Exploring the Unknown - NASA's History Office

50
Enc.
[1]
Since Dr. Fisk is out of town, I am enclosing the statement, which has his agreement.
OBJECTIVE
***
Sincerely yours,
E. I. GREEN
Executive Vice President
PROPOSED BELL SYSTEM EXPERIMENT ON
ACTIVE SATELLITE COMMUNICATION
To carry out an experiment in transoceanic communications with a satellite carrying
an active repeater suitable for multichannel telephony and for television. The experiment
is an important part of a continuing Bell System development program directed toward
large scale application of radio satellites for broad-band communications. The program
includes extensive laboratory research and development work leading to long life and reliable
operation of such a system.
SYSTEM CHARACTERISTICS
Proposed Operating Frequencies: 6775-6875 mc [megacycle] ground to satellite.
6425-6525 mc satellite to ground.
Baseband Width: 2 mc.
THE HISTORY OF SATELLITE COMMUNICATIONS
Modulation: FM with ± 10 mc swing.
Transmission Path: Europe to U.S.A. and reverse.
Satellite: Microwave receiver; 2-watt microwave transmitter; circularly polarized reception
and radiation; solar cells for primary power; nickel-cadmium storage battery. Separate
beacon transmitter, 150 milliwatts at about 136 mc for tracking. Satellite essentially spherical,
about 4’ diameter, weight 175 lbs. or less. The initial satellite will not be engineered
primarily for the long life needed for commercial operation. Orbit of satellite should be
as nearly polar as possible, at an altitude of 2,000 to 5,000 miles. (Note: This experiment
is directed particularly toward normal telephone communication in which one way transmission
delay of 1/4 second, such as would be encountered with a 24-hour satellite, would
be intolerable.)
Ground Receiving Station at Holmdel: Existing 20’ x 20’ horn reflector antenna, used
in Echo I. Improved antenna control system. (Construction of a larger 60’ x 60’ horn
reflector antenna is to be started immediately, [2] but this may not be in operation until
a few months after the first active satellite experiment.) Maser for operation at 6475 mc.
Wideband FM feedback receiver.