A Case Study in NASA-DoD - The Black Vault

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1980-1990 time period are divided into three payload groups (Table 4).
The principal distinguishing feature of each group is the spacecraft
requirements. For example, payloads in groups I and III all require
a spacecraft with nominal capability and either three-axis or spin
stabilization. We have taken this to mean that these missions could
be flown on the AEM, STPSS-S, STPSS-LC, L-AEM-S, or L-AEM-BL spacecraft.
Those payloads in group II require a spacecraft with a high
capability and three-axis stability. This requirement can only be met
by the STPSS-P, L-AEM-P, or MIS.
Of the estimated twenty flights to be flown between 1980 and 1990,
the Work Statement indicated that about 75 percent (15 flights) would
be in payload group I, 10 percent (2 flights) in payload group III,
and 15 percent (3 flights) in payload group II. Using the estimated
division between large (over 150 lb) and small payloads given in the
Work Statement for each of the payload groups, we can presume a total
of 114 payloads for the nominal case or about 6 payloads per spacecraft.
As mentioned previously, Ref. 26 provided a listing of only 52
Space Test Program payloads that were to be considered as representative
of those that would be flown between 1980 and 1990. These payloads
were analyzed in terms of their spacecraft requirements for accuracy,
stabilization, and weight. The results of that analysis are shown on
the right-hand side of Table 4 to allow direct comparison with the
guidance given in the Work Statement for this study.
We found that the overall division of payloads between group II
and groups I and III was a little different from that suggested by
the Work Statement, i.e., only 11 percent, rather than 15 percent, of
the payloads fell into payload group II. We also found that the percentage
of small payloads in groups I and III was larger, i.e., 90
percent, rather than 85 percent. Appropriate adjustments for these
relatively minor mismatches caused an increase in the total number of
Space Test Program payloads from 114 to 151, which is equivalent to
For this reason, group II is distinguished from groups I and
III in the discussion that follows.