Power and Energy

Methods of power generation and storage across space are dependent on numerous factors. Nuclear reactors are the most common source of energy, though the fuel material varies widely. The location of infrastructure within a system is a driving aspect in energy needs and production abilities; for instance, solar power becomes a decreasingly common source with increasing distance from a star. Planetary environments can offer unique energy sources as well, such as tidal energy or biofuels. Lasers can utilize beamed power to transmit energy between points, most effectively in vacuum.

Fission

Nuclear fission is a reaction in which an atomic nucleus splits into two different nuclei, producing large amounts of radiation and energy. Fissile materials are those which can be utilized for controlled fission, a process of self-sustaining chain reactions within the atoms and neutrons of the material. Fissile fuels are very energy dense but are naturally radioactive, due to the characteristic unstable atoms that make them a sustained fission candidate in the first place.

Fission is an expensive and challenging process, and the resultant radiation is a hazard to biological life and electrical systems alike. The associated challenges meant that the first controlled fission reactions were not accomplished until -87FA, after humanity had already achieved a strong foothold in space.

Fusion

Nuclear fusion is a reaction in which two atomic nuclei are combined into a heavier nucleus of less binding energy, resulting in a release of energy and radiation. The best fuels for the process are in general those with lower atomic numbers, as these are lighter (requiring less energy to fuse them) and because they tend to release the most amount of energy.

Fusion reactors require a particular temperature, pressure, and confinement time to reach a sustained fusion reaction. The fusion material must be heated to the required temperature and contained at the needed pressure, an energy state which must then be maintained for extended periods of time. There are a multitude of methods derived for sustained fusion, which see varied use dependent on fuel supply and local needs.

Both fission and fusion are used extensively in sub-light propulsion.

Solar

Solar power is energy harnessed from starlight, which can be converted into electricity upon impact with solar cells and stored for later use. Solar panels are a cheap and effective source of power, and as such are utilized extensively throughout society, particularly for smaller-scale satellites and stations as a primary energy source. They’re less effective with increasing distance from a given star, requiring exponentially larger arrays to maintain the same level of energy output.

Energy which is prepared but not intended for immediate use must be stored in some way. All energy storage methods have two primary measurements of concern: energy density, which is the amount of energy stored per unit mass, and power density, which is the amount of energy that can be extracted from a given volume over a given time. Different applications throughout civilization will have different energy storage requirements; spacecraft in particular are highly concerned with energy density, as every gram counts and higher energy density means less mass.

Superconductor Batteries

Superconductors are materials with no electrical resistance, a technology which has had a profound widespread impact across all of developed society. For energy storage, their main characteristic is what allows them to perform so efficiently; electricity can be put into a superconducting material, where it travels in a closed loop with limited loss since the material has no electrical resistance. Superconductor batteries are especially common in outer systems and beyond where the natural temperature permits a greater variety of ambient-temperature superconductors.

Chemical Batteries

Chemical batteries have existed for many hundreds of years, since electrical power was first harnessed. They operate using electrochemical cells which generate electricity via chemical reactions. Primary batteries are single-use only, manufactured at full capacity and depleted over their usable life.

Secondary batteries are those which can be recharged, accomplished by reversing the internal chemical reaction. Variations of these batteries have applications throughout all civilization, as different chemicals and environments allow for different performance characteristics.

Power Transmission

Power transmission can be achieved both wired and wirelessly. Wires utilize whatever high–conductivity material is readily available for the needed task. Beamed power is utilized extensively to transmit power across the vast distances between installations and infrastructure. Energy is converted into either x-rays (electrical energy) or lasers (thermal energy) and beamed to receivers which either re-transmit the energy or store it for use. Receivers must be large enough to minimize waste and must remain at a safe distance relative to other infrastructure due to the inherent dangers of high-intensity directed energy beams.

Antimatter

Antimatter is a type of substance producible in particle accelerators. It reacts violently with normal matter, and many theoretical concepts for energy production and spacecraft propulsion have been proposed that utilize matter-antimatter reactions. However the technology for storage and application of antimatter is still in its infancy, and it is not yet utilizable at practical scales.