falcon9 isp
const double STG1ISP0 = 2767;
const double STG1ISPV = 3051;
const double STG1MAINTH0 = 2846000;
th_main[0] = CreateThruster(_V(0, 0, -31), _V(0, 0, 1), 7 * STG1MAINTH0, hProp1, STG1ISPV, STG1ISP0);
be 4 isp is 340 s (3.3 km/s)
const double STG1ISPV = 3300
not sure what this should...