The Nuclear Potato Cannon Part 2

As described in an earlier post (see above) in 1957, the Soviet scientists launched Sputnik from the Baikonur Cosmodrome in what is now Kazakhstan. But was it the first man made object shot into space? Maybe, maybe not.

The nuclear test code named Bernalillo had a nuclear device which was relatively puny, having explosive equivalent of less than a kiloton of high explosive. But, small in nuclear terms is still very large and loosing large amounts of energy has hard-to-predict effects.

Dr. Brownlee said that the the scientists working on Bernalillo were trying to figure out what happens during the few micro-moments of the nuclear explosion. The Los Alamos team was testing the feasibility of underground nuclear testing, as an alternative to spreading radiation in the atmosphere with above ground tests. If underground testing was to suceed, then the experiments had to be designed such that scientists could track what kind of nuclear particles were emitted, how many there were, and where they were going.

The data they needed to collect had to be measured in the first few "shakes" after the detonation. A "shake," Brownlee told me, is a unit of time peculiar to nuclear scientists. It is the amount of time it takes light to travel 10 feet. Since light travels at 186,000 miles per second, that makes a shake about equal to 10 nanoseconds, or 1/100,000,000 of a second. That's a small time interval.

When the device was triggered, the scientists evidently got a bit more than they bargained for. The fissioning core emitted high energy particles of light, called photons. In the first few shakes of time, the photons, (or in the quaint lingo of Los Alamos’ tech community, the "shine"), bombarded the steel pipe lining the well, vaporizing it into superheated iron gas. About one third of a millisecond after detonation, the shockwave of gas, shine, and radiation blasted against the steel cover plate at the top of the well.

Brownlee and team had mounted high speed cameras near the well cover to record the blast effects. What the film showed is this: in one frame the steel cover plate is there. In the next frame, it is gone. Where did the 4-foot diameter, Jersey-cow-sized steel plate go? The area was searched carefully, but wasn't found. In fact, in the 40 plus years since project Bernllilo, no trace of the plate has ever been found, anywhere.

Dr. Brownlee told me about the high speed cameras used to record the test. In the film sequence, the plate was there in one frame of the high speed film, and gone in the next. I'm told that the film ran at 160 frames per second, so obviously the time interval between frames was 1/160 of a second. He also said that the field of view, or the vertical area in view in the camera frame captured an area of roughly about one quarter of a mile. Therefore, I reason that the steel plate traversed an area of one quarter mile in less than 1/160 of a second. That calculates out to a speed of an amazing 41 miles per second.

My understanding of Newtonian physics is that you throw something hard enough and fast enough, you can make it through the gravitational attraction of the earth and break free into outer space. The speed required to break free is what Newton called "escape velocity" and on earth is calculated to be just less than seven miles per second on earth. The Los Alamos plate was propelled by the atomic cannon into the summer sky at a speed of more than five times escape velocity.

So, it looks to me that the Los Alamos nuclear potato cannon won the space race. At least, that’s my theory. I’m not stuck on it, but I’ll stand by it until somebody proves (not speculates) otherwise.