CYGNSS team models lunar-eclipse battery risks

(SpaceEnergy) Researchers have developed new models to predict battery state-of-charge losses on NASA’s CYGNSS satellites during lunar-shadow eclipses as their ageing power systems operate with reduced margins.

The Cyclone Global Navigation Satellite System (CYGNSS) constellation has operated in low Earth orbit since 2016. Its spacecraft use fixed body orientation with solar arrays pointed generally towards the Sun, but operators already roll them by 10–16° during high beta-angle periods to preserve battery state of charge.

Researchers said radiation and ageing have degraded the spacecraft’s solar arrays and batteries, leaving less margin for unexpected reductions in power generation.

The team developed one model using historical telemetry to forecast state of charge from beta angle, solar distance and mission age, and a second to predict battery losses caused by lunar-shadow eclipses.

The combined system was used to model the 12 August 2026 eclipse and a further event expected on 6 February 2027, helping operators assess whether temporary solar-power losses could push spacecraft towards safe mode.

The work was presented at the Small Satellite Conference in Salt Lake City, Utah, on 25 August.