sevenperforce

Design Challenge: Orbital Shuttle

79 posts in this topic

27 minutes ago, sevenperforce said:

Are the drop tanks recoverable?

They looked like they were probably expendable, but that's not the design I'm going for.

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8 minutes ago, eloquentJane said:

They looked like they were probably expendable, but that's not the design I'm going for.

Interested to see what you come up with!

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Sorry for no pics on previous post, I was replying from my phone and I had no regular internet due to inclement weather.

Anywho, here's what I call the Double Shuttle

J9RsLLm.png

S5aFALH.png

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tLd1xS1.png

I'll have to tweak the booster stage so that it doesn't act like a lawn dart, the orbiter easily makes orbit and can take a big orange or a crew module or whatever.  I've included Monoprop OMS engines in case the payload requires all the LFO to be used on orbital insertion.

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6 minutes ago, Thor Wotansen said:

Sorry for no pics on previous post, I was replying from my phone and I had no regular internet due to inclement weather.

Anywho, here's what I call the Double Shuttle

I'll have to tweak the booster stage so that it doesn't act like a lawn dart, the orbiter easily makes orbit and can take a big orange or a crew module or whatever.  I've included Monoprop OMS engines in case the payload requires all the LFO to be used on orbital insertion.

Brilliant!

That's called a "biamese launch" and it's quite promising for a lot of reasons. There's even a more advanced version, known as a "triamese launch", spearheaded by the UK's MUSTARD design:

MUSTARD-Britains-Space-Shuttle-w800-h600

The outside vehicles separate and return to a glide landing while the center vehicle continues to orbit:

Air_PK_Mach%2020_EE%20MUSTARD%20separati

With aggressive crossfeeding, the mass ratio for these kinds of designs is ridiculously good. But when this design was created, back in the 60s, reliable crossfeed technology wasn't really within reach.

I'd be interested to see a biamese concept that can make use of propulsive landing or perhaps even partial airbreathing.

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I don't have radial mounted engines?

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11 minutes ago, Andetch said:

I don't have radial mounted engines?

Oh, shoot. There weren't any closeup photos of the boost phase so I assumed the radially mounted tanks visible on the pad were engines.

This wouldn't count as parallel staging. The upper-stage engine needs to fire on the pad.

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As I said, it was my standard bus launching, with the added chutes on the lower stage. The whole upper thing comes back and lands whole. I guess I can modify it some.... Watch this space (and YAY, something to do with KSP rather than trying to take my spaceplane all the way around and back to the runway by hand... on attempt 376, done it once....).

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So here is the reconjiggered design. With the added bonus of the fact that the first launch failed due to thrust misconfiguration, and that the escape facility worked just fine! Sadly on my way into orbit the laptop failed due to screenshots again, but I now have boosted the laptops cooling fan capacity using a desk fan I found so should be okay for another run - posting what I have here again.

The last photo shows separation of the first stage LF tanks okay, and I confirmed that the next tank hanging underneath was draining (being pumped up) and am confident the upper stage would have reached Minimus just fine...

As for recovery of the SRB stage, I would love if unmodded KSP would allow it, but it doesn't unless it reaches sub orbit, which I doubt it will however it is carrying a core, reaction wheels, coms and batteries.

http://imgur.com/a/M5e4D

BLtZrrq.pnguqPWFVJ.pngEDhoqeX.pngWMBlWFe.pngaCe4uY1.pngQWAk9Wg.pngam8odq3.png09sad60.png2IKVJkr.png

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Looks great! Can I see it on the pad?

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1 hour ago, sevenperforce said:

Looks great! Can I see it on the pad?

I will add that photo to the gallery. I suggest people look at the gallery as I don't wanna chug up the board with too many pics, but... epic mission, ending in laptop failure again :(

Gallery

http://imgur.com/a/Hw0ii

Ship

https://drive.google.com/open?id=0BxP5XMEnEjPiNkJrWG81RFpqSEE

I launched the ship into LKO, successfully recovered the SRB stage after suborbital flight albeit with a little damage. (Laptop crash, reboot), back to main ship, go to minimus, land on minimus, refuel in minimus orbit going to the tanker - it is important to me that tankers do not have to move from their parking orbits (not full as I went to the wrong tanker silly me), due to the fuel issue I did a Mun flyby and then back to KSC. Landing very close to KSC on the grasslands... *takes screenshot - laptop crashes. Below are highlights

pmZNImf.pngx1VGoc7.png0DA4v1W.pngDHT8wVi.pngV5AAWLh.pngYW33YIS.pngYqi7HaO.pngNEMFpFl.png5HnjQIM.pngT4wOXve.pngutGpB3u.pngwD89Iu1.png

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Posted (edited)

I've had to alter my plans somewhat. I had intended to design a shuttle which launches on the back of a bigger spaceplane (launched vertically, both of them rocket-powered with auxiliary jet engines for landing). This proved to be too complex for what I was going for (I could've achieved it but it was taking too long and I am not patient enough to design something like that in a single sitting), so instead I've opted for a Buran-style launch on the back of a rocket that bears some similarity to the Falcon 9. I still have some testing to do before I show it, but the basic design works well.

Edited by eloquentJane
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I have added the finished landing of The Holy Grail near KSC shot, although further away than my 1st attempt :(  note I have marked the KSC with a scattering of debris to make it easier to find :D

Also

2 hours ago, sevenperforce said:

Looks great! Can I see it on the pad?

fXsB3cJ.png

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Looks fantastic! Thanks for all the pictures.

