sevenperforce

A Dawn, a reaction wheel, a command seat, a 2x6 fixed solar panel, 400 units of xenon, and a single radial battery for that extra burst of power. Currently reworking my nuclear shuttle...I think I'll add a Klaw and a radial xenon tank and use it to refuel my Mun lander once each trip. Will need a touch of extra LF to be safe, but it's still much more efficient (and environmentally-friendly) than leaving a xenon depot in Mun orbit.

That's what a boostback burn is for. Also, in my testing, the first stage is pretty much just going to go straight up and straight down. The second stage needs to carry all the dV for the actual orbit; the first stage merely acts to lift it up out of the dense atmosphere. Plus, if you are using a Stratolaunch-style approach, then you have enough crossrange to get back to the launch site anyway.

It's very small. Cockpit, intake, nuke, and Whiplash. Four wing strakes, two canards, tripod landing gear. It only needs the fuel inside the strakes to get to orbit. The nuclear shuttle is done; it uses a single nuke for the transfer, injection, and return burns, and it aerobrakes back to LKO. 250 units of LF per round-trip.

Build a ring-shaped set of flotation tanks with a ballast tank and a Klaw underneath. Distribute the ballast to tip the whole affair on its side and dock the Klaw to the back end of the first stage. Dock the second stage, move the ballast (ore) back to the lower tank to erect it. Fuel the whole affair, then set up the engines, throttle up and disengage the Klaw simultaneously, and you should be good to go. And very easily testable in the oceans of Kerbin.

With a high enough apoapse at separation, you should be able to push the second stage into a stable orbit (or at least a nearly-stable one) before the first stage is unloaded. Depending on the trajectory, you can probably manage to switch back over to the first stage and fly it to a landing as long as you get to it before it hits 45-50 km. I recently used this trick to launch a Falcon Heavy clone and recover all three boosters, in stock.

Not my area of expertise, but the level of differentiation in a gas is a function of the turbidity of the ground layer. If there is enough weather kicking the air around, the gases will stay mixed. In a homogenous mixture of nitrogen, oxygen, and carbon dioxide, the only thing you need is a sufficient partial pressure of oxygen. Carbon dioxide only inhibits combustion by physically excluding oxygen; its presence does not retard or interfere with the reaction.

The only mod I play with is Tweakscale but I may think about trying yours out. Anyway, for the time being this isn't a standard, scored challenge so much as it is a challenge to try and do the impossible: namely, get to Eve orbit with a reusable system, in stock.

All right, I've built a tiny shuttle that leaves orbit, land on Kerbin, and go back, using 400 units of LF only. I've also built a tiny single-seat ion-powered Mun lander that can go from Mun orbit to surface and back using 400 units of xenon. Now to build my Kerbin-to-Mun nuclear shuttle.

Well, of course any number of mods enable Eve SSTO.

Good idea. I hadn't thought of using the water to help. The Klaw makes docking much easier, but it also means you can't use crossfeed for a parallel-staged design. It's also harder to get the alignment right, though I suppose some sort of alignment struts might come in handy.

But they don't fold.

I used doubled landing legs (two in parallel at each quadrant) which seemed to work well enough, even for a 3.5m booster.

Eve is always the one problem planet that trips everyone up when they want to do grand tours. Trying to establish any kind of long-term presence on Eve is fraught with the need for expendable multistage landers. I've seen @Kergarin's amazing suborbital catch he uses to get off Eve and reuse his ISRU-equipped everywhere-lander, but that kind of precise timing is way beyond my capabilities, and I'm interested to see if there are any other ways of doing it. Now, I've toyed around with stock props to try and make a propeller-based SSTO, and some designs are promising, but it still stretches the boundaries of what's actually feasible. What about reusable staging, SpaceX or Stratolaunch or Energia style? If we could use the Klaw to mate a first and second stage together, then the first stage could get suborbital, release the second stage, and fly back to the launch site to land and refuel. After reaching orbit, the second stage could rendezvous with a waiting tanker/station, refuel if necessary, then head back down to do it all over again. I've tried it two ways so far: one with a HTOL Vector-powered Stratolaunch carrying an LV-N based upper stage underneath, and one with a VTOL first stage with the second stage slung alongside providing a parallel boost. In both cases, I've been able to make orbit on the second stage, but not before the first stage fell out of render range. Any other ideas? Anyone else want to take a try at it?

Is Tweakscale permitted, then? I'd like to try to make it.

