Northstar1989

Glad you enjoyed the guide so much! It really needs to be expanded to take into account the new stock ISRU system more, but it's something, at least, where I found a sparsity of guides... Regards, Northstar

Not sure if this issue is specific to Stockalike or a general bug with RealFuels. Thought I'd link to it here in case of the latter. Hope this is of help. Regards, Northstar

Here to report a bug- it seems that using TweakScale to resize any of the engines, and then choosing any alternate fuel (a fuel other than the default for that engine- for instance LH2/LOX for the Skipper engine) will cause the engine to try and use the default fuel anyways, and the GUI to appear blank (with no info or options showing) upon reverting to the VAB. Loading up other craft, exiting the VAB, etc. will not fix the issue- the engine becomes unusable until the game is reset. Regards, Northstar

The link to the configs on the front page has stopped working at all (it gives a 404 Error), and there isn't even a link to SmokeScreen and RealPlumes there. If RealPlumes/SmokeScreen with a special set of configs (or, alternatively, HotRockets- also with special configs?) is going to be necessary to restore the engine effects, can we please, please, please at least get a set of instructions and links on the first post of this thread? Regards, Northstar

No, OTRAG perfectly fits the category of "Big Dumb Boosters". It worked too, from what I understand (although I know less about it that Sea Dragon or Aquarius). Proving, we could do better than we are doing right now. Thanks for bringing that up. Regards, Northstar

As for the Sea Dragon, *none* of the technology was unproven (except for the size of certain parts which were just scaled-up versions of smaller well-tested technologies). That was the beauty of it. And while it's possible scaling the technologies used up to that size might not have worked well, nothing about the Sea Dragon line of thinking required scaling up to such massive proportions. Sea Dragon was a *type* of Big Dumb Booster. The basic idea was that you combine simple construction techniques (often used in shipbuilding), cheaper materials (corrugated steel instead of ultra-thin aluminum), and wider engineering margins- and you get a much cheaper per-kg rocket with higher reliability. Nothing about what goes into that was untested, and it was almost guaranteed to work because *nothing* was untested or unproven that went into it (including the construction techniques and materials- once again, often used by shipyards... Our existing fleet of warships is floating proof that this approach works, and generates lower costs...) Saying that Sea Dragon was too large to work, therefore that entire class of Big Dumb Boosters wouldn't work is like saying "Clifford was an impossibly large fictional dog, therefore dogs cannot exist at all". There is absolutely no reason you couldn't scale the Sea Dragon approach to rocket-building down to a more reasonable size. Or simply substitute more reasonable-sized engine clusters for its own monolithic engines. The thing that drove down it's cost was primarily, not its size or use of only one main engine per stage (the lower stage also had numerous radial boosters, in the style of the side-mounted engines in KSP, to aid in attitude control as well as provide extra Thrust) but its use of cheaper and heavier construction materials and techniques to get lower costs at the expense of mass-faction. There's nothing about that you can't scale down to (almost) any size you want... Regards, Northstar

Stop minimizing the project just because you don't like the results. The feasibility was confirmed by TRW and NASA engineers. It's been re-visited multiple times by later engineers and still found feasible. Yes, the cost estimates were $59-$600 /kg (1962 USD). By comparison, Saturn V was $2915 /kg in 1962 USD. Of course the costs have come down with modern manufacturing techniques and such- it's logical to assume that Sea Dragon would be even cheaper if built today. Still, no currently operating modern rockets beat $4735 / kg, which is what the cost would be of Sea Dragon in 2015 dollars. The commonly-accepted figure for currently-operating launch systems is still $10,000 /kg according to NASA. Countries like France and Russia subsidize their commercial launch industries, so the listed costs are not economically accurate. This is not the F-1. The F-1 was an engine with radically different design principles. It was a gas generator design, to be precise. These were pressure-fed engines (on both the upper and lower stages), which, it turns out, are much simpler to design and scale up... Regards, Northstar - - - Updated - - - You could say that about ANY rocket that's never actually been built. The whole point of this discussion is ways we could go beyond the present launch-economics, and get to something more affordable. The logic "it hasn't been done yet, therefore it can't be done" is what has held humanity back for its entire history. If that logic had always been allowed to prevail, we would still all be skinning animal hides with Stone Age tools, or in the very least would never have gone to space in the first place. Stop latching onto the status quo, and start thinking of what *might* be possible for once. Alright, it's 6:15 AM here and I've been up all night. I'd better get some sleep. Regards, Northstar

