herbal space program

In every plane I've built so far in which I used only RAPIER engines at 15 tons/engine or less, I've either had big problems breaking the sound barrier or my engines have flamed out too low because I didn't have enough intakes. Balancing how much intake drag you can push through the SB against how much weight you have to ship in engines is the key consideration IMO. I'm finding that the sweet spot is around 12.5 tons/engine, with enough intake area to keep them burning up to 25km+. By using a nuke as an afterburner, I've been able to get to 28km at almost 1400 m/s, with maybe 150m/s climb at switchover. I've gotten to orbit with 23% of my initial takeoff weight on board in fuel that way. Using 4 RAPIERs plus one nuke, I just landed my most recent SSTO on the Mun last night. I'm not yet sure if I can do it with enough fuel to get back, but it's close. Anyway, I think more power than that is better in the new aero system. You really need those RAPIERs to be working at their peak on air at the high end, or you'll just have to burn through too much atmosphere on bipropellant at 305 ISP. Dang! I just landed it and fell only 65 m/s short of getting back into Kerbin's atmosphere! I've got to be able to squeeze that out somewhere...

Thanks! I guess I can stop worrying about that now. On a related note, would you happen to know if clipping wings into fuselages, etc. alters their effective area and/or drag? I'm not trying to cheat the aero system or anything, but sometimes the shapes you're given just don't fit the design.

Hello all, I've been working on an interplanetary SSTO design, and a big part of that is reducing drag to the absolute minimum for the most efficient possible flight to orbit. Now for a fuel tank, it seems quite clear that flying through the air sideways produces quite a bit more drag than flying through the air end-on, but is this also true for wings? At first it seemed like the delta wings I was using generated a fair bit more drag than the much narrower strakes I ended up with, but now I've seen a fair number of designs around that seem to use both swept and delta wings, which cut a much wider swath through the air than the strakes. IRL, all planes that go super-extra fast, like the SR-71, do have a very long and narrow profile, but is this actually true in stock KSP aero? TIA for any insights on this...

I made about a dozen new craters in the Mun last night trying to land my unflyable Munar landing SSTO. I thought I was being clever by mounting a turbo and a nuke together in the center rear on a vertical bicoupler, with each canted outwards to offset its off-center position. I only wanted one of each kind of engine on an otherwise symmetrical space plane. That actually worked great early in the flight profile, when the CoM was near where it was in the SPH, way out ahead of those engines. The design performed great on the initial ascent, and I was able to get to a 100 km KO with over 2000 fuel and the nuke. The engine still worked fine through all my orbital maneuvers, easily getting me to LMO with like 1400 fuel left. But by the time I was actually trying to land on the Mun with that crooked nuke, the CoM had moved so far back that the engine pretty much just wanted to make the ship go round and round. By burning the straight-mounted RAPIERs with my remaining bipropellant I was able to barely keep the thing under control, but despite maybe 10 attempts I never managed to touch Jebediah down properly. I.e. on the rear-mounted landing legs. I did manage to land on my wheels undamaged one time, but without enough fuel to get home, and when I tried to take off horizontally I cleared the ground but then crashed into a mountainside before I could get my heading up enough. By this time my wife, who had crawled into bed across the room a while before, was giving me and my rocket sounds all kinds of stink-eye, so I hung it up. I guess I'll try again tonight, but that is no way to fly. back to the drawing board...

(facepalm) So THAT's why I seem to be able to get away with all these outrageously tail-heavy designs! should have known something was not quite right. Although I suspect as you said, they did it for playability, I guess you could reason that all the turbines and such, which constitute the bulk of the mass, would actually be significantly forward of the part you place in the SPH.

I just recently built a 45t space plane that (by the numbers anyway) can deliver a Kerbal to the Mun and return to the runwav without refueling, and I honestly don't think that there would have been any way at all for me to do that without the nuke engine: http://forum.kerbalspaceprogram.com/threads/123415-R-A-P-I-E-R-versus-Turboramjet-Surprise-surprise?p=1990869#post1990869. The ions are just too weak to land something so massive and pretty much any other engine does not have a high enough ISP to make it all the way without jettisoning stuff. Please correct me if I am missing something, but I'm pretty sure that's the truth.

