Because of the uncertainties in breakup conditions, the values of A for each B in Table
20 have been plotted against qa in Figure 14. By reading from the plots, a value of A
for the five values of B can be obtained for any breakup qa. deemed appropriate
between 5,000 and 20,000 deg-lb/ft2.

                   6.5
                                                        r················..l.B = 5,000,000
                   6.0
                                ____ __ L                                       _ I_ ---------------r----------------i _______ __
                   5.5
                                                        I               ----.l._B = 500,000                                                 :
           <C
           .....   5.0 .........................l.. .....................1..·--............t---......................1..........................
            C
                                                        i ................ is= 1oo,odo                                      ···-----➔
           -fflC
            0
           (.)
                   4.5 --- --- r- --_-_                                     -r-:-:-~-t-----__
                                                                                   13 = 50,000 !
                                                                                                                                         J-------

           ~ 4.0
           "'C
                                                        !                                                               - - -               !
                                ·························!····························'························-··i·························i····••···················
            0
           :l:?
                   3.5
                                                       I•
                                                                                   I                           I                           I
                                                                          • • • • • • • • • • i • H • - - - ~ i H H - - •.. ••••i••••u. . •••••uu•u••••••




                                                                                    !B = 1,000                 I                            I
                   3.0                                                              i                           i                           i
                               ~~;·::··;·;;;·························I······················· ·····························:·················· ••••••

                   2.5
                           0                     5000                      10000                       15000                       20000                       25000
                                                            Breakup q-alpha (deg-lb/ft2)
                   Figure 14. Effects of Breakup q-alpha on A for Atlas HAS

6.2.2 Launch-Area Mode-5 Risks
The twenty sets of A and B shown in Table 20 were used to compute Mode-5 launch-
area risks for population centers inside the impact limit lines for an Atlas HAS daytime
launch of a Telstar-4 payload from Pad 36A. Results of these and two other cases are
given in Table 21. The Mode-5 Ee in the first line (old baseline case) of Table 21 is
presented for comparison only. It was obtained from data in the first line of Table 45 of
an earlier RTI study 131 . In Ref. [3], the total Atlas IIAS failure probability for the first
two minutes of flight was set at 0.04, with the probability of a Mode-5 failure response
assumed to be 0.005. The second line in Table 21 shows the result of a recomputation of
the Mode-5 baseline risks, again with B = 1000 and A= 3, using newly derived values
for the total failure probability and for a Mode-5 failure response. For flight phases 0 -
 2, a total failure probability of 0.031 was assumed, as extracted from Table 6 for


9/10/96                                                                                 49                                                                               RTI