Northstar1989

What on EARTH are you talking about? The ISRU system in KSP-Interstellar is *strictly* realistic. Every single harvestable resource of conversion in Interstellar is carefully based on real-world analogs. The *only* thing you could argue is unrealistic is that there is just a single ISRU refinery part that "does it all", and even that FracalUK is looking at eventually fixing (through making the ISRU refinery load-out tweakable in the VAB/SPH). Not to mention, all the necessary machinery *could* fit inside the 2.5 meter (Kerbaal-scale, so 5 meters in real life) refinery part used- lightweight Sabatier Reactors smaller than the size of a mini-fridge have already been developed for use in space (on the ISS, where one is *already* installed and operational), for instance. The ISRU reactions in KSP-Interstellar are: Sabatier Reaction (CO2 + 4 H2 --> CH4 + 2 H2O, already on the ISS and operational) Water Electrolysis (electrolysis units have been installed on the ISS and operational since it was first built) Antraquinone Process (relatively simple reaction- no reason it wouldn't work in space) The harvesting options are: Centrifuging Uranium from Kerbin/Eve/Laythe seawater (oceans are MAJOR uranium reservoir IRL, no reason this wouldn't work on another planet/moon with a water ocean, if there was one) Harvesting liquid water or water-ice (NASA is already working on systems to harvest water-ice from the Moon and Mars) Harvesting Ammonia from Eve's oceans (simple matter of centrifuging or distilling, but no use for this in real life) Harvesting LH2 from Jool's clouds (atmospheric accumulators to scoop Oxygen from Earth were designed, but never built, over 30 years ago, same concept with Jupiter and hydrogen...) Harvesting LOX from Kerbin/Laythe's atmosphere (designs to do exactly this from the edge of Earth's atmosphere were created over 30 years ago) Harvesting antimatter particles trapped in the magnetic fields of certain planets/moons (this is something that has been studied in real life with Earth or Jupiter/Saturn- would be perfectly feasible if we had better ways to launch stuff to orbit and store that antimatter long-term) Harvesting land-based Uranium/Thorium deposits (probably the *only* unrealistic option- as these deposits are very rarely shallow in real life) You can also breed Tritium from Lithium, and He-3 from Tritium's natural radioactive decay in KSP-Interstellar. The rates of these reactions and decays are *precisely* based on real life, though- and in fact breeding Tritium from Lithium is how we got the majority of our current Tritium stockpiles... So, the equipment you'd need to do ALL of this: A (small) centrifuge A distiller/condenser unit An atmospheric scoop (this is actually a separate part in KSP-Interstellar) A Sabatier Reactor A Anthaquinone Process Reactor An electrolysis unit A drill (for harvesting water-ice and Uranium/Thorium) A melting unit (for melting/separating water-ice) That's a rather short list, and the 7 pieces off that list found in the KSP-Interstellar refinery (which does not have an atmospheric scoop) *COULD* fit in a multi-ton 5-meter diameter refinery in real life (not to mention KSP-Interstellar also has a 3.75 meter variant of the refinery which is even heavier- and would equate to a 7.5-meter refinery in real life...) In fact, if ANYTHING, the KSP-Interstellar refinery is too large/heavy for a Kerbal-scale version of the real-life equipment, considering the *real* size/weight of a Sabatier is less than that of a mini-fridge, and some variants of equipment being worked on for harvesting water-ice on the Moon using microwaves and sublimation/condensation directly from the regolith are only *slightly* larger than a mini-fridge. In fact, having seen pictures of laboratory versions some of this equipment (and not even the miniaturized-versions being developed for use in space), you could fit all this in a laboratory the size of a coat-closet (having extensive lab experience, it's surprising how much equipment you can cram into a tiny space), which is smaller than the size of a 5-meter diameter ISRU refinery... (remember, KSP parts are 50% real-world scale) The *other* ISRU mods are definitely unrealistic, as they have one resource to "do it all", but not Interstellar. There's not a single reaction or harvesting option in there that isn't carefully based on real-world science. Regards, Northstar

I will be launching a Munar polar lander mission SOON , though I've decided to reneg on the part about leaving infrastructure there for a future base (mainly as KSP-Interstellar Aluminum Hybrid rockets are currently broken due to scaling issues- which makes building a mining outpost on the Munar poles MUCH less enticing than building such a base on the flats of Minmus...) but first I decided to do a little more with flyby missions around the Mun... So, without further delay, I present my Munar Free Return Probe launch: This isn't *entirely* unrelated to my future Mun landings, though- the (hypergolic) Munar transfer stage is over-engineered such as to also act as either the return stage or the return fuel (I haven't decided on specific mission details yet) for the command/service module of my future Mun landing... Anyways, here the Munar Free Return Probe is making its Munar transfer: The plan is that en-route the transfer stage and the probe will decouple, and the transfer stage will perform a burn so it makes a low pass on the *opposite* side of the Mun from the probe (the side of the Mun the probe will have to pass on for a free return would lead to a retrograde orbit) where it will perform a capture-burn... Regards, Northstar

