AeroGav

Alright, they seem to be avoiding making any direct claim of performance in the manner you describe. I don't know what your background in chemistry is, i don't work in a relevant field and only have my schoolboy chemistry to fall back on. I just know this has been touted as the ISRU process that is to take place on the moon, long before water electrolysis was mooted, since there are doubts about finding water ice, in sufficient quantity, concentration and sufficiently close to the surface, to be amenable to in -situ utilization. I presume those proposing oxygen extraction from regolith knew what they were talking about and weren't just trying to con gullible politicians for funding. Obviously the technology is not mature.... but it seems worthy of further development. I mean, if Orion and SLS are considered worthy of funding, so is this ? Or do you have some expertise in the field so you can say it is a waste of time ? Again, can you make your position clear on this ? Do you think this type of ISRU is a good idea ? a bad idea? or do you have no opinion? What about lunar ice ISRU? If you're not keen on this approach, what is your vision for space exploration - i presume you have one, given that you play KSP....

According to the powerpoint i linked, they used temperature of 1600, and electrodes of iridium and molybdenum. The regolith has a composition of 47% Silicon dioxide, 17.8% Aluminum dioxide, 10% iron oxide. I think they were only bothered about reducing the iron ore, the rest can be thrown away. It's not like there is a shortage of Regolith on the Moon.. I'm noticing a pattern of naysayers which is fine, valid objections, but knocking something down is easy. If you think this is a daft idea, what do you propose we do instead? Is it any less plausible than a lunar gateway station, a reusable 62 ton lander, all supplied entirely from earth via the SLS ?

There is only 40kg difference in dry mass between mk1 liquid fuel fuselage and mk2 short liquid tank. The problem is drag and drag alone.

I did a bit of reading around, and used some rocket equation numbers from this site - it's a nice little online calculator that saves you from having to understand the math, you just plug in any three of the four relevant variables, and it calculates the one you left blank ISP Delta V Starting Mass Ending Mass http://www.quantumg.net/rocketeq.html Apparently, the best ISP for hydrolox engines comes when you burn 4.8 tons of LOX for every ton of Hydrogen. The space shuttle main engine ran less rich at 6 tons of LOX per ton of H2, and gave up a percent or two ISP for a less bulky and draggy LH2 tank as a result. Stoich is 8 to 1. The RL-10 engine has experimentally been run as lean as 13:1 , and did not take any damage. Apparently, it's all in the boundary layer cooling, if cool enough, the engine is protected even if the boundary layer itself is lean. Variants of the RL-10 are capable of adjusting mixture ratio in flight and this was done on later Apollo missions, though not to such an extreme degree. https://yarchive.net/space/rocket/fuels/fuel_ratio.html So, if the lander weighs 19T empty and needs 2500dv to go from the surface to LOP-G, it will use 14.5 tons propellant for the ascent. I ran the calcs for 6:1 (SSME ratio) and got 2.07T LH2 and 12.4T LOX. Not having to carry that ascent oxygen all the way from the lunar gateway is potentially another 12.4t payload , or if we're only carrying 1T down, then it only has to depart the gateway with 18.9T of fuel instead of tanks brimmed to 42T. Of course, that assumes you're topping off the oxygen tanks at the lunar gateway as well as on the surface, which you probably wouldn't do. If the lander gets all its oxygen from the surface facility and all its hydrogen from earth, then basically each tank is having to go the full 5000dv between replenishments, and our mass and payload ratios go back to the starting point - 1 ton of payload for 42 tons fuel used per trip. However, at 6:1 fuel ratio, that means we're shipping only 6 tons of propellant from Earth (Falcon Heavy in Re-usable mode?) instead of 42 (expendable SLS block b?) As regards to the process of extracting oxygen from regolith, https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20090018064.pdf Molten oxide electrolysis looks the lowest risk - basically melt the lunar soil, then electrolyse it to separate gaseous oxygen, and you end up with molten metals (mostly silicon and aluminum, some iron) as a byproduct. It looks like this process can scale down to pretty small sizes, but to make the amounts of oxygen this monster lander needs would take substantial plant - or a lot of time. Given the putative SLS launch cadence of once every 2 years however, maybe that's not such a big deal. As for what @DerekL1963 said, yes ISRU is only useful to repeat visits to the same place. As I understand it, the plan is to prospect the moon with robotic rovers, then send manned missions to investigate any promising sites they uncover. So, that makes it sound like we'll not be doing repeat manned missions to the same spot , until such a time as a full base is established with lunar ice ISRU. Or will we ? If Ice is proving elusive, does there come a point where we just go with this setup to tide us over ? Or after finding a promising crater, is there going to be a substantial period of time before a base is established and ice harvesting gets going - perhaps several manned missions would be needed by base architects, and a multitude of cargo missions while the base is actually constructed. This kind of operation could make those flights considerably more efficient.