Why exactly are you debating actual figures from an actual design with "what-if's" and a list of technical difficulties? The fact is, these obstacles were overcome- that's how we got the Sea Dragon design in the first place. There's no point in rehashing a list of the problems with something and saying it can't be done, when proof it *can* be done is staring you right in the face... Regards, Northstar

For the record, some actual Sea Dragon specs: Gross Mass: 18,000,000 kg Payload-capacity: 450,000 - 550,000 kg (LEO, different altitude/inclination used for final orbits for each estimate) Mass-fraction: 2.5% Cost-per-kg to LEO: $600 Sources: http://www.astronautix.com/lvs/searagon.htm https://en.wikipedia.org/wiki/Sea_Dragon_%28rocket%29 As you can see, I was being more than a little conservative in the scaled-down scenario above, just to make the point (I assumed much worse mass-fractions, and much higher cost-per-kg). Note that some of these benefits come simply from scaling- i.e. a 5% mass-fraction *might* be achievable with a rocket this large to LEO using s "smart booster", but the relative benefits vs. a comparable sized "smart booster" should be preserved even with scaling. Regards, Northstar - - - Updated - - - Kryten, if you can't be respectful, I'm going to have to ask you not to post here at all. We need to keep the conversation civil, and phrases like "pulled out of your arse" are not respectful. What's more, it is not acceptable to make personal attacks. *I* did not come up with these numbers, a set of highly-trained experts in the field did. Who know more than either of us about these things. It is not acceptable to personally attack me just because you don't like a piece of scientific or engineering data that clashes with your preconceived notions. NASA had an independent firm, TRW separately investigate the numbers for Sea Dragon, for precisely the kind of reasons you state- they were concerned the numbers might be fudged. TRW found the statistics to be perfectly accurate. Todd Shipyards also confirmed that the construction of the rocket to the required levels of precision was "well within their capabilities" (part of the reason the cost of the rocket was so low was because the engineering margins were wide enough that it could be built with the facilities of a shipyard rather than a highly-specialized manufacturing plant...) Regards, Northstar

