Northstar1989

@NathanKell RealFuels is a great mod. I love how much it enhances the realism of the play experience, and almost couldn't imagine playing without it anymore. You've already done so much great work in it! As a result, I just want to help it improve to be the best it can be- which is why I've been trying to see through an overhaul of the Thermal Fin part from its current white/square design to something that's more realistic (black in color- for greater Stefan-Boltzmann emissivity, and triangular in shape- for better aerodynamics and less drag). I suggested using a re-scaled version of the model for the large, triangular, static radiator from KSP-Interstellar; but I still haven't been able to get any word on whose permission I would need to fork that for a revamp of the Thermal Fin part here... (I need to get a hold of Fractal_UK and find out who the original artist was- he borrowed the model from somebody else) I was wondering if you would be open to replacing the existing part with one based on a larger (and thus more powerful at cooling and more energy-hungry) and more realistic model/mesh if I and/or somebody else did the necessary legwork? Also, are you aware of any other good black+triangular models that are already out there besides the one from KSP-Interstellar? Regards, Northstar

Hey guys. Sorry for the delay in updates again. I've been busy with a few things, and out of town for much of the past two days... Anyways, I launched my next Mun mission: As usual, a magnetically-assisted SpaceX-style launch (if only we would start performing these in real life...) The launch stage made a smooth recovery: After which, the upper stage continued its burn to orbit. FMRS no longer tends to cause my rockets to spin about randomly when re-loaded (although I think installing Kerbal Joint Reinforcement also helped), so I was able to safely load up the upper stage on a sub-orbital trajectory w/o having to lose time to random spinning. The mission vehicle then continued on to its Munar injection, using the lander engines for propulsion (as opposed to giving the Command/Service Module more powerful engines of its own) to save mass: After arriving at the Mun, the mission vehicle then performed a 2-part capture (first capturing into an elliptical orbit, and then circularizing at the next periapsis) to save fuel, also adjusting inclination before circularization, and rendezvoused with the orbital science-station... The lander and command/service module then broke apart, and docked to different parts of the station. Meanwhile, the station jettisoned its engine (used to bring the Integrated Science Module to the Mun) to free a docking port for the Service Module... The engine will remain in Munar orbit as debris- I eventually intend to use it and similar debris as reaction mass for an orbital Mass Driver. The Kerbals then transferred out of the Command/Service Module and into the science laboratory, and fuel was transferred over into the lander and Command/Service Module in preparation for landing... The landing went smoothly, but see if you can't spot what's wrong here: That's right! I accidentally hauled a giant empty fuel tank all the way from orbit down to the Munar surface, when it was meant to remain part of the orbital station as an additional fuel-storage module... Nonetheless, the landing went smoothly, and I'll hopefully have more progress to report Soon. Regards, Northstar

Ahh, I didn't know that. Makes sense to me- a TWR of 120 was on-par with some of the best rocket engines ever built/designed, and the Raptor already has one of the highest thrust to cross-sectional area ratios ever designed. Normally you have to make trade-offs in a rocket's design... I was actually thinking (and briefly suggested- but then edited out of my post) that you just leave the original mass of 3.5 tons intact, and up-rate the thrust to 4120 kN (corresponding to a TWR of 120- or use a lower thrust value if you don't think the thrust plave was included in the figure of 120...) But then I changed my mind about that, because what you've done with all the other engines is tried to maintain the thrust and adjusted the mass instead- even if keeping the mass and adjusting thrust would be more realistic. Sounds great to me! Although, FFSC is an extremely rare and difficult-to-engineer (but high-performance) cycle. Where did you get your information that the SpaceY R1 engine should be FFSC? The fact that its ISP closely follows the RP-1 (lower ISP than the Mainsail) leads me to believe it is probably *not* FFSC... Thanks once again for all your hard work Raptor! I'm happy with the state of things now- the Math/LOX engine may still not be 100% realistic (its thrust and mass values are both too low for its cross-sectional area), but it's now gotten the same treatment as all the other engines (that is, its TWR and ISP values are realistic, even if thrust and mass levels are not due to maintaining the original thrust figures), which is good enough for me! Regards, Northstar

