Northstar1989

@NathanKell So any thought on redesigning the Thermal Fins so they'll play nicer with FAR? Currently, they're almost entirely square, instead of having a nice triangular shape that would make them much more aerodynamic. Oh, and they're way too short (longer fins that are proportionally more powerful and a bit more cost-effective would be preferable). EDIT: I'm sick of discussing this in abstract (mainly with other people besides yourself), without actual images. So here are screenshots of the current thermal fins alongside what I would consider a *REASONABLE* sized aerodynamic control fin for a large rocket (the Heavy Control Winglet from NovaPunch2) that doesn't rely on reaction wheel spam, and a small stock canard for reference: As you can see, the RealFuels Thermal Fin is shorter than both, and MUCH less aerodynamic in shape (triangles are aerodynamic- squares... aren't). What I would consider a REASONABLE thermal fin for a large rocket would be at least 5-6 times as long (so a good bit longer than the Heavy Control Winglet) and triangular-shaped with a gradual slant, much like the design of the (much larger) radiators for the real-life Jupiter Icy Moon Orbiter proposals: JIMO was trying to dissipate the heat of a small nuclear reactor, of course- but I would consider the challenge of trying to dissipate the heat of a 5-meter diameter fuel depot (at least 10-12 meters long) holding LH2 long-term in space to be quite substantial as well... At least meriting 3-4 square meters or so of surface area per radiator (JIMO would have had 422 m^2 total radiator area), and that's BEFORE you account for the fact that RealFuels currently does absolutely nothing to scale-down boil-off of larger fuel tanks in accordance with the Square-Cube Law.. TANGENT/EXPLANATION: (The Square-Cube Law dictates that surface area increases with the 2nd power of tank dimensions, whereas volume increases with the 3rd power. Thermal leakage into the tank is proportional to surface area, and thermal leakage directly determines boil-off rate. That's BEFORE you consider the fuel tanks are also pressure-vessels, and thus larger fuel tanks have proportionally thicker walls- which allow much less heat to leak through to their contents.) The current Thermal Fins each are exactly ONE square-meter rectangles, which is absolutely pathetic (and thus not surprising it currently takes 16-18 of them to stop boil-off for really large fuel depots holding LH2... it would still take 6-8 of them if the Square-Cube law were actually applied...) and ridiculously un-aerodynamic compared to a 5-6 meter long triangular radiator (a 6-meter long right-triangle that extends 1 meter from the rocket body has surface area of 3 m^2) Regards, Northstar P.S. You may find it interesting to note that the Square-Cube law was first described by Galileo. Thus, from a certain perspective, *nowhere* is it more natural than being applied to spacecraft-engineering... P.P.S. The whole bit about the Square-Cube Law is just a tangent. I'd like to make clear my main focus is on seeing longer, triangular Thermal Fins added so that they'll actually place nice with FAR... I only bothered explaining what I meant about the Square-Cube Law so that other players reading this post would have any idea what I was talking about. Please don't mod-hammer me for bringing that up again...

The KSP-Interstellar/RealFuels integration config still needs a fix to change the Monopropellant-producing reaction to produce Hydrazine instead (although KSP-Interstellar also has Hydrogen Peroxide- so I guess could use that for RCS instead if it were properly integrated into RealFuels, and they were willing to deal with the decay-rates, which I think are actually native to KSP-Interstellar...), and the latest version (the one you sent to NathanKell, with any updates you've added since) also needs to be posted on your dev thread's OP so I can finally play-test it and see if there are any more bugs/fixes we need to iron out! Speaking of which, here's a new one- the KSP-Interstellar ISRU refineries' integrated tanks need to be changed into insulated tanks- right now products like LiquidOxygen and LiquidMethane boil off MUCH too quickly, thanks to the fuel tanks being considered non-cryogenic (considering the integrated fuel tanks were DESIGNED to hold LOX and Methane for long periods of time, I doubt they wouldn't have insulation...) Regards, Northstar P.S. There is no catch-all in the version of the config on the OP to change Monopropellant to Hydrazine. Right now the only MM patch is specifically to change just the plasma thrusters to use Hydrazine instead of Monopropellant- there is nothing to alter the function of the ISRU reactors that produce Monopropellant in the first place...