Here is what a sample mission plan might look like, using the lowest-cost, BDB-based solution. Let's say that the payload is a 50 kg satellite with a 50 kg transfer-stage to GSO that only weighs 10 kg when launched "dry"... (so that's 50 kg of satellite, 10 kg of transfer stage, and 40 kg of fuel for the GSO-transfer, all to LEO as the payload) Mission Vehicles: (ROCKET-TYPE #1) Aquarius-style rocket with 20 kg payload-capacity, 0.75% mass-fraction, 66% success-rate, and $1250/kg to LEO (ROCKET-TYPE #2) Sea Dragon style rocket with 60 kg payload-capacity, 0.75% mass-fraction, 99.8% success-rate, and $2500/kg to LEO Launch #1: 20 kg of fuel to LEO depot on Rocket-Type #1. Mission Success. Launch #2: 20 kg of fuel to LEO depot on Rocket-Type #1. Launch Failure. Launch #3: 20 kg of fuel to LEO depot on Rocket-Type #1. Mission Success. Launch #4: 60 kg payload of satellite + transfer stage to LEO depot on Rocket #2. Payload refuels at depot and proceeds to GSO. Mission Success. Total Cost: $25,000 x 3 + $150,000 = $225,000 Compare this to a "traditional" mission: Mission Vehicle: (ROCKET-TYPE #3) Conventional "smart booster" with 100 kg payload-capacity, 3% mass-fraction, 99.7% success-rate, and $10,000/kg to LEO Launch #1: 100 kg of satellite + transfer stage + fuel to LEO. Payload separates in LEO and proceeds to GSO. Mission Success. Total Cost: $1,000,000 Note the following: - Using the "smart" booster the total mission cost is more than 4x as high. - Progressively larger "smart" boosters require larger launchpads. Both styles of Big Dumb Booster are designed to launch at-sea, so you can scale them as large as you want without having to build/upgrade a bigger/better launchpad. - The total chance of mission-success is actually HIGHER with the Big Dumb Boosters. This is because Rocket-Type #2 is actually MORE reliable than Rocket-Type #3, in the same way that Sea Dragon type Big Dumb Boosters would have been MORE reliable than "smart" boosters with a comparable payload-capacity, due to having very wide engineering-margins... - The LEO Depot required for Rocket-Type #1 (the Aquarius-style rocket) is actually factored into cost-per-kg estimates, the same way that launchpad costs are factored into the cost of a typical "smart" booster. However, an Aquarius-style rocket assumes that the LEO fuel depot was purpose-built for storing fuel launched to LEO on low-reliability rockets (specifically, it assumes an annual launch-mass of cheap consumables equal to the average annual mass of cheap consumables such as food/water used by the ISS) and serves no other purpose. The LEO depot is a piece of orbital infrastructure capable of storing both fuel and consumables, however, and could also be useful for storing propellant harvested from Near-Earth Objects (specifically, ice and hydrate-rich asteroids), Lunar ice-mining, etc. Any shared utilization of this depot with other projects, or any mass launched on it in excess of the annual consumables-budget of the ISS would amortize the setup-costs of the depot (which comprise nearly half the $2500/kg cost-estimate of the Aquarius-style rocket, as it was assumed by the engineers that the depot would be launched on a $10,000/kg "smart booster") over more missions, resulting in a further cost-per-kg decrease for Rocket-Type #1. Also, if a Sea Dragon style booster were used to launch the depot in the first place (which is expensive, and therefore must be launched on a high-reliability booster) the cost/kg of Rocket-Type #1 would be lower to begin with... Regards, Northstar - - - Updated - - - Yes, yes you are. No, not necessarily. We can launch 100 kg satellites if we want, and I prefer to use them as illustrative examples to make it clear that Big Dumb Boosters can be scaled to any requisite size. Sea Dragon and Aquarius were only prototypes for entire classes of rockets, they were not the only sizes their respective styles of Big Dumb Booster could be scaled to. No. The cost-figures I gave pages back are the actual total-cost estimates for Sea Dragon and Aquarius (and the #'s in the scenario above are based on even more conservative #'s). Both rockets launched from the sea to avoid the requirement for launchpad-infrastructure (Aquarius because of its poor range-safety, Sea Dragon because of its massive size which was larger than any existing launchpad). All other costs, including crawlers, barges, etc. were already factored in. Mass-fraction, by definition, is the fraction of the total rocket that is payload. This figure takes into account the ISP of the engines, mass of the fuel-tanks, and everything else. Big Dumb Boosters had lower mass-fractions, but not insanely so. Their designers knew that the Rocket Equation still applied, and designed with it in mind. They just cut down mass-fractions by a factor of about 4 (hence the 3% vs. 0.75% earlier) and used the wider engineering-margins this allowed to utilize lower-cost manufacturing methods and materials for the rockets. These were still very expensive pieces of equipment, even if they were 1/5th, 1/20th, or less the cost of their "smart booster" brethren (the cost-per-kg for Sea Dragon and Aquarius still had to deal with infrastructure costs, and in the case of Aquarius, the cost of a LEO fuel/consumables depot. This was *all* factored into the final cost-per-kg given for each rocket of 1/4th and 1/8th the cost-per-kg of a "smart" booster...) Regards, Northstar

Kryten, I think you miss two fundamental distinctions here: (1) The Big Dumb Booster's payload isn't necessarily large. Once more, the Big Dumb Booster derives its size from the relative size of the rocket to the payload. So, you can still launch your little 100 kg payload to LEO, you just might need a 12-ton Big Dumb Booster with a 0.75% mass-fraction to do it instead of a 3-ton "smart" booster with a 3% mass-fraction. The Big Dumb Booster will still be much cheaper despite its larger size, though, due to the much less precise construction/manufacturing techniques that the wider engineering-margins allow you to safely utilize without sacrificing reliability (if you are willing to take a hit to reliability as well, you can get even lower per-kg costs, with better mass fractions, though, like with Aquarius: but that is only suitable for cheap payloads like the fuel to get from LEO to GSO...) (2) Anything that you launch to LEO is payload, by this definition. The "Big Dumb Booster" only encompasses the launch-stage and sustainer/upper stages themselves. Once the payload is delivered to orbit (or, to avoid generating debris, just shy of orbit) it separates from the orbital stage- which is the same, high-cost kind of engineering you're used to. Nobody is suggesting using these low mass-fraction construction techniques for the orbital stages, that would just be stupid. Let me re-iterate, the satellite and its GSO transfer-stage (remember, two burns are required to travel from LEO to GSO: one to reach GTO, and a second to circularize thhe orbit once GSO altitude is reached) are considered part of the payload. What we are comparing here is the cost of getting a 100 kg satellite+transfer stage to LEO with a Big Dumb Booster vs. getting that same satellite + transfer stage to LEO with a "smart" booster. For the high-reliability variant of Big Dumb Booster, nothing differs after reaching orbit whatsoever. (For low-reliability Big Dumb Boosters like the Aquarius, the transfer-stage is launched "dry", and must be fueled in LEO from an orbital fuel depot- which in turn is fueled with Aquarius-style launches. You *do not* launch the transfer stage or satellite on an Aquarius-style BDB, although you can launch them on a high-reliability, Sea Dragon style BDB, while launching the fuel separately and ahead-of-need Aquarius-style.) Regards, Northstar

