Srpadget

Re: "suicide burn" Fixed that for ya. Only if you get it wrong... ;-)

My advice: go to Minmus first, and practice landing there. It takes barely any more delta-v to get to Minmus than it does to get to Mun, and Minmus's gravity is so minimal that everything about landings happens in slow motion with lots of time to recover from errors. Minmus is a SLIGHTLY trickier destination, navigation-wise, but it really is the "training wheels" world that I used for my first attempts at practically every new skill I ever picked up in this game. And then for tips on how to land efficiently, search on the term "suicide burn". (Yes, I know, unfortunate name.) (That said, your description of yo-yo-ing up and down sounds as though you're trying to control your landing with only two throttle settings: "off" and "floor it". For final descent, partial throttle is your friend.)

Lots of talk in the last couple weeks about "wheels being fixed". But very little solid info about what that *means*. They could tweaked enough to be noticeably less-wonky than they are now, and still not be what a layperson would call "fixed". I have a very specific focus, to tell the truth. I actually don't PERSONALLY care much about "wheels" per se--I fly very few planes and I only use rovers for low-speed, local base support (fuel tankers, prospecting, maybe the occasional "collect readings in this area" contract). So airplane gear and powered wheels are pretty easy to work around, for my playstyle. I am actually FAR more interested in LANDING LEGS. Does anyone know if they will once again be a useful option for, y'know, landing on? Or will the best advice continue to be "fins, rocket nozzles, girders...there are lots of better things to land on"? Sliding down a long gentle slope on frictionless "landing legs" may be funny ONCE, but it gets old. And it makes the idea of a permanent base (say, to mine a particularly Ore-rich area) problematic to say the least. I am still using 1.0.5. Mostly because of the landing leg issue.

I don't know about main course dishes, but the menu HAS to include some kind of tasty refreshing minty dessert option. (Wait until you play Science or Career mode, and get to Minmus. Until then, trust me on this.)

I believe I can FINALLY call the "Duna-Ike Invasion Fleet" mission a success--and more importantly, COMPLETE! (20 launches. 16 separate interplanetary craft, some targeting Duna-not-Ike, several targeting Ike-not-Duna. All in ONE TRANSFER WINDOW. I think I can safely say that a project of that magnitude is something less than entirely sane--at least, in a career game.) The original goal had been all-stock except for a couple visual-beautification mods. In the end, I added KAC (for what I trust are obvious information-management reasons) and KAS (for pipes, since working around the limitations of stock docking ports is too much 'work' and not enough 'fun' for me anywhere except the tabletop-flat KSC grounds and Minmus Flats). But I am now set for fuel in Duna-Ike local space forever. 7 of those 20 launches were dedicated to this: http://s570.photobucket.com/user/srpadget/library/Ike Fuel-Refinery Outpost?sort=2&page=1 Yes, it's more complex than it might strictly need to be. But I hardly ever design for aesthetics, and I rather like the appearance of those tanker trucks. :-)

A while back, I posted a few screenshots of what I've started calling The Great Duna Invasion Fleet. Something like 16 separate craft all targeting Duna/Ike space in a single launch window. They have arrived and made orbit. All of them. Much to my surprise, I managed to pull it off! I was allowing quicksave/quickload (just in case), but I never needed to quickload except to rectify a bug (one of my craft just *vanished* in deep interplanetary space). So I'm feeling pretty good about this project. Overview and High Duna Orbit: I probably shouldn't have accepted TWO polar orbit contracts. I only needed one (so I could piggyback a survey scanner on it, of course). Low Duna Orbit: Not all that impressive, really, but then, it's just the Duna Space Station pieces & parts, plus a reusable lander. The real action is around Ike, especially low equatorial orbit: Mind you, most of that isn't staying there. Six (I think? I lose track...) of those orbit lines are a "Mining Outpost In A Box" (okay, several boxes) and will eventually all end up at one site on the surface. Just as soon as I do some prospecting and decide on a good spot. You know, with decent Ore concentration. On flattish ground. Near the equator. Without high mountains directly to the west. In a location where the albedo does not resemble charcoal. (Yeah, right... I'll let you know how that turns out. I may have to compromise some. Probably in the category of "Ore concentration"....) But it's not all infrastructure. It's not really an interplanetary voyage unless you can send Mom a postcard: HI MOM! There was also an Ike landing. Which was successful, broadly speaking. But the crew forgot to take a photo, because the landing was ... "WAY COOL", was the phrase used in Jeb's mission report. He also added the above "FLAT ground, I said FLAT, not BLACK" criteria for mining outpost site selection. And added a recommendation that pilots less heroic than himself should maybe avoid landing right at dawn at a never-before-visited location. But he notes as a bonus that the Ike lander design dust-surfs GREAT on a steep-enough slope. He also assures Mission Control that Engineering back on Ike Orbital Station will be able to straighten out the landing legs with just a few hours' sledgehammer work, and then they'll retract again just like new.

