October 14-15, 2000: Thornton, NH test facility

   Nevertheless, setup still takes more than half a day. The cinder-block housing needs to be cleaned out and the roof removed. The electronics board, kerosene tank structure, and the liquid oxygen (LOX) tank structure, and test stand/engine all need to be removed from the trailer and "unpacked" from shipping. The electronics, kero, and LOX all need to be hung on the outside of the housing and strapped down, and the test stand needs to be positioned inside the housing and attached firmly to the walls. Then the plumbing needs to be run to the proper connections, and the wiring connected. The gas tanks need to be brought down into the field and strapped against the housing. We have a "sound wall" that gets set up directly in front of the test stand to minimize the sound heard at nearby houses. The sound wall consists of fiberglass insulation on plywood, and needs to be attached to a Dexion structure and secured so that the wind does not knock it down.

   The liquid nitrogen and liquid oxygen are in tanks kept up the nearby hill, about 100 feet away. Insulated tubing needs to be hooked to these and run down to the test stand (through some poison ivy). A waterhose (for wetting the entire area during hot fire tests) needs to be run from the house (200+ feet away). Electronic wiring to the control computer, as well as video feeds to the monitoring TVs all need to be run from the house, connected, and checked. The camcorders need to be set up (one is on the inside wall of the housing, just above the test stand; the other is on a tripod, aimed horizontally at the test stand and about 15 feet away) and connected. This was also the first time that we had a high-speed camera, borrowed from the MIT Edgerton Center. This would allow us to shoot at up to 1000 frames per second, and would prove to be extremely useful.

   Once this is all done, it all needs to be tested. The electronic controls and sensors all need to be tested for secure connections and proper wiring. The plumbing needs to be tested for leaks and proper insulation. Weight sensors on the kero and LOX tanks need to be calibrated; they are used to determine the amount of liquid in the tanks. Then gases and liquids are flowed through the system to make sure it all works.

   The high-speed camera also needed to be tested and calibrated. Because it fires at such a high rate, there is very little light available for each frame. Therefore the area needs to be illuminated as well as possible, and the camera needs to be calibrated under conditions as close to the expected firing conditions as possible.

   We performed some liquid nitrogen (in place of LOX) pumping tests to determine how the plumbing was cooling down. It was decided that on Sunday morning we would re-plumb the LOX dump line in order to eliminate some back-flow we were getting due to the cryogenic fluids hitting hot spots and turning gaseous. After a few more tests and modifications, we were ready to do the final spin test. We had run out of liquid nitrogen, and so we ran the final spin test, #1066, with LOX. The spin rate had some confusing bumps in it, but we pushed on for a hot firing - test #1067. The sequence for #1067 was adjusted slightly based on the data from #1066.

   Mission control (the sitting room with the TV monitors and computer system) was tense as we ran through all of the checklists. We began the startup sequence, consisting of pumping LOX through the system in order to cool down the channel most of the way to the combustion chamber. Final countdown began.

   5...4...3...2...1...Fire! But did we get ignition? There was a burst of clouds, but it didn't look like we'd had any combustion. Kerosene was leaking profusely out the bottom of the combustion chamber. After the successful 0.33 seconds firing of six weeks earlier, this seemed to be quite a let-down. The high-speed camera proved to be extremely useful, though. It showed that we'd had about 10 milliseconds (0.01 seconds) of shock diamonds — i.e., combustion. Post-test data analysis suggest that (for reasons unknown at the time of this writing) the fuel mixture was extremely fuel-rich. In other words, we'd flooded the combustion chamber with too much kerosene for the amount of oxygen present.