DrLucky

I normally forget that until I get down to about 50m, but the extra 10 m/s or so is pretty obvious once you\'re that low. I\'ve always landed in surface mode. I usually have loads of extra fuel, so I take my time shopping for a landing spot. Hard to tell if there\'s a slight slope, though, until you\'re down. And I\'ve used three legs made of 2 radial decouplers and a wing each, but they break off like everything else... and I can\'t reinforce them with struts as far as I can tell. One thing I typically *don\'t* do is bring RCS. I\'ve heard people recommend using it to kill translation, but I have good success just pointing directly into the X anti-velocity marker to kill lateral motion. I wonder if my lander\'s just too heavy; I use a vectored liquid engine for descent (and ascent), and in order to finesse the throttle I land as heavy as I can -- if you\'re very light, tiny throttle increments lead to large acceleration variations. And besides, RCS is a lot of mass -- and top-heavy mass at that.

All right, I\'ve been to the Mun so many times now that Jeb\'s getting frequent flyer miles. I\'ve tried 8 different (stock) lander configurations, as well as one non-stock. I\'m having *great* difficulty landing in such a way as to not shatter parts off when I touch down. I have four separate missions now where I\'ve touched down, observed the legs breaking off, and lifted off again before I was permanently stuck there. I haven\'t delved into the details of part strength vs breaking strength vs explosive tendencies, but I\'m wondering if there\'s just a sharp divide (like, orders of magnitude) between stock parts and non-stock parts in that department? I\'m starting to think that no number of struts are going to keep my lander intact. I\'ve had touchdowns at 0.1 m/s absolute that have cleanly snapped an engine off. I can land some of these at KSP without the same problem, and that\'s six times the g-field. Why\'s the Mun such a problem? Someone want to post the details on their lander and their experience vis-a-vis not suffering a RUD on Munar contact?

Oh, and before I forget; my stock craft that got me to the Mun and back: This is the build, (from memory, but I think it\'s right -- note that there\'s no RCS or SAS): Parachute, Mk1Pod } Kearth re-entry stage Decoupler, 2 x Liquid Fuel, 1 x Vector Liquid Engine } Descent, Ascent, Kearth Return Stage 3 x [ 2 x radial decoupler + 1 x Wing] } as lander legs -- thanks, whoever came up with that. Decoupler, 3 x Liquid Fuel, 1 x Vector Liquid Engine } TLI and Mun orbital stage Decoupler, Tricoupler, 3 x [ 4 x Liquid Fuel, 1 x Vector engine] } Core liftoff stage, provides positive control. Ignites at 0:00:00 6 x [ Radial Decoupler, Solid Rocket Booster] } Liftoff Booster Stage 2. Air start. 6 x [ Decoupler, 3 x Liquid Fuel, 1 x Non-Vector Liquid Engine ] } Liftoff Booster Stage 1. Starts at 0:00:00, provides most of the oomph. 6 x [Radial Decoupler, Solid Rocket Booster] } Liftoff Booster Stage 0. Starts at 0:00:00. Put \'em here cuz Jeb asked me to. I think I added struts between the Stage 1 boosters and From Stage 1 to Core. Note that there\'s no SAS beyond the Mk1Pod. Positive control by vectored thrust. If you\'re not used to this, you can only steer while you\'re doing a burn. Not really a problem, and the craft handles very well despite the huge wings at the tip :/

