Solar sail spacecraft is a novel propellant‑free vehicle that utilizes solar radiation pressure as thrust. Without chemical propellants, it relies on large ultra‑thin sail films to capture photon momentum for continuous orbital maneuvering, attitude adjustment and deep‑space cruising. Featuring zero propellant consumption, ultra‑long lifespan, lightweight design, low power consumption and low cost, it serves as an ideal platform for asteroid exploration, heliosphere boundary missions, near‑Earth asteroid defense and space environment monitoring, while also supporting orbit maintenance, deorbiting and constellation configuration for low‑orbit satellites. The high‑voltage electrostatic deployment system is a critical enabling technology for on‑orbit solar sail unfolding. Compared with traditional mechanical spring, inflatable and centrifugal mechanisms, electrostatic deployment delivers ultra‑low mass, wear‑free operation, smooth controlled deployment without impact vibration, and reversible retraction/unfolding, becoming the mainstream solution for large‑scale solar sails from hundreds to tens of thousands of square meters. As the core driver, the high‑voltage power supply provides 10 kV–100 kV DC output for positive/negative parallel electrodes, forming uniform strong electrostatic fields to drive folding polyimide films into gradual unfolding, tensioning and precise positioning. Its high‑voltage insulation performance, high‑vacuum compatibility, long‑term voltage stability and in‑orbit reliability directly determine deployment success and overall mission safety. Electrostatic deployment imposes extreme insulation challenges far beyond conventional aerospace power supplies: 1.Long‑term stable ultra‑high‑voltage operation under 10⁻⁵ Pa–10⁻⁷ Pa high vacuum increases molecular mean free paths, drastically lowering corona and avalanche breakdown thresholds and raising risks of partial discharge, arcing and catastrophic insulation failure. 2.5–15 years maintenance‑free on‑orbit service exposes insulation to intense particle radiation, −180 ℃–+120 ℃ extreme thermal cycling, atomic oxygen erosion and micro‑meteoroid impact, accelerating aging, cracking and dielectric degradation. 3.Ultra‑strict satellite mass/volume constraints prevent simple insulation distance enlargement, requiring superior dielectric reliability within compact lightweight boundaries. Traditional ground and conventional aerospace high‑voltage power supplies suffer vacuum insulation degradation, frequent discharge breakdown, rapid aging and excessive size/weight. The design fully complies with GJB 3758‑99, GJB 7243‑2011, GJB 2438A‑2002 and GB/T 16935.1, meeting solar sail requirements for miniaturization, long lifespan and maintenance‑free operation. This methodology establishes a full‑process framework covering high‑insulation topology, full‑chain dielectric optimization, high‑vacuum discharge suppression, space environmental protection, long‑term reliability and on‑orbit insulation monitoring, applicable to all solar sail electrostatic deployment systems and supporting domestic engineering implementation for deep‑space exploration. Adopting modular multi‑stage cascaded boosting + fully integrated sealed insulation + graded equipotential shielding + fully digital closed‑loop safety control, combined with high‑vacuum compatible dielectric materials and comprehensive electric field simulation, it overcomes traditional limitations and realizes stable long‑term insulation at 10 kV–100 kV for full mission cycles. Five core design principles are defined: 1.Modular cascaded Cockcroft‑Walton voltage multiplier topology divides total voltage across independent stages, reducing single‑device stress to 1/N and simplifying insulation. No ultra‑high‑ratio high‑voltage transformers eliminate winding partial discharge risks. The front‑end full‑bridge LLC resonant inverter achieves ZVS/ZCS across loads, suppressing dv/dt, voltage spikes and initial partial discharge triggers. 2.Fully sealed integrated insulation adopts vacuum degassed epoxy potting with graded curing to eliminate voids, delamination and interfacial defects. The core assembly is enclosed in a hermetic titanium alloy housing filled with dry SF₆ micro‑positive pressure to enhance dielectric strength and isolate vacuum/atomic oxygen erosion. Alumina ceramic feedthroughs with vacuum brazing and rounded shielded high‑voltage cables eliminate tip corona. 3.Equipotential gradient & electric field optimization arranges graded insulation distances and shielding rings for uniform linear field distribution. Full 3D finite element simulation ensures rounded smooth transitions at all high‑voltage joints, keeping maximum field strength below 30% of dielectric breakdown and well under vacuum corona inception with ≥3× safety margin. 4.High‑vacuum radiation‑resistant dielectric materials feature insulation strength ≥20–25 kV/mm, ultra‑low outgassing (TML ≤1%, CVCM ≤0.1%), radiation tolerance and extreme thermal cycling stability (−180 ℃–+120 ℃). Selected materials include high‑purity epoxy, polyimide, PEEK, 95% alumina ceramics, lightweight titanium alloy structures and perfluoroelastomer seals. High‑voltage wiring maintains ≥0.2 mm insulation thickness per kV. 5.Radiation‑hardened FPGA+MCU digital control realizes precision closed regulation, real‑time insulation monitoring, microsecond discharge protection and full telemetry. Dual optical isolation separates high/low voltage with 2× overvoltage safety; redundant hardware/software protection ensures absolute safety during deployment and long‑term operation. High‑vacuum discharge suppression is optimized across key dimensions: Void‑free potting with plasma surface treatment eliminates internal micro‑gaps responsible for vacuum breakdown. Micro‑discharge mitigation adopts polished passivated electrodes, low secondary‑emission coatings and homogeneous electric fields limited below 50% of multipactor thresholds. Surface insulation modification improves tracking resistance; creepage distance ≥5 mm per kV with umbrella ceramic bushings prevents flashover. Thermally matched dielectrics with flexible buffer layers avoid cracking under extreme −180 ℃–+120 ℃ cycling. Long‑term space radiation aging protection adopts three‑level mitigation: radiation‑resistant dielectrics (total dose ≥100 krad(Si)), local titanium shielding and adaptive voltage threshold compensation against aging drift. Full lifecycle over‑design maintains ≥2× insulation margin even after 15 years on orbit; component derating further slows degradation. Optimized thermal conduction/radiation cooling stabilizes working temperatures within −40 ℃–+85 ℃ to prevent accelerated aging or cryogenic cracking. On‑orbit insulation health monitoring integrates UHF partial discharge sensing for real‑time aging evaluation, remaining life prediction and ground telemetry reporting. Four‑layer redundant protection includes 1 μs hardware arc/short‑circuit shutdown, software threshold guarding, high‑voltage current limiting/fuse isolation and satellite‑level safety interlock. Intelligent fault self‑recovery automatically mitigates transient micro‑discharges by voltage rollback and gradual restoration, avoiding mission interruption while isolating permanent failures. In summary, this integrated framework solves critical vacuum insulation, discharge breakdown and long‑term aging problems of conventional high‑voltage power supplies. Multi‑stage topology reduces insulation difficulty; fully sealed void‑free potting ensures stable high‑vacuum dielectric performance; comprehensive radiation/thermal design supports ≥15‑year on‑orbit lifespan; real‑time health monitoring enables maintenance‑free safety. It fully meets electrostatic deployment demands for all solar sail configurations and provides core domestic technical support for future deep‑space exploration.