OK, so did a little checking of the current (0.25) engine configs. Here are the atmosphere and velocity-curves for RAPIER. I've added in notes on what each term means... ATMO: key = 0 1200 (ISP at vacuum-pressure) key = 0.3 2500 (ISP at 30% sea-level pressure) key = 1 800 (ISP at sea-level pressure) VELOCITY: key = 0 0.5 0 0 (% maximum thrust at standstill- 50% here) key = 1000 1 0 0 (this engine reaches maximum thrust at 1000 m/s?) key = 2000 0.5 0 0 (and 50% thrust at 2000 m/s) key = 2200 0 0 0 (and stops producing ANY thrust at 2200 m/s) And for the Turbojet... ATMO: (the atmosphere-curves for the RAPIER and Turbojet are now IDENTICAL in 0.25- so they have *EXACTLY* the same ISP based solely on altitude...) key = 0 1200 key = 0.3 2500 key = 1 800 VELOCITY: (however the velocity curve is now *slightly* more generous than the RAPIER above 2000 m/s- so I guess it got changed since 0.23.5...) key = 0 0.5 0 0 key = 1000 1 0 0 key = 2000 0.5 0 0 key = 2400 0 0 0 Basically, you can ignore what I said about the RAPIER performing better than the Turbojet at high-altitude and speed, because that's no longer the case (EDIT: I went and struck out those phrases, just to make it clear). However, the differences in performance are *minor*, and below 2000 m/s (who would ever fly at 2000 m/s in the stock Kerbin system? I can only foresee see this adversely affecting extreme air-hogging or spaceplanes with both jets and rockets firing simultaneously...), the performances are in every way identical. Which means, performance-wise, the RAPIER is basically a turbojet below 2000 m/s, by which point you probably should have switched to rocket-mode anyways (because at that point in a spaceplane ascent you probably don't have the IntakeAir to run more than a single jet engine at more than 20% thrust- and you're losing over half of that thrust to the velocity-curve with either type of jet engine...) And obviously, once you're out of the atmosphere (which is your goal with a spaceplane- right?), a turbojet engine is completely worthless, whereas a RAPIER is not. Regards, Northstar P.S. If you refuel a RAPIER-equipped spaceplane (say with multiple spaceplane flights, or ISRU), it makes a decent plane for other planets as well, where a standard turbojet would just be deadweight- places like Eve and Duna (yes, it is possible to fly on Duna- go look up the Flying Duna challenge, and submit an entry if you're daring enough... P.P.S. Sorry for the tangent of RAPIER engines. It is one of the main competitors to the aerospike though. Aerospikes also make for decent Eve exploration planes- although on Duna you're probably better off with one of the tiny Rockomax engines, as you don't need much thrust to stay airborne in such thin atmosphere and low gravity...

The Turbojet does NOT perform at 2500 ISP in the upper atmosphere (it's ISP approaches 1200s in the upper atmosphere) The ISP value you're listing is at optimal atmospheric pressure (30% pressure, just under 1 scale-height, or around 4-5 km above sea-level in the stock Kerbin system) and speed (1000 m/s), at HIGHER altitudes and speeds its ISP *plummets*. If you actually look at the velocity-curve of the RAPIER in atmospheric mode, it is a LOT better than the Turbojet[s/] (this has changes since 0.23.5, when I last checked...) At anything above or below the "optimal" velocity of 1000 m/s, you suffer from a turbojet's velocity-curve. Velocity-curve is a "stealth" destroyer of ISP, since it causes the engine to produce less thrust for the same fuel flow, but doesn't actually show up as reduced ISP when right-clicking on the engine. The RAPIER also has a better ISP in the upper atmosphere (anywhere above about 24 or 25 km, if my memory serves me correctly). The RAPIER almost always beats having separate jets and rockets, because it can act as BOTH. That is, if you think of it as getting 85% of a turbojet and 50% of a LV-T30 for the mass (the percentages due to the slightly lower performance for both- though the RAPIER in atmo-mode clearly beats the turbojet above 25 km and 1200 m/s), then it always makes sense to rely on RAPIER engines for the best mass-efficiency. The most mass-efficient small to mid-sized spaceplanes basically only have 1 jet engines anyways, and then rely on rockets for the rest of their thrust to make it to orbit- that's because near altitude-ceiling (you want to build up most of your velocity a bit below it for the lower AoA, but not too much lower), you will basically only have enough IntakeAtm to run one engine at full thrust (more intakes raises this altitude ceiling, but does not eliminate it unless you MASSIVELY abuse intake-spam...) And if you only have 1 jet, you want it to be the type that performs best at really high altitudes, which is the RAPIER (just dial down the thrust when ascending through the lower atmosphere or you'll waste a lot of fuel!) But if you want to have multiple jets, for better TWR in the lower atmosphere, then having multiple RAPIER engines in a *HUGE* advantage over multiple turbojets, because they will also be useful as rockets when you switch over to rocket-propulsion... (it may also be necessary to have multiple jets to climb high enough to where you can only run one jet engine near full thrust anyways...) Regards, Northstar