So, NASA recently proposed the "Lunar Gateway" station as a payload for their SLS expendable megarocket, which has been under development in some form for the past 30 years, but is finally expected to fly within the next 2 - 3. In turn , Lockheed have used this as an opportunity to reveal their design for a re-usable lander, capable of ferrying astronauts from the lunar gateway to the moon's surface and back. Scott Manley simulated this vessel in KSP, with a few realism add-ons : Whereas Apollo used separate Ascent and Descent stages, a re-usable vessel needs to do the whole round trip in a single stage, and this seems to be a problem. Despite using Hydrolox , the mass ratio is miserable, 40 tons of propellant for one ton of payload delivered to the surface. If all 40 tons of propellant have to be shipped from Earth to Lunar orbit via expendable SLS rockets, I can't see re-using the lander working out any cheaper than a disposable design that needs less fuel (total mass shipped from earth) per trip. I'd appreciate feedback on that point, but my real question is, is there any possibility to IRSU oxygen from the lunar regolith , and how would that change the economics of this vehicle's operation ? The long term goal of lunar exploration is to find water ice that can be split into hydrogen and oxygen, but it is only thought to exist in permanently shaded craters near the poles. An extensive prospecting operation needs to be conducted first, then we need to set up a base with remotely located solar panels bringing power for our ice mining operation. Volatile and light elements are rare on moon, which has no atmosphere, magnetic field or strong gravity to help it retain such things, and the surface heats to several hundred degrees in the daytime. If you just want oxygen though, that should be much easier. The moon is 40% oxygen, by mass, most of it consisting of various metal oxides and silicates. Would it not be much easier to extract oxygen from these oxides (smelting metal ore in a solar furnace?) which exist practically anywhere, From what i understand, the LOX component of hydrolox propellant weighs 7 times as much as the LH2 itself. So, even if we still have to bring all the hydrogen for the ascent down to the surface with us, the ability to refill LOX will greatly improve the amount of payload that can be carried per trip, and if only liquid hydrogen has to be brought up from earth, that's far fewer SLS refuelling trips needed for our lunar propellant depot, per trip to the surface. Win/Win. Finally, if you've got unlimited oxygen, would there be any point playing with the fuel air ratio of the engine? I understand hydrogen rich gives better ISP and more stoich gives better thrust - in these unique conditions, would it even make sense to lift off from the lunar surface at a slightly oxygen rich ratio, gradually getting richer as time goes on (need for high thrust getting less, also KSP teaches us to burn our low ISP fuels first? ) Anyone know how the exhaust flame would look ? The Space Shuttle main engines ran only slightly rich of stoichiometric , and had an almost invisible, white flame. Hydrolox upper stages tend to run richer, and produce these beautiful blue colours ..

If the theme is Fedex, that means commercial trucking ops, meaning an emphasis on rapid transit, low costs (as much re-use as possible, or the cheapest expendables possible), and you would expect infrastructure (truck stops) to exist. So, would an SSTO, with a gas station at Minmus and another in the Jool system be ok? I started to build an SSTO with 4 ore big ore tanks (60T) but it has quite a short body, and it's going to look a bit ridiculous if i keep attaching more Wing strakes to add fuel. 40% fuel fraction on an oxidizer free design should get us there nonstop, but makes for a v big ship edit - hmm just test flew this thing, only gets to orbit with 550 m/s left. It's just a bit small for what it's carrying - Dry Mass 49.5 Tons Ore 60 T Liquid Fuel 49.5 T Gross 162.5 Delta V with full tanks is just a hair over 2800, so even if I top it off in Kerbin orbit, it's not got a huge amount to spare for the Jool Transfer burn. Hmm.. should i keep going with this airplane or scrap it for something with a longer wheelbase? https://www.dropbox.com/s/woyypbun7fegshs/Rita Orer2.craft?dl=0 Definitely needs more Strakes...

