Historical Photo of the Month - March 2006

Theodolite
Photograph Number P-1456C

This photo was taken at the Goldstone Tracking Station receiving site in August 1960, when the Project Echo satellite balloon was being tracked. It shows a theodolite, or electronic optical tracking system, which was manufactured by the Contraves company.

When a spacecraft was launched, its position was recorded and the information transmitted to the nearest tracking station in the network. As Earth rotated and the spacecraft rose above the horizon, a high degree of accuracy was necessary to acquire the signal within a fraction of a degree of its expected location. The theodolite was part of the optical telescope evaluation system. It tracked a spacecraft as soon as it could be viewed above the horizon and recorded telemetry data on 35mm film. The reduced data, along with data from other instruments, were used to evaluate the accuracy of the large antenna.

Related Photos: A Contraves theodolite can be seen in a 1959 photo of the Goldstone transmitting antenna.

Archival Sources: History Collection documents 3-1028 and 3-1040, and JPL Publication 30-9. For information about the history of JPL, contact the JPL Archives.

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