I'm amazed that this thread was revived last month, after such a long time. But, since it's active again, I guess I'll re-interate the key point I made earlier... One word- fuel. The vast majority of the mass of any mission is fuel. That expensive, 10 kg probe might be 20% of the mission budget, but it's sitting on 90 kg of fuel that has to get it from Low Earth Orbit to its destination- and that's not cheap. In fact, part of the reason that the payloads are so expensive in the first place is to lower the required fuel mass. Ion thrusters, high-ISP resistojets; why do you think anybody uses these? Because the additional cost of the more complex and high-tech engines is much less than the reduced launch-costs from not having to lift as much fuel to orbit, and thus being able to use a lighter (and therefore, cheaper) lifter. With the low-reliability variety of Big Dumb Booster (REMEMBER- Big Dumb Boosters come in two varieties, the high-reliability ones like Sea Dragon, which are highly-reliable but just have terrible mass-fractions, and the low-reliability variants like Aquarius which have both terrible mass-fractions AND reliability, but *even lower* per-kg cost), you can tell the engineers: "hey, you've got 20 kg's dry mass to play with on the probe instead of 10 kg, and can do it with lower ISP engines too" and lift 300 kg of fuel on separate Big Dumb Boosters (which can easily achieve 1/4th the per-kg launch costs or less), and *STILL* do the whole thing cheaper than with a smart rocket that can launch 100 kg to orbit in a single go. THAT is why that sub-type of Big Dumb Boosters make sense. It's not to launch the expensive parts of interplanetary or even trans-lunar missions, it's to launch the cheap parts: namely the fuel, food & water (for manned missions), extra coolant, spare parts (currently useful only for manned missions or ones operating close to manned stations- but DARPA is working on simple robotic repair probes that could perform some simple repairs and maintenance without the need for humans nearby...) etc. separate from the rest of the payload. You stock up more than what you need, and if the BDB fails to make orbit with the cheap payload, you just load another one up and try again (NOTE: you launch this stuff BEFORE the main mission, in case you need to try more than once...) Regards, Northstar P.S. I think there's been a lot of confusion about this issue, since there are actually two *entirely different* types of Big Dumb Boosters discussed in this thread. Low-reliability variants, like Aquarius, that achieve the lowest cost-per-kg of payload to orbit (even after accounting for a high rate of launch-failures) ; and high-reliability Big Dumb Boosters like Sea Dragon, which aren't as cheap as rockets like Aquarius, but are still much cheaper than conventional "smart" rockets. High-reliability Big Dumb Boosters like Sea Dragon are perfectly safe to load extremely expensive payloads on. They don't necessarily fail more often than "smart" rockets, in fact if anything with their more generous engineering margins they should fail LESS often- they just are much, much larger (and cheaper) rockets on the launchpad compared to the size of the payload they're launching... P.P.S. Sea Dragon was designed to launch larger payloads than Saturn V because it was designed with single-launch Mars missions in mind (to avoid the need for orbital docking of multiple components, like in the modern-day "Constellation" mission-plan). It was also designed to carry heavier payloads because the designers (correctly) assumed that if there was less price-pressure on the payload to shave every possible ounce off the mass, a heavier payload mass would result, as the optimal balance of launch costs vs. costs of shaving payload mass would be different with lower launch-costs. Let me emphasize that there is no reason you can't design a Big Dumb Booster to carry a payload in the size-range of Saturn V, SLS, Ares V, Falcon 9, or even the Falcon 1 if you wanted. Big Dumb Boosters of this type are so-named not because they are necessarily large (in absolute terms), but because they are much larger compared to the size of their payload than conventional "smart" rockets with the same payload-capacity. Thus, a Big Dumb Booster with the lifting-capacity of Saturn V would be smaller than Sea Dragon, but bigger than Saturn V was, and a Big Dumb Booster the size of Saturn V would have a much smaller payload-capacity than Saturn V, but a much lower per-kg launch cost...

