Northstar1989

Fractal, good to see you posting again. Did you notice my list of fixes/changes/suggestions a little while back? They're in this post, and the one immediately after it... The super-short version of the list: - Tweaking Microwave Receiver reception does not tweak WasteHeat generation. WasteHeat is always calculated from the maximum available power. - The Meth/LOX (Methane/Oxidizer) engine has too low ISP and TWR values compared to its real-life analog, the Raptor. - The Haber Process (Nitrogen+Hydrogen-->Ammonia) doesn't currently appear to be implemented, or isn't working properly utilizing atmospheric Nitrogen. - Nitrogen cannot be used as a fuel in plasmodynamic thrusters, but can in real life. *EXTREMELY* useful for Propulsive Fluid Accumulators if it could be. - Atmospheric Scoops don't work above the Karman Line (KSP's edge of atmosphere). They do in real life, and Karbonite mod has already found a way to implement that. - The scaling of the Al-Hybrid and Argon tanks are messed up, creating gaps at the end of the parts. A community patch was created to fix this. - The Magnetic Nozzle has gaps between the part ends and the nodes. A community patch was created to fix this, and the node sizes. - The 3.75 meter parts in KSP-Interstellar almost all fail to use the new, "size 3" nodes than were introduced in the Asteroid Redirect Mission update for 3.75 meter parts. They use 2.5 meter ("size 2") nodes instead at the moment, which are too weak for their size. Regards, Northstar

Addition of Life-Support features could also drastically change the equation- if life support required electricity to operate like in real life or TAC Life Support... Regards, Northstar

Aside from the figures I already pointed out before (about how you can greatly leverage your initial reaction mass using this system), I also wanted to point out that mass-drivers would have GREAT synergy with a system of Propulsive Fluid Accumulators... Essentially, if you made the debris-retrieval tugs Nitrogen-fueled instead of Xenon-fueled, you would have an essentially *unlimited* amount of reaction mass to work with by skimming additional Nitrogen off the edge of Earth's upper atmosphere. Nitrogen-electric propulsion doesn't work well for manned or deep space missions because of its very low TWR (the lighter the atoms in your exhaust stream, the better your ISP but the worse your thrust. Nitrogen is much lighter than Xenon...), but it would work GREAT for a debris-retrieval system like this where the distances and Delta-V gaps are relatively small, and the most important thing is that you don't expend more money retrieving the debris than you gain from using the mass driver to accelerate payloads... You could also stick a couple nitrogen-electric plasma thrusters on the mass driver, and accelerate it entirely with Nitrogen skimmed off Earth's upper-atmosphere if you wanted... This would make transfer orbits to anywhere beyond Low Earth Orbit EXTREMELY low-cost (after the large initial investment cost of establishing the system), as the Propulsive Fluid Accumulator + Mass Driver system would be self-sufficient, and could impart an effectively unlimited amount of Delta-V on any departing spacecraft, limited only by the size of the mass-driver and its access to electrical energy... Propulsive Fluid Accumulators exasperate the energy problem though- you need a way to feed them large amounts of electricity inside the edge of the upper atmosphere, where solar panels create too much drag to be feasible for this below about 150 km orbits... The BEST solution for this is probably to simply beam them power from the surface of the Earth or higher (and more stable) orbits, the same as with powering the mass driver... Regards, Northstar P.S. Atmosphere-Skimming Propulsive Fluid Accumulators were another idea I proposed on my list of infrastructure projects to try and tackle in KSP. However, without that ability to utilize Nitrogen in plasma thrusters like in real life, or skim atmosphere from ABOVE the Karman Line, the system would be DRASTICALLY less effective in-game than in reality...

The absolute amount of energy required per shot can indeed still be a problem- Kulebron is right about that. You have to either accept lower exhaust velocities for larger pieces of debris (remember, there are "safe" bands of velocity at *both* below 2x orbital velocity and above escape-velocity), or grind larger pieces of debris up unto smaller chunks. It's not easy to build a capacitor bank that can hold the energy to expel a 2-ton spent upper stage at 30,000 m/s- it's much easier (and lighter) to grind that debris up into 1 or 2-kg chunks, and expel each of *those* at 30 km/s... Of course, one way to DRASTICALLY lessen the generation and storage requirements on-orbit is to make use of Microwave Beamed Power. If you *beam* the power to the mass driver, you can leave all the heavy solar panels or nuclear reactors on the ground, and won't need nearly as much storage-capacity (if you can beam up power at half the rate it's consumed, for instance, then you only need enough storage for half the per-shot usage... And there are few limits to the rate at which you can beam up power, other than thermal-management issues...) I never said it would be a *disorganized* dumping of debris in orbit. More likely, space programs would start generating extra debris in a new designated graveyard-orbit *MUCH* lower than current graveyard orbits (as the debris wouldn't have to remain stable nearly as long) not too far above the position of the mass driver. A lot of extra reaction mass could be obtained just by not de-orbiting spent upper stages, and using them in the mass drivers to recycle their momentum instead... It might also make sense to establish two mass drivers and such orbits- one for polar satellites and debris (and for utilizing any debris with a greater than 45-degree inclination), and another for equatorial satellites and debris (and for utilizing debris with a less than 45-degree inclination). And, like I said before, if you also set up a mass driver in a retrograde orbit, you could just shoot debris between the prograde and retrograde mass drivers (into special elliptical graveyard orbits for each) to ensure you never ran out of reaction mass for the mass drivers... Regards, Northstar

+1 for that. @OP You really need to make the suggestion title more descriptive. Go into Edit --> Go Advanced and change the title so it's clear this is a suggestion about music. Regards, Northstar

NASA has definitive plans to continue testing the device. No idea how well they're sticking to their original timeline though... Regards, Northstar

10 m/s? 100 m/s? *chuckle* You could launch debris are up to 30,000 m/s (the current max speed of our largest mass accelerators- on very small masses on Earth), which equates to an ISP of 3058 seconds. It's a matter of mass-leveraging. Using 10 kg of Xenon propellant, you could easily drag at least 2 or 3 metric tons of debris back to a LEO mass driver (the Delta-V gap between the debris belts and typical station low orbits is VERY small). Then, you could grind the debris up into tiny pieces (Which would be fired separately), and gain the equivalent of 20 or 30 more times as much reaction mass at an ISP of up to 3058s (the best ion thruster currently in development, the Dual Stage 4-grid ion thruster, has an ISP of 19,300 seconds). Not only that, but you aren't limited by the Rocket Equation, since your mass driver doesn't get carried with the payload- unlike the fuel for a comparable impulse using conventional propulsion. The mass driver also allows you to accelerate the payload as fast as the payload can withstand being accelerated (with very small payloads, you *could* reach over 100 g's of acceleration), which means you take much greater advantage of the Oberth Effect than with an ion thruster- which are the only other means of propulsion with this kind of specific impulse. Regards, Northstar

