A Loop-Heat-Pipe and Deployable Radiator System for Thermal Control of Orbital Production Equipment: Capillary, Radiative and Mass Budgets

This paper presents a computed design study, SIMULATED, NOT MEASURED, for steady equipment temperatures held within a 20 kelvin band during production cycles in orbit, using waste heat from co-located production equipment, ammonia working fluid. The operating principle is distinct from neighbouring production methods: ammonia loop heat pipes collect waste heat from production equipment and carry it, without pumps, to deployable radiator panels, where it is radiated to space. Capillary pressure in the evaporator wick is the pump, and its margin over the loop's pressure losses is the quantity that decides whether the system works at all. This is the enabling system for the other equipment considered in orbital production: every watt of process power becomes a watt that must be rejected. Sizing follows from budgets computed in the accompanying script rather than from analogy with terrestrial equipment. The headline figures are a specific energy of 0.0288 megajoules per kilogram of product, an installed electrical power of 0.12 kilowatts, a supported production rate of 15 kilograms per hour from the equipment it cools, and an annual throughput of 1.19e+05 kilograms over 330 operating days. Rejecting 15 kilowatts of waste heat at 320 kelvin requires 28.7 square metres of radiator, a photovoltaic supply requires 0.294 square metres of array, and the installed mass is 489 kilograms. Moving feedstock from a 400 kilometre to an 800 kilometre orbit costs 217 metres per second of velocity change. The study is a computed study with no targeting or weapon application; it concerns civilian production equipment only, and none of its figures is a measurement.