I don't see the static (rather than deployable) radiators there- and I'm pretty sure they were made by a different artist than ZZZ... GREAT! Thank you so much! Could you post it over in the RealFuels thread so NathanKell could use it in his next release of RealFuels? (otherwise, it doesn't do anyone else any good but you) Preferably with screenshots of what it looks like, so NathanKell can get an idea of if he wants to include it, and I can find out ahead of time if it's the kind of long, triangular (and thus more aerodynamic), *black* (real radiators are black, to increase their Blackbody Radiation emissivity) RealFuels radiator I'm looking/hoping for... Regards, Northstar

The mass values for the Raptor were back-calculated from the announced thrust and TWR values (8200 kn thrust in vacuum, TWR of approx. 120). Sounds like you're extremely close to the real-life TWR values if you're pushing over 100 now. [B]More on the Math:[/B] 9.81 kN is the force of gravity on a metric ton at 1 g. Thus an engine with TWR = 120 produces 1177.2 kN of thrust per metric ton. The Raptor would produce 8200 kN of thrust at a TWR of 120, therfore it should weigh approximately 6.9657 metric tons. As for the ISP values, where did you find any besides 321/380 SL/vac? Those are the *only* reliable numbers I came across for the *latest* iterations of the Raptor. You were likely looking at earlier figures before they upgraded the designed thrust from 4400 kN to 8200 kN and vacuum ISP from 360 to 380? (all at the expense of mass and higher chamber pressures, however) Regards, Northstar

What seems to be the difficulty that is holding you back from doing the same thing in a normal game? Regards, Northstar

@Fractal_UK The Thermal Fin parts in the RealFuels mod currently could badly use a more aerodynamic shape, and a more realistic color for a radiator (*cough* they're currently WHITE rather than BLACK), and I was wondering if I could get your permission to allow a fork of the model for the large, triangular static radiators currently in KSP-Interstellar for a revised version of the part (but scaled-down to a more reasonable size for a craft that is only trying to coll cryogenic propellants rather than dissipate the heat of a nuclear reactor...) The middle, ugly, white, square part in the screenshot below is what the RealFuels Thermal Fins currently look like: Their model could really use some love, as you can see. So if you would allow a fork of the current static radiator models, or someone else could generate a new model for RealFuels (with a triangular shape for aerodynamics during launch, and a black color for realism), that would be GREATLY appreciated. Regards, Northstar

I have the same problem. I was meaning to mention this to you NathanKell, but I got a little caught-up trying to get a more aerodynamic/larger Thermal Fin into the mod. Speaking of which, KSP-Interstellar already has a rather visually-appealing triangular radiator fin; the model for which would make s superior (and better-looking) replacement for the current Thermal Fin. Among other improvements, the radiator is not only triangular (and thus more aerodynamic) it is also black. REAL radiators are black in color, because that maximizes their Blackbody Radiation (color affects their emissivity under the Stefan-Boltzmann Law)- which is the *only* way to cool anything in space. There was a *reason* all the concept art for JIMO showed black radiators... Maybe I could convince Fractal_UK (the creator of KSP-Interstellar) to allow a fork of the radiator model I was talking about (the large, triangular, black one), with a re-scale to bring the model down to a smaller (more reasonable) size? If so, maybe I could post a revised version of the Thermal Fin part using the new model (but same balance), and you could use it in the next release NathanKell? Regards, Northstar