It sounds like a great book, that I only today became aware of for the first time (mere hours before your posts). I'll have to think about reading it some time... Expensive, yes. But the per-launch cost of an Orion was projected to be LESS than that of a Saturn V, while carrying thousands of times more cargo. Not a drastically lower cost mind you, but still slightly less, and with a much higher tonnage... Yeah, magnetic sails would be a convenient way to brake. Also something I only read about today- but the thought concerns me: if you're pushing against the magnetic field of a star (and thus basically using the star as reaction mass), couldn't you significantly perturb its total trajectory if you're braking something on the order of a 100,000 ton vessel from 10% the speed of light? And if so, wouldn't that risk screwing up the orbits of the very extrasolar planets you probably came to investigate in the first place- possibly even causing apocalyptic changes to the orbit and magnetic fields of any inhabited planets that somehow existed? Maybe THAT is the reason for the Fermi Paradox... (other spacefaring races accidentally destroying each other using magnetic sails) Of course, as a biologist with an incredibly deep understanding of history, I have my own answers to the Paradox. My belief is simply that very few planets have the correct setup to support intelligent life, and EVEN FEWER planets have the right circumstances to support an interplanetary (forget interstellar) civilization. I don't think we would even be considering traveling to Mars if we didn't have a Moon we were able to travel to first and prove technologies at, for instance... Regards, Northstar

If we can wait long enough (1.36 million years) without blowing ourselves up, the main sequence K-class star Gliese 710 is set to pass through the Oort cloud... http://en.wikipedia.org/wiki/Gliese_710 Regards, Northstar

If you're looking for something that could actually travel interstellar distances in a reasonable time period using current technology, look no further than Orion Nuclear-Pulse Rocketry: http://en.wikipedia.org/wiki/Project_Orion_%28nuclear_propulsion%29#Interstellar_missions For "just" 10% of the U.S. 1968 GNP, you could get a 133 year voyage to Alpha Centauri (with a 50,000 ton payload). That's quite reasonable for a generation-ship, both in terms of mass and time, and the study was based on materials available in 1968 (modern materials are much lighter/stronger, and thus require less structural mass: 50,000 tons of structure were to complement the 50,000 tons of payload...) Regards, Northstar