Yes. Some types of ion propulsion rely on Argon instead. It actually has a better ISP than Xenon for the same per-atom energy, due to its lower molecular mass (but it also has lower thrust). It also suffers from lower fuel-density than Xenon, and requires lower storage temperatures. Another option is Nitrogen, which can be skimmed off the upper atmosphere: http://en.wikipedia.org/wiki/Propulsive_fluid_accumulator Some pieces of debris ARE short-lived. Others are in highly elliptical orbits, and so spend most of their time high above the Earth, and only a short time in lower orbits. But the debris that would be most useful for mass drivers are simply objects with very high density (and thus very high ballistic coefficients)- like screws and tools dropped off space stations... Regards, Northstar

Keep watching. NASA hasn't forgotten about it, or given up on it (in fact, there's no reason to- all the results have pointed towards it being real/functional so far...) so you probably shouldn't either. Regards, Northstar

I'm not trying to necro this thread or anything, but the announcement that a Resources system will indeed make it into 1.0 kind of changes things. I can now foresee there being a much larger demand for huge solar panels other than just roleplaying on space stations and using clusters of ion engines (mounted on Cubic Octagonal Struts) for ion-tugs. Anyone have some thoughts? Regards, Northstar

The Munar Integrated Science Module is now in Munar orbit. It is a phasing orbit BELOW the Munar Lander (capturing into lower Munar orbits takes less energy), but will still take quite some time to reach the correct position for rendezvous... In the final screenshots, you can also see the re-named Munar/Minmus Fuel Tanker shooting through the closest point of its first gravity-assist with the Mun. The plan is to keep making gravity-assists until it's just a small bump to get it onto a Minmus-transfer orbit... Meanwhile, the Kerbin Polar Expedition rotated back into daylight on Kerbin, so I decided it was time to begin its return to the KSC. I got a little picture-happy on the way back, and made several landings- so the screenshots are split into two albums: One particularly interesting stop was when I noticed a lake that still counted as being part of the Tundra biome. Areas like this have a distinct Science pool from the land version of the biome, so I decided to make a quick landing there... Unfortunately, due to the several landing-hops, and not starting the return trip until noon (polar time), I didn't make it all the way back to the KSC before the sunset. In the final screenshots you can see where I touched the plane down for the night... (since it's solar-powered, it can't fly without sunlight- although it has enough battery storage capacity and glide-capability it probably could have made it back to the KSC if I throttled down far enough...) More screenshots will be coming of both missions soon (the Kerbin Polar Expedition and the Mun Landing Mission). In the meantime, I suggest you check out my discussion thread on the Science Labs about utilizing orbital debris as reaction mass for mass-drivers in real life and in KSP... http://forum.kerbalspaceprogram.com/threads/98615-Using-orbital-debris-as-reaction-mass-profiting-from-orbital-mass-drivers I also suggest you make your opinion heard over on the discussion thread as to what infrastructure project I should begin on first: http://forum.kerbalspaceprogram.com/threads/97427-Announcing-Northstar-s-Collaborative-Kerbal-Career-Campaign-what-to-build-next Regards, Northstar

Another *REALLY COOL* thing is that you could even set up another mass-driver in a retrograde orbit, and bounce reaction mass between the two instead of de-orbiting or ejecting it from the Earth-Moon system (to be precise, you would want to shoot debris into designated elliptical graveyard-obits, and send ion tugs to retrieve them: fuel for which would be the only reaction mass consumed in this plan...) Each mass-driver gains speed, but there is no change in net momentum (kind of like if two people stand on skateboards and push against each other- both start moving in opposite directions, but momentum is conserved). You still need electrical energy to run this system though. This would allow you to re-use the same reaction mass an effectively unlimited number of times, and essentially circumvent the Rocket Equation by coupling each impulse in the prograde direction with an equal impulse in the retrograde direction. Of course, I'm not sure why you would WANT to put payloads in retrograde orbits, unless their ultimate destinations were outside the solar system (in which case, you are ultimately stealing momentum from the Earth-Moon system...) Regards, Northstar