My first trip to the Mun, I knew I didn\'t have the fuel to land and take off again. I lowered my orbit to 70m, and impacted a 325m mountain range. That was using some Sunday Punch Parts. Second trip, I broke the lander. After a bunch of mucking with designs, I completed a round trip, again using SP parts. Then I reduced the rocket to stock parts plus the Lander Legs from CaptainSlug. After messing up that approach, I rebuilt with just stock parts. At landing I had a sideways vector which was most of my 1.4 m/s speed. The engine popped off, and *THUMP* we landed. The boys seem pleased. From previous experience, if I hadn\'t trashed it, we\'d have made it back. Next ship will have limited RCS. That adds a *LOT* to lander mass, though. And I\'ll make some legs out of decouplers or something. I can do the takeoff -> orbit -> TLI -> Mun Orbit -> deorbit pretty easily now. Just having trouble with parts breaking off even on very gentle approaches. Edit: stole the two-radial decoupler-plus-wing landing gear, ditched the SAS completely and threw on 12 more boosters to cover the added weight in the top stage. Had an iffy TLI, so I had to wait a few days to get into the Munar sphere. Straightforward descent, but I had a slightly rough landing, and cracked one wing off on the gear. Since I have no SAS or RCS, I boosted back up and jettisoned the legs before I toppled all the way over. Return trip was uneventful, but I didn\'t pay attention to my earth deorbit burn, so instead of grazing the atmo a few times to kill V, I augered in to the KSP at Mun return velocities. I think I was still going 3200m/s at 28000m. I wish the max G was working properly, since I probably incinerated AND crushed Jeb into a pulp. Anyway, parachute to successful if abrupt landing.

Those parts are from CaptainSlug's Assorted Hardware, I think, although they're designed to work with 1.75m, 2m and 3m parts from other packs, like the Wobbly Rockets pack. There are, as I understand it, two approaches to using the fairings: You can mount the fairings under an attached nosecone. I think this is what you're doing, but I'm not quite sure how it works. or You can use explosive bolts. This is what I do. Here's an example of how: * Build a top stage or two of 1m parts; for example: Parachute + Cmd MkI + decoupler + fuel tank + liquid engine + decoupler + SAS * Attach a 3m (or whatever - I usually go 3m) fuel tank directly below the SAS. Finish out the stage with some engines or something. * Now you have an odd-looking rocket with a sharp diameter change. * Switch to 2x symmetry * Choose the 'explosive bolt' part from structural. Attach them at the top edge of the 3m tank, on the left and right sides (assuming your default unrotated VAB view is the front) The position and symmetry are important, because the fairing themselves have an orientation. * Choose the 3m (or whatever) fairing sides, still in 2x symmetry. Hold these above the bolts until they snap in green. If the orientation is off, go back and adjust the bolts to the correct position. * Add more sides and the nose halves. * Move the fairing and bolt parts to an appropriate stage, typically after you leave the atmosphere, and before you separate the 1m stage. * Launch! If you have questions, and if these are indeed CaptainSlug's fairings, the thread is here.

For a great deal of added difficulty, you could try putting something into orbit - any orbit - while sitting on the ground. Turns out that if you modify parts to activate when disconnected, you can fly and stage a rocket you're not on. I've been playing with this lately. There are some problems apart from the complete lack of instrumentation / camera, such as: you have to attach the parts in reverse order (They're getting farther from the Cmd Module), and the decouplers stick to the bottoms of your engines.

I think I'm going to download the SRBs-get-lighter-as-they-burn patch first.

Ya GOT me!

There's an early Cheapass Games product called 'Kill Dr. Lucky' which purportedly is the prelude to a game of 'Clue' -- everyone's trying to kill the NPC Dr Lucky. At my workplace in the 90s, I was king of the RTS games we played, so multiplayer games tended to be 'Get Him First Or We'll All Lose'. Which seemed fair. So I started calling the games I hosted 'Kill Dr. Lucky', and took the handle 'Dr Lucky' just to make things clear. It stuck. When teaching people how to play 3-or-more-player strategy games, I now use the following guidelines, in increasing order of importance: Rule 3: Let's You and Him Fight Encourage two of your opponents to fight, depleting them both. Rule 2: Don't Lose Seems obvious, but do not make a move which guarantees the loss. No matter how long the odds, play as though a win is possible. If the top card has to be the 8 of clubs to win, assume it is and play accordingly. Rule 1: Win Again, seems obvious, but if you have a winning move, take it. Many, many people miss this one, in pursuit of a grander strategy. Rule 0: Kill Dr. Lucky Need I say more?

