Calculating Launch Vehicle Flight Performance Reserve

摘要

This paper addresses different methods for determining the amount of extra propellant (flight performance reserve or FPR) that is necessary for a launch vehicle to reach orbit with a high probability of success. Vehicle and environmental uncertainty models are assumed to be available for a launch day goo go decision that in part evaluates whether sufficient propellant is available. One approach for determining FPR involves assuming that the various influential parameters are independent and that the result behaves as a Gaussian. Alternatively, high-fidelity closed-loop Monte Carlo simulation determines the amount of propellant used with each random combination of parameters that are still unknown at the time of launch. Using the results of the Monte Carlo simulation, several methods may be used to calculate the FPR. The final chosen solution involves determining distributions for the pertinent outputs and running a separate Monte Carlo simulation to obtain a best estimate of the required FPR. This result differs from the results obtained using the other methods sufficiently that the higher fidelity is warranted.