Glad I could be of help! FFSC has higher ISP and TWR largely because of the higher Chamber Pressures it enables. The chart you linked to assumes a Chamber Pressure of 6,895 kPa (1000 psi). But both the Space Shuttle Main Engines and the Raptor use much higher chamber pressures. The SSME's used a Chamber Pressure of 2994 psi, for instance (according to Wikipedia), and Full Flow Staged Combustion engines (such as the Raptor) are capable of even higher Chamber Pressures. The following comes directly from the "Design" page of the Wikipedia article for the Raptor (emphasis added). Additional characteristics of the full-flow design that are projected to further increase performance or reliability include - eliminating the fuel-oxidizer turbine interseal, which is a potential point of failure in more traditional engine designs - lower pressures are required through the pumping system, increasing life span and further reducing risk of catastrophic failure - ability to increase the combustion chamber pressure, thereby either increasing overall performance, or "by using cooler gases, providing the same performance as a standard staged combustion engine but with much less stress on materials, thus significantly reducing material fatigue or [engine] weight." Thus, despite a 1000 psi Meth/LOX engine using conventional cycles only being able to achieve an ISP of 368 seconds (not coincidentally, the vacuum ISP used for the base KSP-Interstellar part- Fractal_UK probably used that Wikipedia chart without referencing the actual Raptor stats or examining the chamber pressure the calculations were based on...), a FFSC Meth/LOX engine can *easily* achieve 2 or 3 times the chamber pressure (the SSME's had 3 times the Chamber Pressure, and didn't use FFSC), and thus an ISP of 380 seconds in vacuum (the predicted Raptor ISP) actually becomes quite conservative... Bottom Line: I would advise matching the projected ISP values for the real Raptor design. The numbers you used (311/379) are still too conservative for Full Flow Staged Combustion (321/380), and don't allow the Meth/LOX engine to compete effectively with LH2/LOX launch-stages... Cost increased from 3050 to 4200 according to your latest post. The thrust is 1450 (compared to 1500 for the Mainsail in stock- but higher in RealFuels with tech-levels). So it actually seems to be about right for the per-unit cost, considering FFSC is *much* more advanced technology (and the EntryCost is doubled to reflect this) designed with greater cost-effectiveness in mind. However, the overall thrust is still too low- the Meth/LOX engine should have a *higher* thrust than the Mainsail (the Raptor has a higher thrust than almost any comparable-sized engine). The mass should also be increased proportionally (the Raptor isn't as much lighter compared to comparable-sized engines as what you have in the config). So basically, the Meth/LOX engine is still too light and produces too little thrust... Players can still lift heavier payloads with a Mainsail in LH2/LOX mode, which should *NOT* be the case (the Raptor enables larger payloads for the same diameter rocket due to the fuel-density advantages of Meth/LOX and the overall thrust advantages of FFSC). Remember, Meth/LOX is a *lower ISP* fuel than LH2/LOX- so if the engine thrust is also lower, players will be stuck with a *much* lower payload-capacity for the engine... With the current balance, players still have ZERO incentive to use the Meth/LOX engine over a Mainsail (which has a lower EntryCost, is available earlier, can achieve higher ISP when in LH2/LOX mode, and still has a higher base thrust even in LH2/LOX mode...) This needs to be changed. Please adjust upwards the engine mass, ISP (to 321/380), and thrust. I would recommend adjusting the XLS equation so that the cost stays at what it currently is (about 4200) when making these changes, with the new figures becoming the FFSC baseline (there needs to be SOME incentive to use the Meth/LOX and other FFSC engines- if you increase cost much further it won't be worth the *huge* EntryCost...) Thanks for all the hard work, as always! Please consider increasing the Meth/LOX engine thrust- currently the Mainsail has much higher thrust *and* ISP when in LH2/LOX mode! Regards, Northstar P.S. In the base KSP-Interstellar game, the Meth/LOX engine doesn't have to compete against the ISP of LH2/LOX engines- so the stats don't need to be nearly as realistic to make it worth using. However with LH2/LOX engines in play (with RealFuels), the Meth/LOX engine NEEDS more realistic Thrust/ISP stats to be competitive...

