Abstract: A curable coating composition comprising: (a) a silicate, such as sodium silicate, potassium silicate or lithium silicate; (b) a phosphate, such calcium phosphate, magnesium phosphate or sodium phosphate; and (c) a metal oxide, such as magnesium oxide, aluminium (III) oxide, scandium (III) oxide, yttrium (III) oxide, or zirconium oxide. Such curable coating compositions may be used as non-thermochromic (tailored based on expected operating environment) thermal control coating compositions for application to spacecraft and components thereof. As an alternative metal oxide component, for use in lower temperature applications, or in applications for which thermochromism at elevated temperatures is not a concern, the metal oxide may comprise zinc oxide. Also provided is a curable coating composition comprising: (a) a silicate (e.g. as above); (b) a phosphate (e.g. as above); and (c) a metal sulphate, such as a barium sulphate.