Lunar and Mars exploration represent core strategic directions in deep‑space missions. As the key surface probe carrier, landers undertake landing buffering, surface roaming, in‑situ detection and data relay. The high‑voltage power system acts as the central energy hub, supplying stable high voltage to ignition circuits, scientific payloads, robotic arms, thermal control, onboard computers and communication subsystems. Its wide‑temperature adaptability, cold/hot startup stability and long‑term reliability directly determine mission success. Lunar and Martian surface environments impose extreme challenges far beyond low‑orbit applications: lunar temperatures range from −180 ℃ during lunar night to +150 ℃ under direct solar radiation, exceeding 330 ℃ in fluctuation; Martian surfaces vary from −130 ℃ to +20 ℃. Landers also endure thousands of g impact loads during descent, strong vibration, lunar/Martian dust erosion, high vacuum and intense particle radiation. Conventional aerospace power supplies suffer cold startup failure, severe component drift, insulation degradation, efficiency collapse and aging under such extreme conditions. Designs comply with GJB 3758‑99, GJB 1027A‑2005 and GJB 2439A‑2006 while satisfying long‑life maintenance‑free deep‑space requirements. This full‑process methodology covers wide‑temperature topology, extreme thermal adaptation, full‑range performance compensation, impact protection, extraterrestrial environmental resistance and in‑orbit reliability, applicable to lunar, Martian and asteroid landers and providing standardized domestic design guidelines. Adopting modular graded power distribution + wide‑input dual‑loop control + full‑temperature redundancy, combined with ultra‑wide‑temperature components and integrated thermal management, it overcomes traditional limitations and ensures stable startup, continuous operation and high precision from −180 ℃ to +150 ℃. Five core design principles are defined: 1.Modular graded topology divides the system into main high‑voltage conversion, dedicated payload modules, ignition pulse power and emergency backup units with independent sealing and thermal control. The two‑stage dual‑switch forward + LLC resonant main architecture supports extreme bus fluctuation (30%–200% nominal input). The front stage realizes ultra‑wide pre‑regulation; the rear stage provides isolated high‑efficiency soft switching to minimize temperature‑related losses. 2.Ultra‑wide‑temperature component selection employs military/aerospace devices rated −196 ℃ to +175 ℃. SiC MOSFETs and SiC Schottky diodes ensure stable high/low‑temperature performance without freezing drift. Film/ceramic capacitors eliminate electrolyte failure at cryogenic temperatures; precision metal‑foil resistors maintain tight tolerance (≤5 ppm/℃). All components undergo thermal cycling, vacuum and vibration screening to eliminate early failure risks. 3.Integrated active/passive thermal control uses multi‑layer insulation to isolate extreme radiation; high‑conductivity substrates and heat pipes homogenize temperature distribution. Thin‑film heaters activate below −40 ℃ to maintain core device temperatures within −55 ℃ to +125 ℃, guaranteeing reliable cold startup and minimal parameter drift. 4.Impact and dust protection adopts monolithic reinforced aluminum housings with shock absorbers surviving >5,000 g impact. Heavy components are thermally conductive potted; sealed IP68 full metal welding prevents charged lunar/Martian dust ingress causing high‑voltage short circuits. Internal nitrogen micro‑positive pressure enhances vacuum insulation and suppresses corona discharge. 5.Fully digital adaptive control uses radiation‑hardened DSP+FPGA with real‑time temperature sensing networks to dynamically adjust frequency, dead time, PID loops and protection thresholds across the full temperature range, achieving ±0.5% output accuracy and ≥92% efficiency while supporting preheat‑free ultra‑cold startup. Full‑range temperature adaptive optimization ensures stable performance under extreme thermal conditions: Cryogenic startup optimization integrates low‑power auxiliary oscillators for pre‑powering, staged soft startup with low frequency/duty cycle for gentle device warm‑up, and temperature‑adaptive protection thresholds to avoid false tripping during cold activation. Real‑time parameter compensation establishes comprehensive component thermal drift models via full‑range characterization; embedded algorithms dynamically correct switching parameters, reference voltage and loop gain to maintain stability and precision across temperatures. Wide‑temperature magnetic design adopts low drift nanocrystalline cores with magnetization variation ≤20% from −180 ℃ to +150 ℃. Flux density is heavily derated below 30% saturation to prevent low‑temperature magnetic saturation; localized thermal insulation stabilizes core operating temperature. Temperature‑range loss optimization maintains full ZVS/ZCS soft switching; SiC wide‑bandgap devices minimize thermal drift in conduction/switching losses; optimized stacked busbar layouts reduce parasitic inductance and high‑current thermal stress with thick copper PCBs enhancing heat spreading. Extraterrestrial environmental durability and long‑term reliability ensure decades of maintenance‑free operation: Dust/vacuum resistance employs fully welded hermetic sealing, sintered glass connectors and anti‑static dustproof coatings; rounded high‑voltage structures eliminate electric field concentration and tip discharge. Radiation hardening implements component screening, triple modular redundancy for control logic and localized heavy shielding against high‑energy particles, meeting ≥100 krad(Si) total dose and ≥80 MeV·cm²/mg single‑event tolerance. Full redundancy adopts dual hot backup for main converters, N+1 redundancy for critical payload channels and fully isolated emergency power to guarantee core survival during severe failure with millisecond‑level seamless switching. Autonomous health monitoring collects full real‑time telemetry with intelligent fault diagnosis, isolation, redundancy switching and self‑recovery, ensuring mission continuity without ground intervention. In summary, this integrated framework resolves critical weaknesses of conventional power supplies in ultra‑wide‑temperature environments, cold startup difficulty and insufficient long‑term durability. Ultra‑wide‑temperature hardware enables reliable preheat‑free operation at −180 ℃; dynamic thermal compensation maintains precision within ±0.5%; full sealing and redundancy ensure enduring survival on lunar and Martian surfaces. It delivers essential domestic technical support for future extraterrestrial landing exploration programs.