@Streetwind Unfortunately, you're quite wrong. Most of the mass you launch to LEO for a GEO satellite is actually fuel to get it to GEO in the first place. Larger rockets are a LOT more expensive- this is why they say it costs $10,000/kg to get anything to orbit, not such and such price per launch. If you have to launch 30 or 40% the initial mass to orbit, you save a LOT on satellite placement costs. And due to the Rocket Equation, if 90% of launch mass is fuel to get to GEO, then maybe 60% or 70% of that fuel is to get to GTO, and only 30 or 40% of that is fuel needed to circularize... You can also launch twice as many satellites at a time on a given launch vehicle if each satellite only weighs 30 or 40% as much... Physical distance doesn't matter. We're not talking about a chemical rocket that flies blind through the debris-belt, and tries to scoop up as many pieces as possible. We're talking about a TINY ion-probe that engages in rendezvous with each individual piece of debris, and SLOWLY brings it back to the mass driver utilizing the most fuel-efficient route possible. The only thing that matters is how far apart objects are in terms of Delta-V: which when they are in the same orbit is almost negligible (you can enter into a phasing orbit only 1 or 2% higher/lower, and wait MONTHS for positioning for the next rendezvous if necessary...) And de-orbiting each piece of debris reduces that risk. Nothing about this idea requires a huge, impenetrable cloud- in fact that would only make implementation more difficult. The launch costs DWARF the fuel costs. Propellant-grade Xenon can typically be obtained for about $850/kg, although prices range as high as $1200 per kg, according to Wikipedia (which only cites one source for the price, which appears to be on the high end. Even if other fuels were FREE, but you needed to launch 10x as much, they would be MUCH more expensive. Do the math: $100,000 in launch-costs for 10kg of a free propellant with around 400s ISP (basically only LH2/LOX has ISP that high- and is *HIGHLY* cryogenic, meaning it can't be stored for long periods of time in orbit without expensive cooling systems...) vs. $11,200-$10,850 in launch+propellant costs for a single kg of Xenon. And because of the Rocket Equation, you need MORE than 10x as much mass of fuel for a fuel with 1/10th the ISP... It wouldn't be negligible as reaction mass for the driver. If you could catch even 100 kg of tiny pieces of debris like that, and shoot them out the mass driver at Earth escape-velocity (11.2 km/s), then that's the same impulse as 100kg of fuel with an Isp of 1141.7 seconds. And because you don't impart any net-energy to the mass driver (any speed it gains is later transferred to payloads), you completely circumvent the limitations of the Rocket Equation (yes, if the mass driver is loaded down with reaction mass it will gain less speed by firing it retrograde at a given speed- but it will also lose less speed when firing payload prograde at a given speed- energy and momentum is conserved). Just the opposite- the larger pieces would actually be LESS profitable to use as reaction mass, as they would require larger ion tugs just to pull them back to the mass driver. It would actually make more sense to send a tiny tug that cuts little pieces off larger debris and hauls it back to the mass driver in a large number of trips than it would to send a larger tug that can do it all in one go. Not only are ion engines difficult to scale, but you have to launch more mass to orbit in the first place if you send up a heavier tug... The BEST ion tug would actually be the SMALLEST ion tug, with the ability to cut larger debris into smaller pieces. This way, you can use the same tug for both large derelects and tiny screws... If there were a *USE* for orbital debris, people might also be a lot less hesitant to create it. If NASA had known we would be re-using the External Tank on the Space Shuttle, for instance, they could have increased the total launch mass by 10-20%, and put three times the "payload" in orbit with each launch (if you count the External Fuel Tank as a payload), rather than dumping the EFT on a sub-orbital trajectory just shy of achieving circularization... This would give value to retrieved debris AND work well on tiny pieces of debris (in fact, the smaller the better- as you can obtain more energy from each piece of reaction-mass without having to grind anything up into smaller pieces that way). The hard part would be finding+detecting the smallest pieces of debris in the first place, but we could always make a handy profit off the larger pieces in the meantime. There are dozens of decommissioned satellites, and even a handful of intact rocket stages in orbit- probably enough reaction mass to launch at least a couple-dozen satellites on GEO-Transfer Orbits (GTO) if you cut/ground them up and launched each tiny piece retrograde with sufficient velocity... Regards, Northstar

@shynung You *COMPLETELY* mis-understand the proposal. The whole idea is that you DON'T permanently move the mass driver station from its low orbit. If you fire a piece of debris retrograde, you fire a payload prograde. Energy (and momentum) is 100% conserved no matter how heavy or light the mass driver station- a heavier station will gain less velocity from firing debris (and crew capsules) retrograde, but will also lose less velocity from firing payloads prograde by the same measure. Thus, the mass of the mass driver station is entirely *IRRELEVANT-* in fact, as I pointed out in the OP, *heavier* stations are preferable, as they will experience less of a recoil shock when firing debris. Also, you are firing satellites on GTO orbits from LEO with this method, using orbital debris as reaction-mass. This saves on the fuel costs to put them in GEO in the first place- it has nothing to do with stationkeeping fuel (other than that the fuel you would have had to used to get to GTO can be used for stationkeeping instead...) Because the mass driver station is not being accelerated in the long run, it doesn't matter how massive it is. Read the OP before you comment. A grinding station would actually be highly profitable, as it would allow you to harvest more velocity from each piece of reaction mass- but energy is always conserved whether you are accelerating a small station by a lot or a massive station by a little. @Dodgey This makes more sense, as you don't have to haul the mass driver around, and get USEFUL momentum-change out of that reaction mass instead. Regards, Northstar

The Munar Lander made an uneventful capture into Munar orbit, and then Jebediah performed some EVA science: But this was also one of those "DOH!" moments where you realized you messed something up before, but it's far too late to fix it. Namely, the "Kerbin Return Stage" captured into a RETROGRADE orbit. I thought I switched the side of the Mun it was approaching on when it separated from the free Return Probe before (which was definitely also approaching on the WEST side of the Mun- where capturing would have led to a retrograde orbit), but a review of the screenshots confirms that I was mistaken. The "Munar Fuel Tanker" (the heavier transfer/tanker stage from before) is *also* approaching into what should become a retrograde orbit as well... Neither situation is a complete loss, though. The "Return Stage" can still act as a fuel tanker for the Munar Lander- which can freely switch between prograde and retrograde orbits by simply taking off again in a different direction after landing (although retrograde launches take more fuel), or could meet up with it in a polar orbit if it should prove necessary (prograde and retrograde orbits take the same Delta-V to make polar- though I should have captured into an elliptical orbit if I were planning on a plane-change maneuver...) The "Munar Fuel Tanker", meanwhile, I renamed into the "Minmus Fuel Tanker", as the plane-change affected by the Mun's gravity will perfectly line it up for making multiple further Munar gravity-assists: ultimately culminating in it reaching orbit around Minmus for very little additional fuel... (a hypergolic stage is also the best-suited for such a slow process: as it doesn't have to deal with boil-off issues over the potentially months of game-time this could take...) As always, I hope you guys enjoyed the screenshots. Remember to contribute ideas on what infrastructure projects I should pursue first. Regards, Northstar

It's launch season baby, and my Kerbals have got the fever! But first, some pictures of the Mun Lander on high approach to the Mun: Since I'm launching a Mobile Lab to the Mun, it only made sense to collect some science on approach... Anyways, the next launch is of Bill Kerman and the Second Munar Service Module (also known as Munar Service Module #2) The Service Module is en-route to the Mun (screenshots of the transfer further below), where Bill Kerman will rendezvous with the Munar Integrated Science Module and the fuel depot (which should be docked by the time he arrives), and transfer over to await Jebediah's return from the Munar surface with the first Mystery Goo and Materials Bay experiments to be reset (I won't bother processing experiments, as I'll be recovering them- the Mobile Lab only improves science yields when transmitting...) It made economic sense to send a separate Service Module rather than upgrade the service module on the previous launch to 2-Kerbal capacity. The best part for a second Kerbal would have been a Yawmaster Service Module (the same type of crew cabin used on the Lander)- which would have cost almost twice as much (1400 rather than 800), and very likely *not* paid for itself in terms of being able to utilize a reduced number/cost of engines on the launch vehicle and upper stage (it would have probably also required a separate heatshield). Plus, the Yawmaster has terrible radiation shielding vs. the Mk1 Command Pod, and Bill Kerman doesn't need to be in orbit the whole time Jebediah is- so the separate service modules also made sense from a roleplaying/ radiation-exposure perspective... Anyways, economics aside (they're a favorite topic of mine), this was another Space-X style launch: and the launch stage safely made a recovery to the KSC as planned. In fact, I managed to stick a landing ON THE RUNWAY, which was awesome: Also featured, here are screenshots of the Service Module's Mun-transfer: I hope you guys enjoyed the screenshots- and feel free to suggest/vote on which infrastructure project I should begin working on first/next over in the discussion thread- there are a lot of awesome ideas there if I don't say so myself... http://forum.kerbalspaceprogram.com/threads/97427-Announcing-Northstar-s-Collaborative-Kerbal-Career-Campaign-what-to-build-next Regards, Northstar