Rolling new mods is nice and all- but a lot of work, and not exactly the kind of thing I (or most other players) want to be setting out to do just to use a new mod. I'm about as thrilled with RealPlume (or, apparently, HotRockets?) being necessary to still get engine effects as I am with the resurgence of the Mumps in North America, but seeing as (just like the anti-vaccer's) this is just a bit out of my and most other people's control and already grandfathered in at this point, is it possible that you (Raptor) could find a way to make setting up RealFuels+Stockalike to have engine effects again just a bit more user-friendly? Perhaps creating an easy-to-follow guide on installing RealPlumes and SmokeScreen with the necessary configs might help, or better yet doing some of the work for us by having RealFuels+Stockalike port with a redistribute of RealPlumes with the correct configs already installed? (such that it's as simple for the user as just dragging all the folders in a single folder into the GameData folder, without having to go and separately locate/download dependencies and mod-specific configs for them) If nothing else, at least creating a direct link to the configs download on the first post rather than a link to a post with a link to the download would be somewhat helpful. Anything to reduce the grind involved in installing yet another mod- because some of us play with a lot of them! (and making us jump through too many hoops to get just one mod means we will be loathe to use that mod in the first place...) As always, great work, and I appreciate all you guys do! I just hope you can make the installation process just a tad bit easier for us all here- I've already got books to read, an MCAT to study for, jobs to apply to, a military recruitment process to go through, and two mods of my own to help maintain as-is! Best Regards, Northstar

I'm aware there are proximate reasons for requiring RealPlume. But the ultimate effect is that players have not one, but two new dependencies- which happen to be notoriously difficult to install correctly. There must be some work-around, or barring that, a way to return to the previous engine effects system (why was it even changed in the first place?) Regards, Northstar

You're probably right about there being game-balance reasons for not tweaking the power requirements. Plus, you are correct about the currently-assumed concentrations being a little on the high side (although, were you clear about the ALTITUDE of the orbits with the guy from NASA? The ISS orbits at around 420 km, whereas a Propulsive Fluid Accumulator would operate at between 100 and 200 km... At 100 km Earth orbit, your numbers aren't THAT far off- maybe only only 4-5x what they should be...) which is a good enough reason to leave power requirements how they are... As for the NASA guy talking about the economics, he's talking, mainly, about the cost of developing such a system vs. the benefits received. There is NO QUESTION that the marginal cost of operating such a system is much less than the cost of launching the same mass of propellant to orbit- the problem is developing such a system in the first place would be enormously expensive. And thus, probably not worth it in the current era of only messing around in Low Earth Orbit... The moment you start getting more ambitious and seriously looking at traveling to Mars, Venus, and maybe someday even Ceres or Jupiter, it becomes IMMENSELY more worthwhile to develop such a system, however. It is true that it would take years for a small-scale system to generate a significant amount of propellant- but the beauty is there is no real practical limit to how much you can scale such a system up (with more accumulator cross-sectional area, not more power), and you can use the same technology around other planets for return-propellant (CO2 form Mars orbit fed into electric thrusters, for instance- something already being looked at for very highly-specialized unmanned orbiters that would actually orbit inside Mars' upper atmosphere...) One last thought- it ALREADY takes game-years to accumulate any significant amount of resource this way, at least if you power it with a conventional fission reactor. Something I discovered all too late with a Duna mission I attempted in-game with Real Solar System a while back. I ended up only being able to collect a small quantity of Nitrogen from orbit after roughly 54 days of Propulsive Fluid Accumulator operation- enough to top off some small auxiliary Nitrogen tanks on a manned mission that were already mostly-full, but nothing more than that. It takes a massively scaled-up PFA, or a lot of time-warp (a couple years at least) and several missed transfer-windows, to accumulate enough Nitrogen (which is by far the most abundant resource around Kerbin) for anything more than a small probe mission... In real life, they would probably just overcome this obstacle by launching a whole fleet of Propulsive Fluid Accumulators- once you've gone through all the effort of developing the technology for and designing one, launching a few dozen of them doesn't cost that much more (and, at least in the short term, helps make up for the lost profits launch-providers would suffer when we don't have to launch many spacecraft to orbit with more fuel than it takes to reach a propellant depot anymore, and can refuel them before, say, heading to Geosynchronous Orbit...) and it does provide a lot of redundancy in case one broke or got hit by something... In-game, it makes more sense to just leave PFA's with a 4-5x higher collection-rate than they should have (especially when balanced with higher power-requirements than they would have in real life). It's the same old narrative- a large one time investment (developing usable Propulsive Fluid Accumulators from preliminary designs we already have on the books- not a cheap proposition by any means) for huge long-term rewards (being able to fuel all your probes, and with a large enough PFA fleet, your manned missions, at least partially with gasses collected from Earth Orbit). Something we don't seem too interested in doing anymore, unless you're Space-X... Regards, Northstar

