HDRSS- A High Data Rate Storage System for Nimbus B

The high data rate storage system ( HDRSS) is being developed to provide storage and reproduction of data aboard the NIMBUS B Satellite. The system uses a 5-channel 2-speed tape recorder and a 5-channel frequency division multiplexer. The system is tested using a bench checkout unit, which simulates spacecraft signals and ground station processing functions. The high data rate storage system ( HDRSS) (Fig. 1) is being developed by RCA for NASA to provide storage and replay of sensor data aboard the NIMBUS B satellite. NIMBUS B is the third satellite to date in the NIMBUS series. The NIMBUS program involves stabilized, experimental meteorological satellites designed to circle the earth in a 600-nmi, near -polar, sunsynchronous orbit with an orbital period of approximately 107 minutes. The NIMBUS television and infrared sensors provide complete coverage of every point on the earth\u27s surface once in daylight and once in darkness every 24 hours. During each orbital revolution, continuous infrared mappings and 31 single-frame television photographs are made. On NIMBUS I, orbital coverage photographs were obtained using a rapid-readout ( 6. 4 seconds) automatic vidicon camera system (AVCS) and a tape re corder with a 1:1 record-playback speed ratio, re sulting in a video bandwidth of 60 kHz for an 800-line picture. This bandwidth, suitable for transmission to the ~o high-gain command and data acquisition ( CDA) ground stations, is too large for the smaller weather stations provided around the world for use with TIROS automatic picture transmission (APT) satellites. The APT camera readout time is 208 seconds, resulting in a video bandwidth of 1. 6 kHz