The first ground experimental nuclear rocket engine (XE) asembly, (left), in 'cold flow' configuration, arrives at Engine Test Stand No 1 at the Nuclear Rocket Development Station. Cold flow experiments use an asembly identical to that used in power tests, but contain no fisionable material nor produce a nuclear reaction, so no fision power is generated. The aluminum cylindrical closure (right) forms an airtight compartment, permitting testing in a simulated space environment. The 'cold flow' experimental engine underwent a series of tests to verify that the initial test stand was ready for 'hot' engine testing, to investigate engine start-up under simulated altitude conditions, and to check operation procedures not previously demonstrated.
© National Aeronautics & Space Administration / Science & Society