Hey all, Sorry for the delay since the last post! I've been a little distracted with other things lately. Anyways, I began setting up my first permanent infrastructure a few days ago with the launch of some KSP-Interstellar ISRU Refineries. I've posted screenshots below, but I also live-streamed this on Twitch (the total mission length was over 5 hours including vessel-design time and responding to chat, so there is NO WAY I'm uploading it on YouTube). Make sure to check in on my channel there some time! Like all of my launches lately, this was a Space-X style launch. The launch stage returned to actually safely land on the launchpad biome (landing on the actual launchpad is a little too much precision for a casual gamer like me- remember, I'm not doing this for a living like the engineers at Space-X!) The remainder of the rocket, upper stage and all (technically, refueling on LKO would have been more efficient- as it would have meant I wasn't pushing empty fuel tank mass to the Mun, but I launched into an elliptical orbit to begin with...) then performed a Munar insertion, which went quite smoothly, as did the subsequent capture burn... After arriving at the Mun, the designated skycrane section detached and flew the reactor down to the surface. This proved to be quite difficult due to the mass-imbalance from having the solar panel on one side and the docking port on the other. After flying down the first reactor, the skycrane returned to orbit for the second one: In hindsight, I probably should have designed the reactors to be completely balanced in terms of mass (with a small fuel tank on one side to balance the docking port on the other, and solar panels in 2x symmetry), but I guess I wasn't thinking super-clearly when I carried out this mission... Anyways, the second reactor was landed as well without (major) incident after several F5/F9 attempts in which I figured out the correct adjustments to the skycrane's thruster power-levels (asymmetrical thrust was necessary for stability) to account for the mass-imbalance... Then I attempted the (EXTREMELY TRICKY) business of making a "hop" to bring it closer to the first reactor, which resulted in countless explosions and disasters (due to the extremely low fuel levels left in the skycrane at this point) before I finally managed to succeed in bringing the two (somewhat) closer together... Since the reactors are still too far apart to connect via KAS pipes/winches, and are a pain to fly around using skycranes, the next step will be to land a rover to drag the two reactors closer to each other. I'm thinking one with a "Klaw" so that I can line the two reactors up and connect them (as well as a fuel tank connector-section I intend to send over to go between them, and store the Liquid Oxygen they produce from Munar regolith...) without having to use the docking ports, and perform unmanned refueling operations once the refineries are active (using the rover as a "fuel bowzer" for liquid oxygen- integrated oxygen tanks will also make the rover more stable when moving around the refineries) without having to mess with precisely-placed docking ports or Infernal Robotics arms... After that, I'm going to need to attach a heavier-duty power-source (such as a nuclear reactor or Microwave Beamed Power Receiver) and accompanying additional radiator-area (probably on the topside docking-ports originally used to attach the refineries to the skycrane) before the ISRU Refineries will become fully-operational, as they are quite power-hungry, and the integrated solar panels will be able to do little more than power the active-cooling units (RealFuels Thermal Fins) I plan to include on the final fuel tanks, due to their comparatively low power output and the day/night cycle on the Munar surface... I probably would have been better-off leaving out the integrated solar panels, and designing in Microwave Beamed Power Receivers right from the outset- but my hope was that the solar panels would provide enough power to run the refineries at a slow rate with a lower startup-cost (Microwave Transceivers are expensive, like in real life). This proved ill-advised, as the Liquid Oxygen produced by the ISRU refineries boils off faster than it is produced when stored in uninsulated, un-cooled fuel tanks, and the refineries only have the meager power of those two solar panels to run off... However, NONE of this can be attempted before I unlock the "Klaw" and rover wheels- so the next step will be another conventional (hypergolic-fueled, for low boil-off and compact lander size) Mun landing to obtain additional !SCIENCE! I've already designed a new (slightly heavier) lander for this purpose, and some of you watching me on Twitch (either live or in the archived recordings) may have even seen the design already- which I actually launch-tested and got most of the way to orbit before discovering I forgot to set Action Groups, or some silly but non-critical detail like that... (which resulted in a revert) As it currently stands, the Kerosene/LOX transfer stage used to carry the ISRU refineries to the Mun is also still sitting in Low Munar Orbit with just a tiny bit of Kerosene left onboard. Although it is too large and has too high of a TWR (and thus large engine-mass) to be practical or cost-effective for most Kerbin-system missions (such as Munar landings and returns), excepting possibly the movement of very large fuel depots from LKO to the Mun/Minmus; it should make for an *excellent* Duna transfer-stage when I am ready to send my first heavy payloads there (whether manned missions or ISRU refineries). I'll have to refuel it with Kerosene from Kerbin and Liquid Oxygen from the Mun first though... Regards, Northstar

So if I re-release the part with the same license as the original version, it should be OK, right? Regards, Northstar

Those aren't the really dangerous bits. The most dangerous debris are those "massing 1 kg or more" according to NASA. Some debris are as large as entire rocket upper stages or decommissioned satellites. Those pieces should be possible to find. Like I've repeatedly pointed out, if there was a *use* for debris (as reaction mass), you might also see more generation of them... Regards, Northstar

