On May 7, 1963, the Telstar II satellite was launched into an elliptical
orbit almost twice as large as that of Telstar I, ranging from an apogee
of 6697 miles to a perigee of 604 miles. The new satellite circles the
earth once every 225 minutes. The higher altitude provides Telstar II
with longer periods when it is visible at both Andover and ground
stations in Europe, and keeps it out of the high-radiation regions of
space for a greater part of the time. The satellite itself is much the
same as Telstar I, except for a few minor changes that make its weight
175 rather than 170 pounds. Its radiation measuring devices have a
greater range of sensitivity, and there are six new measurements to be
reported back to earth. Telemetry can now be sent on both the microwave
beacon and, as before, on the 136-megacycle beacon. To help prevent the
kind of damage that occurred in the transistors of Telstar I’s command
decoders, Telstar II uses a different type of transistor, in which the
gases have been removed from the cap enclosures that surround the
transistor elements. A simplified method of operation for the giant
Andover horn antenna is now in operation, with the autotrack alone being
used for precise tracking and pointing. Telstar II’s first successful
television transmission took place on May 7, and a new series of
technical tests, radiation measurements, and experiments in transoceanic
communications has begun.