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This final report, dated September 10, 1996, was prepared by the Research Triangle Institute for the Department of the Air Force's 45th and 30th Space Wing safety offices. Titled Modeling Unlikely Space-Booster Failures in Risk Calculations, it shows how rare Mode-5 failures, in which a rocket veers well off its intended flight line, are modeled in the DAMP risk-analysis program. An appendix lists Atlas, Delta, Titan and Thor launch and failure histories through August 1996.
From the source:Release of 2026-05-08 Incident: 9/10/96, N/A. This report describes the Modeling of Unlikely Space-Booster Failures in Risk Calculations, documenting historical launch failure modes and recommending corrective actions to address them using novel modelling techniques.
“Mission Control”17 pages
6.3.2 Launch-Area Mode-5 Risks Using values of A and B from Figure 24 and Figure 25, program DAMP was run to compute Mode-5 launch-area risks for population centers inside the impact limit lines for a Delta-GEM/GPS-10 daytime launch from Pad 17A. Results from these and two other cases are shown in Table 23. The Mode-5 Ee in the first line (old baseline case) is presented for comparison. It was obtained from the first line of Table 55 of an- earlier RTI study31• In that study, the total Delta failure probability during the first 130 seconds of flight was set at 0.02, with the probability of a Mode-5 response assumed to be 0.0025. The second line in Table 23 shows the result of a recomputation of the Mode- s risks, again with B =1,000 and A =3, using failure probabilities derived earlier in this report. From Table 6 and Table 15, the failure probability during flight phases O- 2 is 0.013, and the relative frequency of occurrence of a Mode-5 response is 0.08. The absolute probability of a Mode-5 response thus becomes 0.013 x 0.08 =0.001. Table 23. Shaping Constants and Related Risks for Delta-GEM TB Breakupqa Mode-5 Ee Ps (sec) (deg-lb/ft2) B A (x 104,) 0.0025 130 12,000 * 1,000 3.00 394 (baseline) 0.001 270 12,000 * 1,000 3.00 88.8 (newp,&T,.) 0.001 270 none 1,000 1.90 220.0 20,000 2.90 104.4 10,000 3.10 74.1 5,000 4.30 5.2 0.001 270 none 10,000 2.60 224.4 20,000 2,000 3.15 102.4 10,000 2,000 3.35 72.0 5,000 4 3.50 5.1 * Interpolated from data contained in Figure 24 As in the case of Atlas, Table 23 again shows that the risks in the launch area are highly dependent on qa and thus on A, but relatively insensitive to changes in B if a proper value is selected for A. For example, if qa. =10,000, the computed risks for B =1,000 (A= 3.10) and B = 2,000 (A= 3.35) differ by-less than 3%. For the no-breakup cases where B = 1,000 and then 10,000, the computed risks in the launch area differ by less than2%. Launch-area risks are highly dependent on the vehicle's capability to withstand aerodynamic forces. Except early in flight, low-strength vehicles generally break up quickly after a malfunction turn begins. The later such turns occur, the more likely pieces are to impact downrange of the launch point, thus lessening risks to uprange populations. The effects of vehicle strength on risk are clearly seen in Table 23 where, 9/10/96 64 RT!
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Report, from the pursue collection. The PDF is mirrored here; the original link is under it. 181 pages are in the text index: search them above, or from the library's search.