Solar Cycle 25 peaked in October 2024. As the Sun heads toward its next minimum around 2030, LEO radiation is on its way back up — here's what that means for a mission launching now.
For a Low-Earth Orbit mission, a quieter Sun means more radiation. Trapped-proton flux, cosmic-ray exposure and time spent in orbit all move against a mission launched into the declining half of the solar cycle.
At 400–500 km, proton flux in the South Atlantic Anomaly reaches about 1.9× its solar-maximum level at solar minimum. SAMPEX measured swings of up to 300% at 500 km. The peak comes roughly 1.5 years after the minimum itself, putting it around 2031–32.
Galactic cosmic rays are the high-energy ions behind latchup and functional interrupts (SEFIs), and shielding can't stop them. They also climb toward solar minimum, and sun-synchronous and polar orbits take the worst of it.
Lower drag near solar minimum extends orbital lifetime. At 500 km, a one-year launch slip can take a small satellite from 2.2 years in orbit to 6.4 years — and every extra year in orbit means more total dose collected.
90% of the proton dose arrives in just 3–5% of each orbit, inside a South Atlantic Anomaly that keeps growing and drifting. An orbit-average rate hides how concentrated that exposure really is.
Electronics that did fine on a 2023–2025 mission will be flying into the worst years of the cycle.
This is not the end of the road — there's a solution that starts with a pen and a paper: a complete radiation mitigation stack for critical components.
Latchup protection — per-rail detection and sequenced power-cycle recovery.
Continuous configuration scrubbing — repairs upsets before they accumulate.
Triple redundancy on critical logic — distributed TMR with triplicated I/O.
Error-corrected memory — ECC with background scrubbing on every array.
An independent radiation-hard supervisor — owns power, scrubbing and reconfiguration.
SAA-adaptive operations — scrub harder and defer non-essential work during passes.
Each piece is tailored to your mission class, from CubeSat to multi-year constellations.
This outlook covers Solar Cycle 25's decline toward its next minimum and what it means for LEO electronics through 2031–32. For the device-level effects and mitigation architecture behind each item in the stack, see the SEE in FPGA whitepaper.
Missions launching now will fly through the worst years of the solar cycle. Build the mitigation stack in from day one.