Automatic Picture Transmission TV Camera System for Meteorological Satellites

Nimbus, the second generation meteorological satellite succeeding its successful forerunner, Tiros, is a stabilized platform designed to provide global coverage of earth's cloud cover and a space platform for future atmospheric research. A three-camera TV system operating during daylight and an infrared scanner during the night store the cloud data on magnetic tape for later command readout. — This paper describes an additional camera system, designed for automatic continuous real-time picture transmission during daylight. Although it is planned for trial on a Tiros satellite in a time-restricted mode, its operation on Nimbus later will be continuous during daylight. — The camera makes use of an electrostatic storage vidicon which is exposed for 40 msec, and read out during the succeeding 200 sec. The 800-line resolution and the 0.25-sec scanning time per line are compatible with standard 240-rpm facsimile equipment which can be used for ground display. Full compatibility is achieved by amplitude modulation of a 2,400-cps subcarrier and by transmitting a turn-on and phasing signal during 8 sec preceding the actual picture transmission. The subsystem is independent of the spacecraft except for power and a frequency reference. A 5-w transmitter broadcasts the signal in the 136-mc space telemetry band. FM is used, making a large variety of standard mobile communication equipment readily adaptable. — The value of the system lies in its simplicity both in the spacecraft and on the ground. No command links are required, nor storage. On the ground, a manually tracked or even fixed 10-db helix antenna, with commercially available receiver and facsimile, is all the equipment that is required.

Print ISSN

0361-4573

Published

1964-02

Content type

Original Research

DOI

10.5594/J06121