Gemini Press Reference Book

Instrumentation and Recording Systems

Gemini instrumentation and recording systems monitor specific spacecraft systems, conditions, and events, and sense, condition, encode, reproduce, and transmit data to ground stations.

The instrumentation and recording system performs the following:

The instrumentation system has both an operational and a diagnostic function. The system provides real-time telemetry transmission of data generated in the spacecraft and required at ground stations for monitoring the progress of the spacecraft mission, for assessing the spacecraft status, and for making decisions concerning flight safety. In addition, Gemini instrumentation includes the necessary hardware for generating signals, not available through individual spacecraft systems, for operation of the spacecraft cabin displays. In its diagnostic function, the spacecraft instrumentation system provides a means for documentating significant events and data, throughout the entire mission, by three methods: Real-time transmission, delayed transmission, and onboard recording. Electro- Mechanical Research supplies the data acquisition system for Project Gemini.

DATA TRANSMlSSION SYSTEM PROGRAMMER

The data transmission system programmer provides for data multiplexing, analog-to-digital data conversion, and digital-data multiplexing.

The programmer includes a high-level multiplexer, a low-level multiplexer and a delayed transmission recorder/reproducer.

The high-level multiplexer functions as a high-level analog commutator and on-off digital data multiplexer. It provides for the sampling of 32 high-level data channels, 24 bi-level signals and 16 inverted bi-level pulse signals.

The low-level multiplexer functions as a differential-input analog input commutator and provides a sequential sampling of 32 low-level signals. The delayed transmission recorder reproducer records data during the time the spacecraft is in orbit and out of range of worldwide tracking stations. When the spacecraft is within range of a tracking station, the recorder/reproducer is triggered by either a ground signal or by the astronauts, reverses its tape direction, and plays back the recorded data at an accelerated rate.

Photographic recording is accomplished by two cameras, one a 70-millimeter camera for still photography and the second a 16-millimeter movie camera. These cameras will be hand held and operated by the astronauts and will be stored in the cabin when not in use.

Voice recording is accomplished on a tape recorder installed in the center pedestal. Recording will be limited to astronaut conversations and will occur at any time that the mode selection switches on the voice control center are placed in a record position.

Biomedical recorders are installed in the spacecraft and accept and record data from the biomedical instrumentation centers attached to the astronauts.


Copyright 1997, 1998, 1999 by John Duncan
Comments and questions welcome. All photographs contained on these pages are the author's, unless otherwise noted. No unauthorized reproduction without permission.

Last update: March 1, 1999