@Raptor831 Never one to uselessly point out problems when I have the means to easily fix them, I went and fixed the MM patch for the engine. Here is the version I *suggest* using: @PART[FNMethaneEngine]:FOR[RealFuels_StockEngines] // { @maxTemp = 1948 @entryCost = 32000 @MODULE[ModuleEngines] { @maxThrust = 2270 @heatProduction = 181 @atmosphereCurve { @key,0 = 0 380 @key,1 = 1 321 } !PROPELLANT[LiquidFuel] {} !PROPELLANT[Oxidizer] {} !PROPELLANT[MonoPropellant] {} PROPELLANT { name = LqdMethane ratio = 39 DrawGauge = True } PROPELLANT { name = LqdOxygen ratio = 61 } } MODULE { name = ModuleEngineConfigs type = ModuleEngines techLevel = 7 origTechLevel = 7 engineType = L+ origMass = 3.5 configuration = LqdMethane+LqdOxygen modded = false CONFIG { name = LqdMethane+LqdOxygen maxThrust = 2270 heatProduction = 181 PROPELLANT { name = LqdMethane ratio = 0.39 DrawGauge = True } PROPELLANT { name = LqdOxygen ratio = 0.61 } IspSL = 1.0506 IspV = 1.0506 throttle = 0 ModuleEngineIgnitor { name = ModuleEngineIgnitor ignitionsAvailable = 48 autoIgnitionTemperature = 800 ignitorType = Electric useUllageSimulation = true IGNITOR_RESOURCE { name = ElectricCharge amount = 14.5 } } } } !MODULE[ModuleEngineIgnitor] {} MODULE { name = ModuleEngineIgnitor ignitionsAvailable = 48 autoIgnitionTemperature = 800 ignitorType = Electric useUllageSimulation = true IGNITOR_RESOURCE { name = ElectricCharge amount = 14.5 } } } Comments/Questions on my changes: - I deleted the line entirely to change the engine mass from the first part of the config, and changed the "origMass" line to 3.5 (is that something that even needs to be included if the mass isn't changed?) - I removed the line to change the per-unit cost from the first part of the config (the original cost was fine). Instead, I more than doubled the EntryCost (the cost to unlock the part) to 32,000 to reflect the considerable design challenges. Players who don't use EntryCosts can/should be able to still get the engine cheaply- one of the MAJOR advantages of the Raptor engine is that it would be *much* cheaper to manufacture due to the less stringent engineering margins Full Flow Staged Combustion enables... (despite its higher performance, the Raptor as currently designed is actually *further* from its theoretical maximum for an engine of its type than current rocket engines designs- to reduce costs and improve reusability...) I'm sure you're aware of the exponential relationship between engineering margins and cost- and the engine was already a bit pricey for a 2.5 meter engine (at least compared to several other mod engines from KW Rocketry and NovaPunch2), so it didn't make sense to change the per-unit costs... The engine also requires the extremely-advanced Experimental Rocketry tech node- so between the high Science and part buy-in costs (which were already high, and I more than doubled) of the engine, there ought to be more of an economic advantage when simply using it as a heavy-lift engine (considering this is its design real-life role), from a gameplay-balance perspective, or players will never bother to unlock it in the first place... - I changed the ISP to 321/380, the real-world stat. Yes, that's much better than any Kerosene/LOX engine (as you noticed with the XLS file), AND IT SHOULD BE. Meth/LOX is an entirely *different* fuel-mixture than Kerosene/LOX, more similar to LH2/LOX in its performance *and fuel-density*. You wouldn't nerf LH2/LOX engines to match the ISP of Kero/LOX engines, would you? - I increased the thrust to 2270 kN maxThrust. *This was to respect the TWR you selected before.* I came up with this number by calculating the TWR you had before, and implementing it for an engine that weighed 3.5 tons instead of 2.2 tons, then rounding it to the nearest multiple of 5 (from 2267.x to 2270 kN, to make it easier to look at). Keep in mind the *real* 2.5 meter Raptor would produce 8200kN of thrust with a mass of just under 7 tons (6.973 tons, according to calculations from its known thrust and TWR predictions)- so the TWR is still roughly half what it is in real life. - I changed the fuel burn-ratio to .39/.61, to make it more fuel-rich (like the real Raptor). The real Raptor burns fuel-rich to improve ISP and reduce heat generation- although I can't seem to find any hard numbers of precisely how much so. The new ratio you selected before was nearly stoichiometric, however, and thus far too LOX-rich. Please use my version of the config instead in the dev version and next release (I would suggest just pasting this in and pushing a release, if you have the time). Let me know the answers to my questions when you are able. Regards, Northstar P.S. You might initially think the engine currently has too much thrust for its cost. But consider the cost-effectiveness of SRB's, against which this engine is competing for a role in helping to lift Heavy Launch Vehicles... It's not *MEANT* to be in the same class as normal chemical rocket engines- Full Flow Stage Combustion is a whole different beast when it comes to performance, compared to older rocket engines.