It's not *quite* that simple. There also needs to be a way to scoop Nitrogen from the atmospheres of Kerbin, Duna, Eve, and Laythe (their real-life analogues all have significant amounts of nitrogen in their atmospheres), which is the *whole point* of adding a Nitrogen fuel-mode to the plasma thruster (for the ISRU possibilities). Also, I'd prefer something integrated into the base mod, so everybody can benefit from it, and I don't have to mod KSP-Interstellar again every time it updates. Regards, Northstar

Indeed. I'm in full agreement. Although life support needs to be a toggle-able difficulty factor for precisely that reason, as it makes the game a bit harder... Well *technically* the more life-support you carry the less Delta-V your ship has for the same fuel mass, which might mean you have to take a longer/slower transfer to get to your destination, which means you have to carry more life-support... Of course, it's probably rarely a major factor in this aspect. I do think life support would add in a lot of interesting immersion/realism possibilities besides just "pack a bunch of food and water" (water can easily be electrolyzed for Oxygen and LiquidFuel/Hydrogen). For instance, not just greenhouses, but also the ability to potentially place your crew in hyopthermic "turgor" (surprisingly, this is something NASa is actually seriously investigating for a Mars mission)- which would also reduce the need for living space if that aspect of life support were ever implemented... (a living space/ morale system sounds interesting to me- as long as it can be toggled in difficulty settings...) As I pointed out before, life-support also gives an actual use to a "cycler ship", which could easily be equipped with greenhouses and extensive living-space, as it would only have to be accelerated to its transfer-orbit velocity *once*, and could be re-used many times... Regards, Northstar P.S. If you didn't catch the embedded link, here it is again. It's to a decent article on cycler ships: http://www.damninteresting.com/the-martian-express/

Don't forget that the *best* solution would not be to disable the Monoprop --> Hydrazine fix for KSP-Interstellar, but to eliminate the reasons for disabling ModuleRCSFX in the first place. This means, as I said before: (1) Creating a catch-all so that command capsule RCS tanks all contain Modular RCS tanks (which can contain Hydrazine, N2, etc.) instead of Monopropellant. (2) Creating a fix for the products of the KSP-Interstellar ISRU reaction producing Monopropellant, so it produces Hydrazine instead (the existing ISRU reaction's chemistry/rate etc. was already based on Fractal_UK's assumption that Monopropellant represents Hydrazine- really all that is required is a name-change...) Regards, Northstart

@NathanKell Hi Nathan. Glad to see you posting as always. Any news on integrating the KSP-Interstellar integration config Dreadicon said you and releasing the updated version? Dreadicon said he sent you the latest version some time ago, and though there were a few odds and ends left to fix, I haven't heard anything from him since- so I doubt any more progress will be made in the near future on that. As such, it would seem prudent to integrate the latest config and release it with 8.2 quickly. Regards, Northstar

Please calm down. I don't know where you're sensing evasion or snarkiness, but it's not coming from me. I see. Thanks for the clarification. Do you know precisely which fixes will be coming? First of all, you modified the thermal fins. That *entirel*y circumvents the problem- I was clear that the fins ripped off when *unmodified*. If you made their attachment point stronger, of course they won't rip off... (although I would question the realism- and this still does nothing about the poor aerodyanmics generating excessive drag or the need for part-spam to cool large tanks...) Further, you need to provide more info on how you tried to replicate. What was the liftoff TWR of the rocket? The maximum TWR during ascent? What was the highest speed accomplished? Was it a large rocket with a higher ballistic coefficient, or a smaller rocket that was less aerodynamic? These factors are all INCREDIBLY important to whether the thermal fins will rip off... You also didn't provide much information on how you were trying to replicate the problem. What size tank were you using? When I talk about needing to use 12 or 16 fins, I'm referring to the larger fuel tanks in the game- Rockomax-64 and the SLS-style 3.75 meter tanks... If you were using ProceduralParts mod instead, what tank types were you using? Cryogenic? Balloon? Service? (with Hydrogen, you should probably be using CryogenicBalloon- standard Cryogenic tanks being too heavy for the volume...) Obviously a 1.25 meter fuel tank won't require a boatload of thermal fins... Like I said, longer thermal fins can be more powerful, more aerodynamic (and less prone to rip off, with stronger surface-attachments), and more cost-effective (while also requiring less part-spam). Why are you so resistant to the idea? Regards, Northstar