AaronLS, Still haven't heard back from you one way or the other. Did you get my private message? Regards, Northstar

Raptor, Is any work being done on removing the Real Plumes dependency? I installed this mod in order to perform a RSS 6.4x Constellation-style mission for a YouTube video, but not having the engine plumes ruins the visual. I have enough mods as is, and shouldn't have to install another mod entirely (Real Plumes) as well as its dependency (SmokeScreen) just in order to get plumes for my engines. What's worse- correctly installing these two mods requires a custom set of configs AND is often buggy/problematic for many players (including me- I gave up on even trying it after looking at the relevant files- too much effort to do correctly for something I didn't even want in the first place). This mod is called "RealFuels" not "real smoke effects." If I had wanted better smoke effects, I would have installed one of the many mods for that purpose in the first place. I installed this mod for the realistic engine performance, simple as that- I couldn't care less if the stock visuals are less than perfect (my computer simply does NOT have the free RAM to go installing visual mods...) As always, thanks for the work in creating/maintaining this mod, but the whole "requires Real Plumes" thing ruins it entirely. Regards, Northstar

Hey FreeThinker, haven't disappeared- just been getting used to a new job, and applying to the Air Force ("Space Operations" is one of my specialization preferences, BOOYAH). Also, a question/comment I noticed I think I can respond to: The most power-expensive part of the process is running the pumps- you need *VERY* powerful vacuum pumps in order to concentrate atmosphere at the ridiculously low concentrations it is found in traveling through the Thermospshere. The designs proposed in the 1960's (off which this is based) also included very powerful centrifugal chambers as well to help concentrate the gasses in some versions... The cooling of those gasses from literally hotter than lava (hence why they call it the Thermosphere- the sparse gasses there are VERY hot) to cryogenically-cold temperatures isn't cheap in terms of power either, although most of the power requirements there are due to the inefficiency of available cooling unit designs in the 1960's (the actual mass flow rate of the collected gasses is so low they don't significantly heat up the cooler as they are cooled...) which may have improved somewhat since then... All of these processes could probably be redesigned for greater efficiency- keep in mind current performance is an eyeballed approximation to try and mimic the performance of 1960's designs for propulsive fluid accumulators, and we don't even have hard numbers on a lot of the power requirements... If you could find any (or better yet, updated figures using 2010's or 2020's-tech) that would be GREATLY appreciated. Regards, Northstar

