(Yes, yes, I ran this artwork a year ago. But I’m running it again, this time with more verbage & photos.)
A cutaway illustration of the KIWI-A nuclear rocket test unit. As shown here it is actually upside down compared to how it was tested; as with I believe all the other nuclear rockets that were tested, the nozzle fired upwards towards the sky. This rocket engine was not meant to represent a flight-capable system, rather just a basic proof of concept. And thus it was named after a flightless bird. Note that the hydrogen “propellant” is injected at the nozzle end of the reactor, travels forward through the graphite reflectors, then makes a U-turn and goes through the reactor “plates” that wrapped around a deuterium oxide central moderator. This is not at all like what later, more developed nuclear rockets like NERVA used.
Note that test firings on the KIWI system began in *1959.* That’s 55 years ago when we had the functional start of nuclear rocketry. Today we have… Powerpoint.
A photo of the test setup. The full-rez version is HERE.
KIWI firing. Note orange hydrogen combustion plume. This is not due to combustion within the engine, but due to superheated gaseous hydrogen mixing with the oxygen in the air and burning externally. Full rez HERE.
Probably the most entertaining test must have been the KIWI-TNT (Transient Nuclear Test)test. Here, a KIWI engine was put on a rail car and allowed to go prompt critical, with the result being that the engine blew up with the approximate force of about 100 pounds of TNT. The nuclear fuel was uranium oxide, so it was already oxidized and very likely underwent little to no chemical change; but the graphite reflector was pure carbon. Pure *shattered* carbon. Pure shattered carbon at extremely high temperature. And thus it promptly caught fire int he air and burned, with the result you can see below:
The “sparks” should be chunks of reflector. The fireball would be hydrogen… *if* hydrogen was being pumped through it at the time. I’m not sure that it was, though.