You could say *EXACTLY* the same thing about solar panels. Greenhouses would be not only a way to avoid having to run constant re-supply missions to permanent bases and stations, they would also be realistic (they can be built in real life, albeit with maximum efficiencies between 90 and 98%). What life support + greenhouses add to the game is immersion (and no system is fail-safe, you could always lose your greenhouse, or the solar panels powering it, but not your command pod, in a collision, for instance...) And besides that, greenhouses also look cool, and give a visible sense of permanence to bases. Greenhouses would/should be far heavier than carrying a limited (exhaustible) supply of food/water etc. Where they should REALLY shine is with permanent bases/stations, or "cycler ships" (that travel between two or more planets in a stable orbit that requires almost no station-keeping fuel). Players could configure the maximum efficiency of greenhouses with mods, tweakables (less efficient greenhouses would be cheaper/lighter), or perhaps with a difficulty slider. Thus, players who wanted a little more realism could have it, while players like me who didn't want to be bothered with tedious re-supply missions (and didn't like the idea of an abstracted re-supply system) could have that too... If you're looking for a good model of what I'm talking about, consider TAC Life Support, its various life support recyclers (including CO2-Scrubbers, a Sabatier Reactor, etc.), and the CELSS Greenhouse mod... Regards, Northstar P.S. More information on cycler ships, because they're awesome: http://buzzaldrin.com/space-vision/rocket_science/aldrin-mars-cycler/ https://engineering.purdue.edu/people/james.m.longuski.1/ConferencePapersPresentations/2006GuidanceStrategyforHyperbolicRendezvous.pdf

This is too hilarious not to comment on. Regards, Northstar

Awesome. Why are all the most epic trailers the oldest ones? Now Squad just seems to do cutsy things where a building explodes or something... IMHO, if you're not playing KSP yet, it's because you don't know how EPIC and AWESOME it is- not because you don't know about the latest feature. Squad needs to get back to the basics with their trailers... Regards, Northstar

The recovery operations went *mostly* smoothly. As planned, the first Service Module detached after the first aerobrake pass, and safely recovered to Kerbin's surface (although a bit further downrange than planned...) And the second Service Module also recovered smoothly. But, in the final screenshot, notice anything missing in the Tracking Station? The "Retrograde Fuel Tanker" experienced a "control system malfunction" (i.e. I was too busy to switch to it and perform an adjustment burn to raise its periapsis) and burned up in Kerbin's atmosphere while I was busy landing the Service Modules... Not that I'm terribly upset about it- that tug/tanker was extremely small/cheap, and more importantly, I was thinking about decommissioning it anyways, to replace it with ion and thermal rocketry-based tug/tankers... Speaking of which, I managed to unlock several *extremely* useful tech nodes with this mission... I've unlocked Microwave Beamed Power, Microwave Thermal Receivers, and Clamp-O-Tron Sr. docking ports, among other things... Though on the gloomier side, I basically broke the bank with new part unlocks- and can't even afford the large solar blanket panels I desperately want for solar power-satellites... Regards, Northstar

Uhhh.... No. You don't need to already have apoapsis at the desired height before pointing horizontal to the horizon. Have you ever *tried* seeing what happens if you burn horizontal? Your apoapsis continues to increase, as long as you still have some upward momentum. Therefore, you do indeed want to be pointing completely horizontal quite a bit before you cut thrust and coast to apoapsis... (in practice, maybe a couple degrees above horizontal, since you DO NOT want your engines to burn *even slightly* downwards at any point during ascent) Also, you *want* to reach apoapsis quickly. That reduces total gravity-drag during your ascent. I think what you *meant*, is that you don't want to OVERSHOOT your target apoapsis, which is true. The low TWR, and horizontal facing of the upper stage help prevent that though... Regards, Northstar