That's a perfectly valid point- but we're easily capable of plotting the trajectories of the exhaust. And in the simplest/cheapest version of this plan, the debris would be given retrograde momentum in a range that would de-orbit it: which would REDUCE impact hazards in the long run, and is part of the whole point of this plan... Though, yes, the fact that the mass-driver could double as an anti-satellite weapon might actually serve as a *selling point* to certain politicians... [evil cackle] Regards, Northstar

As I'm sure you're all aware, debris in orbit around Earth is a HUGE problem, and a major hazard to satellites and new launches, due to the literally hundreds of pieces of debris in orbit... Any proposal to actively manage that debris has fallen on deaf ears though, due to the EXTREME cost of most such plans... This is something I've been thinking about a lot lately. But what if we could actually PROFIT off that debris? What if we could use it as *reaction mass*? Thus, an idea was born... Lately, I've been running a number of mods in KSP, one of which is a selection of parts from the Stanford Torus mod including a Mass Accelerator. Not satisfied with the performance of the part, I created my own version with realistic force (up to 11,760 kN/s- the same as the proposed electromagnets for Star Tram gen-1) and power consumption levels, as well as reducing the mass (from 25 tons to 10- closer to real world levels for an aluminum electromagnet coil of that size), cost (one ring was more expensive than the largest rockets- 185,000 Funds. I reduced that to 12,500), and improving the structural integrity-related stats so a coil of these wouldn't explode from their own force when properly braced and fired at close to full power... I intend to re-release the re-balanced parts as a standalone "mini-mod" in the near future, as the license (CDDL-1) is open source and explicitly allows modification and re-distribution. Anyways, the mass accelerators made it into a list of infrastructure projects I was/am considering for my collaborative community game: http://forum.kerbalspaceprogram.com/threads/97427-Announcing-Northstar-s-Collaborative-Kerbal-Career-Campaign-where-to-next?p=1509692&viewfull=1#post1509692 To cut to the chase, one of the ideas I considered was setting up orbital "Momentum Exchangers"- basically space stations around Kerbin and the Mun that would have batteries and a stack of networked Mass Drivers. There stations would be used to fire payloads in opposite directions, taking advantage of Newton's Lwas to maintain a stable orbit (basically, they would fire one payload retrograde, then turn around and fire another prograde, or vice-versa). At first, I was just thinking of using them for crew capsules and landers I wanted to de-orbit, and payloads I wanted to boost into a higher orbit. But then today, the thought occurred to me- why not use these mass drivers on debris as well? Not only would that DRASTICALLY increase the amount of reaction mass eligible for my mass drivers to work on, it would also allow me to shoot debris retrograde at g-levels that would kill a Kerbal (I'm playing with Deadly Re-Entry enabled, and probably TAC Life Support in the near future- Kerbals can die if g-forces exceed certain levels), but also not worry about whether the re-entry trajectories were survivable (in fact, from a reoleplaying perspective, it would be PREFERABLE if the debris burned up before hitting the ground...) Further, why not use this in real-life? The benefits would be much more substantial. Not only does it take a lot more Delta-V to get a kg of anything to orbit, the orbital velocities are MUCH higher. Which means, a mass driver that can shoot payloads retrograde at, say, 190% of orbital velocity to de-orbit them (on a retrograde re-entry trajectory) can give debris or crew capsules a LOT more velocity without sending them into stable retrograde orbits. And, an even MOAR POWERFUL mass driver, which actually shoots debris retrograde so fast as to send them on escape-trajectories from the Earth-Moon system (I should point out now, there is no theoretical maximum speed on mass drivers other than the speed of light- although the length of electromagnets required grows exponentially longer with each additional m/s of velocity you want to give the ejected mass...), well the potential benefits there are almost unimaginable. The plan would look something like this- NASA or some other space agency would build a LONG and POWERFUL coil of electromagnets in a low orbit above Earth (due to the Oberth Effect, more energy is gained from reaction mass when you are moving faster- and LEO is also the cheapest orbit to reach). Since all this would be is basically a really long coil of aluminum wire, it would be easy enough to assemble on-orbit without super-complicated or expensive machinery (the mass driver wouldn't be extremely precise- a 1 or 2 degree variance in trajectories isn't going to matter a lot when de-orbiting debris). The longer the coil of mass drivers, the better, since this would increase the amount of energy that could be gained from each kg of debris/reaction mass, and reduce the recoil acceleration on the mass drivers (so as to not damage any control systems attached to the electromagnets, or payload waiting to be fired in the opposite direction). A small ion-powered tug (to reduce fuel-mass you have to launch for it) would rendezvous with debris over the course of weeks/months, and tug these debris back to the mass driver over weeks/months/years (depending on the mass of the debris- although more massive debris could potentially provide more impulse to the mass driver, making it more valuable...) When the debris arrived in the mass driver, it would be loaded up at the prograde end of the electromagnet coil, and fired RETROGRADE at as high a velocity as possible, so as to either de-orbit the debris or send it on an escape trajectory (or impact-trajectory with the Moon). Ideally, this would be done at periapsis of the mass-driver's orbit, so as to provide the most energy possible from the reaction mass/ debris. The mass driver would then load up a payload (which would usually have attached to the mass driver station BEFORE the firing of the debris) at the retrograde end of the electromagnet coil, and fire it PROGRADE (by reversing the direction of the electric current from the first firing- unlike in KSP, electromagnet mass accelerators don't have innate polarity) with enough velocity to return the mass driver to its original orbit. For payloads requiring particularly large boosts (such as an interplanetary mission), the mass driver could build up energy by firing several pieces of debris in succession (at each periapsis of its orbit), before firing the payload with enough velocity to consume ALL of the accumulated energy. The bread-and-butter of the mass driver payloads would probably be small satellites bound for geosynchronous orbit- which would actually be a good thing, as the most economical/easiest payloads to accelerate this way would be those with a small diameter (as this would allow the same mass of electromagnet-wire to be used to build a longer coil). Although any payload would work- as long as it were thin enough to fit through the mass driver coil (obviously the larger the diameter of the mass driver, the wider a variety of payloads it could be used for), larger ones would actually reap more economic benefit- as the first 100 m/s of Delta-V in a mission always requires more fuel than the second or third... Even a tiny nudge of, say, 50 m/s to a Mars Mission would represent a lot more fuel savings (and thus launch-mass savings) than a push of 150 m/s to a large number of much smaller satellites (assuming the ISP of the fuel were the same). So not only is this scalable- the benefits are actually GREATER with heavier payloads... The only major obstacle to this I could foresee, aside from initial investment costs (the mass driver coil would have to be sufficiently large/powerful to save GEO satellites more launch mass than the fuel required to tug debris to the mass-driver's orbit), would be the high electrical power requirements. This could definitely be solved by having a high electrical storage capacity and low operational frequency (with something like solar panels providing the power to slowly charge the batteries or capacitors), but something like Microwave Beamed Power from a ground-based installation would probably be a much more cost-effective solution (not only would you have to launch much less solar panel and battery/capacitor mass to orbit- the same Microwave Beamed Power installation could also find additional use in launching small Microwave Thermal Rockets...) It sounds like a great idea, at least on paper, and gets "free" momentum without violating any of the laws of physics- basically it steals momentum in the prograde direction from debris that don't need it (said debris then either re-enter, or shoot into much higher retrograde orbits, depending on the size of the push), and gives it to payloads that *DO* need it- like interplanetary-probes or satellites bound for geosynchronous orbit. The energy comes from electricity- which ultimately either comes from solar panels (or nuclear reactors) on the mass driver, or a rectenna and Microwave Beamed Power at a ground installation. Let me know what you guys think of this idea. Regards, Northstar P.S. This idea is similar to, but distinct from, Momentum Exchange Tethers. Another great idea that nobody's seriously tried to develop... P.P.S. This idea also works in KSP- so I intend to see if I can't post some pictures of my own attempts to re-create it sooner or later. Feel free to do the same yourselves, once I post the up-rated version of the Stanford Torus mod Mass Accelerators (the versions from the base mod are far too weak/heavy compared to real life for this to be practical...)