Actually, the day length is 24 hours on Kerbin with RSS 6.4x, according to the config OP (and my own personal play experience). The longer the day-length, the less rotational velocity, and the more Delta-V it takes to get to orbit. So, if you were somehow playing with a 6 or 12-hour day, it would be MUCH easier to get to orbit (drag is also calculated RELATIVE TO SURFACE VELOCITY- so you experience more drag with the same orbital velocity if the day is longer...) Come to think of it, though, I was playing with recoverable lower stages and launching to 200 km orbits when it took me between 8.0 and 8.4 km/s. It might have been closer to 7.6 or 7.8 km/s with disposables (a launch with a perfect ascent-profile to 120 km would cost 7.5 km/s, ignoring any benefits from lift, according to the released RSS 6.4x Delta-V map) Your launches might have beat 7.5 km/s if they were: 1) Disposable (reusable stages tend to require draggier designs and sub-optimal ascent profiles) 2) To less than 120 km initially (atmosphere starts at 92 km in RSS 6.4x) 3) Made heavy use of body-lift (I assume you weren't flying with a winged craft? But FAR still generates "body lift", which helps the same way...) 4) Were extremely large and had great ballistic coefficients 5) Had *very* high TWR (with good ballistic coefficients, terminal velocity- the ideal speed of ascent- becomes MUCH higher) 6) Highly staged with powerful decouplers (don't forget decouplers can accelerate your craft, but their decoupling force doesn't get counted by MechJeb or KER's Delta-V readouts) 7) Made use of a launch site other than the KSC (a higher-altitude launch site means less losses to aero drag AND gravity...) The 7.5 km/s is based on the KSC. Anyways, back to the main topic. If you're new to KSP, I suggest playing with RSS 6.4x. It's really an awesome mod. The only reasons I'm not currently playing with it myself are because I want to tackle the Flying Duna challenge (which is MUCH easier in a stock-sized system, as one of the greatest obstacles is simply getting your Duna-plane to orbit), and that I tend to play with a lot of Microwave Beamed Power in KSP-Interstellar- which has transmission losses that are balanced for the stock system rather than realistic distances... (and my CPU can't handle having a half-dozen power-transmission stations: which is what I'd probably need to make beamed power work as a primary launch system with rockets large enough on the pad to reach orbit with heavy payloads in RSS 6.4x...) Regards, Northstar

That's not encountering it- at least not in the sense I meant- namely, smashing into it. But yes, if you're worried, try not to generate debris in the first place, or de-orbit/self-destruct it (although the self-destruct is a LOT less realistic- as that would actually just generate a bunch of tiny pieces of debris in real life...) Or play with one of the many versions of Real Solar System- with a REALISTIC sized Kerbin (or even the 6.4x scale one), the chances of actually even coming into loading range with debris are a LOT smaller. Regards, Northstar

Unfortunately, currently, limiting reception only decreases the amount of power available to your engines, etc. It does nothing to reduce the amount of WasteHeat generated- which makes no sense, as if you are only receiving 500 MW of power, you shouldn't have to dissipate 18 GW of it (in fact it's EASIER to manage the WasteHeat if you set reception to 100% and use as much of it to do useful work, rather than generating heat, as possible). It's something FractalUK really needs to fix. *cough* Did you hear that Fractal? *cough* Regards, Northstar

I'm getting issues with the Al-Hybrid rocket as well: It's an issue with scaling- the rocket is supposed to be 2.5 meters and a lot taller (just look at the mass, and compare it to a BACC vs. a RT-10 if you don't believe me... Clearly it's not supposed to be that small- and it was 2.5 meters in previous versions of KSP-Interstellar...) Regards, Northstar

The chances of actually encountering a piece of space debris are EXTREMELY low. You can safely have two (or three, or 100) craft in the same or intersecting orbits- as long as they're in slightly different phases. The bigger issue is probably the additional burden they place on your CPU, as mentioned before. If you want to simply hide view of them, you can do that with the tab on the top of the screen. But if you want to actually DISPOSE of them, you can either "Terminate" them, or send up a small vessel with a "Klaw" to de-orbit the vessels (with particularly large vessels capable of surviving re-entry it may even be *profitable* to bring them back to the ground on Kerbin for recovery...) Having an ISRU system set up (using mods) helps a lot with this last option, since it means the fuel necessary to repeatedly de-orbit debris (and then stabilize the orbit of the vessel with the Klaw after detachment) so is a LOT more affordable... And I suggest deploying the probe with a spaceplane or other 100% re-usable launch system, so as to bring down the cost of getting it to orbit in the first place. Regards, Northstar

You mean, like the aerobots of the soviet Vega program, which explored the atmosphere of Venus? Or perhaps you mean an actual airship capable of flying to orbit, like JP Aerospace is working on? Regards, Northstar