I just thought I stop in and thank both of you for the history lesson on Soviet and American rocket development. Don't stop.

I got a PayPal confirmation, but nothing from KSP. My PayPal email differs from my profile one here, but nothing at either. I donated on Aug 21.

In this rocket I use a 7 x 3m core. I use the aero decoupler, with a lateral 2x1 coupler to get the offset required for the 3m booster. The NERVAs move two 3m tanks well, but a stack of 3 above them is a little more than they can handle. I'm very fond of using 7 x SLS engine under my 3m tanks; the thrust is low enough that you don't have to worry about the adapter vibrating, and the 455 kN of thrust is enough to move a single tank easily, barely move two tanks, or serve as a core to a bunch of boosters. If you're careful, you can get 30 1m boosters around a set of 6 3m boosters on a 3m core. I tend to get a frame a second or so with this arrangement.

CaptainSlug, thought you might like to know that your legs feature prominently in my Multi-Lander project -- a (successful) attempt to build a craft which can orbit, land, orbit again, and land again at the KSC. Operating under a triple canopy on the legs made for an ideal lander/ascent module.

Those are from Sunday Punch's Wobbly Rockets pack. If you haven't tried it, do so. It's a pretty well-balanced bunch of parts, and he updates it pretty much every release.

Okay; courtesy of someone's thread about making launchable missiles, I discovered how to make the retros work: Add the line ActivatesEvenIfDisconnected = True to the part.cfg for the retro. Now you can put it in the stage with the decoupler, and works fine. Sunday Punch - you might want to tweak that in your next release.

Ohhh, nice. I've used the pegs (3 of em) to make a little lander that fits within a 2m shroud: Parachute + Command + light decoupler + light fuel tank + SLS liquid engine + light decoupler + light fuel tank + SLS liquid engine (with 3 pegs on this last bit) So it's sorta LEM-meets-command/service-module thingy. Now I'm practicing landing and taking off again with it. It's a little tricky, but fun. Great parts.

For the record, I did try reordering the parts within the stage, and got the same result each time. I didn't try it with additional parts in the stage, and who knows, that might matter. It's pretty clear when the retros fire; they're not subtle and it lasts for 3+ seconds, and I wasn't able to get them to fire when co-staged with the decoupler. edit: Just wondering what you might have been using as ullage engines, if I'm going to try and reproduce? I mean, since ullage doesn't really matter (yet) in KSP, were you using an SRB? Or are you talking about a particular small engine from another parts kit? It might matter... re-edit: I built another test-bed, and I'm unable to reproduce the retros igniting unless explicitly lit before separation. I had noticed that at times I wasn't sure about whether or not the retros had lit, since the decoupler emits some particles as part of its operation. The stack of 6 retros eliminates all doubt It gets... bright... when they go off. Anyway, I've tried staging the retros with the decouplers and solids which remain attached; still no joy. If anyone can reproduce a retro firing with the decoupler, please let us know what you did!

