wumpus

Another big issue for 1968 NERVA was fuel. NERVA pretty much means hydrogen (others insist on other fuels without mentioning exhaust velocities or the temperatures expected for them, but mainly hydrogen). By 1968 hydrogen was fine for a couple orbits and then a burn to Moon insertion, but NASA used Aerozine 50 to get back. Storing hydrogen for multiple months may be possible now (or not), but it was certainly a bigger issue decades ago. Getting back from Mars, Jupiter, etc. would be a problem, not to mention things like capture burns. Still, any improvement in Isp for the big burns would help (unfortunately I don't think *anybody* came up with a NERVA that would work for the surface->LEO big delta-v requirement).

I think a mathematician would quibble on your definition of "proof". Certainly any "solution" would contain the same instability of a simulation (after a million years or so, changes in weather today would alter which side of the Sun the Earth ends up on). There are two issues with KSP's gravity simulation: 1. The spacecraft is only effected by a single source of gravity: fixing this in "unwarped time" is trivial. Just add a "F=Gm1m2/r**2" for each body in the system. Problem: you can't have "physicsless warp" anymore. I'm not sure how they deal with that (and does it make ion drives functional?). 2. The planets/moons are on rails. Well, first you have to fix Jool's moons, because they have been known to be unstable for quite some time (and early simulation showed a moon ejected only after a few orbits). Then your calculations bog down as you get to compute that "F=Gm1m2/r**2" as it scales factorally over the number of bodies you are willing to calculate. Somehow I suspect that for anyone willing to get rid of Squads SOI hack, they feel fixing this is necessary (I doubt it changes the game at all). In the end, the problem is remarkably similar to the "inertial wheel problem". While doing the physics is *hard*, the reason you need to do hard physics is the UI (KSP players like warp and don't want to sit and watch in realtime). Basically it comes down to how accurate you want your maneuver nodes. Computing a maneuver node requires you to simulate all the physics for the entire length of time the maneuver node shows. I'm guessing the UI for running out of available angular momentum is easy. Using RCS to compensate while reducing the angular velocity of the wheels is something else. I'm sure there are kerbal players at APL (Johns Hopkins Applied Physics Laboratory, the place that runs Hubble), can we find them and ask them how they control Hubble's reaction wheels?

Did it in beta, hope you have full heat shields when coming in with a PE>60km (I was really tired of pushing). More likely, I've jettisoned my engine "early" and have taken some really long re-entries. Especially those "lets bring an extra stage back home" re-entries.

From the sound of it, it sounds like it would effect the game roughly as much as the need to settle the fuel before a burn in RO/RSS (maybe even less as there aren't particularly good reasons to wildly keep accelerating in the same axis). I'm guessing it is a lot harder to code (probably the hard part is showing how much angular momentum is available, but it might just be coded in too hard). But it really looks like the modding difficulty is more than the degree of accuracy annoyance. Look at how far the modding community went with N-body physics. Now that is a seriously hard-coded limitation in KSP that several people just couldn't handle (I'm in the "please give us fake SOI at Lagrange points" camp, but wants to play with "fuzzy boundries" at some point).

Also, check a few threads on low memory usage. I'm pretty sure tricks like forcing opengl or older directx versions result in significantly less memory useage (and were critical in using excessive mods before 1.1, at least on windows machines). Here's one: PS. While hp has certainly cratered compared to when Hewlett and Packard were alive, I'm pretty sure there are plenty of KSP players who can top your "worst computer". Some of us even had packard bells at some point.

Only do this if you feel this to be true. I've ground science on KSC too many times to be willing to go at it again. Note that while a maxed out (multiple slow missions?) is 1838, or 3-4 minmus biomes. Note that as some point your "multi-landing" probe will want a refill, so how your docking skills matter. Speaking of docking, if you really want to max out the science, put Jeb and Bob in separate landercans (Jeb for the fancy flying and Bob for science restore) and store all science in duplicate. Have a landercan attached to your "space station" (read flying fueltank) and leave a copy there before you go home. Bring back a mobile science lab (preferably with a crew of trained up scientists, see xp and leveling if they are new to you) and let them unlock every last bit of science. A lot of this depends on if you insist on waiting for launch windows (and I'd assume you would have to with a beeline. Over 3000 delta-v seems next to impossible right after sending probes to Mun and Minmus, but I know I've done it at the 1500 level). I keep looking at the time to launch window and thinking "I could unlock a ton of science nearby". A probe to Duna would be more fun, but having the science lab up there makes waiting for launch windows seem "productive".