Looks can be deceiving. The real-life Raptor isn't supposed to look particularly intimidating either. Part of that is that the exhaust gasses aren't as dense as with Kero/LOX or hypergolics, so the nozzle is a bit thinner to prevent the atmosphere from over-compressing the exhaust trail. The less dense the exhaust gasses, and the thicker the atmosphere, the smaller the engine nozzle. The Raptor would also work on a much more advanced fuel cycle (Full Flow Staged Combustion), which reduces the total size of the engine by eliminating the need for certain components, and allowing others to be smaller/thinner. Part of the reason its TWR is supposed to be so high for a rocket engine is because it would produce a lot of thrust. The other is because it would have an extremely light engine structure for the thrust it produces... http://en.wikipedia.org/wiki/Raptor_%28rocket_engine%29 That's where you're wrong. There's ALWAYS use for heavier launch-stage engines. Try stacking taller fuel tanks on top of the engine if you have a higher TWR than you need- and then just increase the payload mass to compensate. Have too much payload capacity? Then just add some fuel destined for your orbital fuel depot, or some small probes, as secondary cargo. Also, start to get in the habit of stacking multiple payloads onto one rocket... All this will REALLY pay off if you also play with FAR- which rewards long, tall rockets over short, wide ones... Remember the Meth/LOX engine is a whole tech level above even the most advanced SLS engines. So it SHOULD be a *LOT* better than the Skipper engine- especially when we already have real-life design figures on TWR and ISP to work off of that confirm that assumption... NOTHING in KSP-Interstellar is balanced against the stock parts. Just take a look at the DT-Vista engine if you don't believe me. Rather, KSP-Interstellar is balanced against reality- which IMHO is much better when it allows us to get much higher-performing parts than in stock. And it costs a lot of Science Points to unlock Experimental Rocketry (1000, to be precise). By the time I've unlocked the Meth/LOX engine, I probably also have access to spaceplanes, Nuclear Thermal Rockets, and Microwave Beamed Power. So it needs SOMETHING to justify its large Science cost to unlock. Balancing it against real-world performance predictions is just in keeping with the general spirit of KSP-Interstellar... It's not the correct TWR or thrust for its designed role- which is as a super-heavy-lift engine. The Meth/LOX engine should replace the SLS heavy-lift engines, not the Skipper (which have low thrust for their size/mass due the their reliance on LH2/LOX in real life...) The Raptor is supposed to be a 2.5 meter engine with better thrust than many 3.75/4 meter engines in real life... (now imagine what THREE clusters of NINE of these engines can do, and you have the tri-core Mars Colonial Transporter- which should be able to take 100 tons of payload to the surface of *Mars*, not just Low Earth Orbit, in a single launch- with a reusable first stage...) I've been bugging FractalUK to implement a lander-version of the Meth/LOX engine for a while (something Space-X *hints* they might be working on, but hasn't released any hard announcements of like they have for the Raptor). THAT would have more the kind of TWR you're looking for- probably a thrust and TWR level somewhere between the Poodle and Skipper, but a cost and mass commensurate with that. Its ISP would also be *even better* than 380s in vacuum, but significantly worse at sea-level (something like 280/390s would be appropriate- compared to 321/380s for the Raptor...) Regards, Northstar

