Build:Auxiliary Power Systems
7.4 Auxiliary Power
7.4.1 Thermoelectric Generators
Cost: 2 SUs per RTG unit; limited to size 4 vessels and smaller
Power Generation: 2 Power per RTG unit
Source: self-generated
Long before Humanity mastered stable matter/antimatter intermix and duotronic fusion regulation, early explorers of the Sol stellar neighborhood needed dependable power that did not carry the catastrophic failure modes of a fission or early fusion reactor. Radioisotope Thermoelectric Generators (RTGs) filled this niche: converting the steady heat of radioisotope decay (historically Plutonium-238 or Strontium-90) directly into electrical current via thermocouples. RTGs became an early auxiliary power source aboard sleeper ships, deep-space probes, sub-light colony transports, and the earliest impulse-only survey craft of the early and mid-21st century.
Because thermocouple conversion efficiency does not scale well and radioisotope mass/volume becomes unwieldy past a certain point, RTGs are only practical as the primary auxiliary Power source on vessels of Size 4 or smaller. Unlike a fusion reactor, which produces constant Power as long as it is fueled and functioning, an RTG's output declines gradually as its radioisotope core decays. For campaign purposes, apply the following simplified rule instead of tracking exact half-lives: reduce total RTG Power output by 1 Power (across the whole RTG assembly, not per-unit) for every 20 years of continuous shipboard operation without a core replacement. This decay is why RTG-powered sleeper ships and century-old probes are often depicted running auxiliary systems at reduced capacity: the power is still there, just diminished, exactly as one would expect from a decaying isotope rather than a fuel-fed reaction.
7.4.2 Nuclear Reactors
Cost: 3 SUs per additional fusion reactor (or 5 SUs x Size per additional fission reactor)
Available: 2033 (fission for pre-2033)
Power Generation: 5 Power per set (or 3 Power for fission reactor set)
Ref: Spacedock, pp 40-41
In addition to the fusion reactors which form the impulse engines, most ships carry another set of reactors simply to generate power. Each additional fusion reactor occupies 3 SUs and generates 5 points of Power per round. The crew holds auxiliary power in reserve for use in emergency or crisis situations, rather than using it at all times. Most ships have at least one auxiliary power generator for every 4 points of Size.
A crew can use one of a ship’s auxiliary power reactors to replace damaged or spent reactors in the impulse engines. This takes an hour and requires a Routine Crew Skill Test.
Note: Fission reactors are not produced in the antimatter era, so they are far less efficient and undeveloped after 2063. Fusion reactors, however, are still primary sources of power for most static facilities, including space stations.