Assuming you want to play with RSS for the more realistic orbital velocity, rather than the real-world planets (if that's all you care about, just use the 1/10th scale "real" system), I suggest the 6.4x scale Kerbin scale-up. It's about the right size so that stock parts (which are generally between 50 and 64% the size of their real-life analogs: usually only about 50%...) can be used in it for a (mostly) realistic balance, rather than needing to scale them up with Realism Overhaul (a mod which I *despise* because of the long list of required mods and its full or partial incompatibility with a number of other awesome mods...) With RSS 6.4x, a rocket takes between 7.5 and 8.4 km/s to make orbit- rather than 10-12 km/s with the full scale-ups. That extra 3 km/s may not sound like a lot in comparison, but put this way: you roughly need to stack a rocket capable of making orbit in the stock system with FAR installed (3.5 km/s to orbit with a streamlined and tall rocket) ON TOP OF a rocket capable of making orbit in RSS 6.4x, in order to make orbit in the full scale-ups. Which means you'll NEED the Realism Overhaul scale-up to 100% part scale (roughly doubles the size of the stock rocket parts) to make it work. As for mods that I recommend, there's really only 4 you *need* with RSS: FAR (good luck trying to make orbit with the stock "soup-o-sphere", and the body-lift present in FAR but not NEAR helps MASSIVELY) Procedural Parts (you'll NEED the larger fuel tanks- and for huge payloads you may even end up clustering 2.5 meter engines on the bottom...) Procedural Fairings (you'll need the efficiently-shaped fairings, and the procedural thrust plates help with huge payloads...) KSP-Interstellar or Karbonite (when it's 8.4 km/s just to get something to orbit, you'll *WANT* an ISRU system to bring down mission costs...) I also highly recommend adding in RealFuels mod, though, for a more complete "realism" experience. It also adjusts the cost of the fuel resources to more realistic levels (for instance with a Kero/LOX rocket, fuel only amounts to approximately 0.3% of launch costs, according to Elon Musk...) Regards, Northstar

Indeed. The atmosphere is not only higher with Real Solar System- orbital velocity is a lot greater too. Which means, when running FAR (which will *drastically* increase your terminal velocity with an aerodynamically-shaped rocket: especially with any rocket large enough to make orbit in any of the RSS configs), you'll probably be wanting to start your gravity-turn fairly early: as you'll want to reduce the amount of velocity-change your upper stages will be responsible for... What that means is, having an engine that operates well in the lower atmosphere is a MAJOR advantage with RSS. Especially with spaceplanes (though you don't have much hope of building a successful one in anything besides the 6.4x scale config- and even then you'll need a LOT of drop-tanks), as your lift-to-drag ratio tends to better with the smaller Angles of Attack you can maintain in the lower atmosphere (and you want all your thrust directed at the horizon- not being used to directly hold your spaceplane up...) Regards, Northstar P.S. Aerospike engines also work extremely will with rockets that have a *VERY* low TWR (less than 1.10 on liftoff), as they tend to spend a lot more time in the lower atmosphere. So, if you're building some massive beast of a rocket using Procedural Parts fuel tanks...

My tanker mission was a success, and I've got a couple albums of screenshots to show you guys for it... In the first album, I show rendezvous+docking, and the fate of the dropped middle stage: In the second album, I show the recovery of the upper tanker stage: All in all, a good mission. The tanker *was* a bit over-engineered (I could have made do with less fuel in the middle and upper stages), and that did add slightly to cost, and I also lost the MechJeb core on splashdown- but other than that things went fairly well. The main advantages of refilling the existing transfer stage, rather than launching a new one, were that it let me re-use the expensive reaction wheel in the existing transfer stage (which was more expensive than the rest of the upper and lower stages combined)- which was more powerful than the tanker needed- and it also meant I was able to recover whatever vessel I launched next without hauling a parachute all around the Kerbin system... Finally, one last note. I've posted videos of my missions before, and I intend to do it again soon. Only, I've been sick since the day I started this thread (and still have a lingering cough), so I didn't want to make a recording where I would be wearing out my throat and coughing the whole time. I promise you guys, you'll see videos of my missions again soon . Regards, Northstar

One thing at a time (either the landing or the depot). But a Mun/Minmus landing sounds good... Just don't forget you're dealing with one of the more experienced players on the forum, though. I've actually written a *guide* on orbital refueling, if you check my signature... I think you meant one of Kerbin's poles, but I wouldn't mind visiting Minmus' poles either. Since I'm only taking two new suggestions after each mission, and yours was technically the third, I'll meet you halfway by conducting a landing on one of the Munar poles. It also seems like a good place for a first landing, since I eventually intend to build a base there (to extract water from some of the small amounts of ice near the poles, similar to the ice we think exists near the poles of our own moon...) I can leave some equipment behind that will help with that in the long run... OK, so I've got my next mission plan- a Munar polar landing. No more ideas will be considered for the meantime, until that's done. Regards, Northstar

He's referring to the (expected) performance of the superconducting version. Check the Wiki page- there are links there where you can find those numbers. Regards, Northstar