Note: the Juno engine comes in at 250 kg, so it's not possible to get under 450 kg and still have four engines. If we can use Tweakscale, though, we might be able to get a little closer.

No docking? Every vehicle has to be direct ascent? Then, like I said, the winner is just going to be whoever's computer can support the largest parallel-staged monster, which isn't much fun. Just because people make an SSTO for their Kerbin-side shuttle doesn't mean that every craft is identical. People have a LOT of choices about how they want to set up mission architecture. You could do a dedicated Mun-side lander, or you could have a single capsule that docks to various vehicles at various stages. If you want to make it more interesting, you could always specify no airbreathers, but I don't think it's necessary. Another way of making it interesting would be to allow docking, but specify no crew transfer, so you have to do the whole trip in a single ship/capsule. Also, I scored your FH.

Anywhere but Eve and Jool.

You say "no orbital tugs" -- do you mean people cannot leave part of the ship in orbit? My go-to approach would be to launch an SSTO along with a reusable nuclear single-stage Mun lander, an ion tug, and a fuel depot, then have the Kerbals cycle back and forth until the fuel depot is expended. But if you're saying no docking, then this will just be won by whoever can build the largest parallel-staged monstrosity.

I wanted to give it another go, after my last disastrous attempt, so I decided to mix it up this time. I've never actually built a fully-functional Shuttle clone, but I've had a lot more experience with spaceplanes now, so I'm going to give this a go. This will be tricky. Getting a Shuttle to work right and glide right, WITHOUT testing, is...challenging. Even moreso if you've never built one before. By my count, that's 60 points with a 2x multiplier, so 120 points.

Yes, I am well aware of the "DragonFly" prototype used by SpaceX. But this post has nothing to do with SpaceX.

Think you're mistaken. http://dragonfly.jhuapl.edu/

You say "powered by RTG" but that would only work for an electric rotor.

I think they look hotter, myself.

Less of a theory and more of confirmed fact. The side core cones are less draggy than the big open-ended interstage, so they need to move the center of pressure higher, so they need the larger grid fins. Larger grid fins also provide a better glide ratio for the stage, meaning less fuel is required for the boostback. Also, the center core has a lower chance of recovery, and adding titanium grid fins would not appreciably increase recovery odds, so why risk reusable titanium grid fins on a core that won't need them and might lose them?

So, I built a Grand Tour ship. With a dedicated Eve lander. Went to Minmus to refuel. Ran out of fuel just before landing and bounced, but righted myself with RCS. Flag-planting and refueling went as planned. Then I went to Eve! At least, I flew by. Then to Gilly, to refuel again! Nifty money shot on Gilly descent: And apparently there is, like, NO gravity on Gilly. I was just sitting like this, supported by reaction wheels. Next plan was to use the mothership to put the Eve lander into an aerobraking orbit, and let the Kerbalkind Gods take care of the rest. Point of no return.... I picked too high an periapse, so there was a LOT of aerobraking. But after a long time (and burning off virtually all my ablator), I was headed for Eve's surface. See what I mean? The first problem came when I jettisoned one of my heat shields a wee bit too early and blew up my Mainsail. Not to worry, though; the design was a tripod asparagus staged monster, so there was still a chance I could get off the ground with the three Vectors alone. Chutes away! Uh-oh. The chute ripped the three upper stages off the landing stage. So...this is not good. At least Val is alive...for now. Tried burning to arrest my descent and perhaps make it back into orbit (again, I have three-stages to work with here), but the Dart just didn't have enough umph. So....here we are. Val is not thrilled. Oh well! Back to Gilly with the mothership! Refueling, then off toward Moho! The plan was to burn off my lowest-isp prop first, starting with monoprop, then biprop, and do the rest of the flight on the nukes alone. Coming into the Moho injection, I realized that I was running a wee bit low on propellant. So, just after making orbit, I drained and jettisoned my nifty reusable drop tanks. Moho descent! My calculations said I had plenty of TWR on the nukes, so I went straight for a suicide burn. And...suicide it was. Not because I didn't have enough thrust, actually, but because I simply ran out of fuel. Flipping... Ended up coming down without any fatalities, but I certainly won't be getting off Moho in this rig. So...that's a wrap. So, let's see. Kerbol orbit, Moho orbit + landing, Eve orbit + landing, Gilly orbit + landing + ascent, Kerbin orbit, Minmus orbit + landing + ascent. 195 points.