Hi guys, long-time lurker, first-ish time poster with two questions.
1. I'm building a Minmus refinery and launchpad, which means liquid methane and liquid oxygen production, which means the Sabatier process and water electrolysis. I can get the electrolysis working fine, but not the Sabatier process... because there doesn't seem to be an option for it anywhere, across all the various modules, even in the VAB. What am I missing?
I haven't found an answer to this, but I have landed a refinery base on Minmus with a Regolith drill on board, which digs up regolith, unsurprisingly. This can be converted into minerals and elements which can be rendered from the rock (which vary by location, so do your orbital surveying first), including methane and Borate (no first name given). The former can be converted into its liquid form using a cryotank, and the latter can be converted into boron (30%) and oxygen (70%) via Borate Processing, which can also be frozen. Boron can be used for exotic fusion, but I believe is mostly otherwise useless (feel free to correct me!!).
2. Is there any way to alter the settings on any of the fusion reactors/engines or nozzles to achieve a higher thrust but lower ISP? My lofty goal is an antimatter-powered tug that can push 100 tons anywhere with a decent TWR for low Kerbin orbit (est. 0.45+). No degree of ISP sacrifice is too severe, I'd be perfectly happy to be getting chemical rocket-like performance if it meant my tug could start flinging colony ships to Sarnus.
The answer to this question turned out to be the fuels the fusion rockets were burning. Liquid hydrogen is great, and easy to make, but methane, for example, gives a much lower ISP but higher thrust; I'm currently pushing a 73 ton 3.75m science lab to Slate and a vessel to get its crew home, with an LKO TWR of 0.42 before burning, using a Tokamak, a plasma engine, a Thermal Electric Effect Generator, and a couple dozen tons of liquid methane. Also the main fuel can be used with the main fuel of your conventional rockets; which is useful in emergencies.