I just built a test-bed to try out various configurations. The test-bed rocket is pretty simple - I put a lateral tricoupler near the top of a powerful 1m central stage. Then I'd hook whatever test rig to the top or bottom of the lateral. The best results I obtained were the following: - decoupler - retro - rest of stage With the retro staging before the decouple, and staging by pressing space twice. This yields a small velocity decrease, but the retro works fine. Putting the retro in the stage with the decoupler and staging them together appears to do nothing; that is, the retro is a dud and the decoupler works fine. Trying to stage the retro later than the decoupler does not appear to work. Bear in mind that the retro is effectively a small solid motor with a 3.33 second fuel supply and the thrust vectored up. Despite the four-flame appearance, it's really just one thrust, straight up, due to the way KSP works. At any rate, it behaves like any other solid rocket, just backwards. To see the operation of another small solid, try installing a lateral tricoupler under the command module, and put the following stack (bottom to top) on top of each limb of the tricoupler: - light decoupler - small solid motor - 1m parachute adapter - parachute Set the staging so the the solids fire a stage before the decoupler. Put the parachutes in a stage following the decouplers. Like so: Go to the launch pad, and zoom out a ways. When you light the first stage, the solids will turn on, but be captive. Once you commit the second stage, the decouplers will let the lit solids go, which will fly away. Let the solids burn out, then activate the chutes. They should hit the pad either side of you if you don't punch the chutes too early: Now try it again, but move the solids and decouplers into the same stage. Note that the solids never light. You can try it with the solids in a later stage, too, but they don't work there, either. Retros do the same thing as these small solids -- if you don't light them explicitly prior to separation, they don't function. Parachutes are the only parts which seem to work (ie: are triggerable) after separation. The good news is that the retros are only 60 thrust for 3.33s, so if you're using them on a beefy rocket, they won't do much to your velocity. I also played with making a burnable decoupler - I moved the heat tolerance of a few decouplers down to 1 and 100, so that the retro would burn through them when activated. The results were not great; at a tolerance of 1, the decoupler is prone to break spontaneously during lower stage operation. At 100, it takes about as much time to burn through as staging manually would, plus there's an off-putting explosion (although it works). Perhaps there's a happy medium, but I didn't experiment long enough to find it. edit: Okay; courtesy of someone's thread about making launchable missiles, I discovered how to make the retros work: Add the line ActivatesEvenIfDisconnected = True to the part.cfg for the retro. Now you can put it in the stage with the decoupler, and works fine.

I played a little with this, and 3x symmetry works (on the 3m to 1mx7), but 4x on the 5 and 6x on the 7 both fail. I think this one's back in HarvesteR's court. Shame, because the new stage parts grouping makes design a lot easier for grouped parts.

They're a little sketchy, but with some care they can be made to work like this: They're designed to attach kinda like radial couplers - that is, they attach to the exterior surface of the rocket. Because of the gap, it doesn't look like it, but that's what's happening. They're sized to work on 1m parts, and they match a 2m diameter. For practice, whip up the following stack: Parachute Command Module Light Decoupler Small Liquid Fuel Tank SPS-10 Liquid Engine Light Decoupler 2m to 1m shroud (yes, the one that narrows, not widens) 2x long 1m fuel tanks M-50 Engine Then pick up the side panel, set 4x symmetry, and bring it in close to the 1m section above the 2m to 1m adapter. You should see them snap into place, and with a little fiddling you can make them look good. Add another set of the cylindrical panels, and that the nose caps. The only area of the part that physically exists afaik is the bottom centre of the piece, so if you need to pick them up to adjust, aim between the two small circles in the texture. Ignore the blue attach point, I think that's an artifact of the way KSP designates parts. When the part stages, the panel blows clear; it's effectively a decoupler. So add a stage to your rocket at some point when you'll be exoatmospheric, and dramatically blow the shroud at that point 8)

Yup, couplers sever. I've never had one hang up on me. I have had them torn apart by ill-advised rockets. Speaking of ill-advised, I decided to try a stupidly tall rocket using many, many of the new Wobbly parts: Astute observers will note I'm not flying with SAS... too unstable. This design isn't efficient, or terribly easy to fly, or even a good idea in any sense, but it is tall. And flyable. It reached orbit with the last stage (lost a lot of ground on the 2m stage - it was wayyy too heavy for the 2 engines, so I had about 1.5 tanks too many and the engines were overheat prone and shaking violently.) but I had plenty of dV left to deorbit and parachute land. It's a little over 2x the height of the launch gantry, accomplished by building the 3m stage and putting it to one side, and adding it on at the end. It's substantially taller than the VAB.