And you have to balance that benefit against the greater amount of time it takes you to get up there with less thrust. In my experience flying with different amounts of RAPIER engines, I found that all the planes where I had to climb slowly to 13km then dive to 10km to get above 420m/s ended up with considerably less fuel on orbit than the ones where all I had to do was level off around 11km, in spite of the added weight of the engines. My solution to get the best of both worlds was to add like 1 turbo per 3 rapiers to the mix, because their improved performance near Mach 1 offset their worse performance near flameout. Based on doing that over and over, I came to the conclusion that the ideal profile to get the greatest payload on orbit per ton of vessel would be to lose like 1km of altitude going trans-sonic, but I have not yet found a combination of available parts that yields that profile. - - - Updated - - - This is of course true, but the limited number of configurations available in KSP, combined with the implied objective of getting the maximum payload fraction to orbit, constrains the design parameters quite significantly. I made the estimate I did based on those constraints, although there is no doubt some wiggle room even within them.

I'd say it really depends on how slowly you're climbing to your highest subsonic altitude and how much of a dive you have to take to punch through. The best efficiency point probably lies on a profile that requires around 1000m of altitude loss before pulling up. More than that and I think your ascent to orbit will take too long for the reduced weight of shipping less engine power to have a real benefit. Also, it's just kind of a pain in the end that should not point towards space to have to go through such contortions to get to supersonic flight.

I'd say it depends what you're trying to do. With due respect to those truly lovely designs, my ship is not intended just to tag LKO and go home. It's intended to land a Kerbal on the Mun and come back to the runway at the KSC. That's why it has that heavy nuke, which is indispensable AFAICT for what I'm trying to do. I was also incorrect FWIW about how much it weighs. That version is actually 45t on the runway, which can be seen in the album I posted. Anyway, I'm not sure how you calculated your payload fraction, but I'm arriving at a 100km orbit with 9.5 tons of fuel , a Mk1 cockpit (1t), docking port (0.1t) , 4 LT-2 landing struts (0.4t), and 8 RCS thruster blocks (0.4t). That would represent a payload fraction of 25%, which is comparable to what you posted. If you also count the nuke as payload, we're talking 34.2%. I've really got that nuke on board just to land on the Mun. It's totally dispensable to get to orbit. If I replaced it with an LV-909, I would probably end up with just about the same payload fraction at LKO. Another thing this design has going for it is that you don't need to do any fancy bobbing and weaving to get this through the sound barrier. It flies straight to orbit, and although I totally understand the mass-based argument for just being able to get over that hump, planes I've flown that work that way have somehow always seemed to end up in orbit with less fuel than ones with enough power to break the SB on a continually ascending profile. So I guess what I should have said to communicate my design goals properly is that I believe this is the magic formula for a well-performing, fully functional interplanetary SSTO. One important thing however that I do take away from looking at your designs is that I definitely seem to have too many intakes! I should try losing about a third of the ones I have on my plane and see if it performs significantly better. I also haven't explored the MK3 parts yet to see if they have a better lift/drag ratio than the Mk2. Mk1 AFAICT is just an all-around loser. ...So after flying the thing for a couple of hours last night with fewer intakes, which definitely improved performance, I was able to get to LKO with 12 tons of fuel left, for a 26% payload fraction in just propellants. Unfortunately, the tilted engine performed great until the actual landing, by which time the CoM had moved so far back that it no longer wanted to push the ship in a straight line at all. I'm pretty sure I could land it eventually, but that's no way to fly. I guess tonight I will see if I can lose the turbojet by cutting down the intake drag to a minimum, but I feel like I've been down that road already with this design.

The 42 ton design I posted above has 2 small winglets as vertical stabilizers, 4 wing strakes as main lifting surfaces, and 2 Elevon 4's. It has a takeoff speed of around 170 m/s. In this new aero system, I would never use a wing that stuck out too far. It's just too much drag when you're up there trying to rip a hole in the stratosphere. My fastest planes all look like flying Mrs. Butterworth's bottles. - - - Updated - - - Setting that thing down on Minmus would be too easy. Landing it on the Mun is way harder because of the much deeper gravity well and the barely adequate thrust of the single nuke. If I can manage the Mun, I think I might have a decent shot at Duna.

