Brotoro

"Without a pilot, there is no SAS." Wut?

I've also read that the tidal effects of the Moon and Sun change the shape of the atmosphere, but I don't recall by how much.

I have about a dozen installs on mine...mostly because I keep the previous one as a backup, and never got around to deleting any.

Nice launch. Good onboard video. Happy camper!

No Atlas. Delta IV Heavy.

Well...I did some more stuff on Pol and Bop, but haven't written it up yet. I was spending time doing some other stuff: making an updated Eve return vehicle...and making some Duna exploration ships.

Most of my SSTO flights are for crew transport. I use rockets for equipment payloads.

Single Stage To Orbit? Sure it is.

I completely agree that it must be playable. But I think a resource system that is not overly simple is what's needed to keep the game INTERESTING once you have progressed beyond a certain point (leading to long-term playability). Setting up resource extraction and processing SHOULD (initially) take more work than simply shipping fuel out to distant locations...but, once set up, it should save time in getting more fuel to explore those distant locations.

Yes, I personally would like the challenge involved in carrying a feed resource from one place to another to make propellants. A simple "poke your drill into one place and get everything you need" is too easy to be appealing to me. I don't think I'd want to haul ammonia from Laythe to Duna...I was thinking of shorter trips than that. Anyway, I would expect that you could get ammonia and water on Laythe, and just make fuel and oxidizer that you could ship to Duna. Or, better, I would hope there are sources of nitrogen on Duna (in its atmosphere or nitrates in the regolith) that use could use with Duna ice to make what you need. As to where you could find ammonia, it is the forth most abundant chemical in jovian planet atmospheres (after hydrogen, helium, and methane), so I don't think it's unreasonable to find it in the outer solar system (so, the moons of Jool and Gas Planet II). The spectra of comet tails indicates that ammonia ice is part of their makeup, so icy bodies or bodies with subsurface ice could be expected to have some. Some people have suggested that Laythe's oceans are a mix of water and ammonia. Tylo seems strangely lacking in volatiles (since it lacks an atmosphere), so I wouldn't necessarily expect to find it there...but maybe there are nitrates in the rocks. But in any case...I really don't want to ponder this whole thing TOO much just because if I DO come up with some idea for how to do resources that I really like, I'll just be all the more disappointed with what Squad comes up with if it's different (as it likely would be). But I do want to point out things that I think should be avoided, like hydrogen as a fuel (unless we want to re-do all the tank sizes or masses...which seems unlikely). EDIT: The Haber–Bosch process can be used to create ammonia from nitrogen and hydrogen (so planets with nitrogen in their atmosphere, and water/ice as a source of hydrogen, could get you ammonia).

I was never suggesting that such things needed to be simulated in the game (this is where you confused me). My point was that to find out what what ratios of fuel and oxidizer to use in KSP engines, you should look at real-life rockets to find out the ratios they use...because there is more to designing an engine than getting a 100% burn of fuel and oxidizer. You may need to use more or less propellant or fuel to cool the engine. You may want to use more hydrogen in an LH2/LOX engine because unburned hydrogen in the exhaust makes the average molecular weight of the exhaust gas lighter, and therefore results in higher exhaust velocity and greater Isp. But you don't need to simulate that in the game. You just get your propellant usage ratios from real-life rocket engineering and build them into the game. Why be less realistic than you need to be? I also wanted to point out that liquid hydrogen is not a good match for liquid fuel in KSP. The tanks would need to be huge. You simply can't get the mass of fuel we use into the size tanks we use if it's hydrogen. And it makes no sense to me to ignore the basic engineering of rocket engines and fuel tank capacity to include some particular chemistry that isn't realistic. And, I DON'T want to have to calculate boil-off of propellants, which is another reason I don't want to use liquid hydrogen as the fuel, since it's much more realistic to ignore boil-off of mildly cryogenic propellants and storable propellants.

I was considering the question: "What kinds of propellants do KSP rockets appear to use based on what we see in the game (tank sizes and masses, and the oxidizer-to-fuel mass ratio used by engines)?". I had previously calculated some of this in a spreadsheet, so I dug that out and added a few new numbers. The data on propellant densities and optimum oxidizer-to-fuel mass ratios mostly come from Encyclopedia Astronautica at www.astronautix.com. Some of the oxidizer-to-fuel mass ratios come from real rocket data (such as from the Space Shuttle SSME and Saturn V). The tank used for these calculations was the FL-T400. I placed a capsule on the launch pad and EVA'd the kerbal to measure his altitude...and then I placed a capsule on top of a stack of 20 FL-T400 tanks and did the same thing. The result is that an FL-T400 tank is 1.9 meters tall. Measuring the length and diameter of the tank on the screen showed that the tank was 1.112 meters in diameter. This is not the 1.25 meters expected because I measured the surface of the tank that is indented in the image. Assuming a wall and bulkhead thickness of 2 cm, this gives an internal tank volume of 1.661 m3. If you want to ignore the on-screen measurements of the apparent indented diameter and use 1.25 meters as the diameter, you get a tank internal volume of 2.116 m3 (again, assuming 2 cm wall and bulkhead thickness). The 2 cm thickness is enough to easily account for the 0.25 metric ton dry mass of the stage (allowing for double-wall aluminum construction with insulation between). Whether this is a reasonable thickness for enough insulation to allow long-term storage of liquid hydrogen is questionable. The results from my spreadsheet are in the image below: The real-life propellant combination that comes closest to KSP's ratio of 1.22 is hydrazine and nitrogen tetroxide...storable propellants that can easily survive during long space voyages. This propellant combination also results in about 2 tons of propellants in an FL-T400 tank (using my smaller tank diameter), which is what we observe in the game. For the full 1.25 m diameter tank, the closest fit to 2 tons is kerosene/LOX. I was sad to see that my preferred choice of methane/LOX does not result in getting 2 tons of propellants into the tank. Squad could easily change the fuel/oxidizer mass ratios of their tanks...but they would need to make the tanks bigger to allow them to contain 2 tons of methane/LOX...and MUCH bigger if you prefer LH2/LOX. So...what would it take to manufacture Hydrazine and Nitrogen Tetroxide off Kerbin? Probably ammonia or some other nitrogen-rich compounds that could be used to derive ammonia...and you'd need water or water ice to make the hydrogen and hydrogen peroxide that would also be needed to manufacture the hydrazine. The hydrazine/N2O4 propellant combination has the unusual advantage that our liquid fuel would also be our monopropellant.

