A Case Study in NASA-DoD - The Black Vault

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orbit-adjust module, while the SAGE configuration includes a second
momentam wheel and a tape recorder.
F r Air Force use, the SAGE configuration was selected as being
most appropriate. The only modifications that were considered relate
to the conversion of the communication system to make it SGLS-compatible.
These changes are itemized below and discussed in detail in Appendix C.
Basically, the changes involve replacing some of the AEM communication
,0 equipment with the appropriate STPSS communication equipment.
o Replace S-band transmitter with STPSS S-band (SGLS) transmitter.
o Replace S-band transponder with STPSS S-band (SGLS) transponder.
o Replace command demodulator with STPSS dual signal conditioner.
o Modify pulse code modulation (PCM) encoder for dual baseband.
o Modify command decoder/processor.
Although the power system of the AEM is very limited ("'50 W),
no changes were made in this system for Air Force use. Also, the nonredundant
design of the AEM was unaltered. In addition, the current
AEM design does not allow for the use of encryption equipment--this
was not changed because it is not a requirement for all Air Force
missions considered in this study.
STPSS
Each of the three available STPSS configurations (summarized in
Table 2) consists of a core and an orientation module (or a spin-control
module in the STPSS-S case). In addition, a variety of mission-specific
equipment is available for each configuration. The core module is the
same in all cases. The orientation or spin module determines the attitude
stability and pointing accuracy of the spacecraft. The configurations
used in this study are those identified by TRW in their study.( I )