You *could* make boil-off just scale with the 2/3rd power for the cryogenic tanks (assume the smaller tanks are insulated to the same relative rate of heat leakage for their volume), and make the mass of the cryogenic tanks scale non-linearly (such that larger tanks weigh relatively less when cryogenic). You can assume fuselages and Service Modules are both insulated as well (in fact, highly pressurized tanks have comparatively VERY LOW rates of boil-off, as their surface area is very small relative to their propellant mass- which also makes them cost much less mass to insulate, and the structural components of their walls are much thicker...) Non-cryogenic tanks (default and balloon tanks) *should* scale with the 4/9th power, such that it's almost impossible to have tiny tanks that don't boil-off very quickly: this is actually how it works in real life. One way or another, there needs to be more of an incentive to use large fuel tanks. At first I suggested tank structural mass scale with the Square-Cube law, but it turns out that is completely inaccurate as fuel tanks are pressure vessel in space. The Square-Cube Law *does* apply to the relative amounts of insulation required for the same effect with different tank sizes, and the base rates of heat leakage, however- which means the required amount of insulation mass should scale with roughly the 2/3rd power of volume (actually, it's even more favorable for larger tanks than that, as the thicker walls require for structural integrity act as low-quality insulators in themselves...) The also currently aren't enough ways to mitigate boil-off. Thermal fins are heavy, expensive, and currently almost impossible to use with FAR as their surface attachment is too weak, and they tend to tear off during ascent. Even if they make it to orbit, they seem to be bugged and not all that effective. Plus, why should they work? All a thermal fin can do is cool a rocket to ambient temperature (which actually should be quite high near Kerbin or any other planet, in comparison to cryogenic temperatures, due to IR give-off from the planet...) Active Cooling systems work MUCH better, because with enough power, they can cool a fuel tank to any given/desired temperature. Creating a realistic (4/9th power) relationship between tank volume and boil-off is one way to mitigate that, as it would allow players to somewhat reduce the effect simply by making the tanks bigger. Allowing players to more heavily insulate (perhaps with a tweakable insulation slider- where insulation mass scales with the 2/3rd power of volume), and actively cool their fuel tanks would be another. One way or another, it shouldn't be harder to mitigate tank boil-off in KSP than it is in real life (in real life, you can make the tanks larger, better insulated, and actively cooled. You can also store propellants in chemically-stable low-boiloff forms, such as LH2/LOX as water.) Regards, Northstar

