Wissinger, D. B. | Search NASA

NASA NTRS1988

Space Station core resupply and return requirements estimation

A modular methodology has been developed to model both NASA Space Station onboard resupply/return requirements and Space Shuttle delivery/return capabilities. This approach divides nonpayload Space Station logistics into seven independent categories, each of which is a function of several rates multiplied by user-definable onboard usage scenarios and Shuttle resupply profiles. The categories are summed to arrive at an overall resupply or return requirement. Unused Shuttle resupply and return capacities are also evaluated. The method allows an engineer to evaluate the transportation requirements for a candidate Space Station operational scenario.

Wissinger, D. B.↗

NASA NTRS1982

STS-1 orbital trajectory reconstruction using unmodelled acceleration estimation

A postflight trajectory reconstruction and analysis were conducted in order to determine the effects of unmodeled thrusting on the Space Shuttle Orbiter, to generate representative thrusting uncertainties for input to error analyses, and to evaluate the accuracy of the Ancillary trajectory data product and real-time vectors. The methods of selecting appropriate data arcs, time placement of compensation forces, limitations of the orbit determination process, and methods of evaluating solutions obtained from various force combinations are presented. It is shown that the estimation of forces to compensate for uncoupled attitude maneuvers and attitude hold maintenance thrusting significantly improves the postflight reconstruction of Space Shuttle Orbiter trajectories. A reduction of measurement residual statistics due to dynamic model uncertainties yields improved accuracy for postflight orbit determination.

Lacarna, R. J.↗