Well, I swapped the chute for a 'putnik and also removed the nose cone from the rear attach node of the LV909. Drag from open nodes has been reduced in 1.4, and Kerbal Wind Tunnel still thinks we can go supersonic, so I add a battery for my 30th part.

Landing vid here

FAR is a funny one. Takeoff / Landing speeds double or triple compared to stock, but it is a lot easier to bust mach 1. On the other hand, above about mach 4, drag starts to increase above stock again, whereas for stock, lift to drag ratio doesn't change any further once you get past mach 1.7.

Craft file here. Getting a Juno supersonic is very hit or miss, Kerbal Wind Tunnel reveals there's a narrow corridor you must walk down if you want to cross the sound barrier. If you start from 0.9 Mach, fuel is extremely tight. If Val manages to coax Mach 1.6 out of the jets like she did in the video, there's a fair bit left... i bet we could have gotten some high orbit science... My concern with the Stayputnik is battery - how much EC per second does it use? I managed to fly with no reaction wheel below 65km (and SAS wouldn't be missed really, it's very stable once you get it off the damn ground). But six and a half minutes elapsed between jet flameout and us passing out of the atmosphere, and probably twice as long again on re-entry, will the batteries on the stayputnik and command pod last? The LV-909 has no alternator :-( https://www.dropbox.com/s/3am0v60cay3xf9k/Dolly Bird2.craft?dl=0

Here 's the flight to orbit, anyway.

This is hard ! I had a saved craft called Dolly Bird, which I had to take a knife to so as to fit within the limitations. You can see my solution to not having retractable gear is a "Dolly". I think it still qualifies as an SSTO so long as the dolly can be re-used (not damaged) on takeoff. The orbiter can land via parachute (tends to break stuff as it's undersized, but saves the crew) or it can ditch in the sea next to the space centre. I think so long as you're just off the beach and you don't damage it.. this should still count. In the end, I finally got airborne, spent 10 minutes climbing, then realised i'd left the jet fuel tanks empty and the junos had guzzled much of the vacuum engine fuel. Great. After flying the complete mission successfully, I reread the challenge notes and realised i'm supposed to do all this with a Tourist on board , meaning i need a Stayputnik , an Antenna, and a bunch of batteries? Good luck busting mach 1 with all that hanging off the front, even if you find a way within the part count.

I think you would have to put the docking port inside the fairing - ore tank, then fairing base, then docking port. If the docking port is attached to another docking port, you need to make sure the fairing encloses both. Once in space, you can jettison the fairing and undock/redock as many times as you need. The "shielded : no" is not reliable - i've seen it on components that were inside a service bay, and the drag readout on those items was showing 0. I think it's meant for indicating when a component is disabled due to it being inside a bay - some things like batteries are just fine being inside, others like antennas, air intakes and landing gears need to be able to go " hello world"

