Seyvern

I'd suggest if you are going to make it a seamless extension, you'll need to reconcile your Nuclear thermal rockets with stocks. Honestly your stock values drove me nuts and kept me from using hte mod for a while, but then I just altered things to bring your rockets in line with stocks. now I don't use stock NERVA anymore, which was the goal. I posted my spreadsheet values on page 120 or something around there. -Seyv

Honestly, your biggest issue with relights for interplanetary missions has nothing (very little) to do with the engine itself (assuming you design it with that in mind) and most to do with your fuel. For example, if you are using liquid Hydrogen as a fuel, you can basically forget about keeping it around for any length of time due to boil off. Thats equally true for LH2 /LOX chemical engine, or a LH2 NERVA. Someone mentioned above that Kerosene has problems, which is true, not due to boil off, but due to fouling. Some options do exist tho: For long duration deep space missions, there are hypergolics that have very low loss. Their ISP kinda sucks, but thats what we currently use now for satellites and space probes (when not using Ion engines, which is becoming more common). For non-hypergolics, there are still options. One of the most popular right now is Liquid Methane / Liquid Oxygen. It has fairly good ISP (about 380, not LOX / LH2 numbers, but not bad), can be stored at relatively high density compared to LH2 (which makes the size of the tank much smaller for a given mass, and thus makes up for some of the ISP deficiency) and while technically cryogenic, is relatively easy to prevent boil-off. It also has the ability to be 'mined' from places you can get ahold of carbon and water and electricity (e.g. mars). Space-X is looking to make their next generation upper stage engine Methalox, probably more for the storage of the propellent features i mentioned than the 'mining' feature (as one can also make LOX/LH2 from water and electricity). For NERVA engines, you can use most anything. LH2 still has the problem of boil off and large tank mass, so generally the consensus is that the best option for long duration missions is Ammonia, which is still very light (and thus has good ISP) and isn't cryogenic. It also can be stored at relatively high densities (small tank volumes). In a pinch, you could use LOX or methane, but they are less optimal (although perhaps easier to 'mine'). There was a really good article someone wrote up (I think on Space.com, but I can't find it anymore) where somone build huge spreadsheets of the various fuel options as a function of engine size and tankage, looking for the optimal points. It was a good article, and went into great detail on which fuels work best for what. I wish I could find it and link it, but this is the basic gist. As for the ignition question specifically above - that part is relatively easy. You can use ullage motors, or let the natural outgassing of the fuel to pressurize before ignition, there are a bunch of techniques people have come up with to get the fuel to the pumps. ** footnote - Ammonia was the propellent arthur C. Clarke used in 2001/2010 for the reaction mass of the Discovery space craft, which I believe was using a plasma engine (not sure if that last bit was true). He did this for the same reason cited above - H2 boil off was unacceptable for a Saturn mission, so he picked the best compromise fuel.

See HoneyFox's answer - one way you can do it is use hypergolic tanks just to ignite the fuel. The number of reignites depends upon the size of those tanks. Another way that is used is what might be described as heavy duty sparkplugs. The reliability comes down to how you engineer the system to survive the hostile environment its got to live in. Generally speaking, thats not as bad as it sounds, because engines you might want to start and stop often - e.g. manuvering thrusters, are generally relatively low power and so the reignition system (or in teh case of hypergolic engines, the reaction chamber) can be made more robust without a huge weight penalty. Space shuttle OMS is a reasonably good example of that. They were designed to deal with multiple, relatively short lived, re-igntion sequences as necessary (and indeed be reusable after overhaul from flight to flight). If we ever do a mission to mars, we will probably need a robust re-igniteable non-hypergolic system. Robust because it needs to be able to reignite multiple times, over the span of years. non-hybergolic because we want it to have some reasonable ISP so the mission can be done. In that way KSPs ahead of our real space program. We don't have many situations yet where we are sending vehicles on long distance travel and doing significant re-ignites (other than small course correction burns on space probes), which can be very small hypergolic engines and thus probably count from this mod's point of view.

Gotcha, makes sense.

Thats cool, but I would suggest the opposite. It makes no sense to upgrade parts individually - do I forget how to make a gas core reactor every time I build one, and have to start from scratch? Leave the science rates alone, or possibly even up them. Then add in some sort of persistence file that records which parts are unlocked. Or perhaps, if you can figure out how to implement it, make two variants of the various parts, but the only ones that show up in the VAB are the ones that have unlocked in the persistence file?