Isn't "magical RCS" an important part of the game as well? As in RCS has no effect on the ship you are docking with (presumably semi-plausible with deliberately inefficient design to minimize such effects, but of course non-zero IRL). At least this was true back when Scott Manley released his docking videos and it has been close enough ever since.

[tl;dr] lag scales badly, hardware scales linearly. Throwing hardware at the problem won't fix lag (especially if you are at the top end of hardware already). You're missing the obvious issues. First and foremost: what resolution? As far as I know, all the physics is handled by the CPU (unity might have Physx, but I don't think it offloads anything to a [nvidia] GPU). There's nothing a 1080 will do to help part count lag. Mods typically are a matter of RAM. Since 4GB (likely 2GB) was all KSP could use before 1.1, it is next to impossible for 16GB to not be enough unless one of your mods have a memory leak (can you even have a memory leak with C#?). Most mods should have a nominal effect on CPU time (unless you want that one that uses N-body gravitation. Push that one and it will bring a Broadwell-E to its knees, although I suspect using it within reason should still work with an i5). Scatterer and similar shader mods are the only thing that will change the GPUs effect on speed. To put it bluntly, KSP just isn't a graphically complex program. It basically builds a bunch of rockets and/or planes plus some planets with some sort of procedural (I hope) geography. The only reason for it to lag is high component count, and that tends to blow up either geometrically or exponentially (not sure, but once it lags you should stop adding parts. I'd suggest testing all your parts on the ground, i.e. hooking up your completed spacestation on the pad (and held in place by launch clamps) and making sure you can pan around it with a working frame rate. Also consult the threads for advice in avoiding overly laggy spacecraft: somebody noted that docking ports are some of the worst parts you can add (they have to check for all other docking ports (including ones on the station?) to see if they are docking). And as I mentioned in the [tl;dr] section, lag scales either geometrically or exponentially. In practice this means that *even* if you were limited by your GPU, going from a 970 to a 1080 card would only allow you to add a few more parts (maybe not even an extra docking port). Really, the best we can hope for is some sort of collaboration between Squad and Flying Tiger to produce algorithms that will work on wimpy jaguar processors (console processors are *tiny* and designed for low power).

I bet that's it. I always wondered about it, but had too much else to worry about when taking those classes.

I don't know. I didn't have him and was wondering if it was a bit more common (similar to things like epsilons being controversial in calculus). This is all true, but generally the stress is pretty small. Do you really think their isn't a tiny spike with a >20g acceleration when it lands? Of course, you can typically just reattach a hose or something then (assuming you are willing to inspect it. Which was never part of the original plan). The stresses of the weight of the booster are pretty much locked in and unchangeable. The stresses on tiny components attached to the booster are minimal and easier to design around. I've designed electronics for mil-spec 810 and it wasn't a real issue (the mechanical guys who build heavy structures had to worry about it, I had to worry about 461 and EMI issues). Small components are remarkably capable of handling 9g of acceleration (I'm guessing this is the force typically exerted by dropping a few inches. Any mechanical engineers out there with shock/vibe experience?). NOTE: this doesn't really apply to "getting the dregs out of the fuel tanks" which as far as I know is the current speculation as to why the falcon9 [booster] crashed. Running any engine down to zero is not recommended (if at all possible, not always possible in rocket science) , and then suddenly changing the situation from 3g to 9g can't help.

One reason not to close the thread is inclination adjustments. Hopefully you had your inclination absolutely perfect as you aligned your flyby/periapsis. If you want to adjust your inclination, you should stop your capture burn the moment the orbit closes. Then fly out to either apposis or your ascending/descending nodes and burn there (this will minimize cost of inclination burns). After this, adjust your periapsis at apposis (be *very* careful of adjusting ascending/descending nodes on the way down, you can easily hit a collusion course. Just use your blue (up/down) nodes to move your periapsis inefficiently if you have to.

F=ma * the acceleration is higher, but the mass is lower (100*5>25*9). The force is therefore less and you have less stress on the structure (I'm surprised it is that close. Note that it has ~500t of force** just sitting on the pad and then taking off with a TWR of 1.3? makes it go even higher). * at least one professor at my college refused to teach this equation (I didn't have him) and my later professors had to apologize about using it. Any reason it might be controversial (I'm guessing it has to be taken as an axiom, where most other things in physics can be derived). ** yes, those are metric tons and not a unit of force. Convert to imperial tons (which should be within the single significant digit) for units of force (I *think* tons are force, and never did any funky conversions between 2000lbs to one 1 ton, but try to avoid doing science in imperial).

