Thermal design and thermal testing of the UK-3 spacecraft

The factors affecting the thermal design of a spacecraft are first discussed in general terms. Attention is then given to the thermal design problems on UK-3, and in particular to the difficulties associated with the gold plateand white paint which had to be used as the main thermal control surfaces. The distribution of the thermal control surfaces finally chosen is given together with the predicted temperatures for the more critical items of equipment. The form of the simulation of space heating conditions provided by the R.A.E. 1/2 metre Space Test Chamber is discussed together with the details of the trials performed on the UK-3 to ensure the accuracy of its thermal design. Finally, a comparison is made between the temperatures predicted and the temperatures measured in orbit: an overall correspondence to better than 5 deg C was obtained.