Okay, this is still a little bit voodoo for me, but I can usually build a stable rocket. On reading your post, I threw together something similar to what you described, I think: From the Top: Top Stage: Command module 3 x FLS-100 tank (long 1m) LV-T30 Liquid Engine (stock 1m) QS-91 Stack Decoupler (Shrouded 1m) Core Stage: RCS Module SAS Module 1x3 Module Adapter Shroud (1m to 3m adapter, non-decoupling) 2x FL-T3000 tank (3m long - the big one) 3M7X1 Adapter Plate (3m to 7x1m) 7x K2-X Liquid Engine (One of the lighter 1m ones) Boosters (3x, symmetric, each with:) Aero Decoupler 2 x FLS-100 tank (long 1m) M-50 Liquid Engine (Large Liquid 1m) 1 strut attaching bottom of lower fuel tank of each booster to central tank [li]I positioned the boosters so that their engines ended just short of the central group.[/li] [li]I moved the 7 central engines into the same stage as the boosters so they all light right away.[/li] At the pad, I press 'T', hold shift to ramp power to max, then press space. No need to fly it at all, and that's a pretty tall (a fair bit more than the launch gantry) and moderately heavy rocket using only two extra RCS/SAS pieces. (You'll need to throttle down after a bit to avoid cooking the engines, mind you). It's a little slow, but mostly I wanted to point out it can be done. Here are the key points: [li]Don't overpower the 7 engine part. There are problems inherent to KSP right now that prevent you putting large thrusts (ie: 7x M-50 or even LV-T30s) on there. If you do, it'll vibrate until an engine or two breaks off. This is fun, in the Dwarf Fortress 'Losing is fun!' sense.[/li] [li]Don't rest a reeeeeally huge rocket on a 5- or 7- engine part; they sometimes seem to crack under the weight, so you launch with fewer engines, leading to instability and fun. Stick some boosters or something down there.[/li] [li]Don't put the RCS too close to the center of mass. It's more effective out toward the end. I only use RCS on medium sized or larger rockets, but I've never needed more than one.[/li] [li]I sometimes use extra SAS modules, but I'll do something like put them on boosters which I jettison - as the rocket gets lighter, I don't need them or the mass they represent. I have a 17,500 m/s rocket which uses only 7 of them - one just like the sample rocket I gave, and 6 on boosters which I drop around 30 km up.[/li] [li]Make your rocket rigid with sparing use of struts. If your upper stage tends to fold around a certain engine or decoupler, turn on 3-way symmetry and tie the upper tank to the one below the engine.[/li] [li]Many SAS modules on parts that are wobbly compared to each other often fight or overcorrect repeatedly, effectively paralyzing their effectiveness. Use as few as you can.[/li] [li]More often than not, the uncontrollable tipping is due to one engine in you cluster being broken - try turning your engines off, shifting the camera and looking to see if that's the case.[/li] [li]Particularly floppy assemblies may twist under the stress of thrust and skew one way or the other. If this is uneven, it will uncontrollably steer your rocket. This happens a lot with SRBs on radial decouplers.[/li] [li]If your thrust to mass is super high, the rocket becomes hard to control - this often happens just before booster burnout, when lots of fuel is gone. Try to always have a liquid component to your thrust, and turn it down a bit if you're losing control[/li] I'm off to see how tall a rocket I can still fly. Let me know if this helps. If it doesn't, assume I'm wrong; it happens a lot. Edit: Tried flying this one a few times; it gets squirrely toward the end of the boosters/core stage as the centre of mass moves forward toward the RCS. I usually fly a 2xlong fuel tank as my last stage instead of 3x, and this helps a lot. But this thing will still easily put you into orbit. Just dial that thrust down as the boosters empty.

I'm testing mine out some more to see what I'm doing differently. My configuration is a core of 2x5000 fuel 3m tanks with 5 SPS-10; the boosters are 6 x (aeros with 3x1000 fuel 1m tanks and the big M-50 at the bottom) I kickstart the thing with 12 solids, and start all the liquids at the same time, but throttled back. As the fuel burns, it gets light enough to keep going after staging. When I stage down to just the core, it's going ~650m/s and loses a little speed until it gets higher/burns more fuel, then goes to 4.9kps at burnout. The top stage is 2x1000 fuel tanks and a K2-X engine, for another batch of kps. On further inspection, it's not doing what I thought - it's consuming from the 6 booster tanks and the central tank simultaneously. So, for some reason it's not cross-tanking, but the central 5 engines only burn 10 fuel a second combined, whereas the outer ones burn 22 each from 30% as much tankage. So when the staging occurs I've burned a bit off the top of the central tank, I just mentally registered it as 'full'. I'll edit my post to correct it.