Those turbos just run out of steam too soon to get you high and fast enough on air. You end up having to burn all your bipropellant just to make orbit. Plus unlike the Mk1 parts the Mk2 parts give you a fair bit of lift along with their drag, which you just can't ignore if you're trying to make orbit with the least amount of deltaV possible. I'm scaling up my design now to see if I can get more out of it.

At this point, I can throw together a Munar orbit rendezvous Munar landing mission in about 5 (OK maybe 10) minutes. My biggest station, which required docking of 12 separate large modules into a square closed structure, required probably 200 hours from start to finish, maybe 20 of which were spent actually building all the individual pieces: My Jool 5 mothership,which had the highest part count of any single thing I ever launched, probably took me about 8 hours to build: .

So I figured out how to mount both turbo and nuke engines in the middle by canting them outwards, and this is the SSTO I came up with: I haven't successfully landed it on the Mun yet, but i should have enough deltaV to make it and back. Based on its performance, I think 4 RAPIERs, 1 turbojet, and 1 nuke is indeed the magic ratio for optimal SSTO performance. I'd love to see all-stock designs that can do better than this one with a different configuration....

Thanks! I guess it was that last little bit with the image number that caused the problem

I've been working on this fairly obsessively for the last few days after getting bored with my career game. Here's the best I've managed so far in terms of performance for a fully functional interplanetary SSTO: https://imgur.com/a/d1ZYq#0 It has landing legs, RCS, and a docking port, and can make orbit with about 3600 deltaV in the bank. Im still trying to land it on the Mun, but I'm convinced I'll succeed eventually. Touching that massive ship down gently with just that weeeak little engine is tricky! I dealt with my 4+1+1 symmetry problem by mounting the Nerva and the Turbo together in the middle on a bicoupler, with each engine canted outwards enough to (almost) offset it's off-center position. The thing flies poorly, but I'm pretty sure I will make Mun and back, which means Minmus should be a breeze and Duna is not out of the question. This is still a fair bit less than SSTOs could do in the previous game, but it's not hopeless!

I've been spending a lot of time fooling around with this in the last few days, and for me it seems that 3-4 Rapiers, 1 turbojet, and 1 nuke is the combo makes for the best deltaV on orbit. It seems like with the current atmosphere model, breaking the sound barrier is the biggest hurdle in any ascent profile that's trying to get as much mass/deltaV per ton as possible on orbit. In a 3-hull Mk2 design with 4 RAPIERs plus a nuke, it's always been a long process for me to break the sound barrier and go into the silly thrust zone. I would have to climb to 14km on the RAPIERs at like 290 m/s,then nose down and engage the nuke, hoping that I could hit like 420 m/s and pull back up before getting below 10km. Very tedious and fuel-consuming. Adding one turbojet to the mix dramatically improved the efficiency with which I could get to that point by providing that extra little push at the transition. With 4 RAPIERS and 1 turbo, I was easily able to get a 42 ton craft to the 400+ m/s range on a constantly ascending profile. Keeping the RAPIER/Turbo ratio to 3 or 4 to 1 left enough thrust at the high end for me to get up to 12-1300 m/s surface at 24km with enough climb rate that I didn't burn off all my rocket deltaV getting up out of the soup. Unfortunately, there's no symmetrical way to place 3+1+1 or 4+1+1 engines, so I had to mount the turbo to an empty tank behind the nuke on a decoupler, then jettison it for the circularization burn. Obviously this is no longer technically a SSTO design, although dragging the turbo the rest of the way to orbit, if it were somehow possible, would still have left this ship with close to 4000 dV on orbit. I haven't taken this ship to the Mun and back yet, but I'm pretty sure I'll make it when I try. Landing a big ship like that on just the nuke is pretty costly though. A previous version without the tacked-on Turbo could make Munar orbit and back, but just didn't have enough deltaV to land and get back off.

I think the air itself is pretty well balanced, although it does seem to disappear pretty abruptly around 22km for no obvious reason. The engines OTOH need some tweaking. I like the idea of a real transition in performance at the sound barrier, but the thrust curves on the RAPIER engine are a little extreme. It seems really hard to go transonic with any ship that might arrive in orbit with any fuel left. At least for me. The best I've managed so far is maybe 700 m/s dV left in a 100km orbit. If the RAPIER had just a little more oomph around 300 m/s, it seems like a lot more SSTO designs would become feasible.

