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)

 

The first thing I did when I got out to JPL was to sit down and put down on paper, in black and white, all the circuit schematics.  I was still working with bits and pieces of notes from my notebooks, and so I had to sit down and draw those out by hand.  JPL then picked up the work.  They set up the fabrication of the electronics.

 

I should mention, by the way, that at the time this happened, I was just finishing the prototype Vanguard unit, as I mentioned earlier.  I carried that out to JPL and handed it to them, and that was used, for one thing, for a fair amount of publicity.  The engineers also had it – they were using it as a physical model and reverse engineering the electronics.  Interestingly enough, I have that particular package, the very one, sitting on my desk here six feet from me.  (It has subsequently been donated to the Smithsonian Air and Space Museum.)

 

 

How long did you continue to work with JPL on the Explorer satellite electronics?

 

For Explorer II, which, as I mentioned, failed to achieve orbit, and then for Explorer III, which got into orbit.  I stayed there until 11 April.

 

 

Oral History – George Ludwig

(Continued)

 

Once the Explorer I data started arriving, our Iowa group found that on a couple of the passes, the instrument seemed to have failed because the counting rate appeared to be zero.  That was a bit of a puzzle.  It was happening primarily over the South America stations.  It was not until we had the data from Explorer III with its onboard tape recorder that things really sorted out.  On Explorer I, of course, we just received data during the 15 minutes or less when the satellite was over a station.  So most of the orbits had no coverage – we just had snapshots.

 

 

So, did you think there was an instrument failure on Explorer I?

 

That was one possibility, but we didn’t harbor that for too long.  Van Allen, Carl Mcllwain, and Ernie Ray, were working on the Explorer I data.  Van Allen and I had a lot of confidence in the instrument, and knew its operating characteristics very well.  Furthermore, our group couldn’t find any correlation of the pattern with anything except orbital position.  It was only near the equator at high altitudes that we saw the effect.

 

 

 

 

Go To Ludwig Oral History, Page 15

 

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