I was immensely disappointed to see HarvestR's apparent dismissal of Life Support based on "babysitting crews" during long-term missions. *What* crews is he talking about exactly? There's no reason any player should have Kerbals sitting around doing nothing (if they're on a pre-planned mission, they should have been sent with plenty of life support for it), unless they're in a space station... And there's a *SIMPLE* solution for that one fringe case of permanent stations/based- just add a "greenhouse" part that with 100% efficiency recycles LifeSupport waste back into the Life Support resource(s), using light and/or electricity. It's NOT that complicated, or far from reality- from a certain perspective *Earth* is just a giant space ship, and plants+bacteria recycle our life support resources (food, water, breathable oxygen, etc.) from their waste-products. Sure, it's hard to achieve that 100% level of efficiency in real-life with a manmade system, but this is a game- and I'm sure most players (myself included) would be OK with that level of abstraction if it meant they could have permanent stations/bases without any babysitting and yet still have to provide life-support for that 5-year mission to gas planet #2 (if it's ever added...) The greenhouse part could/should be HEAVY, so that players don't send it on flag-and-footprints type missions. (and besides, launching heavy parts on large rockets in just FUN and COOL to watch...) Really, from a balance perspective, it's not all that different from the Mobile Processing Lab- which is only worth sending to permanent outposts (which without life support or ISRU-refueling, don't currently have much use) or on a mothership in multiple-landing missions... Regards, Northstar P.S. I also like the idea of some sort of living-space requirement for long-duration missions, so life support doesn't just become a matter of a tiny capsule plus a huge oxygen tank- although players can always choose to provide living space for roleplay reasons anyways...

Those are pretty cool videos. And to steal GloriousWater's phrase, it certainly beats what I can accomplish with my old coal-fired computer! Regards, Northstar

And I guess you were going for "Time to bail out!"? Unfortunately, your plane can't disappear for that distinction though (obviously, that wouldn't be useful for actual operations around Kerbin- say to para-drop Kerbals to hook up a surface base: something I've actually used para-crop planes for before...) So you need to try different mods, or drop the Kerbal while gliding low+slow, and only deploy the parachute really close to the ground (or have the plane circle around while the Kerbal falls within loading-distance...) Did you try using Flight Manager for Reusable Stages to get around your plane disappearing? It's an excellent system when dropping cargo- and my guess is that it work with dropping Kerbals as well... Regards, Northstar

OK, so that's... "Watch out for the canopy Goose!" and "Atmospheric Specialty" Anything else I'm missing? I'm really tired today for some reason... Regards, Northstar

No, I'm just not interested in modding my mods any further than I'm already doing (trying to develop an updated KSP-Interstellar/RealFuels integration config in combination with Dreadicon) just to get what should be a rather core/essential part of the mod working. If the surface attachment points are too weak *for the current size of the thermal fins*, then NathanKell should push a fix to the base mod. However, what *I* suggested is larger/longer thermal fins, which would kill two birds with one stone- both the problem of needing to spam thermal fins for larger fuel tanks, and the issues with thermal fins ripping off (once again, a fin with twice the length, the same radius at the base, twice the mass, and twice the surface attachment area would be far less prone to ripping off...) Your "fix" only solves one of these issues- and not in a very realistic/satisfactory manner either (the reason the fins rip off is because they're not shaped very aerodynamically- not just because the surface attachment points are too weak. Longer fins can be made MUCH more aerodynamic- consider the differences between a 1x1 right triangle and a 1x8 right triangle, and tell me which is more aerodynamic...) You asked if KSP-Interstellar had radiators- I answered your question, and then went on to point out that they don't work with RealFuels. I missed nothing. Why are you being so abrasive/critical lately? You've completely confused me by writing there would be no fix, and then crossing that out without a real clarification. Are there going to be any fixes to the Thermal Fins in the base RealFuels mod or not? The current Thermal Fins are far from usable/acceptable (besides being too small, thus requiring part-spam; and too blunt- thus ripping off with FAR; they also aren't nearly powerful enough compared to real-life active-cooling systems, and *in aggregate* are heavier and more expensive when you're using dozens of fins for the same effect a single device would accomplish in real life, *especially* for the larger fuel tanks, which benefit heavily from not having to miniaturize cooling technology as much...) Regards, Northstar