I actually succeeded just now with a somewhat different plane. What I had was way too draggy because you need way less wings with this aero than in 0.90! I also figured out that I was losing a lot of speed by pitching up too much after switching to rockets. In the old aero, you didn't suffer a big penalty for going crosswise to the wind like that, but in this version if you get much off your prograde vector the rate of velocity loss is tremendous. By managing my trajectory better I was able to make orbit with just enough fuel to get back. Still, this game seems quite a bit tougher on SSTOs than the previous version.

I spent several hours last night trying to make a space plane SSTO. It sure has gotten harder with 1.0 aero! I think my current design, based on models which worked fine in 0.90, is too draggy for the current game, because I can't seem to get above about 1100 m/s at 22km, which is about as high as I seem to be able to go at all now on air. My hat is off to all those who have succeeded.

I'm pretty sure they nerfed the aero model and reentry heating because not to have done so would have made the game just about unplayable. they hide the deltaV and TWR info because they want you to figure it out on your own. Anyway, calculating TWR is truly essential but it's really easy if you know the weight of the ship. Having exactly the right deltaV is seldom critical for any mission. You experiment, then overbuild, then gradually learn how to do it at higher and higher efficiency. If you can just look all that stuff up from the get-go, IMO it nerfs the game worse than any of the other stuff you mentioned.

Vanilla currently tells you how much your ship weighs on the pad, and it also tells you how much thrust each engine has. Truly, adding the latter numbers for your first stage, dividing by ten, and then dividing that number by the weight of your ship does not seem to me like too much to ask of the player. Calculating the vacuum deltaV of a given stage from those numbers is a little more complex, but if I really felt like I needed to know that number exactly, it would take me about 5 minutes to cook up a spreadsheet to do it, and believe me I'm no math whiz. Now back in the day before Vanilla even told you how much your ship weighed, THEN it was a real pain in the end that should not point towards space. The funny thing though is that even though I've sucessfully completed the Jool 5 challenge (too lazy to post it all for the badge, but I will one of these days), and have done countless other fairly difficult missions, I've never actually once calculated the vacuum deltaV of any of my stages exactly. In a few cases, I've estimated it by burning for a set amount of time/fuel in a circular LKO and scratching out a few numbers on a piece of paper. If your stage has a given TWR and burn time ( burn time is easily calculated from the engine description in the parts tabs and the amount of fuel in your stage), you basically just multiply those two numbers by each other then by 10, and that's your minimum deltaV! In reality of course it will be more than that, especially if the stage you're calculating for has a significant percentage of its weight in fuel. But generally speaking, you want to have that added cushion anyway, because it is almost never a good idea to embark on a big mission with exactly the minimum amount of fuel you need to do it. That's all I've ever needed to do to complete all those missions, and I've never really gotten burned for it once.

Actually, I think it would be much more about forcing you to have multiple missions going simultaneously later in the game rather than forcing you to do more missions overall, but clearly it's not a very popular idea anyway.

I started with all stock, then went to using a variety of parts mods, and now I'm back with all stock. I think I will stay there until the 1.xx release cycle stabilizes and I have played and discussed it to death, probably another 200 or so hours. After that, I presume it will be a good long wait before the devs come up with anything new, so I will surely be counting on all those mods to keep things interesting.

Hello all, There's been a fair bit of discussion on this, mostly revolving around the idea of having an AI competitor agency in the game, but I don't think I've seen this idea come up yet in the discussions of this question. It seems fairly obvious though, so my apologies to OP(s) if it has been discussed at length before. How about having your space agency require a certain amount of funds annually to maintain operations, based on the level of the buildings you have? I've heard it discussed before that there should be an annual budget for the agency, but as funds coming in not going out. With that type of system, there would be a real incentive to meet ambitious time lines in the game, mostly as you start exploring other planets, but possibly earlier with some other minor tweaks. There would also be no need to implement anything nearly as complicated as a rival agency, which I can't imagine the devs even considering for quite a while. It could of course be a toggleable/slideable option in the game config, but would be part of at least the default moderate and hard modes. I think that type of system would add an interesting new dimension to both the time and money aspects of the career game. Thoughts?