A Case Study in NASA-DoD - The Black Vault

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Appendix E
REACTION CONTROL/PROPULSION SUBSYSTEM:
A COMPARISON OF AEM, STPSS, AND MMS
by
J. R. Hiland
Comparative technical evaluations were made for the reaction
control/propulsion subsystems contained in the three basic spacecraft
designs discussed in this study. There are two versions of the AEM
spacecraft:
configurations:
HCMM and SAGE. The STPSS designs encompass three basic
(1) spin stabilized, (2) three-axis stabilized (lowcost),
and (3) three-axis stabilized (precision). The MMS spacecraft
is a single three-axis stabilized design that can employ several subsystem
options within this basic categorization.
The reaction control/propulsion subsystems discussed herein use
either cold gas (GN 2 ) or hydrazine (N 2 H 4 ) as the propellant and perform
functions such as spacecraft stabilization, reaction wheel unloading,
orbit adjustment, and orbit transfer.
Solid propellant rocket
motors, which in some cases are also used for stabilization and orbit
,
transfer, are considered separately and not included in this discussion.
Cold gas and hydrazine RCSs consist, essentially, of the same basic
components, i.e., tank(s), fill and drain valves, isolation valves,
pressure regulator and/or transducer, filters, thrusters, plumbing,
and, in cases where the RCS is a separate module, some mounting structure
and electrical harness.
In this analysis, when the RCS is a
secondary subsystem to a particular spacecraft module (usually orientation
or attitude control system), the structure and harness is assumed
accountable to the primary subsystem. The primary difference in cold
gas versus hydrazine system components is in their relative complexity
and hence cost.
Other potential differences in degree of technological
development within a given propellant type have essentially been nullified
In this study, the stable of solid rocket motors described in
Ref. 1 were used for the kick stages to provide orbit translation and
circularization.