I continue the (long and tedious) process of final orbit insertions for my Ginormous Flotilla currently arriving at Duna and Ike. (6 craft in low orbits around their respective destinations, 10 to go; then I'll find a good spot on Ike for the ISRU facility, and can finally get on with the POINT of all this!) But (as mentioned above) it begins to get tedious after a while. So, when it turned out that one of my Duna-bound ships was going to end up skimming through Ike's SOI (I mean, that's pretty much guaranteed to happen when launching that many ships, amirite?), I decided to make it a bit more interesting. Sure, I was just going to skim barely inside the edge of Ike's SOI, and could easily enough have either tweaked myself just outside it or done a tiny correction after coming out... but I figured I may as well take advantage and make it a bit more interesting. So I set out to make it my first-ever reverse gravity assist to help brake the incoming vessel and reduce the size of the orbit-insertion burn when it got to Duna. In the end, I don't think I really saved much propellant (Ike was in more of a "get in the way" position than a "yay, gravity brake" location in its orbit, after all), but as a trajectory-design exercise it WORKED. Plus, a bit of added fun during a tedious part of this interplanetary invasion mission!

My gawdawful huge "Duna/Ike flotilla" is arriving at its destination. I'm gonna be busy for a while doing capture-and-circularization. (Over, and over, and over...) But for now, the random-looking cloud they made during the interplanetary trip has neatened up into a delightfully well-ordered lineup. I must be doing something right!

So today, this happened: Or, at least, the last parts of this portion of it happened. 6 new or heavily-modified designs, 5 existing or only slightly-modified designs, 19 launches (counting refueling tankers left in LKO for later recovery), 16 separate craft making the interplanetary transfer, eventually to be reconfigured into 21 independent craft on or orbiting around Duna and Ike (2 of which will eventually return to Kerbin, the rest either to become infrastructure or get tossed by the wayside once their contracts are complete). Ya know, it is entirely possible that this may have been a bit too much to be considered entirely sane for one transfer window...? NAAAAAW! **MOAR IZ BETTER**

Well, I managed to get it safely down. And even back up again, though that was a close thing. Started from a 63km circular orbit (i.e., just slightly above the annoying 10x - 50x warp boundary). Lander remarkably similar to the one in Reactordrone's pic, but with more solar and a suite of science instruments mounted above the lander can. Multiple attempts had established that any Pe from about 20km or thereabouts up past 30km really didn't seem to make much difference in the endgame: lithobrake at around 550 m/s, vertical velocity maybe 75-100 m/s. Coming in oriented normal/radial rather than retrograde didn't make any appreciable difference, as the landing can's anemic (by Kerbal standards, anyway) reactions wheels didn't have enough control authority to maintain that attitude below around 20km--just where drag started to have some meaningful effect. So I went for a more 'active' approach--I hit the engine at 15km altitude, slowed under power until the drogue icon went yellow, cut the engine, staged the drogues. Everything from there went pretty much as intended: drogues deployed, I staged the mains as soon as it was safe, they deployed; terminal velocity with chutes deployed was around 20 m/s and so a short engine burst just before touchdown brought ship and crew safely down. It helped that I happened to come down in the lowlands--I'm not sure it would have worked over higher ground. (I cannot claim any virtue in "choosing" that location. I'll doubtless improve with practice, but right now I'd be doing well to "target" a landing to within a band of, oh, 20 degrees of longitude or thereabouts. This "atmosphere" thing is going to take some getting used to!) But I'd used something in excess of 300 m/s of my fuel supply on that landing. In THEORY, I could get back to orbit, but I wasn't sure about in PRACTICE. There was precious little margin, especially since I'd never done this before and don't have a 'feel' for how this lander behaves in 1/3 gee and in the presence of an atmosphere (albeit thin). I think I made the gravity turn too sharp/aggressive/low and lost more to drag than I should have, but I managed to clear atmo and get to orbit. On fumes. There was something like 9 units of total combined LF/O in the tank when I finished the circularization burn about 5 km below the station and its supply of lovely lovely fuel. By the time I'd rendezvous'd with the station up at 65km, there were less than 3 units left. Still had over 39 units of monoprop left in the lander can, though. So, really, TONS of fuel. Right? So I'm putting this in the "win" column today. First landing-and-reorbit on an atmospheric world (other than Kerbin of course), yay me! But... this is supposed to be a routinely-reusable lander: dock with the station, refill the tanks, refurb the science package, repack the chutes, and we're good to go again. And this kind of nail-biting lack of fuel margin is NOT something I want to be doing routinely. So I'm going back to the drawing boards, and either figure out some way to stick airbrakes on this thing, broaden the base and boost the fuel supply with some radial-attached 1.5-m fuel tanks, or possibly both.