Ugh. Given the 'Science Price' associated with parts being so high, i was hoping it was the other answer. Don't think thats something I can mod either, since pretty sure that bit lives in the .dll

I'm up and running a modified version of this mod. Now that I'm about ready to upgrade equipment, question - do science points get used to upgrade a single part, or do they upgrade all like parts from that point onward? Thx, -Seyv

Actually, I know about rocket engines. I included the comment about the link above because I saw he posted something that did not support his point. And yes, it might be more realistic for engines like mainsail. The problem with hardcoding it, tho, is that its artificially limiting. For example, the Saturn IVB engine was designed for multiple restarts, except that first it was designed for only one start (when it was part of the Saturn I). Generally, speaking, if you were using mainsail's for first stage boosters, they would be designed for single ignition. THen, down the road, you might build some spacecraft that you hypothetically wanted to use a mainsail in as a booster (unlikely, given the ISP and thrust output, but lets say you did). What you would do in real life is make a small change to the engine to add multiple ignite capability, and designate that a variant of the mainsail. THere are hundreds of examples like that where engines are slightly redesigned for various uses (e.g. Merlin D vs Merlin D vacuum). You could model that in KSP by making 3 variants of each engine, or you could just make one generic engine thats sufficient to capture what you are really trying to do, which is essentially what the game does now.

No its not particularly realistic. Usually rocket engines fall into three broad categories. 1) engines that are designed to ignite only once, with a specific single use igniter. These are usually first and second stage engines. 2) non-hypergolic engines designed for multiple restarts. These have different igniters and do have a design life, but aren't like shotgun shells: you don't have a specific set number of uses. Exmaple of such an engine is the new Merlin-1D vacuum engine (with dual igniters for redundancy) or the Centaur. This is not the most reliable of methods, it can fail, which leads to #3 3) hypergolic engines. Put oxidizer in contact with fuel and it spontaneously ignites. Example would be the AJ-10 from the Apollo CSM. Suffers from generally a relatively poor ISP, but if you need it to start every time, on time, this is the most reliable method. The link PrivateFlip posted above mine doesn't say what he thinks it does. Basically, it describes single shot igniters (SRBs, and first stage engines (e.g. pyrotechnic charge) and it describes multiple start systems (e.g. plasma igniter/spark plugs)

I started playing with this mod, and then got annoyed with it, as cool as it is, because the thrust values are so out-of-wack w/ stock KSP. I searched the thread, and saw the reply where the mod developer admits this, but is ok with it. I'm not, because I'm not going to play with this when a LV-N is so much superior to a 'stock' nuclear reactor and thruster. So I went in, figured out the equations used in the Mod, and reverse engineered a new set of part values. I haven't played with the plasma engines, just the thermal- i don't think it will mess them up balance-wise, as I believe they were ok (it will change the thrust to weight ratios somewhat, but in a useable way, IMO). In any case, if you change the part file parameters as listed in the following chart, you will get ISP, Thrust, and T/W Ratios as per the chart. Note that the values fall directly in line with the LV-N (ISP is better per the mod, but I made the weight slightly higher to compensate): ............waste.heat.....Core.Temp.......Thermal.Power....Thrust...........ISP...........Reac.Mass.......Jet.Mass.....Total.Mass.......T/M.R N625........112.50.........2900.00..........20.00............4.46............914.91........0.225...........0.001........0.226............19.72 N625U.......112.50.........26100.00.........60.00............4.46............2744.73.......0.225...........0.001........0.226............19.72 N1250.......2500.00........2900.00..........350.00...........77.99...........914.91........3.00............0.00.........3.00.............25.99 N1250U......2500.00........26100.00.........1050.00..........77.99...........2744.73.......3.00............0.00.........3.00.............25.99 N2500.......30000.00.......2900.00..........750.00...........167.13..........914.91........6.00............0.00.........6.00.............27.85 N2500U......30000.00.......26100.00.........2250.00..........167.13..........2744.73.......6.00............0.00.........6.00.............27.85 N3500.......150000.00......2900.00..........1600.00..........356.54..........914.91........12.00...........0.00.........12.00............29.71 N3500U......150000.00......26100.00.........4800.00..........356.54..........2744.73.......12.00...........0.00.........12.00............29.71 A1250.......500000.00......10000.00.........5000.00..........600.00..........1698.95.......2.00............0.00.........2.00.............299.85 A1250U......500000.00......1200000.00.......55000.00.........602.49..........18611.03......2.00............0.00.........2.00.............301.10 A2500.......4000000.00.....10000.00.........18000.00.........2160.00.........1698.95.......6.00............0.00.........6.00.............359.94 A2500U......4000000.00.....1200000.00.......198000.00........2168.98.........18611.03......6.00............0.00.........6.00.............361.44 A3500.......13500000.00....10000.00.........40000.00.........4800.00.........1698.95.......12.00...........0.00.........12.00............399.97 A3500U......13500000.00....1200000.00.......440000.00........4819.96.........18611.03......12.00...........0.00.........12.00............401.63 for comparison LV-N 60.00 800.00 2.25 26.67 Just edit your parts (save it somewhere so you can copy over updates) and you will have baseline parts that are equivalent to Stock, and all the functionality of the mod. These parts are all reasonable, IMO. A 2.5m AM engine has a thrust not very different from a mainsail, but great ISP. seems balanced compared to stock. If you like it, enjoy it. -Seyv