Huh? You do realize that rockets weigh less when landing then when launching? The only way the rocket could reach launch stress is if it weighed well over 1/10th the launch weight (and remember the whole upper stage isn't there when landing). Price of error remains the same. There are nine rocket engines on the booster regardless of however many are firing on the way down. Loss of one booster either way. My guess is that if there is room for the fuel for a single engine landing, they will go that way. If not, then a three engine landing it is.

Except that this is almost certainly the ideal mission for ion propulsion (biggest problem: you have to use RTGs instead of solar power, so maybe next to certain complicated mercury missions). From memory, when people were wondering if Far Horizons could have orbited Pluto, I noticed that early NASA ion propulsion systems were just coming on line. It turns out that they could have likely deposited the spacecraft in Pluto orbit, but would be betting on yet another untested (at the time, tests were just starting) system. Remember: if anything goes wrong with that spaceship, all the people you saw cheering New Horizons are out of academia and looking in industry for a new career. I'd also expect that an ion propulsion system would take a bit longer. It might get faster as the spacecraft slowly inches [is mm up to speed an idiom yet?] up to speed, but then it has to start slowing down years before it gets to Pluto to have a chance for a capture burn. I'm not sure how much we would get beyond seeing the unknown side (and presumably poles and other barely perceived areas). Don't expect a high priority, and remember that you need a team in for the long haul (somewhere between 10-20 years). And forget about fusion. You don't need it for this mission, and it needs more time in the lab.

Falcon9 is only planned to work on Earth. As far as I know, SpaceX has no plans to land on planets with zero atmosphere (Mars has .5%? of Earth's). We go through this many times (and SpaceX started with trying to use parachutes on Falcon[1]). For any break between 0-100% parachute landing, SpaceX figures on 100% retrorockets, 0% parachutes. Some things they have done to improve vertical landing: Paddle controls: Pretty much real life a real-life cross between the KSP AV-R8 and AIRBRAKES part. I wonder if they might make them bigger for these "hotter" landings. Expect any additional aerodynamic means to slow descent will involve something like this. Three engine descent: A single engine should have a TWR ~3, meaning significant gravity losses. Three engines stopping the rocket on a dime will have much less gravity losses, at least until they turn the descent over to a single engine for the final landing. I'm guessing they still need to work out fuel margins, and that is what doomed today's launch (cutting from three engines to one). The Soyuz combines both parachute and retrorockets. I suspect the parachute is sized such that the cosmonauts can survive without the retrorocket, leaving a parachute so large the thing often drifts *way* off target. Falcon9 routinely hits the barge, often where "x marks the spot".

I don't think anyone has built an ISRU device. As far as I know, it would work fine. The real catch is the kerbal babysitting it doesn't need life support. The nuke is perfectly reasonable, except that it should be burning hydrogen and not "rocket fuel that is really RP1" (if you check, "fuel" is much heavier than "oxidizer"). So the nuke engines really are roughly as unrealistic as most of the high-ISP vacuum engines (they are modeled after hydrogen burners), that blithely avoid all the issues of hydrogen and its fuel tanks. The prototypes for the nuclear engines were built at least by the 1970s, so they don't need "high tech". Isn't the minimum .1m/s display in KSP way too fast for "real life" docking? My plan remains enjoying this game while getting good, then moving over to RO/RSS. KSP realism works in the game, but I'd like to try my hand a something more like the real thing. How complicated would "realish" ASA units be? Would you manually have to "desoak" them, or would they just use up RCS undoing their momentum changes? And how much thrust would you lose (I'm assuming that only capsule control would make sense, and then you would be afraid to touch time warp because it would be so slow). I'm not sure that the ISPs are two high on the jet engines, it is more an effect of letting them go too fast (the ISPs might work if averaged over 0-1000km/s). Once they start going faster ISPs should drop even more. And going nearly all the way to orbital speed really kills realism of spaceplanes [note the x-43 hit mach 9.6, wildly faster than any kerbal spaceplane* and possibly the start of a real SSTO]. Life support is bad. Stuffing a kerbal in a mk1 cockpit all the way to Duna (or even Eeloo) is worse. * spaceplane in the atmosphere. Obviously you can crank up the speed with a nuke and go off to the Mun at >3.0km/s.