I am finally going interplanetary (yay!) (...'bout time...) and am having some trouble with Duna's pesky atmosphere. I adapted the lander from my existing Mun science lander: two-Kerbal landing can, 2.5-m 4.5-ton "tuna can" fuel tank, Terrier, full load of stock science instruments, and misc "important small bits" (ladder, legs, lights, solar, battery, probe core, RCS jets, docking port). The whole thing masses a smidge over 9 tons with full tanks, and presents a 2.5-meter cross-section (Terrier and tuna-can) on a retrograde re-entry. Total dV in a full tank is a bit under 2000 m/s, so there should be a few hundred m/s not needed for the return to orbit, but I don't want to cut into it too much, and had kind of expected I'd be able to land via a combination of atmospheric drag and chutes, with just a wee little rocket burst immediately before touchdown. I should probably note here that I am running KSP 1.0.5 w/ stock physics/parts (mod list is EVE, KAC, Texture Replacer. I also have KAS installed, but this lander is entirely stock parts.) I am given to understand that reentry behavior changed (again) in KSP 1.1.x, so that may be relevant. For the life of me, I cannot seem to find an entry Pe that allows the dang thing to slow down enough for the DROGUE icon to go from red to yellow before smacking into the ground. I started with a Pe to 10 km, on the supposition that I'd need to go deep to get significant aerobraking. Mistake. Still going about 750 m/s when I hit the ground at probably a 20-degree angle or more. Okay, so that was TOO deep. Bumped it up to 20 km, for more 'hang time' in the middle atmosphere. Better, but not enough: I smacked into a hillside about 4900 m above datum, at around 550 m/s. Bumped Pe up to 25 km. MUCH longer reentry (like, half an orbit), but it didn't seem to have a significant effect on the 'endgame': plowed into the ground at > 500 m/s, somewhere around 4500-5000 m above datum. Drogue icon still red. So do I just need to keep raising the Pe? 30 km? 35? Or am I condemned to burning precious LF/O to drop my speed from 700 m/s-ish down to drogue-safe speeds up around 10km? I have of course thought about airbrakes, but I honestly have no clue where I'd put them; this vehicle is just too short and stubby, and so much of its upper surface is already covered in chutes and science gear....

Today I learned that struts don't just provide mechanical strength and rigidity. They are also a HIGHLY EFFICIENT heat-transfer pathway. NERVs have a low thrust and don't really need reinforcing anyway. I've just always strutted the engines on my nuclear tugs for aesthetics. And I may even continue to strut them, just because I like the looks of it. But I will never again strut them to a hitchhiker or other crew compartment. Not for a design that has to do more than 10 minutes of solid full-power burn all in one go....

...today a whole flotilla of infrastructure arrived at Duna. Lander, station, ISRU, Ike/Duna in-space-only tug/transports, the whole nine yards. And then I noticed via the tracking station that one crucial part of the ISRU mining base is sitting in LKO, with a maneuver node a couple hundred days in the past.... ::facepalm:: (Hey Jeb, you didn't REALLY want to, like, get refueled and come home or anything, did you? Better hope the snacks hold out until the next window comes 'round.)