First of all, sorry to be AWOL for a while guys. Real life has really been getting in the way of Kerballing, as has a certain frustration on my part than 1.0x just isn't stable on my computer like 0.90 was. I'm hoping 1.1 will be better- because the frequent CTD's in 1.0x (even completely unmodded) have driven me bonkers and to other games in my free time! I've also been working on a video project to carry out a Constellation-style mission to Duna in Real Solar System 6.4x in what limited Kerbal time I have been spending, as well as trying to get back into the swing of KSP-Interstellar Extended (another mod I helped get off the ground and develop) modding... OK, down to business a little. I will have to take a look at the actual files Aaron released, but immediately, I noticed this: Actually, Aaron, the force the Mass Driver produces (which leads to varied acceleration based on the mass of the cargo launched) is based on real-world figures. The Mass Driver is a replica of the performance expected for the StarTram project (the generation-1 design, to be precise: which still had some room left for improvement in future generations of the design...) Which could produce, to be precise, 30 Earth-gravity's (g, or 9.81 m/s2) of acceleration on a 40-ton cargo. It was simply a matter of calculating and back-calculating the numbers from there to get the maximum force the part can produce. So, the part is not overpowered. At least not compared to the real world. The problem is REALITY can seem a bit overpowered in a Kerbal-sized universe. For what it's worth, though, even at this level of performance tracks of mass-drivers many kilometers long were planned. I haven't been able to construct a stack more than 500 meters long that remained stable upon launch on Kerbin (although I suspect a larger stack might be usable in orbit, if I were to somehow get one there- which would probably require either HyperEdit or Extraplanetary Launchpads, as there is no way I'll be launching something that tall AND massive anytime soon...) Keep in mind also that the reason every real-world design includes very long track lengths (often 10-12 km or longer) is both to reduce the acceleration rate to something humans can more easily handle (when designing the system to only accelerate a tiny capsule, rather than a giant 40-ton rocket carrying lots of cargo...) and to not only escape the atmosphere, but do so as horizontal speeds closely approaching orbital velocity- so only a tiny push is necessary to reach orbit. It's been known as far back as Aristotle and Archimedes that the faster you travel through a think medium like air or water, the more drag you encounter- and that this requires an exponentially faster entry speed to exit that medium with a slightly faster exit speed, or travel through a slightly thicker medium. Real world mass driver designs are meant to launch on a shallow trajectory (which GREATLY increases path-length through the atmosphere), after a long low-g acceleration (not to exceed 3 g's for a manned capsule, typically) and still be traveling horizontally at close to orbital velocity at apoapsis: which all mean that a MUCH longer mass driver track is necessary than what is needed, say, to simply launch straight up at high enough speeds to catapult a cargo at high G's onto a suborbital trajectory that narrowly escapes the atmosphere and is moving very slowly at apoapsis... Anyways, I appreciate your efforts to keep this mod alive Aaron. I hope you will carefully think about what I posted. If you'd be willing, I'd love to officially bring you on as a co-developer of this mod- however I really strongly do wish to keep the "standard" version of this mod as closely based on real-world performance as possible. So, it will kind of be a requirement that you be willing to develop a version that is based on real-world designs for which hard numbers can be found for the expected performance (at least, how many g's you could accelerate such-and-such a mass rocket at), such as StarTram... Regards, Northstar - - - Updated - - - Aaron, I will send you a PM- but to be clear, I would very much like to bring you in on this project. I am thinking of starting a version 0.2.x thread for a re-designed version incorporating some of your changes. It would be nice to have somebody with more proficiency in code and code-writing working on this project (for the most part, I just ripped some existing code from the little-known Stanford Torus mod: with the author's permission, of course- and then then tweaked the config to match real-world data for the force produced, and for practicality increased things like the collision tolerances to reduce the chances of spontaneous explosions with long Mass Driver stacks...) Also, keep in mind the CDDL-1 license does require us to attribute previous contributors to the project- thus, even if you go off and start a new thread without me, you would need to attribute both the creator of the Stanford Torus mod and myself (if you worked off my version) for the project. You could work off the original ST version to shorten the attribution list if you wanted, of course. Regardless, I would prefer to work WITH you rather than compete with you anyways. Your work would likely displace mine, as you are better at coding- but I could still do a lot to spread word about the mod, helping to bring in more users, as well as doing more real-world performance research (at which I am very good- being a real life scientist) and such, if we worked together. Regards, Northstar

Here, there, every which where. I'll try to share a bit about what I've been up to eventually, but right now I've got some catching up to do... ModularFuelTanks is kind of the precursor of RealFuels. Or in a biologist' terms (what I am educated/trained as in real life), more accurately they are from closely related phyla and share a very recent common ancestor. Basically RealFuels and ModularFuelTanks used to be one mod a not so long time ago, but then the two split apart as some players just wanted the ability to tweak fuel tank capacities... All the code should basically be identical to the RealFuels code that allows tweaking of fuel tank contents, with the exception of a few small bugfixes (that might have been made to the code of one but not the other since divergence) and that the code normally refers to stock fuel resources only rather than to integrating more realistic fuel resources. Finally, I would like to suggest pruning a couple of parts folders from the mod that don't really serve any purpose anymore (but am posting here rather than PM'ing in case somebody is aware of a use for these parts I am not familiar with..) The first of these is the LiquidFuelOnly tanks. These parts are basically just ugly, scaled-up versions of the original stock Mk1 fuselages, and serve virtually no purpose in a mod that has TweakScale as a dependency. Beyond that, KSP-Interstellar doesn't use the LiquidFuel resource anymore, and with the new InterstellarFuelTanks with switchable contents, it is perfectly easy to get large quantities of Hydrogen or Kerosene (what the LiquidFuel should be replaced with) on the launchpad in a much more useful and less ugly container... The second is the Methane Fuel Tanks. They are basically just versions of the stock Rockomax fuel tanks designed to hold Meth/LOX instead, and with a slightly different (and IMHO aesthetically-pleasing) texture. The InterstellarFuelTanks with swappable contents have superseded them, as they can BOTH hold Meth/LOX and other fuels on the pad (and swap fuels mid-mission). The Methane Tank textures/models are nice, and may be worth keeping or storing away somewhere (although, if I'm not mistaken- weren't they the basis for the InterstellarFuelTank textures/models? I seem to recall the folder once even containing the same model names as the Methane Fuel Tanks...) but the tank configs themselves are just a waste of memory, unnecessary maintenance work for mod developers, and clutter in the parts catalog... Regards, Northstar