I have to point out that thrust CAN be overclocked in real life. Often, rocket engines are CAPABLE of exceeding 100% of their "nominal" thrust. Whether it's safe to do so is another thing entirely. What I suggest is that ISP be left entirely alone (changing it would break the laws of physics), but that if the devs *insist* on tweaking rocket stats, thrust be able to increased above the "normal" maximum *at the expense of a random explosion risk*. That is, overclocking the engine *might* cause it to explode. More experienced Kerbals could have the ability to automatically shut down an engine instead of having it explode. That is the *only* feasibly way I can see to affect TWR/ISP, and even then, I don't particularly like it. I'd prefer if Kerbal XP was just a badge system, perhaps with a few minor "perks" like auto-bailout instead of dying with a destroyed capsule... Part-editing due to XP should be absolutely out-of-the-question in my opinion. Regards, Northstar

Why not thrust? (efficiency I can understand- there's no way to boost ISP in real life, other than possibly spiking the rocket fuel with certain dangerous additives...) They boost thrust in real life! Some rocket engines can be clocked up to 133% of their nominal thrust rating... (he "official" ratings are often a bit conservative) Regards, Northstar

WELCOME! It *is* a nice place here. I'm glad you think so already. Regards, Northstar

I know this may seem like old news to some of you, but back in August, NASA's Advanced Propulsion Physics Laboratory tested a device known as the "Cannae Drive" - which appeared to be the second propellantless thruster ever validated. This built on earlier tests of the "EM Drive" a similar, but bulkier and better-performing drive, which was tested back in January (but the results were not released until NASA had also tested the Cannae Drive in August) and appeared to work as well. I suggest reading the Wikipedia article for a more complete history of the devices. http://en.wikipedia.org/wiki/EmDrive When this hit the media, there were two waves of articles. The first wave simply expressed astonishment at the exciting discovery and its possible implications. The second wave largely criticized the device- based either on the "it's too good to be true" line of logic (with no evidence to back up these criticisms other than that the device *appeared* to violate known laws of physics- but remember, a law of science is only a law of science *until we find an exception to it*. Theory, must explain results, rather than the other way around..) or on pulling apart the abstract of the NASA paper (which was released ahead of the full article) and making dangerous assumptions about the paper (and that the tests were performed improperly) which turned out not to be true. As an actual scientist in real life, I was quite upset by all of this. First, very few scientists ASK for this kind of publicity- in fact the Chinese professor who validated the EmDrive ahead of NASA actually said "the publicity was very unwelcome". Second, the buffoonery of automatically assuming an experiment is wrong, simply because it defies established notions of how things works, simply baffled me. I spent a period of time working in an equally controversial (perhaps more so) field to theoretical physics- stem cell research. And the degree to which people outside of the field would *consistently* mis-understand and mis-represent results in the field (especially when they challenged established notions, such as how aging and cancer work), never ceased to irritate or amaze me. So, having some sympathy for the poor physicists whose results and credibility were being unjustly attacked (I can *guarantee* you many of them were hesitant to publish their data for precisely this reason), and the idea behind an EmDrive actually being one I had independently thought of myself one day when pondering what would happen when you shined light (or microwaves) in an asymmetrical resonant cavity (although clearly I never did anything with this idea- since I never majored in physics, and figured there was probably some reason I didn't know of it wouldn't work...), I largely kept my quiet (after a few ill-fated attempts to defend the scientists' credibility to people who were simply unwilling to listen), and waited for more facts to come out about the drive, and for myself to have time to look them up... Well, anyways, long explanation aside, there *were* more facts to the story. Some of them didn't take very long to come out at all. For instance, just a week or so after the major wave of criticism, Wired released the following Q&A to clear up common misconceptions about the drive: http://www.wired.co.uk/news/archive/2014-08/07/10-qs-about-nasa-impossible-drive For instance, one of the most COMMON misconceptions about the NASA test, which was fairly obvious to me even back when the abstract was released, was that people were mis-understanding what was going on with the "Null" device. Basically, the situation was this: the lead scientist behind the "Cannae Drive" (Fetta), had certain theoretical ideas about how such a device should/would work, and what were the reasons for that. These led to him engraving "slots" into one of the ends in his resonant cavity of his device, which he THOUGHT were necessary for the drive to work. However NASA tested versions of the device with *and* without the slots, and BOTH produce thrust. Many *INCORRECTLY* interpreted this to mean that the "control" had produced thrust as well- which would have obviously invalidated the results. THIS WAS NOT IN FACT THE CASE. Anyone who had bothered even to *carefully* read