Former Dev, yes. But after he was no longer a Dev is when the Devs added the feature in-game that specifically lists the masses and radii of the bodies. The numbers are there in black and white...so I am forced to use the reported values.

This just means that the flats were formed after the bombardment that left meteorite fragments scattered across the face of Minmus...and that's not a problem. The maria on our Moon were formed after the early bombardments of material that cleared out the small bodies left over from planet formation were cleared out of our solar system. The flats on Minmus were apparently formed (or at least refreshed) relatively recently. And the meteorite fragments would not have craters under them if they are ejecta that came bouncing and rolling to a stop.

Rock boulders are OK on an icy surface if they are meteorites deposited onto the already solidified surface. The Antarctic ice sheet is one of the best places on Earth to go hunting for meteorites.

I agree with MartGonzo. Have some kerbal snacks.

The explanation of a different gravitational constant could have been used when our only source of data on planetary mass was the unofficial wiki...but now that KSP displays the planet masses in kilograms, we no longer have that out. The simplest solution is to accept the existence of some super-dense material in the cores of the planets and moons. Perhaps a heavy variant of protons and neutrons (made from the more massive quarks...or kwarks, as the case may be) are stable in the Kerbol system. Matter made from these massive nucleons would be super-dense and would naturally tend to sink to the centers of the bodies, which are otherwise composed of normal matter, so we don't have to deal with it at all in the game.

This is the kinds of missions the contract system inspires?

They really want to land on barges as a long-term solution? I thought they were only going to do this until they convinced the powers-that-be that they are able to reliably plop the stage down onto a chosen landing spot. In which case I wouldn't think it would even matter (for that purpose) if the stage fell over later due to the shifting deck.

This is going to be cool.

Oh... and Red Iron Crown has been pushing the idea that liquid fuel is RP-1 based upon in-game data ...and while that is TRUE (heck, the old Mk-1 liquid fuel tanks even said "kerosene" on them), I would prefer we use methane as our liquid fuel because it is more likely to be found in space than kerosene, and is possible to make on other planets (by techniques discussed in Zubrin's Mars Direct plan). It's a realistic fuel, and will make future real-world plans to exploit methane as a fuel made on Mars make more sense to the people who learn about it playing KSP. So: GO METHANE!

I'm not sure what question you mean. Please re-ask your question. I don't think I'm moving on to other issues. You were talking about liquid fuel being hydrogen (you certainly aren't the first one to do so, so I'm not picking on you in particular about this...but that's where I came into this today). I posted some information about real-life liquid hydrogen rockets (propellant volume and mass ratios) to point out that there is more to rocket engineering that calculating the ratio of propellant to oxidizer for complete combustion (such as extra fuel being needed to cool parts of the engine, or protect its surfaces with soot in low-chamber-pressure RP-1 engines, or decrease the atomic weight of the exhaust for better efficiency...so LH2 engines are run fuel-rich, if I recall correctly). I don't think it's a good idea to try to make liquid fuel be liquid hydrogen because it doesn't fit with the masses and sizes of the tanks in KSP. That is the point I'm trying to make. That's what all my posts today have been in aid of. Sorry if I'm not being clear here.

Not slippery at all. My position is: Come up with the most "realistic" chemistry that fits what SQUAD has given to us in the game. Liquid Hydrogen as "liquid fuel" is NOT a good fit. Methane is better. Only mildly cryogenic...can be used in rocket engines...can be used in jet engines...and the high dead-weight of our tanks in KSP compared to real life makes holding methane/LOX for extended periods more reasonable. Given that, make the chemistry fit. DON'T start with 'Well, obviously, liquid fuel is liquid hydrogen'... because that won't fit what we see. The order of importance of realism in KSP is (in my opinion)... 1) Orbital mechanics (patched conics is good enough) 2) Rocket engineering (realistic ISPs and engine performance) 3) Other Engineering (the sizes and masses and strengths of parts should be reasonable) 4) Space Science (realistic values for things we measure in SPAAAACE and on planets/moons) 5) Chemistry (build to fit the more important items)

Yes. But finding or manufacturing methane off-Kerbin is much more likely than finding or making kerosene, so I prefer to think in terms of methane. In the near future, Space-X will be using methane to fuel some of its rockets.

If you want realistic chemistry, you should also keep in mind what that's going to do to our rocket engineering. That's why I dislike the idea of "liquid fuel" being liquid hydrogen. Other fuels (kerosine, methane, UMDH/hydrazine) fit much better with the tanks we have been given... so any attempt to make realistic chemistry should be done with that in mind.