The 17 lessons cover power sources, power management and power budgeting. Public references explain the physical principles. Preset missions, cell ratings, efficiencies and mass factors are illustrative assumptions unless a specific public source is cited.
SI power, voltage, resistance and mass; energy in Wh and duration in h. Solar power uses inverse-square irradiance, cosine incidence and independent retained fractions. The I–V curve is an ideal-diode teaching shape scaled to that peak power. Battery circuits solve the low-current constant-power branch. The orbit model integrates constant mode loads and charge/discharge losses, enforces a reserve and reports unmet energy.
The sizing model uses integer series/parallel counts, EOL capacity, one-string-out peak current, exact recharge closure and the stated study mass factors. The 3D geometry, tracer speed, photon spectrum and representative pack are illustrative.
Build a pack, then lose a string: Use minimum loaded voltage for this check: a 28 V bus and 3.0 V per cell require at least ten series cells before converter headroom is considered.
Keep energy in reserve: Capacity retention is an explicit input. A cell-specific lifetime model requires validated cycling and temperature data.
Fuel cells consume their energy source: Apollo and Shuttle used fuel cells. Voyager uses RTGs; Orion and Dragon use solar power with batteries.
Area, attitude and deployment: For this cylinder geometry, 1/π is approximately 32% retained output, not a 32% loss.
Find the maximum power point: A required series-cell count rounds up to the next whole cell. Verify the resulting voltage over temperature, loading and aging.
Electricity from radioactive decay: Voyager uses radioisotope decay heat. Its generators do not need sunlight to supply electrical power.
High power requires heat rejection: SNAP-10A flew in 1965. KRUSTY was a ground demonstration, not an operational flight reactor.
Route, regulate and protect: ISS uses DC power on both U.S. and Russian segments. The U.S. primary network is about 160 V DC and secondary distribution about 120 V DC.
NASA · Solar irradiance ↗Public 1,361 W/m² solar reference. Cell ratings, thermal derating and mass factors in this app are separate teaching assumptions.
NASA · Small Spacecraft Power ↗Solar cells, energy storage, management and distribution. Model presets are separate illustrative assumptions.
ESA · Power Systems ↗Array sizing, battery recharge, regulation and safe-mode load shedding.
NASA · MMRTG ↗110 W beginning-of-mission power and 45 kg generator reference.
NASA · Radioisotope systems ↗Decay-powered generators and historical/development concepts.
NASA · Dynamic power conversion ↗Reciprocating Stirling conversion compared with static thermoelectrics.
NASA · ISS power system ↗U.S. 160 V DC primary and 120 V DC secondary power networks.
DOE · SNAP history ↗SNAP-10A nuclear reactor flight in 1965.
NASA · Voyager spacecraft ↗Voyager RTGs and 1977 launches.
NASA · Orion electrical power ↗Orion solar arrays and battery-powered interfaces.
NASA · Commercial Crew ↗Dragon trunk solar power.
NASA · ALSEP termination report ↗Apollo surface experiments terminated September 30, 1977.
Sources reviewed November 5–6, 2026. Published hardware values, study assumptions and illustrative model parameters are identified separately.