Judging from the various abandoned projects lying around: building a game engine isn't all that hard. Building a game engine worth using is a *lot* harder. And being able to tell them apart takes a rather long time, so game designers don't want to be the first ones to build a game on the engine. Consequence: game engine designers need to build games on their own engines (and then *still* have trouble selling them). Note: the engine from crytek was on absolute fire sale a few months ago. Presumably it has outrageous performance, outrageous graphical beauty, and outrageous amounts of bugs. I doubt it was easy to make, but I would think that just the games the parent company made proves it had value. This isn't to say it isn't that hard. To build something that KSP can move to you need to clone Unity 4/5, a system that has grown to meet the needs of a *ton* of games and game designers. You won't pull it off for just one game. If you still feel the need, find out what orbiter does (presumably something custom, non-made-for-reuse code) and build your "engine" around that. Orbiter seems like a reasonable target, KSP does not.

Oddly enough, as the aero model gets more complex and accurate, I tend to build out to the side more (wobbly rockets flip over so much easier post 1.0.0). While there is a lot to be said for streamlining, I've found that you can often make a cheaper rocket by throwing a bunch of SRBs to the side (the bugs in the fairing haven't helped. Were they fixed in 1.1?). Don't forget you can download the demo from Squad and re-experience a far more limited [stock] KSP. It is a nice place to limit that focuses you attention on making a more pure kerbal rocket (you are pretty much forced to asparagus due to part limitations). It is a great place to visit but I wouldn't want to live there. I'll keep my main game in 1.1 (and later) and keep my mods.

In another thread (potential KSP DLC, I think) I floated the idea of a "KSP Raid". Pretty much "one seat in NASA mission control = 1 KSP player". Just one flight, but full realism and a small army to control it. Somehow I doubt it would be all that popular. You might try an orbital mod.

Well, if you can pull that off you have KSP 2.0. I feel that whoever replaces HarvesteR had better understand gaming (rockets, gravity, simulations and programming are pretty much done. Career mode and good gaming systems are another thing). Once career mode is "done", such a game designer could presumably start a KSP 2.0 built from Kerbin up to make a better career mode (instead of the ideal sandbox that HarvesteR made). Personally: I suspect I'd rather play the .18 demo than play such a KSP 2.0 game, but that is likely because I'd rather play Squad's demo than nearly any other game published. KSP 2.0 (sim rocket program) might very well be a great game on its own.

I needed that earlier (it wasn't working with shift and angle snap). Now all I need is some way to measure the angles (these were pretty minute, the angle of a tall rocket needed to start a gravity turn).

The catch with compression schemes is that a "universal compressor" (an algorithm that always produces an output smaller than the input) is impossible. From the sound of it (a coding scheme) that seems the case. It may have been a "lossy compressor" that outputs some image/sound/movie that appears "good enough" to human eyes, but is not quite perfect (and as shown above, you can make movies with only a few k of memory, but they have to fit specific conditions). The proof is simple (called the pigeonhole principle you can probably get a better explanation by googling pigeonhole compression). Since any binary input has to effectively be a stream of 1s and 0s, covert that into a binary number. Then produce all possible numbers with that many bits (this is basically infinite and for mathematical proofs only). You now have 2^(string length) inputs and you want to compress them in half, so you compress them all. You now have 2^(string lengths) strings that are "string length"/2 in length. So you make a set of 2^(string length/2) pigeonholes and number them from 0 to 2^(string length/2)-1. You then start filling each pigeonhole with a compressed string, but suddenly run out of pigeonholes and have to fit multiple strings (on average 2^(string length/2)) into each pigeonhole. The fundamental impossibility lies here: your "universal decompressor" will have to magically determine which identical string was the original and how to decompress it.