Look forward to it. The heating system not working properly makes me not want to install this mod again until it's fixed... Regards, Northstar

Hiyas FreeThinker! Glad to see this is chugging along. I'm back after a long hiatus from serious mod development, and will try and offer help where possible. It looks like you've done a lot of great work! The descriptions on the front page have a few minor spelling/grammar errors I can help you clean up, and I will prob help write up some of the missing descriptions later on, but awesome to see so much progress while I've been away! PM me, let me know what you need the most help with. I've got a lot of stuff going on in real life still, so go easy on me, but I look forward to helping again however I can! Regards, Northstar

Any idea when this might be fixed for Career Mode again? I hear 1.1.0 is coming out soon, and I'd def like to use this mod with it if possible... Anyways, great work as always! Will be finally swapping to RSS 64K for 1.0.4 now as I have a Constellation-style mission planned that is a bit too ambitious to complete in my current Career Mode save anyways... And I'd love to do it in RSS 64K if I'm going Sandbox anyways... Regards, Northstar

KSP is part game, but part simulation. Some people like to design a mission that could actually get funding in real life (yes ISRU *is* something we're developing technologies for in real life). To say your playstyle is superior just because it's easier is... a bit self-indulgent. Also, and more importantly, not everybody (I'm a prime example) has a computer that can HANDLE a massive, 500-part craft that can carry out something like a Jool grand-tour in a single launch- at least not with KSP's current poorly-optimized program structure. In this regard, for players with weak computers mining is a godsend. Before, I had to launch an entire flotilla of tankers just to refuel a craft in LKO for a large mission, unless I was using a lot of parts mods with 5 meter diameter rocket parts at a bare minimum (or better yet, something like Procedural Parts for 10 meter fuel tanks and Procedural Fairings for multi-engine thrust -plates and interstage-fairings...) Now, I can send ISRU equipment to whatever system I'm headed to, and mine my return-fuel there, massively reducing the size of my vessel in LKO... (I may still have to launch a tanker or two for the largest of missions, where I still can't launch a sufficiently large craft from the ground on Kerbin to make it to Jool or wherever in a single launch without orbital refueling...) Yes, setting up ISRU systems in the Kerbin system is hardly worth it if you don't have much time to play KSP, though. The example I gave of a simple and efficient LKO refueling-system is still a massive drain on play-time compared to just launching expendable tankers to LKO... Regards, Northstar EDIT: Sharpy hit my thought right on the head w.r.t. not all computers being able to handle "glorious examples of excessive indulgence".

Well, there are a variety of solutions, but here is one possible system: You place a refinery on the surface of Minmus, as well as a reusable lander to carry fuel to orbit. You park a tanker (not a depot) in Minmus orbit, refuel it with several launches from the lander (which need not refuel it in a single launch- having a smaller lander saves you on initial setup costs) and then have the tanker return to Low Kerbin Orbit- using the atmosphere to drop the orbit back down over one or more aerobraking passes from a return trajectory (which is EXTREMELY cheap from Minmus- if you eject from Minmus' SOI heading retrograde relative to the moon's orbit around Kerbin...) If done properly this is actually cheaper in Delta-V than returning to LKO from Munar orbit, due to the weaker gravity-well and much lower orbital velocity of Minmus than the Mun... The tanker can be quite large and designed without the thrust needed to land (it also doesn't need landing-legs, which is another reason to have a specialized lander...) using something like an LV-N for propulsion, for instance. The tanker meets up with craft needing refueling in Low Kerbin Orbit and refuels it, leaving just enough fuel to return to Minmus to refuel again. The tanker can also double as a tug or transfer-stage, and can be used to haul modules back to Minmus that are too large to refuel in LKO in a single trip... (keeping the two vessels docked reduces the number of transfer and capture-burns you have to make, and allows use of the tankers possibly higher-ISP engines) This plan can also be carried out with the lander returning all the way to LKO, to reduce the need for rendezvous and docking, but this will be much less efficient in terms of fuel "gear-ratio". By the time the lander even makes Minmus orbit, it will have already emptied a portion of its fuel tanks and you will be wasting fuel moving empty fuel tank mass back to LKO. Additionally, a lander would likely have landing-legs, and would be forced to have higher Thrust than a dedicated tanker (which could actually get away with a TWR less than one on Minmus' surface, as it never lands...) Regards, Northstar