A Case Study in NASA-DoD - The Black Vault

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necessary to scale this number up by a factor of 2.48 to yield a
closer approximation of the complete program. Consequently, both the
numbers of payloads and their aggregated weights taken from Tables H-2
to H-5 were multiplied by 2.48 in developing the program options.
Other numbers of total payloads in the ten-year period, 92, 138, and
228, were assumed in some of the cases to test the effect on results.
As above, appropriate multiplying factors were used.
Groups of payloads (for a given orbit) were assigned to specific
spacecraft with the following limits being observed:
1. Maximum payload weights that can be loaded on a single spacecraft:
AEM - 150 ib; STPSS - 1000 lb or 1500 lb; MMS
4000 lb.
2. Maximum circular orbital altitudes reachable by the spacecraft:
AEM(x) - 1000 n mi; AEM(y) - 19,372 n ml; STPSS and
MS - 19,372 n mi.
3. The maximum number of payloads that can be loaded on a single
spacecraft in separate program options was assumed to be 6,
8, 10, or 13.
4. Maximum experimental power: AEM - 50 W; STPSS-S - 290 W;
STPSS-LC and STPSS-P - 400 W; MS - 850 W.
5. Maximum data rate: AEM - 8 kbps; STPSS - 128 kbps; MKS
= 64 kbps.
The number of spacecraft flights for six different cases, four
different program options, and four different assumed upper limits on
the number of payloads that could be placed on a single spacecraft are
summarized in Table H-6. As may be seen from Table H-6, the total
number of shuttle flights required to place all of the STPSS payloads
into orbit ranged from a minimum of 12 to a maximum of 26.
The ranges
in numbers of launches, as a function of the assumed payload limitations,
are shown below:
,
The power limitation affected only the payload packages for the
AEM and STPSS-S spacecraft; for all others, different limitations were
more critical.