If messing with Module Manager, .config files, etc. is too intimidating, I have a solution similar to Snark's, but which only requires editing a .craft file in a text editor. This may be less intimidating for some folk (though it's not QUITE as elegant as Snark's .config edit for reasons I mention below): Design your ship in the VAB, using the LF/O tank(s) that you'd like an LF-only version of. Save the ship, and quit out of KSP. Find your ship's .craft file, and open it in a text editor. Search for the LF/O fuel tank you'd like to change to LF-only. In the part description, find: RESOURCE { name = LiquidFuel amount = xxxx maxAmount = xxxx and: RESOURCE { name = Oxidizer amount = yyyy maxAmount = yyyy Change the 'amount' and 'maxAmount' values for LiquidFuel to xxxx+yyyy. Change those same values for Oxidizer to 0. (Do not remove the Oxidizer resource section completely. If you do this, KSP will think it's a corrupt file and will helpfully "fix" it for you.) Repeat the above as necessary for any other LF/O -> LF-only tank conversions desired. Save the edited .craft file. Restart KSP, go to the VAB, and load your ship. Your tanks will, as with Snark's method, look exactly like the LF/O tank, but they work as LF-only tanks. I mentioned this is not as elegant as Snark's solution. There are two drawbacks: 1) These tanks do still generate a line for Oxidizer in resource displays. You can't DO anything with it, but it's there and cluttering up your displays. 2) You will have to go through this process every time you design a new NERV-powered ship using rocket-based fuel tanks. Me, I recommend going the Module Manager route that Snark laid out above. (Or a mod with stockalike LF-only tanks, which is functionally the same thing really.) I only offer this as a potentially less intimidating option.

I finally got around to visiting a Mun Arch. For the first time in 1.0.5. And it turned out to be a "World's First" progress milestone...! Yeah, that's probably common knowledge, and I'm the last one to figure that out. [What can I say? My space-tourism service just isn't all that exciting, I guess.] But I'm all jazzed by it. Now I'm going to have to go hit the Armstrong Memorial, and a Munolith, and and and ... Holey Moley, I wonder if the KSC Monolith or the Island Airfield count, too...? Hmm... It's never occurred to me to try SCIENCE! up there. I wonder if "on top of a Munar Arch" counts as its own separate mini-biome for EVA Reports, sample collection, etc....?

Thanks everyone for all the suggestions! KAS has been installed, and the pipe function checked out on ground at KSC. I don't foresee much need for winches, etc., but I am casting a lustful eye at the strut connector. I suspect a minor redesign of all my standard space station modules will be happening soonish...

Snark, Thanks for the confirmation that KIS is not necessary for this. The KAS blurb was unclear to me regarding the need for KIS for this sort of activity. I absolutely agree about the EVA-deployable struts, as well. (Insert rant of frustrated professional: "I got to use deployable struts for on-orbit assembly of the REAL space station! Why can't I use 'em for my PRETEND space station?!?") And I can't even use Kerbal Joint Reinforcement to beef up the floppy joints. Turns out that my standard multipurpose space station core has a vestigial Kraken drive somewhere in its design, and KJR magnifies it to the point that I've inadvertently dropped it right out of a stable 20km circular orbit and crashed onto the Mun in less than half an orbit upon installing KJR and focusing on the station. Though I do note the experiment made me MUCH more adept at docking quickly!

Nightside: That EVA Transfer modlet looks like it should do exactly what I need. Thanks! Plusk: I've heard of people who do ground-based docking the way you describe, but I've always been afraid I'd drive into a landing leg and send the whole base crashing down Somtaw and Snark: You make a good case for using KAS and just ignoring all the bits that are extraneous to my needs. You have convinced me to give it more serious consideration. (I'm trying to remember when and in what context I saw the "KAS/KIS is complex and overkill just for fuel transfer on the ground" statement. It's doubtless somewhere in the Forum histories.) I've never used a part mod before. But seeing as I recently hand-tweaked myself some 2.5-m LF-only tanks to resuscitate some of my older NERV designs, I guess I can't exactly claim ideological purity. At least until Squad gets around to giving us stock solutions for these two biggest remaining holes in the current version of the game...

