Pecan

Solar panels definitely but as to the rest - what's the rover for? If large & crewed then just design and build it like a normal lander except that you use wheels instead of legs. Although parachutes work on Duna the atmosphere is so thin that whether they save more mass than they add is questionable. I'd recommend first designing your lander/rover without them. At the other extreme if you just want a small, drone rover then a parachute should be sufficient and your design should focus on making it as light as possible. Either way, note that rovering around planets gets old really fast. A lander/rover that can do several 'hops' and refuel in orbit is far more versatile and less boring.

Software developer, computer analyst, future watcher and avid gamer. If I'm not working on my computers I'm playing with them. Even then, I'll play games with half an eye on how they're written and what technical techniques they use. KSP stands alone with approaching 4,000 hours played. Others that have been serious time-sinks (>1,000 hours) include: Strategy: Total War series - especially Rome & Medieval II Mount & Blade Warband RPG/FPS: Elder Scrolls series Witcher series Builders: Cities: Skylines Rimworld Tropico series

Buddhists get infinite retries.

A: Micrometeorite. B: Just KSP behaving as normal (I've never really trusted anything 'landed')

You rang sir?

After first Mun landing I don't do one-shot missions, therefore everything is reusable infrastructure.

All launch systems have abort action-group at least shutting-down engines. All crewed launch systems have some some sort of escape/survival setup. All crewed launch systems > 1.5m have LES. Everything that reaches orbit has a (rescue) docking port.

"The real advantage of Sensi's idea seems to stem from the ignition of all engines simultaneously ..." Yes, the advantages of radial-type staging is having more engines firing plus using-and-discarding stages as quickly as possible. Normal stack-staging has the limitation that upper-stage engines are just deadweight until their moment of fame. Onion-staging uses fuel-lines to use and jettison outer stacks as quickly as possible. Asparagus is just the optimal special-case for the minimum symmetrical number of stacks (everything takes from 2 stacks at a time), which is why it is most efficient. As you say - everything is being used all the time, from launch to orbit. The question always was - how can you drop just 1 tank at a time without unbalancing the vehicle? Twisted candle is the answer to that but was always limited by i) the difficulty of placing lower engines so they aren't hit by the exhaust from higher ones, ii) the additional structure (with mass and drag) needed to side-mount most engines or the limited choice of radial ones, iii) similar awkwardness with the fuel-flow. In my tests I also found a fair bit of structural heating just from engine gimballing but how important that becomes in practice is a matter of individual design. Of course, once you've accepted the drag-penalty for side-mounting engines you can extend them further from the tanks to avoid that. You have done the work (that I didn't bother with) to show how the fuel-flow system removes the need for fuel lines and struts so that makes the whole strategy much simpler - perhaps we'll see more of it thanks to you :-) I wouldn't worry too much about TWR dropping as you jettison stages as that is also true with every other staging strategy and what you're aiming for anyway - TWR around 1.5 for launch but only 0.9 or so (initially) for the last ascent and circularisation stage(s). It's also easy to vary the TWR by using different amounts of fuel in each stage - note my design had TWR 1.56 for several stages. Also note that radial staging types also allow you to vary the engines and fuel-load in each stage so there is a lot of flexibility. Have fun.

So no more twisted nightmares?

Hoorah, congratulations and how nice to have someone who knows what they're doing for a change :-) Having never looked at the (new-by-my-standards) fuel-flow system I wouldn't have known where to start, so thanks for that.

To paraphrase Imelda Marcos, "I get so tired of 1,000 hours here, 1,000 hours there; it's just so petty". (Approximateley 3,700 hours)

Yes, I shouldn't have said "presumably". I should have said "It doesn't work without very careful engine positioning, because exhaust from one will destroy another or other structure as they gimbal". It's possible but just another indication of how hard it is to build twisted candle.