the abstract, and maybe educate themselves a little about Fetta's underlying theory, would have immediately realized that the no-slots device only invalidated the need for SLOTS in the device. In fact, NASA tested a *THIRD* device- this one with a resistive, rather than resonant, cavity. THIS was the control- and as expected THIS produced absolutely no thrust. All NASA proved with the slots vs. no-slots device is that Fetta's underlying explanation for how his device worked was wrong, and there was absolutely need to carve slots into the device in order to make it work (in fact, this slightly *decreases* the performance of the device). The *actual* control produced no thrust- so the test was valid. To quote the scientists at NASA: "Finally, a 50 ohm RF resistive load was used in place of the test article to verify no significant systemic effects that would cause apparent or real torsion pendulum displacements. The RF load was energised twice at an amplifier output power of approximately 28 watts and no significant pendulum arm displacements were observed." As I pointed out earlier, THEORY FOLLOWS FACT. This is *absolutely essential* to understanding science/technology, and a key lesson for any good scientist. That means, we don't start with a theory, and then twist the facts to support it (in fact this is one major mistake many researchers in biology make- which better scientists such as those I trained under as a student at friggin' Cornell University, a school I am *VERY* proud of being able to call my alma mater, had to *constantly* point out is the WRONG way to do things...) Rather, we *must* start out with observed results, and adjust our hypotheses (which is any ideas we have before those results) to come up with a theory that can explain our results. To take a famous, but probably fictitious story from the life of the very scientist whose "laws" the EmDrive results are purported to violate; Isaac Newton didn't *start* with the theory of gravity, and then use the fall of an apple to justify it- rather he started with the fall of an apple, and then came up with the theory to *explain* observed results. The same needs to hold with the Canne/EmDrive. If the device appears to violate the Conservation of Momentum by using no propellent, we can't simply state that it's impossible because it violated preconceived notions- this is *exactly* the kind of thinking that used to trap us in the faulty scientific theories of the late Middle Ages (where many results that violated the prevailing theories of the day were rejected simply because they did not conform to faulty expectations- it was not until the introduction of the Scientific Method that this kind of thinking *truly* got thrown out the window...) Rather, we need to carefully analyze the results and experimental methods with a critical eye. If no fault can be found with them, we have to *consider* that our preconceived notions (that there are no exceptions to the Conservation of Momentum, for instance), may in fact be false... Now note I'm NOT saying the Cannae Drive *did* really prove Newton was wrong, or that all our existing theory should be thrown out the window- only that the criticism leveled against it was, largely, illegitimate. The masses of people who jumped on the band wagon about the no-slots version of the Cannae Drive is just one example of what I'm talking about. So, I would like to revive discussion of this apparently "old" news here. Largely, because the Cannae/EmDrive HASN'T gone away. The media (with its 3-second attention-span, and the scientific literacy of a 5 year old to match) simply lost interest in the subject, and many people implicitly assumed that the ill-founded criticism against it was valid, and the whole thing had been dropped. This is, of course, not the case. NASA's "Eagleworks" division continues to work on improved versions of the testing apparatus (and higher-powered versions of the device itself), while additional labs at NASA, and across the country (including John Hopkins University, for starters) line up to test the devices after NASA is done with it. There will be *quite* a few more articles on the Em/Canne Drives in the not-too-distant future, it hasn't been discredited in any way *yet*, and may not ever be. It is quite possible that 30 or 40 years from now, we may indeed be flying in EmDrive airplanes (most likely powered by wireless power transmission, as the EmDrive requires no propellent, but DOES require large amounts of electricity to produce usable thrust levels), spaceplanes, and even rockets to Mars. If you can circumvent the need for propellent, you can circumvent the Rocket Equation, and then the sky (truly) no longer becomes the limit in a *very* real way... Regards, Northstar P.S. If you're curious, there are *several* possible theoretical explanations for the EmDrive. The Chinese team justified it with a certain interpretation of Maxwell's Equation. Fetta defended it with a theory that required the use of slots, and turned out to be wrong. And perhaps my *favorite* explanation, because it means there actually *is* a propellent, even if it never enters or leaves the drive in a conventional manner, is that it pushes against particles that spontaneously pop in and out of existence anywhere in the universe as predicted by the Heisenberg Uncertainty Principle- particles that have sometimes (incorrectly) been referred to as the "quantum vacuum plasma" (they don't behave as a plasma, at least not in the classical sense of the word- but there *ARE* such particles, this much was already well-studied and extensively validated *long* before the invention of the EmDrive...)