A while back, I developed a sweet little highly-efficient, all-stock ISRU mining operation involving a dedicated mining/refining factory, a tanker rocket that shuttles between the mining operation on the ground and a refueling station in low orbit, and a fuel truck that runs between the refinery and the landed tanker rocket. As it's all stock, it uses carefully-placed Junior docking ports to handle fuel transfers between vehicles. Which, of course, means the whole setup is really only suited for use in one place: the flats of Minmus. So now I'm working on the bigger and more important problem of ISRU operations out around other planets. The obvious way to go is to develop a system that works on Mun--because anything optimized for Mun is also going to be pretty well suited for Ike and Dres. And as I'm jealous of mass fraction, I don't want to go with an all-in-one solution that keeps hauling all the mining infrastructure (drills, ore tanks, converter, power/cooling, engineer's control pod) up and down the Mun's gravity well. And I am decidedly NOT the sort of ace pilot who's ever going to be able to land the tanker ON the mining station and dock directly to it. So I'm leaning toward a refinery/truck/tanker setup similar to what I've already got working on Minmus...but I'll need some method other than conventional docking ports to connect the truck to the refinery and tanker. In stock, there's the Klaw. But that's aesthetically displeasing to me, and well-known Kraken bait. That seems to leave KAS/KIS as the obvious way to go. But I am given to understand that KAS/KIS is a hugely-capable pair of mods (with associated learning curve) and overkill for the single job I am intending here. So, educate me: is there a smaller simpler mod that can solve the "ground-based docking/connecting/fuel transfer" problem? Or, alternately, is there a decent KAS/KIS tutorial out there that can help me with the learning curve? Note: I prefer to READ tutorials, with still screenshots where visual examples are useful. That way I can reference back and forth between sections easily and go at my own pace--and I read fast. With videos, I inevitably get tripped up when I miss something vital that whizzes by in what looked like a momentary insignificant aside, and I end up spending endless hours watching the dang thing a half dozen times before I 'get it'. So videos tend to actively ANNOY me. (Yes, I'm aware this makes me a fossilized relic of the last century.)

Screenshot of the vessel in question, with CoM when fully-fueled on the pad. And yes, the vehicle CoM is WAY LOW on the Twin Boar, but climbs as the outboard tanks drain.

That would certainly explain what I'm seeing. I have always had more issues with wobble from tall rockets than with drag from short squat rockets, so my SSTOs in particular tend to be squat. it would not surprise me at all if the vessel CoM is below the Twin Boar CoM. This would also explain why it does not seem to be a problem in the upper atmosphere (I'd been puzzling over that, as fins don't do much good up there and thus maintaining prograde becomes all about gyros and vectored thrust. But if my problem is as blowfish describes, then I can expect thrust vectoring to work correctly later in the mission as fuel is burned and CoM moves forward.

Well dang. I was really hoping that someone would tell me something in the config got corrupted, and provide a quick-and-easy way to fix it. ::grumble:: So how do I move this to a different sub-forum?

