Generation
How power is made beyond Earth. Solar arrays, space nuclear power, fission surface power, radioisotope systems, and ideas still on the drawing board.
Solar generation
Photovoltaic arrays remain the workhorse of spacecraft power. Modern roll-out arrays, multi-junction cells, and concentrator designs push specific power toward 100 W/kg and beyond. The trade is always between cell efficiency, radiation tolerance, deployment complexity, and the inverse-square falloff of sunlight as a spacecraft moves away from the Sun.
Nuclear generation
Radioisotope thermoelectric generators have powered outer-planet missions for decades by converting the heat of plutonium-238 decay into electricity. Fission surface power systems, now in early design, aim for tens to hundreds of kilowatts on the Moon and Mars, where long nights and dust make solar-plus-storage mass-prohibitive.
Why generation shapes every other decision
The choice of generator sets the voltage, thermal load, mass, reliability, and operational rhythm of the entire power system. A radioisotope source runs continuously for years but delivers modest power; a fission reactor offers scaling but brings shielding, safety, and launch-approval burdens; solar is mature but sunlight-dependent. The daily analysis stream tracks how these trades evolve.