Measurement of Thermal Emittance on Hard Anodized Surface for Spacecraft Thermal Control

Measurement of thermal emittance of hardanodized coating on aluminium sample at different temperatures from −80°C to +100°C has been made using steady state calorimetric method.

The measurement sample consists of two aluminium circular discs hardanodized on all surfaces except on assembly contact areas. A thin circular heater was sandwiched between the discs. The assembled sample was suspended inside a vacuum chamber with LN₂ cooled shroud and maintained at different temperature levels using electrical power. The thermal emittance of the sample is determined from the sample equilibrium temperatures and from the elect rical power input.

An error estimation has been performed, it shows a maximum uncertainty of ±3.3% on the emittance.