to do it back in .25 with little success, so it will be hard, but not impossible.

That cap is for aerodynamic purposes during transport. the engines are too draggy otherwise.

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StageRecovery mod

Essential IMO for making doing career mode properly, allowing recovery of lower stages that pass out of the physics bubble.. assuming they'd actually survice the descent, that is (ie you still need chutes or enough fuel & active engines if you want to simulate a powered landing).

In this case though, even that wouldn't really work since this would be coming in for an aircraft landing which I don't think StageRecovery can really handle very well..

If you want to though, the way I usually achieve the effect of that sort of launch is to build the shuttle section, then use decouplers to add your 'atmoshperic components'.. radial decouplers around the middle somewhere to bolt wings on, some jet engines, intakes, and fuel mounted to them... similar idea with an in-line at the rear for engine/tail surfaces and even a nose-cone or intake for the front.. Slap 'enough' chutes on each bit so it'll just float back down once its jettisoned (set the minpressure up a little so they don't open while in 'Fiery Phoenix' mode) and you're good. I launched my space station to Minmus like that.

It's probably easier though (for anything other than really physically big payloads) long-term to add some rocket engines and fuel to the launch plane itself and turn it into an SSTO. Your payload then can be focused solely on the mission task without having to worry about launching and atmospheric flight. You then have a single launch vehicle with a standard launch profile you can follow to put your payloads into orbit, which is what the shuttle is really all about anyway. The 'Shuttle Piggy-back' idea there (the Russian An-225 was built with that specific purpose in mind, hence the dual vertical stabilisers out in 'clean air' either side of where their shuttle sat) is really about transporting the shuttle more than launching it... I'd suspect that with the relatively low speeds of the transporters and without its external fuel tank & boosters, the shuttle just doesn't have the dV to do anything significant from that sort of launch.

So yeah.. you'd need significantly more performance out of your launch vehicle.. right up to the limit of atmospheric flight, which in current versions is around 1km/s somewhere between 20-28km or so, and you still need a big chunk of dV from there to LKO.. Enough that carrying the extra weight of that 'atmos' gear probably isn't the best way to go.

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that wouldn't really work since this would be coming in for an aircraft landing which I don't think StageRecovery can really handle very well..

I can handle the landing if StageRecovery can grant me just a few minutes of flight until I put the shuttle to orbit. Got too much to do these days to test if the mod works that way. Will do in the near future I guess. Otherwise I should settle with a disposable plane as others suggested.

build the shuttle section, then use decouplers to add your 'atmoshperic components'..

Yeah, one of the first thing I did when I tried KSP and got bored with the standard rockets back in the 0.2 days. I'd say it's too easy.

turn it into an SSTO.

Had and still having my share of SSTO fun, but thanks anyways.

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I can handle the landing if StageRecovery can grant me just a few minutes of flight until I put the shuttle to orbit. Got too much to do these days to test if the mod works that way. Will do in the near future I guess. Otherwise I should settle with a disposable plane as others suggested.

All it really does is throw some calculations around when the part is unloaded to 'simulate' the rest of its descent. Rather than just have it go poof as happens in standard, it'll work out what sort of impact speed it would have and if it's slow enough it'll give you back (a configurable proportion if, if you want to "simulate wear") the part costs minus the usual 'distance from KSP' recovery cost.

So it won't really "give you time to land it" as such. If you think about it, you'll need to keep both craft within the same physics bubble, which means 22km. Let's be generous and say your launcher can maintain a 25km altitude. That means your shuttle can get to 47km. That's two craft, and they're both still in atmosphere. As soon as the one you're not controlling moves outside that, it's gone.

So no, I don't see a way you can do it like that.

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There is (or at least there was back in 0.90) a way to actually reproduce it the same way it should be without mods, I've seen it done around here but I could not remember who was the designer. It was tricky but not to hard to execute so with some tweaking it might still be doable.

Btw, the design used was a very nice spaceship one/white knight mock; he went for an almost vertical climb on top of the KSC up to 75000m with the carrier, he released the ship for the suborbital flight and swiftly turned 180° to land back at the KSC before the ship reentering the atmosphere, preserving both crafts.

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If you can get both craft out of the atmosphere - even if they're not circularised, it can work. The physics bubble is only applied in atmosphere, otherwise it just slaps the craft on rails and follows an orbital path (even if that orbit dips into the atmosphere). The difficulty is in getting that carrier craft into space. With the current aero and jets.. you could perhaps massively over-engine your craft and blast pretty much straight up at 1200m/s at 20km and hope to carry enough speed to get up, but you'd face a massive circularisation burn once you got to space with almost none of that gained velocity being carried over.

You're basically using it like a rocket with no gravity turn, so you may as well dispense with the wings (they're just drag & weight, in that case) and just slap a few chutes on it and think of it like a jet first stage, that's much closer to what it's doing.

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There is (or at least there was back in 0.90) a way to actually reproduce it the same way it should be without mods, I've seen it done around here but I could not remember who was the designer. It was tricky but not to hard to execute so with some tweaking it might still be doable.

Btw, the design used was a very nice spaceship one/white knight mock; he went for an almost vertical climb on top of the KSC up to 75000m with the carrier, he released the ship for the suborbital flight and swiftly turned 180° to land back at the KSC before the ship reentering the atmosphere, preserving both crafts.

That's an idea worth trying. I have used jet engines to escape the atmosphere before, and I have had time to recover boosters after circularising orbits with my current heavy lifters, so it sounds like it would work.

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