Work

Radiation-Hardening Techniques and In-Orbit Robustness Validation for Trapezoidal Dual-Axis Sun Sensors in LEO Environments

Year: 2026

Type: article

Abstract: This work presents a sensor-level and algorithmic strategy for limiting radiation-induced angular drift in a previously developed trapezoidal dual-axis sun sensor without requiring dedicated radiation-hardened components. Radiation-induced degradation of the photodiodes is decomposed into additive dark-current offsets and multiplicative responsivity losses. To evaluate the proposed compensation strategy, the sensors were irradiated with 30-MeV protons to a cumulative dose exceeding$\mathrm {4735~krad(Si)}$. This dose exceeds typical LEO mission requirements, enabling evaluation over an extended degradation range. Unbiased sensors were reserved for post-irradiation characterization, while biased units were operated in situ to collect photocurrent data. Experimental results show a 60-fold increase in dark current and a 30 % reduction in responsivity. Under nonirradiated conditions, the sensor had previously demonstrated angular errors within ±0.3°. Following proton irradiation, the uncompensated maximum angular deviation reached 4.8°. An embedded shielded dummy photodiode was used to compensate for dark-current drift, while ratio-based angular reconstruction was used to normalize responsivity degradation. Together, these methods reduced the maximum angular deviation to 0.53°. Low-dose-rate60Co gamma irradiation up to$\mathrm {30~krad(Si)}$was further conducted to evaluate enhanced low-dose-rate sensitivity in the readout electronics, where common-mode gain drift was effectively suppressed through both circuit-topology selection and ratio-based cancellation. The system also maintained continuous functional operation throughout 221-MeV proton irradiation, with no destructive single-event latch-up observed within the monitored parameters. These results indicate that the proposed sensor-level and algorithmic approach has the potential to provide a viable, low-cost radiation-tolerant solution for long-duration LEO missions on resource-constrained small-satellite platforms.

Source: IEEE Sensors Journal

DOI: 10.1109/jsen.2026.3727622