OK, I had a play with that sleek looking mk2 from Teddy_Radko, https://kerbalx.com/Teddy_Radko/SX-60B I eventually was able to make it into this - 2 Junos, 1 RAPIER (air breathing only) 2 NERVs. Original a/c is 3 RAPIER with 1 hidden NERV clipped into central RAPIER. Even though the mk2 body is actually only a small part of the ship, there's a whole bunch of cylindrical tanks which a chem ship needs but add too much drag for a LF. Despite removing the RCS ports and adding extra strakes, the supersonic lift/drag was horrific, 1.2 to 1. You could chuck on more RAPIERs to get TWR over 1 to compensate but at that point you might as well just strip off the wings and make it vertical launch ! So, I angled the wings up about as much as i could without spoiling the looks. This keeps fuselage closer to prograde and reduces its drag - The trick here is to angle the front wings up slightly more than the rearmost, so they start to stall first. This is also has the effect of making the airplane adopt a slight nose up attitude when there is no control input, but it resists going too far as the front end gets into "diminishing returns" before the back end does when AoA rises further. The airplane was still draggy however. I could add more jets, but it could not be able to sustain itself on 2 nukes when they flamed out. then i discovered hidden part. The original file contained a RTG that had been clipped inside the fuselage, but in fact the rear fuselage was attaching to this RTG rather than the attach node of the fuselage section in front. So you had a mk2 attach surface, joining to a tiny size part (the RTG) , then the other end of the RTG was hooked up to a mk2 again. The mismatched nodes were causing a lot of drag. Even after all these fixes, it's still a bit of a barge. Here's the excess thrust chart with the NERVs off ... and here it is with them on - I kept this screenshot on my other monitor when flying it to orbit, and thus was able to reach space. Even then , the lift to drag numbers were poor. It could go over 2 to 1 , but spent most of its time at 1.8 to 1 while supersonic. The above graph indicates that the NERVs should not be able to sustain level flight on their own, but by the time the RAPIERs quit you're going at a substantial fraction of orbital velocity, which greatly reduces the spacecraft's apparent weight, which enables it to do the remaining acceleration over 30km where drag is low. My other designs like the Sparrow get lift to drag of 3 point something or even 4 point something to one at hypersonic speed. My version here https://kerbalx.com/AeroGav/SX-60L

If you look on the Wiki, all these engines' thrust and altitude curves are on there but you have to click on the Spoiler icon. Yeah, the Panther loses power rapidly after 14km and mach 2.5, but by that point your RAPIER is making 8x normal power, so it doesn't matter all that much. From what i can tell, your craft has a gross weight under 40ton, a single rapier should be able to push that to mach 4.5 easily in level-ish flight at 20km or so, but obviously a single rapier woudl not have enough thrust below mach 1 to get you supersonic, or even take off.

Biggest issue I suspect would be that when the cargo bay is empty, you won't have enough mass upfront to balance all those engines at the back. You could offset the nukes forward, but that might spoil the craft's looks. Or you could swap out some rapiers for some panthers, which will reduce the weight of the total engine pack. You can see that the RAPIER gets a huge boost to its power once you get supersonic (thrust multiplier goes to 8x at 900 m/s!) but it really dies off after 1200 no matter what, so if you swap one or two RAPIER for panthers you'll get almost the same airbreathing top speed, but will shave a couple tons off the back end and also have stronger thrust for breaking mach 1. In terms of liquid only cargo, it can be done..https://kerbalx.com/AeroGav/Andromeda

If you have a look in my KerbalX history, it is possible to make liquid only mk2 designs, but you might say you have to do things that compromise their looks so much it's not worth it. By that I mean 1. The MK2 fuselage parts have to be kept to a minimum, so it ends up a stubby fuselage with a huge mass of Big S wings and strakes grafted on. Definitely do not add mk2 parts for fuel storage - keep all your liquid fuel in wing parts. When you add mk2 fuel tanks to the design, it ends up getting to space with LESS space fuel than with no tank at all , due to all the drag. 2. Pointy cockpit is at risk of overheating on the optimal liquid fuel ascent profile. Sure , if you climb steeply, zoom above 27km at no more than 1000 m/s, switch to RAPIER close cycle mode to get over 35km before the craft hits mach 5, you won't see any heat bars, but you'll barely have any fuel left. So, you end up using the mk2 inline cockpit, and none of the nose options are particularly great looking. 3. Engines at the back looks sleekest, and will fly ok with full tanks, but becomes tail heavy with the fuel gone. Especially so with lots of heavy NERVs. 4. Angling the wings up (adding an "Angle of Incidence") as they attach to fuselage enables you to get lift with the fuselage flying at smaller angle of attack, reducing the drag penalty (but it is still there). That makes orbit with about 1600 delta V left , and takes a while to accelerate. NOT MINE - this looks like a mk2, but is mostly mk1 parts... hmm lemmie try something .. Edit - Also, I just had a brainwave. Is it just me, or are these Juno engines at lot better than I previously thought for getting a single RAPIER design to mach over ? 20kn static thrust for 0.25 ton - panther in a/b has 130kn for 1.2 tons... panther is only 33% better TWR and a lot harder to integrate in small ships. hmm

