# Solar & orbital power

Sunlight is an opportunity. Reliable delivered electricity is an engineered system.

Type: Research + examples · Reviewed: 4 October 2026

## Separate two concepts

Using solar electricity onboard a spacecraft and beaming power from space to Earth address different problems. Onboard generation supplies local equipment. Power delivery to Earth adds conversion, transmission and receiving infrastructure.

NASA’s 2024 study considered space-based power delivery for a possible 2050 operating horizon. Under its assumptions, costs exceeded terrestrial sustainable alternatives, while capability gaps could change future economics. These conclusions should not be substituted directly for onboard-compute economics.

Source: [Space-based solar power study](https://www.nasa.gov/organizations/otps/space-based-solar-power-report/) — NASA · 2024. A 2050-oriented study of power delivery to Earth, distinct from onboard electricity use.

## Generation, storage and mission life

NASA’s spacecraft power guidance accounts for eclipse periods, solar angles and end-of-life performance. Panels cannot generate from direct sunlight in Earth’s shadow; usable output may degrade with mission age.

Generation must supply the compute load, spacecraft services, losses and storage recharge. A sun-synchronous orbit is not automatically a guarantee of continuous sunlight in every configuration and season.

Source: [Small spacecraft: power subsystems](https://www.nasa.gov/smallsat-institute/sst-soa/power-subsystems/) — NASA. Solar arrays, storage, eclipses and end-of-life power budgeting.

## A simplified storage calculation

For an assumed 10 kW total load during a 30-minute eclipse, 5 kWh must reach the load. At an assumed 80% usable storage fraction, nominal capacity starts at 6.25 kWh, before extra losses and reserve.

This is a planning example, not a spacecraft specification. Real design also includes degradation, charge/discharge limits, thermal behavior and failure cases.

```text
E_storage ≥ P_eclipse_load × eclipse duration / usable storage fraction
```

## Compare power architectures

| Architecture | Potential benefit | Required evidence |
| --- | --- | --- |
| Grid-connected compute | Mature operation and servicing | Local supply, overhead and emissions. |
| Ground renewables + storage | Cleaner supply and flexibility | Hourly matching and storage losses. |
| Orbital onboard solar | Power where spacecraft work occurs | Sunlight profile, mass and mission life. |
| Power beaming to Earth | Remote orbital generation | Conversion chain, reception and lifecycle economics. |

## A grounded research direction

Start with terrestrial experiments that can be repeated. Treat orbital generation as a use-case-specific frontier. Compare delivered useful work across the full system rather than assuming one location is inherently best.