Power Analysis¶

Power Analysis evaluates spacecraft electrical balance over time using solar arrays, batteries, and user-defined loads.

Engineering Questions¶

How much power is generated by the selected solar arrays?
What is the total spacecraft load over time?
Does the battery remain within SOC limits?
When does a power deficit occur?
How do eclipse and incidence angle affect power generation?

Inputs¶

Input	Description
Spacecraft	Provides position and eclipse context.
Solar arrays	Generate power from area, efficiency, incidence, and solar flux.
Batteries	Store and deliver energy with SOC and power limits.
Loads	Static, average duty-cycle, orbit-duty-cycle, sunlight-only, or eclipse-only loads.
Time step	Simulation step in seconds.
Solar flux mode	Constant, custom, or distance-corrected.
Battery policies	Initial SOC override, charge/discharge enable, minimum SOC handling.

Load Modes¶

Mode	Behaviour
Always on	Full load power at every sample.
Sunlight only	Active only outside eclipse.
Eclipse only	Active only in eclipse.
Average duty cycle	Applies average power as `power * duty / 100`.
Orbit duty cycle	Toggles full load power for a fraction of each estimated orbit period.

Simulation Pipeline¶

flowchart TD
    T["Timeline"] --> E["Eclipse state"]
    E --> S["Solar flux and array power"]
    T --> L["Load power"]
    S --> N["Net power"]
    L --> N
    N --> B{"Net >= 0?"}
    B -->|Yes| CH["Charge batteries"]
    B -->|No| DIS["Discharge batteries"]
    CH --> SOC["Record energy and SOC"]
    DIS --> SOC
    SOC --> OUT["Payload and summary"]

Main Configuration Parameters¶

Field	Meaning
`spacecraft_guid`	Spacecraft being analysed.
`solar_array_guids`	Solar arrays included in generation.
`battery_guids`	Batteries included in storage.
`time_step_s`	Simulation step.
`solar_flux_mode`	Constant, custom, or distance-corrected.
`include_eclipse`	Sets generation to zero in eclipse.
`include_incidence_angle`	Applies solar incidence cosine.
`override_initial_soc`	Uses analysis-level initial SOC instead of battery asset value.
`allow_battery_charging`	Enables charging when net power is positive.
`allow_battery_discharging`	Enables discharge when net power is negative.
`minimum_soc_policy`	Defines how deficits below minimum SOC are handled.

Outputs¶

Output	Description
`total_solar_power`	Total generated power time series.
`solar_power_by_array`	Per-array generated power.
`total_load_power`	Total load power time series.
`load_power_by_load`	Per-load power series.
`net_power`	Solar minus load power.
`deficit_power`	Unserved power after battery discharge.
`battery_energy_by_battery`	Stored energy in Wh.
`battery_soc_by_battery`	SOC percent per battery.
`eclipse`	Boolean eclipse state timeline.
`solar_flux`	Solar flux used in W/m2.

Interpretation¶

A positive net power does not automatically mean the system is healthy if batteries are already full and generation is wasted. A negative net power does not automatically mean failure if the battery can sustain the load. The key outputs are minimum SOC, total deficit energy, and the timing of deficits.