Congratulations. Presumably you had to twist the candle more to fit 3 engines in place of each of mine - which would have had the exhaust from the topmost thuds hitting the bottom ones. If your launch mass is less for the same payload then that's perfect, after all the point is to maximise payload ratio. I'm convinced though that, like multi-layer asparagus, any theoretical efficiency with twisted candle is lost to practical construction restrictions and difficulty.

Yer 'tis: What tonnage do you get? I tried 3x engines and things but couldn't find a comfortable match between payload, thrust and tankage that you need for payload ratio. Plus, of course, more engines on each stage make it much harder to avoid exhaust hitting something on the lower stages. I'd have preferred to use 1.5m tanks for this sort of payload but the thud's thrust is so low and so many stages required that that became ridiculously - and unflyably - long. (It's also unflyable if you make the payload 2.5m)

It turns out, as far as my testing went, that aerodynamics are only a problem regarding where to fit fins for drag/control. That said, the best I got is only 21.48% payload ratio (which isn't at all bad but not as good as asparagus): 13.88 tonne payload, 64.6 tonne launch vehicle, total launch mass 78.484 tonne, 47 parts, 32,300 funds Stage 1: Rocomax x200-16 fuel tank, twin thud engines (the cub is nothing like a Skipper, by the way! - 33.75kN vs 568.75) TWR 0.98, 1,048m/s dV Stage 2: same as stage 1, TWR 1.36, 680m/s Stage 3: same as stage 1 plus 2x AV-R8 Winglets, TWR 1.56, 501m/s Stage 4: same as stage 3 plus X200-8 fuel tank, TWR 1.56, 571m/s Stage 5: same as stage 4 without winglets, TWR 1.56, 447m/s Stages 2 - 5 all have fuel line to cubic octagonal strut and then another to tank in stage above (unless there's a better way to drain tanks from the bottom). I found the minimum twist was 6x shift-E rotations, by the way (hope that makes sense) - narrower engines (eg; spider) might allow for 5, I didn't try. (3-stage asparagus for comparable 13.77 tonne payload is 23.35%, being a 52.25 tonne vehicle and is also fewer parts and cheaper) As noted before, I really don't have much experience with twisted candle so I'd be interested to see any examples that do it better than this.

You're asking a hard question because I don't think I've built a twisted candle for about 4 years! Having said that, aerodynamics should favour the design as thinner than radial/onion/asparagus, not having the side-boosters that they do. The drawback, as I noted, is the fuel-lines & supporting structure you have to build up the stack, in order to ensure tanks empty and can be dropped from the bottom up. Also note I said "usually" and "limited choice" regarding the engines. At certain mass-points the engines available may be good choices and twisted candle a viable option. At others there's simply better choices for normal engines, so the comparison is not just between the staging strategies. I might have a play with the candle to see what I can do ..

I have lots of ... Stuff that the April 'update' to Windows last-choice wiped out. Now just the Steam version left.

Welcome to the forums. Please help us help you. What have you already done and what are you stuck on? Without that we don't know if you're looking on basic advice for getting into space, specific solutions to whatever you're stuck on or refining a spaceplane to go around the solar system.

Yes, twisted candle means twisted nightmares. In case you didn't find it when trawling through the archives I think this: Is about the best overview of staging strategies. Be warned though that it's four and a half years old so any mention of specific engines/fuel tanks/other parts is almost certainly irrelevant. Analysis of the different strategies is permanently sound though. BTW: The reason twisted candle doesn't usually compete with asparagus (or even onion) is that it relies on radial-attached engines, which means limited choice. Using normal node-attached engines with the strategy instead requires building girder frameworks for them, which adds a lot of mass and drag. Same thing for the fuel-lines which you have to run up the stack (although this may be changed by the fuel-priority system, I haven't tried it).