O.o I don't know why I didn't think of that before. I was looking in the KSPI_MFS file for the MM patch, instead of the normal engine config file... EDIT: MAJOR problem with the MM patch, though... You actually *decreased* the ISP of the engine (from 309/368 to 300/365) when one of the biggest issues that was wrong with it already was that the ISP was lower than the real Raptor engine (321/380). So you actually made the problem *worse*. Remember that Meth/LOX *is not* Kerosene/LOX, it's an entirely different fuel-mode (more similar to LH2/LOX in ISP and fuel-density). How many LH2/LOX engines have you nerfed so they match Kerosene/LOX engines in ISP? (that's basically what you did the equivalent of here) You also more than DOUBLED the cost of the part (from 3050 to 6554), while only reducing its mass by 1.3 tons (from 3.5 to 2.2) and increasing its thrust by 25 kN (from 1425 to 1450). And you over-corrected the burn ratio (the ratio you uses is about stoichiometric, whereas the *real* engine burns fuel-rich. The *correct* fuel/LOX ratio should be about .4 to .6 or .39 to .41 instead of .443 to .557 (the previous RealFuels ratio) or .375 to .625 (the ratio you are now using). So, OVERALL, you actually made the engine *less* realistic than it already was. The costs are now too high (the per-unit costs were correct before: Raptor engines would be cheap to manufacture for their performance- remember, they're meant to be used in clusters of 9 or more... To increase costs realistically, increase the "EntryCost"), the ISP is LOWER when it needed to be made HIGHER (remember, the real-world figure is 321/380- which the RAPTOR *needs* to be able to compete with LH2/LOX, due to its much lower fuel-density than Kerosene/LOX), and the mass is too low for an engine that size (the thrust needs to be 59.1% higher than the original instead of the mass being 37% lower if you want to maintain the TWR you choose). Also, remember if you reduce engine mass without reducing heat production (like you did) you cause the engine to overheat much more easily (I'm not even sure the engine can safely be fired at full-throttle now: which is *not* as issue the real Raptor would have.) I drew up and posted below a revised config I'd like you to include. Please do- I really need a more accurate RealFuels-compatible Meth/LOX chemical engine for my current playthrough... Regards, Northstar P.S. Whatever fuel/LOX burn-ratio you settle on also needs to be mirrored in the base RealFuels mod, for the KSP-Interstellar NTR fuel options. Currently those suffer from burning far too fuel-rich when it Meth/LOX mode as well...