You know, in all this scratching around for the most elegant 4 passenger design, I never considered the obvious - stretching my original concept "Sparrow" 3 seater, and simply mounting the wings to the outside of the NERV nacelles so as to not have worry about clearance issues. THe thing is, in previous version of KSP, issues with the physics engine meant that attaching wings to something other than the main fuselage stack would cause the plane to constantly roll to the left or right by 1 or 2 degrees per second throughout the flight - seriously annoying. This bug does not appear to be active right now, but in the past i have built craft in this way that were apparently free of the bug, only for them to start rolling once KSP updated. The only cure was to remove and reattach the wings in SPH, which got pretty tedious. Not only is this the simplest variant, it has the most delta V. https://www.dropbox.com/s/tmv3lf1lot3ga82/sPARROW super.craft?dl=0 Are there any other craft out there people are working on ? What's proving to be the sticking point, drag, controllability ? I'm bored and would love to help !

Very good ! If you want to optimise it further, my only suggestions would be (in decreasing order of importance) 1. Those mk1 tricouplers are extremely draggy. They are light but have many times the drag of a 2.6m tricoupler 2. As far as i can tell, you're using a mk3 engine mount on the back of the fuselage (space shuttle style). You have a 2.5m quad coupler attached to the central , large 2.5m attachment node and you aren't' using the three 1.25m engine mounts. Empty attach nodes generate the same drag as a missing nose cone on the front . Also, the quad 2.5m adapter has twice as much drag but only 33% more engine than the triple, which is why my preferred mk3 arrangement is this - I am using all 3 1.25m attachment points, and the central big node as a 2.5m tricoupler with another 3 engines. Maybe do this and get rid of the horrible 1.25m tricouplers you have either side of the main fuselage? You could angle the wings up a bit (https://en.wikipedia.org/wiki/Angle_of_incidence_(aerodynamics) this enables the craft to fly on Prograde hold like in the picture above, and it greatly reduces the drag from the fuxelage (which is most of the drag in Kerbal Space Program). However, this can make it difficult to fly the correct flight profile - you end up fighting the airplane's tendency to climb when trying to get max speed out of your jet engines 4. "Small Beer" - bearing in mind what i said about empty attachment nodes generating drag, that is why i attach nose cones to the back of my NERVs then offset them inside the engine so as not to block the exhaust. This is probably quite minor compared with the drag from that big fat fuselage. Sometimes I skip this step to keep part count down 5. "Very Small Beer" - Could a single Vernor thruster replace the 6-8 monopropellant RCS I see on the nose ? Would be less drag and lower part count @sturmhauke @Alchemist Re: Wings falling off My chemical fuelled version of the 225 seat Monstrosity suffers from this. You have to pitch up VERY gently with trim ( ALT S) only on takeoff, or the wings come off. If you pitch up too much, the wings snap off, not enough, she goes into the water. The NERV version of this ship (the one i pictured above when discussing your engine mounts) does not have this problem, but they have the same fuselage. The Liquid Fuel only version is actually lighter - 245 ton instead of 305 Ton because of all the oxidizer the chem ship is carrying, though in orbit this switches around again as the oxidizer will have burned off while the NERVs are still there. Also, the NERV version has 14 pairs of Big S wings, the Chem version only 8, so the amount of force each wing has to generate to take off is less, which avoids overstressing the joint.

But, it has an oxygen atmosphere so you can run jet engines up to a certain altitude. I did make a two stage spaceplane that got to orbit , it basically had panthers and rapiers mounted to fuel tanks on the wing tips, which it dropped when they flamed out. The rest of the journey to orbit was via NERVs. Lots of parts and things got very hot though. For a stock rocket, i can see why this would be murder. I've gotten out of Tellumo, but not escaped from Eve (with stock parts), i suppose it depends whether you're talking rocket or space plane.

