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



Dr. George Ludwig Oral History References


[1] “Cosmic-Ray Instrumentation in the First U.S. Earth Satellite”, George H. Ludwig., The Review of Scientific Instruments, Vol. 30, No. 4, April, 1959.

[This is a “Must-Have” article for those interested in early transistor history.  Excellent coverage of the state of transistor technology available for the first satellites].


[2] U.S. Army Historical Webpage - Explorer Info

[This site contains a wealth of historical information relating to Explorer and Jupiter-C.  Be sure to watch the Army movie “The Big Picture” which captures all the excitement of the January 31, 1958 Explorer I launch].


[3] “Instrumenting the Explorer I Satellite”, Henry Richter et al, Electronics, Feb 6, 1959. 

[An excellent companion article to [1] above.  This article covers the work done at the Naval Research Lab and JPL to develop the transistor transmitters for Explorer].


[4]  University of Iowa – James Van Allen Day 90th Birthday Recognition, 2004.

[This is the premier site for Explorer information, and detailed discussion of Van Allen’s work.  Dr. Ludwig has contributed several articles and multiple photos to this site].


[5] “The Early History of Spacecraft Electronics”, Mark Williamson, IEEE Engineering Science and Education Journal, Vol. 10, Issue 2, April 2001. 

[Useful technical information and photos of Vanguard, Explorer and Sputnik.  Well written].


[6] “Signal Conditioning for Satellite Borne Energetic Charged Particle Experiments”, George H. Ludwig, NASA Technical Note D-1080, August 1961.

[This paper by Dr. Ludwig documents additional transistor circuitry for use in satellite instrumentation intended to measure cosmic rays.  It is interesting to note the progress in transistor technology evident in this 1961 paper, compared with Ludwig’s classic 1959 paper [1], referenced above]. 






Oral History – George Ludwig


These Audio Links are Excerpts from a

June 2004 Interview with Dr. Ludwig.


Learning Electronics in High School and the Air Force 

George Ludwig Audio Clip #1


Starting Work in Van Allen’s Cosmic Ray Lab at the University of Iowa in 1952

George Ludwig Audio Clip #2


Getting the Assignment in 1956 to Design Satellite Electronics

George Ludwig Audio Clip #3


How Were Transistors Used in Vanguard and Explorer Satellite Designs

George Ludwig Audio Clip #4


Discussion of Early Transistor Types Selected for the Explorer I and III

George Ludwig Audio Clip #5





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