OK guys, so a Munar polar landing is in full swing, and a Kerbin-based polar expedition is also currently landed on the northern ice cap and awaiting daylight to fly back to the KSC (it's an electrically-powered plane with large static solar panels built onto the wings). Both of those efforts will take me quite a while, and I still need to launch a second 1-Kerbal service module for the Munar Landing (the Mobile Lab takes 2 Kerbals to operate). You can find the latest progress HERE... While all that's still in progress, though, I wanted to solicit opinions on the next main effort- infrastructure. Beyond the simple station I'm building in Munar orbit, which comes with a Mobile Lab, 2 Clamp-O-Tron Jr's and one standard Clamp-O-tron docking port, and substantial storage capacity for MMH/N2O4 (a hypergolic fuel mixture), I'm looking to tackle some much more ambitious (and useful) infrastructure projects in the long run- ones that will actually save me launch mass in the long run beyond the simple benefits of a multiple-use lander... The projects I am currently considering (feel free to suggest additional options) are all significantly complex, and enabled by the mod-package I'm using. So take a look at my installed mods if you want to add different/new ideas... Here's what I've come up with so far: Munar Regolith-Mining Base: This idea revolves around constructing a Munar surface base to mine regolith for LqdOxygen and Aluminum (KSP-Interstellar allows me to set up ISRU refineries for this purpose- but they have rather large electrical power requirements to operate at full capacity). In its simplest form, this would have me deploy a base with a pair of built-in Gigantor solar panels, and use those to power the ISRU refinery (in the newest versions of KSP-I, surplus ElectricCharge gets converted to MegaJoules- and solar panels can directly run MPD's and refineries...) A more complicated, but cost-effective plan, would see me leave the heavy solar panels behind, and power the refinery with Microwave Beamed Power from the KSC (produced from either nuclear or solar sources), and begin deploying a series of orbital power-relays (repeater stations) in orbit as well. Orbital Mass-Relays/ Momentum-Exchangers: One of the more complicated ideas, this relies on me exploiting Conservation of Momentum to my space program's advantage. Basically, I would set up a space station with two sets of Mass Drivers facing in opposite directions (in 2x symmetry with a central "loading area" in the middle). Then, whenever I had two payloads needing to travel in opposite directions- for instance a crew capsule ready to return home or a piece of debris I want to de-orbit, and a fuel tanker I'm looking to boost into a higher orbit- I would fire off both mass drivers in rapid succession. Alternatively, I would build just one longer coil of Mass Drivers, and turn the whole station around using RCS or reaction wheels. Would be tricky to get right (I need to impart equal momentum to both payloads- which probably means tweaking the power levels between launches), and likely require installation of ExtraPlanetary Launchpads to construct the whole thing in orbit (Mass Drivers- as little more than simple coils of aluminum wire- are one of the few things we could realistically build in orbit in the near future...) The payoffs would be relatively slight either way, although I could construct two such stations- one in Kerbin orbit (crew return capsules go retrograde, almost anything else the other way), and one in orbit of the Mun (landers and fuel ferries go retrograde to surface bases and unexplored biomes, vessels finished making refueling stops the other way...) Microwave Beamed Power would also help this to work efficiently, as the Mass Drivers require a lot of power to function... This idea also birthed a discussion thread on the Science Labs sub-forum: http://forum.kerbalspaceprogram.com/threads/98615-Using-orbital-debris-as-reaction-mass-profiting-from-orbital-mass-drivers Mun/Minmus Ground-Based Mass-Drivers: Like the mass drivers I've been using to assist my launches on Kerbin, except hauled to one of its moons (or built there from hauled materials using ExtraPlanetary Launchpads), and deployed mostly horizontally due to the lack of an atmosphere (when launching on atmosphere-less moons, you want to tip over and build horizontal velocity as soon as possible) The tricky part about this is properly supporting the Mass Drivers with KAS ground pylons, so the recoil doesn't send them flying in the opposite direction, and deploying the Mass Drivers into a horizontal position in the first place (a sufficiently tall stack, when tipped, could explode...) I also have my concerns about launching horizontally- namely, how do I line up my rockets properly? This might require specially-designed craft or ground-based cranes/winches (and possibly Infernal Robotics- which I've still never tackled the challenge of learning) in order to load the craft into the Mass Driver- which would *greatly* limit its utility. Still, it can't be denied that free Delta-V (especially on a moon where there is no atmosphere to sap it away) is always nice... Microwave Beamed Power Network: Eventually, I'm going to be relying on Microwave Beamed Power to the point that I use it for Heavy Launch Vehicles (like I've done in past saves- just check out "Kerbin and Beyond: a Maturing Space Program"). But in the meantime, I've yet to unlock the required tech node (Specialized Electrics). The science from my first Munar landings could change that- but it's going to represent a significant investment of my valuable Science points, slowing down my progress in other areas as a result. Still, it opens up or saves costs on a lot of exciting possibilities. From large interplanetary "motherships" which carry a KSP-Interstellar refinery onboard, and use beamed power to split stored water into LiquidH2 and LqdOxygen (thus allowing storage of LH2/LOX in deep space at much higher density and without any of the associated boil-off issues) right before they or parasitic ships perform orbital maneuvers or landings, to using beamed power to power both orbital and surface-based offworld Mass Drivers and ISRU refineries, the possibilities are endless. It could also come in rather handy for small ion-powered probes in the short run (even providing the power of a couple Gigantors, with only the small mass of a Microwave Receiver, is well worth it for an ion-powered Jool probe...) Kerosene Fuel Depots: When it comes to specific impulse for chemical rockets, LH2/LOX propulsion is king. But it has serious boil-off issues, and the only good way to handle those (without an active-cooling system option to mitigate boil-off: which NathanKell, the creator of RealFuels, has vaguely hinted at might eventually be coming with a "RealHeat" mod- but I don't foresee getting to use anytime in the immediate future...) is by storing in as LqdWater and electrolyzing it- which requires large amounts of electrical power. A simpler option is to store Kerosene long-term in orbit of the Mun (which doesn't have boil-off issues) and complement it with LqdOxygen launched using reusable Aluminum-Hybrid rocket launches (the Mun might not have much water outside of the poles, but Aluminum-Oxide regolith is one thing it has in abundance). The Kerosene still has to be launched from Kerbin in tankers, of course (although it *is* possible to manufacture it on carbon-rich planets/moons in real-life using the Reverse Water Gas Shift and Fischer-Tropsch reactions, something I have long been bugging FractalUK to implement as a reaction for Duna and Laythe...) This way, I only have to launch only a portion of the fuel mass as if I continue to rely on hypergolics for deep-space operations, and get to benefit from Kero/LOX's moderately improved ISP vs. hypergolics. If I choose this plan, I might also install the engine parts (and some other odds-and-ends, such as KW's 3.75 meter docking port) from KW Rocketry, since few of the NovaPunch2 engines currently can utilize Kerosene (although this is something I should take up with NathanKell- I don't see any good reason for this restriction...) Atmosphere-Skimming Propulsive Fluid Accumulators: This one is a long-shot. I've tried developing these designs before (in "Kerbin and Beyond: a Maturing Space Program"), but was hindered by stock KSP's fuel-burn ratios (10 tons of LiquidFuel are burned for every ton of Oxidizer), and my inability to utilize the majority of the atmosphere that was generating drag for my harvesting-ship (Nitrogen, despite having a number of potential uses in real life: from ISRU processing into N2O4 to use in Nitrogen-electric engines, has absolutely no use in KSP-Interstellar). However, this time I have FAR installed, which should allow for a more realistic drag model (and relatively less drag skimming the upper atmosphere as a result), RealFuels- which should allow me to burn fuel mixtures that are more realistic and thus more Oxygen by mass (Kero/LOX is over 70-80% Oxygen by mass in its stoichiometic ratio, and LH2/LOX is 88.9% Oxygen by mass- so I have relatively more demand for my harvested LqdOxygen) as well as having realistically higher ISP than stock LFO, and the option of simply installing Karbonite and circumventing the madness of 65 x 65 km harvesting "orbits" by skimming LqdOxygen from *above* the Karman Line (what I assume the edge of the atmosphere represents in stock, and where real Propulsive Fluid Accumulator designs would actually operate), thus drastically cutting down on my fuel-expenses for station-keeping in the first place... I'm also bugging FractalUK to add a Nitrogen resource (which I could easily convert to the RealFuels version with a MM patch) and fuel-mode for the KSP-Interstellar plasma thruster, and possibly allow players to skim atmospheres from above the Karman line (like can be done in real life- there are still occasional atmospheric particles above this altitude), either/both of which would make this proposition MUCH more realistic/profitable- if still somewhat tedious... (no time-warp above 4x below the Karman line, or 10x just above it) Permanent Science Outposts: KSP-Interstellar adds Science Labs, which can produce Science points at a very gradual rate if supplied with enough electricity. FractalUK (the mod author) is also working on integrating them into the stock science system- although I don't know how much progress he's made with that yet (they may already be integrated in the version I'm running- I haven't checked yet...) This provides an actual incentive for building permanent stations/outposts: whether on the surface of the Mun or in orbit of Kerbin. The further out from Kerbin I go, the more lucrative the research is- but also the more expensive it's going to be to resupply them if/when I install TAC Life Support, since they require a crew of 2 Kerbals to operate (unless the ECLSS Greenhouse mod ever gets updated for 0.25- which would allow me to equip these stations/outposts with biological regenerative life-support systems and virtually eliminate the need for regular supply missions- at the expense of a very high mass I would have to get to orbit- as greenhouses are rather heavy...) Without TACLS, or with an adequate number of greenhouses, I could even make a profit off the research- by converting the science points into funding through Strategies... All of these are ambitious infrastructure projects, although some are much more difficult than others. I would appreciate player feedback on what to pursue first/next... Regards, Northstar

Another magnetically-assisted launch in my Mun Mission- this one of a Mobile Laboratory: As you can see, this was a DIRECT launch to Munar orbit- not fussing around with a parking orbit first. Basically, I opted for this method because it was faster/easier, and only slightly less fuel-efficient than if I had waited for my orbit to come back around to periapsis before finishing the transfer... The launch, once again, was a hybrid magnetic-assist/Space-X style deal; and the launch stage touched back down safely (because the launch stage had very light engines, relying on the launch-assist for the initial burst of speed, I used all my fuel to try and get as close to the KSC as possible rather than for a softer landing, though...) The Mobile Lab is integrated with a pair of large fuel tanks, and will be added to the fuel depot module traveling with the lander/CSM when it arrives in equatorial Munar orbit. The tanker/tug arriving in a polar orbit- which I forgot has a docking port incompatible with the lander- will transfer to an equatorial orbit (this will be cheaper around the Mun than at Kerbin- especially if I only capture into an elliptical polar orbit at first) and rendezvous with the budding station as well- after which it will return to Kerbin orbit. Beyond that, I still haven't decided what to do with it yet- as it is becoming increasingly outdated (not only is its reaction wheel much older/heavier than the advanced stock unit, but it also relies on an older/heavier docking port, and hypergolics for fuel- which I will eventually be replacing with more efficient propellants requiring additional infrastructure...) Speaking of which, my next major push (after my first Mun landings- as many as hypergolic fuel supplies at the station and my own patience allow for) will be towards off-world infrastructure. I've decided to open that up for input on the associated discussion thread (up to 3-4 opinions will be considered) so please feel free to chime in. Regards, Northstar