One guy complaining - that is expressing his frustration in terms of some unsubstantiated threat to the dev team - does not mean you should worry. I personally think the update cycle is slow and frustrating. I am also unlikely to pretend (unlike the person your responded to) that my frustration anyway translates to 'lack of interest in the game.'

Generally agree w/ the sentiment that range of challenges is good and Eve should be left alone. That being said, I personally think Tylo is the hardest body in the game, if one doesn't use mechjeb. The DV requirements are huge given the need for a powered decent on a near Kerbin sized gravity field, and w/o using mechjeb, doing an _efficient_ powered decent takes massive skill. (Note - i'm not a mechjeb hater - just makes powered landings alot easier)

I'd love to fly on one monitor, and look at the mapview on the other - with maybe orbital parameters thrown in Beats looking at this forum as i fly.

Up till now, we (the global we) have had parallel staging. However, Falcon 9H is going to have true asparagus staging, albeit with only one asparagus stage. So its not really a cheap trick.

Then ignore me, but sitting in timewarp for 20 minutes isn't really playing, as a number of people have pointed out. I'll get 'uppity' with your cheerleader as I like when every single response he makes to anyone who points this fact out is a combination of techno-babble and 'deal with it'. In any case implement your mod however you want, you've heard my opinion.

I really don't care what your opinion of made up physics should be. From a gameplay perspective, the current scan 1 pixel at a time sucks and ruins most of the enjoyment of the mod, and the purpose of my post is to covey that sentiment to the mod developer, not to get in a debate with you.

sigh. I keep hoping that there will be kethane update with a less annoying swath width scanner, but it never happens.

You were the one that brought up USAF in the first place. As support for the fact that F9H is a bad idea. Whatever - congratulations, you win this internet argument. F9H is a horrible horrible idea. What could SpaceX be thinking. Back to the originally scheduled thread - Yes, boosters feeding mains is a good idea, and SpaceX is using it (no doubt just to waste their own time and money). It also works great in this game. Sorry for the threadjacking.

I work in this field. Rubish back at you. First, there is the space station. They would build larger more efficient modules if they could. But I don\'t care about the ISS. Here is a real easy example - New Horizon. Ran past limit of the DIVH capability - had to use a unique atlas configuration.

disagree. Plenty of things you might build if you had half the lift capacity of a Saturn V. Currently noone builds them because that lift capacity doesn\'t exist.

Nice pic!

Had fun playing with this, but the second stage (landing leg decouplers) are still iffy as hell. I\'d say 50% of the time they destroyed the ship.

See Falcon 9 Heavy (they use this this type of staging)

its actually near the south pole. I was conforming to the standard on this thread and not giving too many hints about the exact locations.

My explorations: gratuitous use of ion engines included: My first Munlith: By gavicola at 2012-04-08 For explorations in atmosphere: (this aircraft, dubbed the Ion Flyer, flys so sweetly!) By gavicola at 2012-04-08 By gavicola at 2012-04-08 My first Kerblith By gavicola at 2012-04-08 and second, in the mountains By gavicola at 2012-04-08 And just now, third, in the Kalps! By gavicola at 2012-04-08 second on the mun, the Pit By gavicola at 2012-04-08