​ Phase 1 of a very large purpose-built environmental test building, hereinafter known as R100, is complete. This is a new and innovative addition to the Harwell Oxford Campus Space Gateway, accommodating a co-ordinated set of space facilities, supported by world-leading integration and calibration teams. R100 will have two 5m diameter large vacuum chamber suites and a number of smaller TVAC chambers.

​In order to ensure the correct and long-term operation of instrumentation destined for space it is essential it is functionally tested in space-like conditions on the ground. This is achieved by thermal vacuum testing, whereby the vacuum is created either using turbo-molecular or cryo-pumps to simulate the conditions found in space and the temperature of the test item is varied through its operating range to ensure functionality. This is done by heating and cooling either radiatively using a thermal shroud, or conductively using thermal straps to link the test item to a thermal control plate. These facilities also lend themselves to thermal balance testing where the test item is surrounded by a number of thermally controlled plates which are allowed to stabilise whilst the temperature at several points within the test item are monitored for comparison with its thermal mathematical model.​​