3Davideo

Well I'm glad that these ideas are being considered! The resource system definitely has quite a bit of potential and I'm happy the devs are looking to expand it.

When I saw the Isp's for KSP's liquid fuel engines I noticed that they were quite a bit lower than I expected. Having read some on the IRL space race, I know the best chemical rocket fuel is liquid hydrogen (LH2) and liquid oxygen (LOX) which burns with an Isp somewhere between 420 and 450 seconds (examples: upper stages of Saturn V, Space Shuttle main tank). Space flight on Earth would be extremely difficult without this fuel combination; the Kerbals are doing ok probably only because Kerbin requires half the delta V to get into orbit that Earth does. So I was a little surprised to see the Kerbal engines with such low Isp, which I can only presume is some sort of hydrocarbon/LOX mixture (LiquidFuel sounds like kerosene). So I propose that a new series of engines and fuel tanks be added that utilized liquid hydrogen as a fuel. LH2's chief advantage is the higher Isp, but its main disadvantage is that it is cryogenic: to keep it liquid, LH2 needs to be chilled below 14 K or so. As this requires more complicated rocketry, this would be an interesting technology to add to career mode's tech tree when it is added. So how would this new fuel behave? LH2 can be burned with the existing Oxidizer resource in engines that have Isp's higher than the existing hydrocarbon engines. However, the LH2 tanks take ElectricCharge to run their refrigeration systems, proportional to how much LH2 is in the tank. If power stops, you start losing fuel. On the launchpad, this isn't a problem, since the launch clamps provide all the power you need, but this will pose problems if you want to store LH2 in orbit. Ok, so so far it's just an alternative fuel with better performance but with storage problems. But there's other things you can do with hydrogen. One can combine hydrogen and oxygen in a fuel cell and get electricity and water, or combine water and electricity and get hydrogen and oxygen. So you could use hydrogen as a fuel tank for a generator, or if you had a source of water you can make more rocket fuel... in space! So the addition of LH2 as a resource can easily lead into implementing some sort of resource gathering system, if desired. And one can use hydrogen or water as realistic fuels for the nuclear engine, rather than the unrealistic liquidfuel. So, in short, using liquid hydrogen as a rocket fuel can increase the performance of our rocket engines significantly, but requires refrigeration and more advanced technology as tradeoffs. Hydrogen and Oxygen can be exchanged for water and power (and vice versa), providing an "in" for in-situ resource utilization. And the nuclear engine will finally get a suitable fuel.