The title pretty much sums up my issue; I was wondering if this is a known bug, or if something's gone screwy in my install (and if the latter, how to fix it)? Since 1.0 rebalanced jets, I have used SSTO vertical-launch rockets rather than spaceplanes. Which to me generally means liberal use of the Twin Boar as a core booster once it's unlocked...and dealing with its quirks. And by "quirks", I mean heating (of course), and my long-standing observation that Twin-Boar-based boosters seem to need unusually large fins/aero control surfaces. The former is well-discussed here, but I don't think I've ever seen anything about the latter (maybe this should have been my first indication that something was wrong). I have noticed a tendency for my TB-based boosters to yaw west right around the beginning of my gravity turn, before eventually pulling east as intended. I always assumed that was because my TB vehicles tend to have fins at angles other than 0/180 degrees (3- or 6-fold symmetry, or 4-fold in an x config rather than a + due to the TB's engine cowlings), thus no aero control surfaces suitable for pure yaw control. Seems I was wrong. With 1.0.5 and its rebalancing of heating, my fins have been blowing up during reentry. Not a big deal, as by then they're not only unnecessary but a nuisance (big draggy things with lots of lift capability at what is now the FRONT end of my retrograde-oriented vehicle), but it was aesthetically displeasing, and didn't do any favors for the vehicle's economics. So I decided to see if I could do without the fins -- I've seen many assertions here that larger vehicles actually have LESS need for fins, after all. That experiment was an unmitigated disaster: they tipped rapidly to the west and never recovered...unless, oddly, I commanded a yaw to the west. In which case I got a prompt eastward gravity turn...up until it turned into a flip-and-tumble around Mach 1. So I sat some TBs on the launchpad, arranged the camera to get a good view of the nozzles, and just hit the WSAD keys to see what happened. W and S behaved as anticipated, but A and D resulted in counterintuitive nozzle motion. As a check, I did the same thing with a Terrier: that nozzle moves as expected, so I haven't accidentally reversed the controls. (Also, the yaw monitor in the lower left deflects as expected, so again it appears the issue is with the TB's reversed response to a correct command.) Is this a known bug? Or is something corrupted in my install somewhere? And how do I fix it? Locking gimbals prevents the undesired gimbal behavior, but reaction wheels by themselves really don't provide enough control authority around max-Q (flip-and-tumble is NOT my friend, no matter how much Jeb and Val enjoy that roller-coaster feeling!), and the whole point of this exercise was to get rid of fins. The most satisfactory solution is to fix the TB's nozzle response, but I'm at a loss as to even where to begin. ================= EDIT: I should probably add, this game is mostly-stock. Beautification mods EVE and Texture Replacer (but the only non-stock textures I use are suits so I can distinguish professions easily, no part textures), KAC, and Claw's Stock Bug Fix/StockPlus. The latter is the only one that I would think could affect craft behavior, and I saw the "yaw west until speed is high enough for aero surfaces to 'bite'" behavior long before I ever installed that one.

Phil: Historically I try to work with entirely stock parts/physics/etc. (My only current mods are EVE, KAC, and Texture Replacer so I can give different suits to different professions and distinguish them by eyeball.) However, that point is kind of moot now, as I've tweaked LFO tanks to LF-only for the current iteration of the tug in question, so I cannot truthfully claim it's a virgin stock craft anymore. And that ballute is very pretty--plus the modder appears to have given thought to real-world-ish design considerations and compromises... cantab/Snark: I don't believe I have a picture of the tug handy, and my KSP time is about to be sharply curtailed (my son and his fiancee are flying in to town tomorrow for a week's visit). If I can grab a few KSP minutes in the next few days, I'll grab a screenie and post it. But I'm not optimistic re lifting reentry. Snark: I rather like your idea of a replaceable heat shield, and I may even be able to make it work with this design (likely have to rearrange a few parts to shift the CG appropriately, but that's not a big deal. Numerobis: I have no idea if the tug would survive a normal reentry rather than retrograde, I may have to try that. (Though I must confess I do get impatient about aerobraking and would like to get it done in a single pass. Which is kind of weird, given that this von-Braun-esque infrastructure requires three ships, two orbiting stations, and four docking operations (plus associated undockings, for a total of eight) just for a Munar round trip....

I finally got around to redesigning my Kerbin-SOI reusable infrastructure craft for V1.05. Or, at least, I tried to. I am having trouble with my nuclear-powered tug. Specifically, I am having trouble aerobraking on return from Mun or Minmus. What I WANT is a ballute. Ever since reentry heat became a thing in 1.0, I've been using the (overpowered, yes) airbrakes deployed in the very high atmosphere as a sort of stock ballute-substitute. Airbrakes, of course, got nerfed in 1.05. That 1.04 strategy seems to still work okay for lowish-mass craft in 1.05 -- at least, I've been using them to good effect with return trajectory direct to reentry from Minmus on a craft consisting of Hitchhiker, Mk 1 lander can, 2.5m heat shield, assorted low-mass science/utility gear, and 4 airbrakes. Pile on the substantial added mass of 2 nuclear engines and added fuel tankage, though, and the technique fails spectacularly due to the airbrakes' low melting temperature. Pulsing them does not help: they'll go from <350K to *kaboom* faster than the deploy/retract cycle. I *assume* the issue is that the more massive vehicle gets lower into the atmosphere (and hence into a more challenging heat regime) without appreciably decelerating. So has anyone had success with airbrake-assisted aerobraking of a 10-12-ish ton craft? Do I just need to use more airbrakes in proportion to the higher mass? I am tempted to ask for help bumping the airbrake temperature limit back up to 2000K, but would prefer to find a "stock" solution if a reasonable one exists....