I ended up going with a "Bail and Flail" plan, as I decided to nickname it- and have the lander use up all its fuel to launch on a suborbital trajectory before detaching its probe core (for "recovery of a vessel" science points) and Bill Kerman with all its stored experiments, to circularize with his jet-pack. Lacking sophisticated modeling algorithms to compute ascent trajectories (like NASA has), it took me a couple F5/F9 tries to determine the correct suborbital trajectory for this- but I eventually got it... Of course, NONE of this would have been possible in real-life, where jet-packs don't hold NEARLY as much fuel- but no real-life space program would have so badly mis-calculated the amount of fuel it took to land and launch back to orbit, and stranded a Kerbal on the surface of the moon in the first place... Anyways, after the Kerbal and probe core were successfully in orbit, I sent my Service Module to retrieve them, and prepare to head home: I decided to recover Jebehiah as well. Technically, I could have just left the Munar station with only one of the Command/Recovery Pods, and left Jebediah Kerman in orbit for a few more game days or weeks until the next Mun lander (and corresponding Service Module) arrives to collect more !SCIENCE!, but I didn't feel like placing the pressure on myself of having a Kerbal still waiting in orbit (even if I'm not yet running any life-support mods...), and I figured I'd give poor Jebediah a break. It's not as if I won't be sending him up on the next rocket to the Mun anyways... Regards, Northstar

@Fractal_UK I made a good point! Awesome! Now I just wish I could hear something back about the Nitrogen fuel-mode for the plasma thrusters... I feel like I'm just talking to a wall every time I suggest this, but I *did not* suggest those just out of features-bloat type thinking. I have a serious use in mind for them (Propulsive Fluid Accumulators) that absolutely would not work without them, so long as I can only scoop atmospheres *below* the Karman Line... (70 km in KSP) Nitrogen plasma thrusters also provide a useful middle-ground in the TWR/ISP relationship based on molecular mass- N2 (diatomic molecular mass = 28) is lighter than Argon (molecular mass 39.948) and Xenon (molecular mass 131.293) despite being a diatomic molecule, but heavier than Lithium (molecular mass 6.941) and Hydrogen (diatomic molecular mass = 2), and is far more abundant/common than any of those- it is present in the atmospheres of Earth (78.1%), Mars (1.9% - compared to 2.1% for Argon), and Titan (between 4.9% in the troposphere and 98.4% in the stratosphere: I'm assuming Laythe is a Titan analogue, as there's really no better direct parallels in the real solar system). As I've pointed out before, the ability to harvest atmospheric nitrogen would also be *incredibly* useful for ISRU production of Ammonia (though... the Haber Process still seems to be missing from KSP-Interstellar 0.13?), as it would allow a player to, say, scoop Nitrogen from the edge of Laythe's atmosphere, and combine it with Hydrogen (LiquidFuel for those not using RealFuels) scooped from Jool, without having to actually land on either body or carry the refinery equipment into Laythe's atmosphere... Regards, Northstar P.S. I've still got my fingers crossed for a Karbonite-style ability in KSP-Interstellar to scoop atmospheres from ABOVE the Karman Line, at low concentrations while in time-warp, by the way...