Thanks. I'm trying to keep it relatively simple this playthrough, but ultimately I tend to get very ambitious (in my first Fan Works posting, I eventually had an armada of over 20 ships heading to Duna before the 0.24 update eventually caused me to start all over...) Haha, you've got a strange sense of humor. Do you *KNOW* how heavy nukes are in RealFuels mod with "Stockalike" settings? Because "Stockalike" attempts to replicate real-world TWR's and ISP's, but doesn't change engine thrust, they become ridiculously heavy (real NERVA engines had quite a bit less thrust). A probe mission would be far too small to justify using a nuke (other than one of the KSP-Interstellar particle bed reactors- which are based on later reactor designs for nuclear propulsion after NERVA that had better TWR than the original NERVA project. Look up "Timberwind Particle Bed Nuclear Propulsion Project" if you have the time- I linked to the Wikipedia article on it here.) Not surprisingly, the New York Times did a TERRIBLE job of explaining the rocketry behind it to the public when the project was "exposed" in 1991. For one, they completely missed out on the distinction between high-ISP, low-TWR rockets, like almost any form of Nuclear Thermal Rocket (including Timberwind), and engines that are actually useful for launch vehicles rather than just orbital maneuvers and long-burn upper stages... http://www.nytimes.com/1991/04/03/us/secret-nuclear-powered-rocket-being-developed-for-star-wars.html If you read the Wikipedia article closely, you will notice that the Timberwind rockets, unlike NERVA, actually did have enough thrust to lift their own weight- a TWR of about 30. But the specifications PALE in comparison to the TWR (and raw thrust figures) for comparable-sized chemical rockets, which can easily reach a TWR of over 100 and more than 12 times the raw thrust of the largest Timberwind rocket designs. so definitely NOT a good heavy launch stage. The largest Timberwind design had a diameter almost as large as Saturn V (8.9 vs. 10 meters) and a sea-level thrust of "only" 1,912 kN, with an 8.3 metric ton mass. Anyways, I currently have access to Timberwind-style reactors (my Kerbals, unlike fools like Mr. Aftergood, don't have overblown fears about nuclear rocketry- which is *FAR* less dangerous than atmospheric nuclear warhead tests), but I don't intend to use them for any missions just yet. The best-ISP fuel for a Nuclear Thermal Rocket is LqiuidHydrogen, and that has serious boil-off problems in RealFuels (even the alternatives, LqdMethane and LqdAmmonia, still boil off at a slow rate). My plan is to wait for generators and Dreadicon's final KSP-I/RealFuels integration config, and then send up LqdWater as a stable storage medium for hydrogen. I can also use the Oxygen component for an afterburner-like effect to increase the thrust. Using LOX decreases the ISP substantially, but you actually get more Delta-V for the same fuel tank volume this way than just carrying LiquidH2 due to the much higher fuel-density (and substantially better thrust thane using the electricity for plasmodynamic engines- while still exceeding the ISP of LH2/LOX or especially Hypergolic chemical rockets...) Regards, Northstar

I've finally been won over to the cause of using LH2/LOX for my launch stages rather than Kerosene/LOX or Hypergolics. The first vessel to see the benefits of this decision was my newest model of fuel tanker (built explicitly for refueling my transfer stage from the Munar Flyby mission). The deciding factor was the low, low cost of tank volume in the new version of Procedural Parts (version 0.9.19), which finally makes the MUCH larger tank volume needed for such a low-density fuel cost-effective. Actually, it seems almost too low- I think the mod creators might want to look at increasing the cost of fuel tanks a little (real fuel tanks also have to act as structural elements capable of bearing the weight of the rocket above them- which greatly increases costs over a simple pressure vessel...) It also makes me wonder whether in real life, shifts in the relative costs of fuel tanks vs. engines haven't favored one fuel over the other from time-to-time when it comes to rockets. More expensive fuel tanks obviously favor higher-density fuels, like Hypergolics (which tend to have lower ISP), whereas cheaper fuel tanks and more expensive engines strongly favor higher-ISP fuels (which also tend to have lower density...) But, without further delay, here are the screenshots: Another change in my tanker design was the switch from a monolithic 2.50 meter engine to a cluster of smaller engines. This wasn't driven by any good engineering balance reasons so much as that the 2.5 meter engine was providing far more thrust than I needed for the mission profile (which was to re-fuel my transfer stage from before- not to launch fuel as cost-effectively as possible or in large bulk). The 1.25 meter engines are actually heavier and more expensive per unit of thrust- but I needed less of it than a 2.5 meter engine could provide. If I had access to a 2.00 meter engine, I would have made use of that instead, and it would have been more cost and mass-effective... Anyways, the launch stage for this tanker was another Space-X style vehicle, and even with the cheaper engines, it still comprised the majority of the cost of the rocket: One final note about this tanker design, which may be instructive for those of you attempting to build reusable rockets with FMRS and realism mods installed. I settled on a mission profile based on having three stages, the first and last of which are reusable, and the middle of which is disposable. The reason for this is simple- the first stage can return directly to the KSC, and the last stage can perform a full orbit or two before returning, but the middle stage is stuck in an unhappy medium- it neither has enough velocity to make it around Kerbin, but too much velocity to simply turn around and head back the way it came. It also has to deal with re-entry heat (with Deadly Re-Entry installed), which adds cost and complexity to building in recovery-capabilities. Which makes recovery far less worthwhile, when it travels halfway around the planet first... All that being said, the main reason the middle stage wasn't worth recovering was simply because the parachute alone would have been almost as expensive as this part of the rocket- with a small engine (cost approx. 400) and a Procedural Parts fuel tank (cost less than 50), adding a parachute (cost 422) and a guidance system (cost 700 for a radial MechJeb unit- can be brought down a bit with inline fairings and an Okto probe core instead) would have actually LOST me money after recovery- and that's not even accounting for any reduced payload capacity... As you saw, though, the middle stage was over-engineered, and actually made orbit along with the upper stage/payload. The problem is, without a larger-diameter rocket engine, or an engine-cluster (which I didn't unlock the Procedural Fairings part to allow me to build thrust plates for until AFTER this launch- all I had access to was a NovaPunch 2.75 meter thrust plate), I couldn't have built a monolithic upper stage with a good enough height-to-width ratio to not fall over and explode after landing... So I decided to concentrate all the expensive parts (guidance systems, docking ports, reaction wheels, etc.) in the upper stage, and just abandon the middle stage (I'll try to de-orbit it for roleplaying though, even if doing so is going to cost me...) Enough analysis though. I tend to get a little carried-away with explaining the reasoning behind my decisions (sometimes I think I should work for NASA, where this kind of careful analysis is necessary- I already love space- but unfortunately I did not major in a field like aerospace engineering or physics...) Here are the final screenshots, of contracts offered after the fuel tanker mission (which fulfilled a launch clamps contract and unlocked a couple others), and my progress in the tech tree so far: As always, I hope you guys enjoy. And I hope all the cost-analysis didn't bother you- trying to figure out the most cost-effective ways to get payload to space has become a passion of mine lately... Regards, Northstar