Link please. MUST SEE! Seriously, though, they might have the same problems with incorrect ISP/TWR values. No idea if they based those off the real engines or not... By the way, I noticed that the changes to fix the Meth/LOX engine ISP (and slightly improve the TWR to be more realistic) aren't currently part of the latest version on GitHub as far as I can tell. Didn't you say you already fixed that (in the same post I quoted before) some time ago? In fact, the current GitHub and Release versions of "Stockalike" don't have MM patches for the engine at all as far as I can tell! (meaning the engine won't work in RealFuels at all, as the engine uses Oxidizer without a MM patch...) I'm using an older version of "Stockalike" still until this issues is resolved, but I also need to update so that my RAPIER and NovaPunch2 M2 engines won't burn Oxidizer as well- so please update soon! Regards, Northstar

One more issues I just noticed, going through the files. The current dev version of RealFuels (where I managed to find the file you sent NathanKell before- so it's not as important to post it here anymore- until you make further changes) doesn't have a specific part fix for the tank capacity of the radial Ammonia tank in KSP-Interstellar. I already whipped something up for this before, although it didn't up-rate the capacity at all, despite the decrease in resource density (meaning it now holds less mass of Ammonia than before). Here it is, for reference: @PART[FNAmmoniaTank] { MODULE { name = ModuleFuelTanks volume = 10731 type = Default } } I don't have any idea how to submit pull requests, or I'd just submit this change to NathanKell directly. But the tank volume also needs to be increased, to maintain the same mass fraction as before, so it's not ready to go yet anyways (I'll try to get back to you with the correct numbers for tank capacity, remind me about it if I forget). Also, one last thing. NathanKell seemed concerned that I might be "bugging" you too much about this integration config. I hope I'm not getting on your nerves about it? I understand what's it's like to get your wisdom teeth removed and then have to catch up with everything afterwards- so I'm certainly not trying to be bothersome about this. Let me know if you'd prefer I stop updating you about tweaks/fixes that need to be made to the config entirely. Regards, Northstar

What about just using tweakable tank types, B9 Aerospace/ Firespitter style? You could probably even just re-use/re-release the same modules they did to make tank types switchable (with permission of course). It's not like the mod isn't already sorely in need of more tank types anyways. The Ammonia, LiquidWater, and Methane tanks are all extremely limited by only coming in one type/size (radial or 2.5 meter inline- and only in a few sizes- I can't make a really short 2.5 meter methane tank for a lander, for instance). Adding a few catch-all tanks that work equally well for Ammonia, Nitrogen, or even pure LiquidFuel (maybe you could just use the models you did for the LF-only tanks) would probably be a good idea... Such tanks would also make it easy to add a couple other desirable resources, like Carbon Dioxide (useful if you could scoop it off the edge of Duna's atmosphere, and run the Sabatier process in orbit), and Carbon Monoxide (it's possible to produce it from CO2 and Hydrogen using the Reverse Water Gas Shift Reaction, and then burn it with Oxygen for an entirely ISRU-propelled rocket that doesn't require locating ice deposits...) Personally, I use RealFuels and ProceduralParts, though, so I have any tank type I could need anyways- I just need a way to harvest Nitrogen and the resource to store in the first place... This would open the door to lots of propellant (Nitrogen-electric propulsion, mainly) and ISRU purposes (including Propulsive Fluid Accumulators and the Haber Process) like you said- so maybe it's worth the time? I'm sure you could get some of the players here to help you create general-purpose fuel tank models/artwork, so all you have to do is the coding aspect of it... Great! I'm always grateful/thankful for all your hard work Fractal! By the way, any thought to adjusting the ISP/thrust of the Meth/LOX engine to match the real-world Raptor (currently the ISP is too low, as is the TWR). I already managed to get a patch added to the RealFuels Stockalike engine config for a realistic ISP, so I won't be *too upset* if it never sees its way into the base mod; but I figured the mod is fairly closely based off real-world values to begin with, so why not get this one right... Regards, Northstar

Telling me to make a mod for a mod, generally isn't a very helpful solution. If it's so simple to add (somehow, I don't think it is), then why doesn't Fractal_UK just add it to KSP-Interstellar, and have it done with once and for all? Regards, Northstar

