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| 05.13.09 Division Highlights Contents
Experiment to Simulate the Effect of Prolonged Weightlessness on Space Shuttle Pilot Performance: An experiment on the Vertical Motion Simulator (VMS) explored the effects of prolonged weightlessness on pilot performance during approach and landing of the Space Shuttle using Galvanic Vestibular Stimulation (GVS). GVS stimulates the pilot's vestibular (balance) nerves, which transmit motion information to the brain, through small electrical currents applied to surface electrodes placed behind each ear. The stimulation reproduces the motion sensation anomalies observed by astronauts as they return from space. NASA has determined these sensations pose a threat to crew operations and the operation of the vehicle; Space Shuttle landing performance data suggests that pilot performance is degraded following an extended period of microgravity exposure (weightlessness). In this study, seven evaluation pilots, including two former astronauts, flew 109 landings of the Space Shuttle Landing and Rollout simulation, with and without GVS. The goal of the study is to determine whether the GVS system accurately reproduces the effects of microgravity on pilot performance during shuttle landings. If the GVS can effectively represent human motion sensing system disturbances induced by prolonged exposure to weightlessness, it may potentially be used to improve future training of astronaut pilots by increasing the realism of landing and docking simulations. The study was conducted by Dr. Steven Moore from the Human Aerospace Laboratory, Department of Neurology, Mount Sinai School of Medicine (New York, NY). + Back to Top Boeing/NASA In-Flight Efficiency Results at Fort Worth Center: On March 18th, Boeing presented the results of recent flight trials conducted at Fort Worth Air Route Traffic Control Center (ARTCC) in collaboration with NASA, FAA and Southwest Airlines. The objective of the trials was to conduct an operational evaluation of a trajectory-based automation concept that provides smart, direct-route requests to pilots via their airline dispatchers. Pilots request the direct routes from a controller through normal air traffic control procedures. These smart requests guarantee flying time savings for the airline and are more likely to be approved by air traffic control, because they are requested only if predetermined to be conflict-free. Boeing developed the system from NASA's Center/TRACON Automation System Direct-To software. The trials were conducted in Fort Worth Center airspace during November 18 – December 31, 2008. Results show that Southwest Airlines realized nearly a 30-minute per day flying time savings during the trials. Substantially more savings could be realized with a production system if data communication delays were eliminated. Airline dispatchers and flight crews expressed support for these operations. NASA and Boeing are collaborating under a Space Act Agreement and a license agreement for use of NASA's patented Direct-To concept and software. + Back to Top Integrated Traffic Flow Management Decision Making: A generalized approach has been developed that supports integrated traffic flow management decision-making at both the U.S. national and regional levels. The approach can consider trade-offs between alternative optimization and heuristics-based models, strategic versus tactical flight controls, and system versus flight/fleet preferences. Preliminary testing of this integrated approach was accomplished with good, moderate, and bad convective weather scenarios that were derived from operational weather and air traffic data. The results were analyzed considering total delays, sector congestion, the number of weather incursions, and airline equity. Strategic scheduling algorithms that assigned ground holding controls alone were found to reduce total delays by nearly 40% under bad weather scenarios when compared to similar strategic models that assigned both airborne and ground holding controls. In terms of airline equity, standard heuristic-based scheduling algorithms, such as ration-by-schedule and ration-by-distance, were found to be the most equitable, whereas scheduling algorithms, such as ration-by-passengers, were found to be highly inequitable due to their adverse impact on general aviation flights. The final results of this study will be presented for peer review feedback at the AIAA Guidance, Navigation and Control Conference that will be held in Chicago, IL from August 10-13. + Back to Top Model for Departure Runway Management: A mixed integer linear program for departure runway management has been developed. The model performs runway queue management and schedules departure aircraft, as well as arrival aircraft runway crossing, to maximize runway throughput. The model incorporates prioritization of different departing aircraft as well as different methods of queue management (e.g., first in first out, dedicated lane for high priority flights). For typical peak operation scenarios of 15 minutes (scheduling 15 departure aircraft), the algorithm gives good solutions in under 30 seconds. The model was compared with a generic first-come-first-serve scheduler and preliminary results show up to a 30% decrease in overall queue time. Methods have been developed to utilize the algorithm over extended traffic periods (3 hours or more) while incorporating uncertainty; the model is currently undergoing such testing in a simulation environment based on real-world data. + Back to Top |
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