Yes, fuel flows through them, which leads to interesting possibilities -- as far as I can tell, the game draws fuel from one symmetric set of tanks at a time. If you can arrange the tanks so that the booster tanks get emptied first, and have a configuration with liquid fuel engines in both the core and boosters firing at once, you can throttle back and drop the boosters after they're exhausted leaving the core engines with full tankage. EDIT: This isn't what's happening, as others have pointed out, just my puny core engines are not consuming much of the central tank before I stage, and mine's *not* cross-tanking for whatever reason. Sorry for the confusion /EDIT I believe this is how Spacex intends to get extra payload out of the Falcon 9 Heavy when they get that going - having two Falcon 9s as boosters for a core Falcon 9, and cross-tanking to keep the centre one full until the boosters stage. I used this principle and got an 18 minute burn for my core engines (7xSPS-10). The result was a pretty rocket which lofted a (Command + 2 x FLS-100 + K2-X) final stage to 4900 m/s. That final stage is good for about 9000+ m/s dV, so it was a satisfying launch. EDIT: well, that's what the rocket does; just not why I've also spent a while trying to figure out what's wrong with the 3m to 5x1m and 3m to 7x 1m adapters. There seem to be two problems involved. The first is that when the rocket is placed on the pad, I'd swear it gets dropped there. The forces involved with just standing there is often sufficient to break off one or more liquid engines, and results vary with the position of the spacecraft in the VAB. So when you launch, Bad Things happen. However, if you attach, say, some SRBs that extend lower so that the core engines don't take the weight, they're usually fine. Secondly, and more dangerously, the combination of high thrust and an adjacent heavy mass gives very large vibrations of the adapter relative to the tank it is attached to. e.g if you put on 5 or 7 M-50s (the largest single liquid engine) for thrust in the 2000 or 2800kN range, you get .5m+ oscillations. This usually breaks off an engine or three eventually, and certainly yields stability issues. I'm wondering if there's a programmed-in vibration to these engines that's identical (ie: using the same RNG seed) and results in a compounded vibration when using multiple engines. Certainly it doesn't help that these monsters are directly stuck to the heaviest part of the rocket, so there's a tremendous amount of inertia to work against. It's not clear that there's any way to fix this through the part.cfg Since running heavy, inefficient engines at part-throttle makes no sense, I've tended toward using 7xSPS-10 on a couple of the new 5000 fuel 3m tanks. While not enough thrust to lift the stack at 10m/s/s from the pad, with prudent use of boosters to get them to higher altitudes and lower gravity, they are stable, work well and burn forever. (At full thrust, almost 12 minutes!) Also, for those who haven't adjusted their part.cfg for the Aero Decouplers, do so! The decoupling of a bunch of symmetric boosters using these softer charges is really pretty.

Sunday Punch First off, thanks so much for your parts packs. I'm always eagerly awaiting the next. I'm a big fan of your work, keep it up, please! Ok, I've been trying to debug the parts in 1.09. The aero decoupler, from close, zoomed-in analysis, is ejecting *into* the rocket body. Comparing your part.cfg to the radial decoupler's, your 'UpX' vector is negative. Any chance that the line node_attach = -0.55, 0.0, 0.0, -1.0, 0.0, 0.0 is what decides the *direction* of the decouple charge? ie: the stronger the more you're imploding? I tried setting the eject force to 0 and it works fine, though no clearance, obviously. edit: changed the ejection force to ejectionForce = -5 and it works splendidly. So if anyone's having issues with the aero decouper, just change the sign on the ejectionForce to patch it.