http://smartech.gatech.edu/handle/1853/8331 Search the Channel search http://smartech.gatech.edu/simple-search http://smartech.gatech.edu/handle/1853/29921 Title: Analysis of Human-System Interaction For Landing Point Redesignation <br/> <br/>Authors: Chua, Zarrin K. <br/> <br/>Abstract: Despite two decades of manned spaceflight development, the recent thrust for increased human exploration places significant demands on current technology. More information is needed in understanding how human control affects mission performance and most importantly, how to design support systems that aid in human-system collaboration. This information on the general human-system relationship is difficult to ascertain due to the limitations of human performance modeling and the breadth of human actions in a particular situation. However, cognitive performance can be modeled in limited, well-defined scenarios of human control and the resulting analysis on these models can provide preliminary information with regard to the human-system relationship. This investigation examines the critical case of lunar Landing Point Redesignation (LPR) as a case study to further knowledge of the human-system relationship and to improve the design of support systems to assist astronauts during this task. To achieve these objectives, both theoretical and experimental practices are used to develop a task execution time model and subsequently inform this model with observations of simulated astronaut behavior. The experimental results have established several major conclusions. First, the method of LPR task execution is not necessarily linear, with tasks performed in parallel or neglected entirely. Second, the time to complete the LPR task and the overall accuracy of the landing site is generally robust to environmental and scenario factors such as number of points of interest, number of identifiable terrain markers, and terrain expectancy. Lastly, the examination of the overall tradespace between the three main criteria of fuel consumption, proximity to points of interest, and safety when comparing human and analogous automated behavior illustrates that humans outperform automation in missions where safety and nearness to points of interest are the main objectives, but perform poorly when fuel is the most critical measure of performance. Improvements to the fidelity of the model can be made by transgressing from a deterministic to probablistic model and incorporating such a model into a six degree-of-freedom trajectory simulator. This paper briefly summarizes recent technological developments for manned spaceflight, reviews previous and current efforts in implementing LPR, examines the experimental setup necessary to test the LPR task modeling, discusses the significance of findings from the experiment, and also comments on the extensibility of the LPR task and experiment results to human Mars spaceflight. <br/> <br/>Description: AE8900 MS Special Problems Report; Space Systems Design Laboratory (SSDL); Cognitive Engineering Center (CEC); Guggenheim School of Aerospace Engineering; Georgia Institute of Technology; Atlanta, GA Mon, 25 May 2009 22:58:59 GMT http://smartech.gatech.edu/handle/1853/26718 Title: Design Space Pruning Techniques for Low-Thrust, Multiple Asteroid Rendezvous Trajectory Design <br/> <br/>Authors: Alemany, Kristina; Braun, Robert D. <br/> <br/>Abstract: In 2006, the 2nd Global Trajectory Optimization Competition (GTOC2) posed a “Grand Asteroid Tour” trajectory optimization problem, where participants were required to find the best possible low-thrust trajectory that would rendezvous with one asteroid from each of four defined groups. As a first step, most teams employed some form of design space pruning, in order to reduce the overall number of possible asteroid combinations. Because of the large size of the problem, teams were not able to determine if their pruning technique had successfully eliminated only bad solutions from the design space. Therefore, a small subset of the GTOC2 problem was analyzed, and several design space pruning techniques were applied to determine their effectiveness. The results indicate that the pruning techniques chosen by the participants likely eliminated good solutions from the design space, because they either did not accurately represent the low-thrust problem or could not be considered independently without the effect of other factors. <br/> <br/>Description: AAS/AIAA Astrodynamics Specialist Conference, August 2007, Mackinac Island, MI. Wed, 29 Aug 2007 22:58:59 GMT http://smartech.gatech.edu/handle/1853/26717 Title: Mars Gravity Biosatellite: Engineering, Science, and Education <br/> <br/>Authors: Korzun, Ashley M.; Braun, Robert D.; Wagner, Erika B.; Fulford-Jones, Thaddeus R.F.; Deems, Elizabeth C.; Judnick, Daniel C.; Keesee, John E. <br/> <br/>Abstract: The Mars Gravity Biosatellite is a novel program aimed at providing data on the effects of partial gravity on mammalian physiology. Physiological problems intrinsic to prolonged stays in microgravity have long been concerns of manned spaceflight and will continue to be a significant obstacle in achieving the goals outlined in NASA’s Vision for Space Exploration. This student-developed, free-flyer spacecraft is designed to carry a payload of 15 mice into low Earth orbit, rotating to generate an acceleration environment equivalent to Martian gravity. After 35 days, the payload will be de-orbited and recovered for study. Data collected during the mission and post-recovery will be used to characterize the physiological changes incurred under partial gravity conditions and validate the models used in designing the spacecraft. This paper presents the preliminary design of the spacecraft. By providing groundbreaking flight data on the effects of partial gravity on mammalian physiology and engaging over 500 students to date, the Mars Gravity Biosatellite program is working to enable successful human exploration of the Moon and Mars while training and inspiring a new generation of scientists and engineers. <br/> <br/>Description: 58th International Astronautical Congress, Hyderabad, India, 24-28 September 2007. Wed, 29 Aug 2007 22:58:59 GMT http://smartech.gatech.edu/handle/1853/26456 Title: A Value Proposition for Lunar Architectures Utilizing Propellant Re-supply Capabilities <br/> <br/>Authors: Young, James; Wilhite, Alan <br/> <br/>Abstract: The NASA Exploration Systems Architecture Study (ESAS)ⁱⁱ produced a transportation architecture for returning humans to the moon affordably and safely while using commercial services for tasks such as cargo delivery to low earth orbit (LEO). Another potential utilization of commercial services is the delivery of cryogenic propellants to LEO for use in lunar exploration activities. With in-space propellant re-supply available, there is the potential to increase the payload that can be delivered to the lunar surface, increase lunar mission durations, and enable a wider range of lunar missions. The addition of on-orbit propellant resupply would have far-reaching effects on the entire exploration architecture. Currently 70% of the weight delivered to LEO by the cargo launch vehicle is propellant needed for the TLI burn. This is a considerable burden and significantly limits the design freedom of the architecture. The ability of commercial providers to deliver cryogenic propellants to LEO may provide for a less expensive and better performing lunar architecture. <br/> <br/>Description: 58th International Astronautical Congress September 2007, Hyderabad, India. Wed, 29 Aug 2007 22:58:59 GMT