Spacecraft Eclipse Thermal Cycling

Every satellite in low Earth orbit passes through direct sunlight and Earth's shadow roughly every 90 minutes, and each crossing drives its skin temperature through a swing that can span hundreds of degrees. This simulator models that cycle with a real lumped thermal-capacitance energy balance — solar flux, Earth albedo, Earth infrared and radiative loss to space — while a 3D scene shows the spacecraft orbiting a shaded Earth with the sun vector and eclipse cone drawn to scale. Tune the orbit altitude, the coating's absorptivity-to-emissivity ratio, the spacecraft's thermal mass and the sun/orbit beta angle to see how thermal engineers choose a coating and orbit geometry to keep hardware inside its survival temperature range.