Thin-film thermo-optical coatings for spacecraft applications

Thin-film thermo-optical coatings for spacecraft applications

Solar influence is by far the most important form of environmental influence on human activities in space. In particular, electromagnetic solar radiation has a crucial impact on the thermal balance of a spacecraft. Passive Thermo-Optical (T.O) elements must be applied to the external surfaces directly exposed to the sun, to protect the system and prevent overheating of structures and of sensitive electronic instrumentation.

C.R.E.O. has developed a thermal coating called ‘Interferential CERMET’, with state of the art  thermo-optical performances and extreme durability against UV rays, ionized particles, and high temperature thermal cycling. Interferential CERMETs are  based on thin-films technology and work as first surface coatings. As such, in principle they are suitable to be applied to any substrate material and on all the external surfaces of spacecrafts.

The C.R.E.O. thermo-optical coatings with low alpha and high epsilon are:

  • based on thin-films technology (industrially technique for large surfaces);
  • applicable directly on spacecraft external surfaces;
  • applicable on any smooth substrate material (including metal and polymeric films) with no degradation of performances;
  • chemically inert.


Thermo-optical coating as MLI  
  • Thickness: < 12 microns
  • Tolerance: < 0.5 micron
  • Surface Finish: depending on substrate


Radiation Resistance

Thermal Response
Tape test – Adhesion >4B UV/VUV exposure (8800 ESH@693 K) Thermal shock: from 653 Kto 77 K in 5 sec
Withstands cleaning withsoft tissue and mostcommon solvent (acetone,IPA, toluene,etc…) Electron, low and highprotons Repeated cycles from RT to783 K (air-vacuum-nitrogen)


Solar absorbance α <0.15
IR Emittance ε >0.80 @RT;  >0.90 @600 K
Density < 10-2 gr/cm2
Sheet Resistance * ∈[104,107] Ω/⎕

*Easily tunable.


  • Alpha (α): between 250 and 2500nm
  • Emittance (ε): between 2 and 27 microns
  • Sheet Resistance: measured with four-points probe

© 2012 - Consorzio C.R.E.O. Centro Ricerche Elettro-Ottiche
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