I wasn't having much luck with a SpaceShip One style "mothership" launch (even once I got it working correctly from the plane side, the rocket was having serious control issues after detachment, and the plane wasn't showing up under FMRS to be piloted back to the runway rather than simply disappearing...), so I went back to good ole' electric-propeller designs, and quickly threw together a Kerbin Polar Expedition: This design made use of the Stanford Torus mod Sunforce NXT solar panels- which were quite handy, and looked much nicer than the Multipanels mod scale-ups of the OX-STAT. So much so, that I'm questioning whether I should even install the Multipanels mod... Nevertheless, no solar panel, however powerful, can operate without sunlight- and as you'll notice from the final picture of the landing site, the sun at that latitude shortly after touchdown... I'll pick the mission back up after a cold polar night for the pilot and the completion of the next steps of my Mun Mission... Currently, I'm also working on fixing the KSP-Interstellar tech tree, as the new tech nodes aren't showing up on it thanks to TreeLoader being broken. I've found a new Tech Tree manager mod called "Tech Manager" developed explicitly for KSP-Interstellar which I'm going to give a try. We'll see how that works out... Also, I've deleted the Firespitter battery part you saw in the tech node screen on the final page of the Polar Expedition album (the one calling itself a "Lemon-Potato" battery in its description), as its mass-power density and cost-effectiveness are strictly inferior to stock radial batteries, ProceduralParts Service Modules, NovaPunch2 Yawmaster Service Modules (with RealFuels installed the ElectricCharge storage can be set much higher, at the expense of fuel tank volume...), or any of the inline batteries or capacitors from Nearfuture mod. In short, it's a completely worthless (and ugly) part- so I got rid of it... Regards, Northstar

@FractalUK Three more things that I want to make sure you're aware need fixing: (1) The scaling on the Al-Hybrid Engine and Argon Tank are currently messed up. It's a simple matter to fix- in fact there was already a community patch released for it in your brief absence... (2) The Magnetic Nozzle currently has gaps between the model ends, and the nodes. Once again, a community patch was made for this. However, please note, THE COMMUNITY PATCH STILL FAILED TO FIX THE NODE SIZES- the 3.75 meter variant still only uses a size 2 (instead of a size 3) node- which negatively affects joint strength and structural integrity... (3) A lot of the parts in KSP-Interstellar fail to scale up the node sizes to use the Size 3 nodes introduced to KSP with the ARM mission. Such parts include (this is *NOT* an exhaustive list) the 3.75 meter thermal and magnetic rocket nozzles, *all* of the 3.75 meter reactors, the 3.75 meter electrical generators, the 3.75 meter refinery, the 3.75 meter Thermal Power Receiver, and the 3.75 meter LiquidFuel tank. In fact, going through the WarpPlugin folder, I can't find a single part that uses Size 3 nodes where appropriate... Finally, I wanted to remind you one more time of the large performance gap between KSP-Interstellar's Meth/LOX engine and the real-life "Raptor" Engine off which it is clearly based (besides being made by Elon Musk's Space Exploration Corp vs. Elon Kerman's Space Exploration Corp., it is also 2.5 meters with the same fuels, combustion ratio, and role as a heavy-lift engine- and so should be the model for the Interstellar engine's performance). The Interstellar engine's performance is VERY weak by comparison to the Raptor it is based off... Interstellar's "Deinonychus 1-D" Thrust 1425 kN (thrust does not vary with atmospheric pressure in stock engine module) Mass 3500 kg (for the record- that's a TWR of 41.5) ASL ISP 309 s VAC ISP 368 s Space-X's "Raptor" ASL Thrust 6900 kN VAC Thrust 8200 kN Mass Unknown- but TWR predicted likely to exceed 120 (which would equate to a mass of less than 5867 kg- 5860 kg is a good KSP approximation) ASL ISP 321 s VAC ISP 380 s Regards, Northstar

@FractalUK (this is a re-post: the original post was 5 pages back, and I want to be sure you see this) Adding to the list of things I've noticed so far that need fixing in KSP-Interstellar (current list: 100% of beamed power available being turned into WasteHeat rather than Reception limiting WasteHeat production, and the Meth/LOX engine having too low of an ISP and TWR compared to its real-world counterpart) are two more that deal specifically with the atmosphere of Kerbin. Namely, there's not much we can do with Nitrogen. Despite Nitrogen being abundantly available in Kerbin's atmosphere, it doesn't appear that we can perform something as simple as the Haber Process to produce our own Ammonia, and thus eventually, Monopropellant from it (this could be useful for a variety of reasons...), and we cannot use the Nitrogen as a plasma thruster propellant, despite this being perhaps the single closest design of plasma thruster to actually seeing real-life utilization: http://en.wikipedia.org/wiki/Helicon_Double_Layer_Thruster I would very much like to be able to perform BOTH of these functions (the Haber Process, and using Nitrogen as a plasma thruster propellant). Ideally, WITHOUT having to land on the surface of Kerbin, so I can build something like a Propulsive Fluid Accumulator for Ammonia... http://en.wikipedia.org/wiki/Propulsive_fluid_accumulator Using Nitrogen as a plasma thruster propellant would actually make it feasible to maintain a 60 km x 60 km "orbit" on Kerbin to collect Oxygen (and possibly also surplus Nitrogen) for a fuel depot, using Nitrogen from the upper atmosphere in a plasma thruster to counteract drag... (Thermal Tubojets don't operate at such high speeds, and if they did would have too low of an ISP to counteract the drag produced by even just their intakes at those speeds...) Speaking of which, it would also GREATLY be appreciated if you allowed Atmospheric Scoops and ISRU refineries (utilizing gas resources) to work *JUST OUTSIDE* of the atmospheres- like is ALREADY implemented in the Karbonite mod- so we could accumulate atmospheric gasses at a slow-rate in time-warp without having to babysit a plane or rocket flying at 4x physics warp in order to run an atmospheric scoop, which can get EXTREMELY annoying... Doing so would also open the door to allowing these atmospheric-accumulators to work when the craft is unloaded- much like Tritium Breeding (and nuclear fuel decay) currently does; and Antimatter Collection, ISRU mining/refining operations, and Science Labs all *should* (and do, to various degrees of effectiveness, depending on the current version and bugs...) Regards, Northstar