A more interesting example comes between "realism" and "difficulty". Or "realism"=="micromanagement". Some of this stuff (read docking) gets much harder with increased realism (well, size. But also remember that it takes 3 days to dock with the ISS. Docking speeds are *slow* in real life). Then there are issues with the fact that launches simply take longer while doing almost exactly the same mission. I'm guessing that the "realism"=="micromanagement" faction will cause the most forum angst. Mission control is full of seats: since NASA does all this (in real time) there really isn't any reason for *you* not to do it. To be honest, I could see something like this as a "KSP Raid" where a guild of KSP players sit down and literally replace *every* single NASA function in a painfully accurate simulation. I just have no idea how much such DLC would cost (presumably with a fairly low volume of subscribers) nor can I see Squad wanting to do it (sublicensed DLC anyone?). The real reason that game designers are forced to choose between "real" and "fun" is real: reality exists in a single way, it may or may not be fun. Non-real systems exist in many ways: many won't be fun, but some typically are. It is a strange situation where the most fun one happens to be the single realistic simulation. Here are some examples: Spaceplanes are popular in KSP. Presumably, you would not see so many topics on spacesplanes in these fora if they were not fun. Unfortunately spaceplanes are completely unrealistic: all existing spaceplanes are suborbital*. Making an orbital spaceplane is essentially impossible and only works in KSC due to making orbital speed something like mach 5. Realism overhaul kills the idea of spaceplanes. Rescue missions are popular in KSP. Probably the most fun mission is to go out and rescue a downed comrade. In reality, such an error almost always results in total loss of crew (check arstechnica's excellent writeup of NASA's analysis of a potential Columbia rescue). A realistic KSP won't have rescue missions at all. Politics: NASA missions take years to plan, but Congress only appropriates funding for a single year at a time (mostly due to constitutional reasons). So expect to justify your funding every year, and accept mission creep multiple times between accepting contracts and finally lifting off. I suspect that this will never become part of RO/RSS because it would be so unfun. There should be plenty of fun in a realistic KSP, but don't simply assume that by adding realism you don't alter the fun. While it certainly isn't a single axis (fun on one side and realism on the other), the two axis aren't completely orthogonal. PS. This is one of the few DLC ideas that I would enjoy buying. I suspect I would buy others just to keep KSP production going, but that would involve different reasons. This just seems such a complete split with the current direction of KSP (call it the HarvestR direction) that I would understand Squad wanting a separate money stream from it. PPS. Does anybody know how KerbalEdu works? Could that be available as DLC (and would anybody want it?).

TL;DR - Funds matter (if only for unlocking buildings). If you overdo your strategies, expect hard decisions. A word of warning for anyone excited by the "leadership initiative": make sure you can afford all the building upgrades before pulling the trigger (and cutting your money off). I cranked "leadership initiative" up to ~80% (that reputation gate is brutal), and came back from Minmus after hitting 6 biomes previously untouched by kerbals (a few had probes on them). Result: 6800 science (2k from strategies!). Unfortunately, this means I now have about 4k of unspent science and a hard decision about unlocking stage 3 of my science center (1.6M kredits). Best guess is that only probes will be sent to Duna the next launch window, but the MPL on Minmus will grind through all available science (my 6800 science mission has a second copy of all possible Minmus science floating around in space). I still don't regret my "leadership initiative" (although I expect to undo my "funds for science" and "funds for rep" minimal strategies). Just expect that the costs will be higher than you initially budgeted. Having less grind and more "boldly go where no kerbal has gone before" will still be worth it.

Well, "what I did yesterday". Finally collected two copies of every "science" in every biome on Minmus. One copy delivered to KSC, one copy in (Kerbin) orbit. The point of the second copy is to go in a mobile lab, preferably on a Minmus polar region (and yes, I stuck a flag at a site that can have 24x7 sunlight: this mission got everything done). The reason this was an important mission is that it was the whole reason my 1.0.x career start ground to a halt. I had 3 copies of all KSC science in a train of mk1 capsules near the launchpad and a dread of manually dragging each copy up into a rocket, to say nothing of doing a mission exactly as above only with 4 copies of the science. Finally dropping three mobile labs on Minmus (and at least joining them temporarily for a specific contract) was burning me out. The nerfing of multiple labs was a relief: my original plan to stay on 1.0.x and finish the grind was easily dropped when I heard about the "leadership initiative". Since I prefer milestones to contracts, this spurred me to 1.1 (and then finding out about the "reputation gate*", oh well). Problems: I returned with 6800 science (I had already one crewed landing on a biome and had been landing my probes on the various flats of minmus when they were finished). I was able to unlock everything up to the level 3 gated techs (which cost ~$2M kredits**). Unfortunately, my "leadership initiative" might make it difficult to unlock the rest (it is responsible for at least 2k of the science) due to that is about 90% of my current funds... I still plan on launching the "Minmus Institute of Technology" (the mobile lab on Minmus's pole), but don't expect to use any of the science for awhile. * reputation gate: The "leadership initiative" at 100% gives you a 150% to all milestones hit and a 50% bonus on science "field work", but cuts all your contract rewards in half. While this level only costs about 100 "reputation" (which as far as I can tell is only visible when attempting to start this program, otherwise it just gives a percent), it requires something like a reputation of 700 to start. I started it at about ~80%. ** Has anybody made a US+ keyboard with a "coke bottle***" button to allow "GBPounds", "Euro", umlaut, and other buttons that I would have to tape up a "alt + keypad" cheatsheet (opposite of my dear KSP subway map)? It looks like "kredits" are no longer "roots" but "pounds", at least in my game. *** old EMACS joke.