@NathanKell Just a thought on Xenon tanks. You know that in real life, space-grade Xenon tanks are typically highly-pressurized, right? I hope you're considering that in assigning them capacities- they should hold a *LOT* more Xenon than a comparable-sized unpressurized fuel tank. Of course, since Xenon tanks are so pressurized, the tank mass is also quite high for the size- due to the laws of pressure vessels (tank mass is directly proportional to volume that can be held at 1 atm- double the pressure or double the volume, and the wall thickness has to increase proportionally, creating a strictly linear relationship between capacity and dry mass...) All that being said, I'd rather have a highly-pressurized Xenon tank than one at low pressure- the mass fraction is the same, and it means I can pack more Delta-V into a tiny probe that fits inside a tiny fairing. If the tanks were less pressurized, the probe would be bulkier, and I'd need a bigger (and therefore more massive and draggier) fairing. The current Xenon tank capacities don't seem in line with real-world Xenon tanks- the capacities and tank masses should both be higher (the pressures normally used are much higher than stock seems to assume...) Regards, Northstar P.S. On Deep Space One, the Xenon was stored in a supercritical state (this is *highly* pressurized- Xenon has a critical point of 15.9 degrees Celcius, 841 psi; which equates to over 57 atmospheres pressure). Which in fact created several engineering challenges in bringing the pressure down for the ion thrusters: http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/14210/1/00-0619.pdf

Hey Raptor, I saw this a few (almost 3) weeks back when you posted it, but then haven't heard anything more about it since, or seen any related commits in the dev version of Stockalike. I would LOVE it if you did include a 3.75 meter version of the Meth/LOx engine that actually did clone the real-world specs (or something closer to them) like you suggested to fulfill the heavy-lift role. A 2.5 meter engine simply isn't powerful enough to lift a 3.75 meter rocket... (unless you use the real-world Raptor stats for the 2.5 meter version) It's worth noting that there were a couple reasons the Raptor stats are way out of line with the XLS for 2.5 meter engines. One is because almost all the engines in KSP produce less thrust than their real-world analogs, and have inferior TWR values (real rockets are much taller, and thus require much better engines, due to the greater Delta-V requirements to reach orbit). The other is because the Full Flow Staged Combustion cycle used in the Raptor is a MUCH more advanced engine design that almost any other engine out there. I think there were ever only 2 other engines that were designed to use it, and neither of them made it off the test stand (although they DID work as expected in testing) as there was no need for an engine that powerful (its greatest advantage is that it makes re-usable rocket stages much easier when you have an engine that powerful- but nobody ever seriously attempted reusables until Space-X) and it is significantly more expensive to engineer in the first place (but not to build- a higher but-in cost in the tech tree is the best representation for this)- something that also deterred its development until Space-X's efforts at reusability... Also, that engine design doesn't offer very substantial benefits when using LH2/LOX- so most rocket designers preferred to just stick with LH2/LOX for high-performance launch stages, rather than move to Kero/LOX or Meth/LOX engines with a Full Flow Staged Combustion Engine (I should note that LH2/LOX is a poor choice for reusable launch stages, due to its low fuel density- it makes it difficult to build a launch stage with a low enough Center of Mass that it won't tip over after touch-down, an issue Space-X is currently struggling with despite using Kero/LOX- they already lost one launch stage in a recovery test to it tipping over in the sea and the fuel tank rupturing...) I should note I launch almost all my rockets Space-X style in KSP, so I would LOVE to have a Full Flow Staged Cumbustion engine at my disposal, even if its tech tree buy-in costs (I play with those enabled) were considerably higher than other chemical rocket engines... (the per-unit cost shouldn't be, however- the engines aren't actually harder to manufacture, only design) Anyways, enough tangents about the performance aside. I deeply hope you'll follow up on this idea you mentioned before. Also, some investigation reveals the KSP-Interstellar Al-Hybrid TWR and ISP are, surprisingly, perfectly accurate already. Several design limitations about how the Aluminum can be packed in (in such a way that the Aluminum can be replaced via ISRU, as it can be in the KSP-I version) tend to increase its dry mass substantially (leading to a rather low TWR compared to what can theoretically be achieved with this propulsion system...) Thus the current TWR is spot-on with design projections, as far as I can tell... I know you asked about this before, and I wanted to follow up with this information. Thanks for all your hard work so far! Regards, Northstar