Now I'm wondering if something like this would be possible IRL. It would definitely avoid the off-axis thrust problems that tend to plague parallel-staged orbiter designs. 

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I can speak for the off-axis thrust problem, my design wouldn't be possible without Vectors.

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17 minutes ago, Thor Wotansen said:

I can speak for the off-axis thrust problem, my design wouldn't be possible without Vectors.

Thrust-balancing is what tends to confine shuttles to the late-game. The least amount of engine gimbal range I've managed to successfully make a shuttle with is still 5 degrees of gimbal (with SpaceY's Moa engine, which was vastly overpowered for the size of the shuttle). It's possible to get very good balancing of thrust if you can make a design where the center of mass barely changes, but it's also incredibly difficult to do that without placing the orbiter atop the main booster stack.

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14 minutes ago, eloquentJane said:

Thrust-balancing is what tends to confine shuttles to the late-game. The least amount of engine gimbal range I've managed to successfully make a shuttle with is still 5 degrees of gimbal (with SpaceY's Moa engine, which was vastly overpowered for the size of the shuttle). It's possible to get very good balancing of thrust if you can make a design where the center of mass barely changes, but it's also incredibly difficult to do that without placing the orbiter atop the main booster stack.

I've toyed with adjusting the thrust limiter of one engine in-flight to produce thrust balancing via differential thrust. It's possible, but very difficult to do.

The US Space Shuttle was not particularly aerodynamic; the line between the center of thrust and the center of mass ran through the side of the External Tank, not through the top of the stack. It practically flew sideways. That's why Challenger broke apart; when the SRBs disintegrated and the External Tank came off, the orbiter was so far from a prograde heading that the aerodynamic forces shredded it.

Still, if you are going to stick to a single separation event rather than an asparagus approach, it's what you've got to do.

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I'm thinking of trying to make a "dragster" style design, with the boosters being mounted above a spaceplane to keep it stable.  I'm thinking of something like quad or tri dual big orange and a twin boar boosters, all connected together with a frame (separate ones might exceed 20km away while landing) and semi-propulsively landing with parachutes to keep it pointed in the right direction.

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I've discovered that MechJeb has a "differential throttle" option as one of its utilities. My shuttle works well enough without it but I imagine it'll be helpful for some larger payloads.

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I have another design too! Although, not sure if it counts. Only got one picture of it, just after the separation....  It involves one central fuel tank, with a core, battery and chutes, and four radially mounted orbital runabouts, complete with chutes for a landing. It is designed for 4 Kerbals on a space flight come death pact. It launches on the engines from the runabouts (the central tank has no engine) and is damned hard to get to crossfeed enough fuel from the center tank into the runabouts! Have a look and tell me if it still counts?

P.S sorry for night shot

x5bjuW8.png

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@Andetch You could have a death star in that image and we wouldn't know it.

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@eloquentJane, you can't see the death star? Hmmm.....

Try turning your screen brightness up, and room lighting down. Lol

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35 minutes ago, Andetch said:

Try turning your screen brightness up, and room lighting down. Lol

Brightness is at maximum and lights are off. The image is just too dark.

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@eloquentJane that's a shame..... Well I hope you can see the death star more clearly here!

For when you wanna put an orange tank into orbit (not quite first attempt, gonna try with a tiny bit more fuel), try the 3Chal4U! Hope this counts as the orange tank doesn't have engines....

TzUFwBy.png4ptgncU.pnglL4AKb5.pngck9krUX.png

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Posted (edited)

On 3/15/2017 at 7:07 AM, Thor Wotansen said:

Sorry for no pics on previous post, I was replying from my phone and I had no regular internet due to inclement weather.

Anywho, here's what I call the Double Shuttle

S5aFALH.png

I'll have to tweak the booster stage so that it doesn't act like a lawn dart, the orbiter easily makes orbit and can take a big orange or a crew module or whatever.  I've included Monoprop OMS engines in case the payload requires all the LFO to be used on orbital insertion.

This thing deserve a place on KerbalX. Any Chance?

Edited by Jestersage

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18 hours ago, Rath said:

I'm thinking of trying to make a "dragster" style design, with the boosters being mounted above a spaceplane to keep it stable.  I'm thinking of something like quad or tri dual big orange and a twin boar boosters, all connected together with a frame (separate ones might exceed 20km away while landing) and semi-propulsively landing with parachutes to keep it pointed in the right direction.

The frame would be prohibitive if used IRL, but it's an excellent kerballed solution.

What about something like a revisited S-ID approach? 

dc0910f4ffa921745f43de30fd16bf26.jpg

The idea was to take a standard Saturn V first stage and place four of the five F-1 engines on a skirt, similar to the one used by the Atlas rockets. All five engines fire on the pad, but once 70% of the propellant has been burned, the four outer engines MECO and the skirt drops away. In theory, the skirt could be chuted and recovered for reuse.

In a modern redux, the skirt could contain crossfeeding fuel tanks feeding the central engine. Then, with modern restartable, deep-throttling engines, the skirt could return to a propulsive landing easily. If you really want to mix things up, you can leave an air gap between the skirt and the core body so that the airflow boosts the thrust of the core engine, making it a partial airbreather.

Trouble, then, is how you go about recovering the core, if you're expecting to use this as an orbital passenger shuttle. Boosting a large body into orbit isn't such a bad idea, since a larger body gets draggy at a higher altitude (assuming you use a normal attitude rather than a retrograde one) and experiences lower peak heating. Final recovery is the only sticking point.

Might play around with some numbers to figure out what kind of mass fractions this would give us. Suppose we use five Raptor engines...

Anybody want to try building this?

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