OK, it turns out Minmus is about as far as it can go, fuel is very tight in fact, i wouldn't want to do it unless you got some orbital infrastructure for refuelling. Getting there is easy enough, but getting back to Kerbin a bit doubtful. Obligatory "clown car" shot, 43 seats. This took a long time to do ! On re-entry, i managed to stretch the glide all the way across the desert and reach the space centre. We're only gonna get one shot at the actual landing though Well, we were a bit too high to land directly but didn't quite have enough for a circuit. Cut the circuit short and tried heading straight for the space centre and, you can say we definitely got to the space centre. In fact this is much shorter walk back to the astronaut complex, those that could still walk Anyway, time for me to stop cluttering this thread ! Finished vessel https://kerbalx.com/AeroGav/Hammerhead5

Feature Request - This mod is very helpful in showiing the optimum altitude for busting mach 1, whether your design is in fact capable of mach 1, and the best altitude for hitting max speed on air breathers. But can you update it to take into account the "lift" you get from orbital freefall effect, which is quite significant by mach 4+, and also have a checkbox to enable the thrust from rocket engines to be taken into account. For example, you can toggle on the thrust from your NERVs to enable you to break through the sound barrier so long as you're not right down in the weeds. Most important of all, if you're building a liquid fuel only spaceplane, does it have excess thrust when operating on NERV power alone after the jets quit? If the mod took account of orbital freefall and had an option to take into account the thrust from the NERVs, it could help you with this

What if you add more strakes in place of cylindrical tanks, any way to get more lift without messing up CG? Also what if you swap some rapiers for panthers (lighter)? The Hammerhead design is finished. About 1900dv. Lift/Drag ratio is not amazing, doesn't go above 3 supersonic, maybe because of all the fuselage parts and the wings don't have an incidence angle on them. But, it's got enough power and fuel to overcome that. Now to see how far i can actually take the thing. I'm rubbish at orbital maneuvering.

A couple of Hangar Queens, that have never seen the light of day Might be too draggy. Also NERVs clipped into fuel tank - naughty, naughty . Engines above and below the cabin, Genius ! I thought it would end up looking like a hammerhead shark, but that wing profile is kind of nice. Unfortunately, too few cabins for the amount of engines (it really is overpowered at this point). Fuel fraction is too low, even before we add extra cabins. And not enough wing area for weight, even before we add cabins and fuel. Particularly, not enough wing area forward. I've been trying so hard to get my CG forward, and now that i succeeded, i can't bring CoL far enough forward to match - this is gonna be a lawn dart. So, to progress this unexpectedly aesthetic design, i've got to hit it with the ugly stick and dump a whole load of extra strakes. Could i clip them into the fuselage and handwave as wing/body blending (turns to the Dark Side of the force)....

Is anyone else finding CG problematic ? Can't put crew cabins too close to the front, nervs need to go forward but their exhaust must clear the wings... As Faith No More once sang, in "A Small Victory" My demo live build video managed to solve this with a conventional enough layout when there was only one cabin, but two makes it hard ! My entry for the actual challenge ended up as a bit of a Kludge, and I felt unsatisfied. Is there a more elegant solution ? Today, I tried violating my own house rule on biplanes, and made this, the KAAB Friggen (SAAB Viggen, geddit ?) There is an equal number of strakes above the wing as below it, so it doesn't have large CoM changes as the fuel burns. We have a bit of a tunnel, for our NTR exhaust, and it results in an incredibly compact vessel (still tips the scales at 25 tons though). It's nicer to fly than the Me 163 Komet lookalike, though not quite up there with the Sparrow demo craft or the Vagabond SSTO conversion i did, which automagically pitch themselves to 5 degree AoA when you take SAS off. This thing wants to pitch down slightly at sonic speeds and i couldn't get 5 degrees (more like 2 or 3) without having excessive pitch up when subsonic, which messes with the ability to get supersonic in the first place. I guess you have to actually fly the thing, damn. Eventually i put a tiny trim flap bound to action group one, with pitches the nose up slightly. It's deployed by default to aid takeoff, but can be turned off for most of the airbreathing flight (you want the nose to stay down and go fast) then deployed again when you've started the nukes and no longer need to stay low enough in the atmosphere for the jet to get air. https://kerbalx.com/AeroGav/KAAB-Friggen Oh well, keep searching for an elegant solution i guess. Join the dark side and make a mk2 fuselage ship? Noooo