@noobsrtoast Please stop triple-posting the thread with poorly-formatted (you're not even making use of capitalization) run-on posts. It's it bad form. @Streetwind I think you're beholden to some misconceptions- the bombs used in Orion *already are* a type of fusion propulsion- they are small thermonuclear warheads, which means the majority of their explosive power actually comes from the fusion component of the explosion. The fusion proportion also goes up with larger bombs (the quantity of fissile materials necessary to initiate fusion remains relatively unchanged as you scale up the bombs- meaning you can pack in a larger percentage of fusion components), which is one reason the ISP of Orion actually *increases* the larger you scale-up the system... Oh, and since the fusion components don't generate significant fallout, only the fissile materials do- a 25 km diameter Orion generates roughly the same fallout as a 250 meter version... Thus *any* size of Orion comes in at about 1-2 total deaths caused by radiation per launch, and as the smaller (*less* cost-effective) designs are already at a lower cost than a Saturn V (one of the *major* breakthroughs Project Orion scientists made was in figuring out how to mass-produce small thermonuclear warheads- for obvious reasons those parts of the document are still HIGHLY classified...), you could *easily* use the money saved vs. a Saturn V (or SLS) sized conventional rocket to save dozens of lives in the developing world by providing people access to clean water, food, vaccines, condoms, education, etc... Regards, Northstar P.S. I have never been one of those "we have too many issues to deal with here" type people when it comes to space exploration, as I *strongly* believe looking to the stars and pushing human limitations inspires people to peace and innovation back on Earth; BUT I believe it is a *MORAL IMPERATIVE* to meet our space-exploration goals as cheaply and efficiently as possible, so we have more money left over to deal with problems here. In other words, explore space, but don't be wasteful about how you do it...

I've been running my own Twitch channel for some time. Come check it out any time! http://www.twitch.tv/northstar1989 Regards, Northstar

Hey Vsully. You said you have a lander "around" the Mun- does that mean you haven't managed a landing yet? If so, I *highly* recommend watching my Twitch live-stream (which I'm going to be starting up in a few minutes), where I'll be launching a Mun lander to Kerbin orbit and then proceeding onwards to making a Mun landing. I'll be checking chat periodically, and I'd be more than happy to answer any questions you or other players have... Regards, Northstar

It sounds like you're just burning straight up, and expecting to get to orbit Rayge. You know you have to perform a gravity-turn (that is, slowly tip over until your are burning horizontal during your ascent) to make orbit, right? Orbit is basically the state of moving so fast *horizontally* that you continuously fall and yet always miss the ground. Once you're there, getting *anywhere* is usually just a matter of speeding up, slowing down, or burning at a right-angle to your velocity so as to alter the inclination of your orbit. If you see this message on time, I *highly* recommend watching my KSP Twitch live-stream which I'm going to be starting up in a few minutes. I'll be starting off by launching a Mun Lander to Kerbin orbit, which should be *highly* instructive if you're struggling just to get to orbit yourself... Regards, Northstar

Citation needed. Regards, Northstar

The license is CDDL-1. Thinking about adding a link to it in the OP. Does that help you answer my question? Regards, Northstar

Glad to have you aboard Rayge! How much progress have you made so far in the game? An idea of what you already are (and aren't) able to accomplish would do a LOT to help narrow down the tips to things that would be specifically useful for you... Regards, Northstar

Glad to have you aboard Vsully! What exactly seems to be the problem you are having with your Duna landing? Is it smashing into the ground at high speeds? Are you just struggling to figure out how much fuel you need to carry with you? Any additional information would help more experienced players a LOT in giving you some pointers... Regards, Northstar