It's a discussion of ideas for the missions to be carried out in the main thread. It's not really a Fan Work in itself, so I couldn't find somewhere it seemed to better belong where it would be noticed. You're also a lot more free to go off on discussing tangents here (although I discourage it, I'll probably be guilty of it myself) , as it won't clutter the main thread. A Minmus base is a nice idea, but still a little beyond my means (though I'm working towards some of the necessary tech nodes). Take a look at my latest post (will be up in just a second) for the latest on where I am in the tech tree (I've now got the construction and rocketry nodes up through Very Heavy Rocketry and Advanced Metalworks, and up to about the tier where you get the more advanced ladders across the rest of the tech tree). Infrastructure projects aren't a bad idea (I generally like doing them), they just need to be feasible. For instance, I've been thinking about trying to develop a "SpaceShip One" style mothership launch-assist system using Flight Manager for Reusable Stages, once I unlock a couple more tech nodes. And a LKO fuel depot is finally within reasonable reach... Anyways, that was one of the next two suggestions. Any others from someone else? Regards, Northstar

A whole bunch of screenshots for the Munar Flyby Mission here, which is now complete! First of all, you guys remember that module I dropped on the First Orbiter mission? I certainly do! It formed one of the two science modules for this mission, and also provided additional fuel for the trip- AFTER I rendezvoused up with it and docked, of course: After that, it was to the Mun! But I wasn't done yet. Using the Mun's gravity to my advantage, next I was off to Minmus: Of course, getting there is always the most exciting part of any voyage: And thanks to my majestic double gravity-assist earlier (even when capturing to Minmus orbit I expended less fuel than it would have taken to circularize at that altitude around Kerbin), I had enough fuel to make it out to the Sun's Sphere of Influence and beyond the edge of Kerbin's gravity! No trip is complete without a return home though... The status of things is now thus: I have two science modules scattered around the Kerbin system- one still attached to the reusable transfer stage from before, and the other in Minmus orbit. Both are currently in inclined orbits- which means intercepting them will take a bit more planning in my launch/transfer windows to minimize/avoid excessive orbital plane-changes. I also have access to a large number of new tech nodes thanks to this mission. I continued to focus on rocketry-related nodes, which means I've now unlocked up through Advanced Metalworks (Clamp-O-Tron Jr's and bigger Procedural Parts fuel tank limits) and Nuclear Propulsion; With a few more nodes, I should (hopefully) be able to start setting up ISRU facilities (I've still got to unlock the ISRU refinery itself, and generators unless I want to power it with solar panels using the new Ec-->MJ functionality). In the meantime, I've got enough propulsive and rocket-building options to send nearly any payload anywhere. Oh yeah, and I also unlocked the Mk1 Lander Can, so I'm almost ready for some Mun/Minmus landings (I just want to unlock the Impactor experiment which KSP-Interstellar replaces the seismic sensor with first...) And as always, the question looms- where to next? Feel free to post ideas for my next mission (likely a probe) on the discussion thread, which I've now linked to in the OP so you don't have to go searching for the other link in this thread, or hunting through the forum... Regards, Northstar

OK, the Munar Flyby Mission (which evolved into a double-flyby of both the Mun an Minmus, as well as a trip to the Sun's SOI and back) is finished. The question no is, where to NEXT? Regards, Northstar

Will you guys *PLEASE* stop complaining about the Magnetic Nozzles having low thrust. It's SUPPOSED to be that way: it's a high-ISP, low-Thrust option. That means, it has great fuel-efficiency but low power. You can have one or the other: TWR or efficiency. You can't have both. It's one of the fundamental trade-offs of rocketry, so please stop complaining about it. Now, if you have a legitimate case for why the low TWR is wrong/unrealistic, like with the Meth/LOX chemical engine (which has better TWR *and* ISP that in Interstellar in real life), then feel free to post about it. Otherwise, learn to love physics time-warp and MechJeb for long burns. Regards, Northstar