Transistor Museum Oral History George Ludwig Explorer I Transistors Page 13

A Transistor Museum Interview

with Dr. George Ludwig

The First Transistors in Space - Personal Reflections by the Designer of the Cosmic Ray Instrumentation Package for the Explorer I Satellite

Oral History – George Ludwig

(Continued)

You understand that when we got those, there was a lot of selection done. We ran them through temperature extremes in a temperature oven individually, and hand-picked every transistor. We certainly would not have gotten the reliable operation without doing that.

Were there any transistor failures with Explorer I?

No failures in orbit. Now, of course, we did have some failures during testing. We ran tests of two general types. One was what we called engineering prototype tests, and the other was flight acceptance tests. The general philosophy was that in the engineering prototype tests, we over-stressed (that is, we took them to temperature extremes and vibration levels and shock levels quite a bit beyond what we expected) to make sure that we weren’t operating right on the threshold of serious problems.

We never overstressed the flight components. We carried the flight components to expected flight environmental levels. The primary purpose of that was to detect any incipient failures. Tests were made on individual components, and then on assemblies, and finally on the complete satellite payloads.

Were you directing the development of the electronics System in the Explorer I program?

Oral History – George Ludwig

(Continued)

I was in charge of the pre-Sputnik era Vanguard instrument development, pure and simple. As I mentioned, some of those portions, such as the transmitter, receiver, and high voltage power supply, were designed by others. But I worked out all the other circuits, the system design, and integrated the whole package.

Now when Sputnik was launched, and the Army got permission to go ahead with Jupiter C as a launch vehicle, then JPL took over responsibility for the satellite. I made a very hasty move from Iowa City out to Pasadena, to be there to help with the adaptation of my instruments to the new configuration and oversee the scientific aspects of the work.

This was an absolutely wild time. I went out there on about a week’s notice, with my family (my wife was about six months pregnant at the time). We had to close up our house in Iowa City, dash out there – it was all "hush-hush" – it was classified "Secret." I couldn’t even tell my professors when I pulled out of their classes, why I was going out there. This was in the early winter of 1957/58. I was working on my early graduate studies. I had received my bachelor’s degree in February 1956, just about the time I started working on the satellite.

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