Transformation Into STADAN
As satellites grew bigger and more sophisticated, there were a number of problems that Minitrack could not handle well, and some capabilities that were not needed. These included:
- Satellites in polar orbits. This required new sites to track.
- Satellites in synchronous orbits. These have bearings that change slowly (or can be completely stationary). This makes angle tracking much less useful. What is needed in this case, especially for maneuvers of such satellites, is range and range rate. Minitrack could not make these measurements. A very similar situation exists for satellites are near apogee in eccentric orbits.
- A need for much larger data return bandwidths, and hence larger antennas. Nimbus was the first satellite that stressed this issue, as it began to return pictures rather than just basic telemetry.
- More, and more automated, telemetry and command facilities, as the number of satellites, and their sophistication, increased.
- Much less need for blind tracking. As the launch ranges improved their tracking, good orbital elements were available before the missile even left the range.
To meet these new needs, a number of fundamental changes were made to the Minitrack network.
- Site changes, closures, and additions.
- Adding larger 12 meter and 26 meter dishes at some sites.
- Adding the Goddard Range and Range Rate tracking equipment (GRARR).
- Adding new automatic tracking telemetry and command antennas (SATAN).
- Larger and more automated ground communication links between stations.
The resulting network was called the Spacecraft Tracking and Data Acquisition Network, or STADAN.
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