◆ SpookStack

Traditionally, a value of B = 1,000 has been used by the 45 SW/SE in ship-hit calculations, and by RTI in performing launch-area risk analyses for the 45 SW/SE. Using this value. of B, for each vehicle values of A were found that produced a good match between simulated and theoretical data. The results for qa = 5,000, 10,000, and 20,000 deg-lb/ft2 are given in Table 31. As discussed earlier in the report, no single value of A could be found that produced a good fit over the entire 180° sector, although with one exception a good match did exist in the uprange portion of the sector from about ±90° to ±180°. For launches from Cape Canaveral, most population centers are located in this uprange sector. For any launch-area population centers located in the downrange sector, the risks are almost surely dominated by the Mode-4 failure response. Table 31. Summary of A Values for B = 1,000 Flight TB Breakup qa (deg-lb/ft2) Vehicle Phase (sec) 5,000 10,000 20,000 Atlas HAS 0-2 280 3.45 3.20 2.75 Delta-GEM 0-1 270 4.30 3.10 2.90 Titan IV 0-1 300 3.50 3.25 2.95 LLVl 0-2 290 2.75 2.70 2.60 Other vehicles --- --- 3.5 3.1 2.8 Other values of B were investigated to find combinations of B and A that provided the best possible data fits over the largest possible portion of the 0° to 180° sector. Although no combinations of A and B could be found that produced good fits for the entire 180° sector, the values shown in Table 32 extended the fit from the uprange direction to within about 40° of the downrange direction. Table 32. Summary of Optimum Mode-5 Shaping Constants Flight TB Breakupqa Vehicle · Phase (sec) (deg-lb/ ft2) B A Atlas 0-2 280 5,000 5,000,000 6.30 Delta 0-1 270 5,000 4 3.50 Titan 0-1 300 5,000 1,000 3.50 LLVl 0-2 290 5,000 1,000 2.75 Launch-area risk calculations were made for Atlas and Delta to ascertain the effects of using radically different values of A and Bin the Mode-5 impact-density function. For example, for a breakup qa of 5,000 deg-lb/ft2, values of A= 3.45 and B = 1,000 from Table 31 and A= 6.30 and B = 5,000,000 from Table 32 were used to determine total Mode-5 launch-area risks for an Atlas HAS launch from Complex 36. The total risks differed by about 10%. (Other results for Atlas HAS are given in Table 21, and for Delta in Table 23.) Other calculations for Atlas and Delta show that the value of B is not 9/10/96 77 RTI