VO₂-based switchable radiator for spacecraft thermal control

Area of Science:

• Materials Science
• Aerospace Engineering
• Thermal Engineering

Background:

• Spacecraft thermal control systems require efficient methods for managing internal temperatures.
• Passive radiative cooling is a desirable technology for its low power consumption and reliability.
• Dynamic control over radiative properties can enhance thermal management capabilities.

Purpose of the Study:

• To investigate the performance of a solid-state passive switchable radiator for spacecraft thermal control.
• To measure the radiative properties and cooling power of a vanadium dioxide (VO2) thin film based resonant absorber.
• To present theoretical and experimental data for radiator performance and VO2 optical properties.

Main Methods:

• Direct calorimetric measurements were conducted in a simulated space environment.
• The radiator utilized a multilayer VO2 thin film exhibiting thermochromic phase change for dynamic emissivity control.
• Infrared spectroscopic ellipsometry was employed to determine the optical properties of VO2.

Main Results:

• A significant radiated power difference of 480 W/m² was measured between 300 K and 373 K.
• This power difference corresponded to a 7x variation in radiative cooling power.
• Theoretical and experimental radiator values (normal and hemispherical) were obtained.

Conclusions:

• The developed solid-state passive switchable radiator shows promise for effective spacecraft thermal control.
• Dynamic emissivity control via VO2 phase change offers a substantial improvement in radiative cooling.
• The study provides valuable data on VO2 optical properties and radiator performance for future applications.