expendable launch vehicle analysis

Expendable Launch Vehicle Performance Optimization

Ported trajectory optimization program from Cray XMP to VAX/FPS system, adding enhancements to improve modeling accuracy for mission peculiar performance calculations.
Calculated performance associated with new-concept Titan IV launch vehicle (LV) with a modified 12-foot Centaur upper stage.
Defined range of practical LV configurations, estimated stage component weights, determined propulsion system potentials, assessed payload improvements, and selected the most promising configuration with regard to performance improvement and development cost/risk.

Modified trajectory optimization program step size calculation logic to improve convergence characteristics and provide greater accuracy for the modeling of specific launch vehicles.
Implemented an updated Atlas Detailed Propulsion System (DEPRO) model baselined to data contained in the mission specific reference trajectories. The updated DEPRO model significantly improved modeling accuracy.
Implemented Instantaneous Impact Point (IIP) steering methodology in LV trajectory simulation. This algorithm automates the process of steering the IIP about a specific geographic point during the launch vehicle ascent phase. The addition of this feature greatly improved accuracy and efficiency of trajectory simulations.
Implemented Alpha-Biased Steering algorithm in the USAF Program trajectory simulation program, providing the capability for specifying a total angle of attack profile during the booster phase of flight.
Incorporated digitized data of world coastlines and lakes into the MS Excel to expedite the plotting of sub-vehicle traces and instantaneous impact point profiles from trajectory simulation data.

Investigated performance effect of a proposed AC-71 corrective action that extended the Centaur first burn chilldown time. Found that extending both L02 and LH2 chilldown times by 9 seconds resulted in a performance decrease of approximately 52 pounds for the worst-case mission space trajectory.
Performed IV&V of Atlas/Centaur performance for East- and West Coast launches of Atlas II, IIA, HAS, and DSCS-III configurations for one, two, and three upper stage burn mission scenarios. These analyses involved the development of mission-specific trajectory simulation models, as well as MathCAD, Visual Basic, and Excel pre- and post-processing models.