I wouldn't dream of launching with a nuke and terrier but then I also wouldn't dream of taking my launch vehicle to Mun. You didn't ask how to launch but what the most fuel-efficient engine arrangement was. It's one nuke. If you *also* introduce the requirement for a LFO engine, it's one nuke and a terrier. If you *also* insist the LFO engine is a poodle, it's one nuke and one poodle - there is no escape from the fact that including lower-ISP engines, or more engines always reduces the fuel-efficiency, because you're adding mass. Given that any LFO engine is going to consume fuel and oxidiser at exactly the same, 9:11, ratio that they are stored in fuel tanks any fuel required for nukes will always be extra. No possible arrangement will even-out the discrepancy between LF and O consumption, unless you abandon the nukes altogether. In that case your most fuel-efficient engine arrangement is one terrier.

The most fuel-efficient is one nuke. Anything more adds mass but contributes less, ergo reduces fuel-efficiency. If you *must* keep another engine then use the lightest, highest ISP available. That'd be the terrier

Whereas the spaceplanes have, flying throughout the solar system, mine and processing ore on other bodies to refuel as they go? Everyone happy with the years-long missions never leaving the seat and surviving on snacks? You read that part as well, I take it?

" So.. (bad vegetable) staging is complex and kills frame rate and not used in real life for the same reason. You did 73 tons to LKO with 33 parts. How can that happen without the complexity of (bad vegetable) staging, how can it be made simple?" I'm sorry, I don't understand what you're asking. Are you really saying 33 parts is a lot and kills frame rate? Do you really think 3-stage asparagus is complex? Do you think many Kerbal things happen in real life? (There has never been a real-life SSTO for a start BUT, haha, we invented the ladder before the rocket!). However you arrange your staging you're going to depend on your last one to deliver the required TWR - so what? We're talking about a core stage with four boosters here. The only difference between asparagus and radial is that there are fuel lines between the tanks. You could presumably lose a couple of them by using fuel-crossfeed instead. That's it. If you really mean how can you get the same payload ratios using radial or serial staging the answer is simple - you can't. With a three- stage serial design you'd save - exactly 4 fuel-lines and 2 decouplers*. You still need 2 stack decouplers and 3 sets of engines. Of course your upper-stage engines have to deliver the required TWR but now all the lower-stage engines have to as well, because they aren't helping each other. So your serial-staged design will have massive engines and tanks to feed them so a lousy payload ratio. With radial you can do a bit better because all the booster-engines can fire at once but you won't save anything except the fuel lines. Onion is close - and you get a Korolev cross, like radial - but you won't save any parts (the fuel lines just run straight into the core from all 4 boosters). I note "Here on IMGUR is a 5.75 to 1 -- 69 ton booster of 46 parts for a 12 ton payload dV of 3384 and on the pad TWR of 1.22 -- This I built in 1.3.1" - is 13 parts more and seems to have a lot of fuel lines. My nearest equivalent is 17 tonnes lighter, 14 parts fewer and designed for 13.5 tonnes. I do not include parachutes for stage recovery though so you'll have to think about how to standardise that. (*Probably fewer, larger tanks as well actually) Ha! There is an even more efficient (theoretically) staging system than asparagus called 'twisted candle'. If you think asparagus is complicated though you'd probably hate that - even though it's stack-staged.

And another quick check:- 3-stage asparagus using Kerbodyne tanks, mammoth+mainsail cluster engines gives you better than 20% for a 615 tonne payload but that's about your max payload for high-efficiency and a (comparatively) simple build I think.

"The most difficult problem for the heavy loads has been design of the booster core of the lowest stage. It has to still carry at low altitude the payload and maybe the multiple stages above it so requires many engines for the needed TWR it alone has to support during ascent." Meh, I hardly ever serial-stage except for the last. Everything else is onion/asparagus so all the engines are working for their pay right from the start. If I can't lift it with 4 asparagus stages (core plus 3 booster-pairs, which is the most that fit conveniently around a same-size core) I'm not interested. Hehe, at that I've never wanted to lift anything more than around 80t so I've never really tried ^^. That NASA site is great for everything about rocketry. It's one of the places I learnt from when I started with KSP.