Figure 20. Physical layout, flight-similitude system.
This equipment has been used in testing instruments to be flown and also equipment which is used in the launching and preparation before release. For example, the Du Pont S64 squibs, which have been used in conjunction with the flight-termination switches and also for severing launching lines, were tested in this chamber and found to fail when subjected simultaneously to cold temperature (-50 $ ^{\circ} \mathrm{C} $ ) and low pressures (10 millibars) although tests at either low temperature or low pressures alone produced no failures. As a result of these tests, a new squib, the S59, has been produced by Du Pont and is used in current flights. Other equipment which has been tested in the bell jar and the cold chamber includes the Lange barographs and the Olland-cycle pressure-measuring instruments.