Optimization of Disaggregated Space Systems Using the Disaggregated Integral Systems Concept Optimization Technology Methodology
Wagner, Katherine Mott
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This research describes the development and application of the Disaggregated Integral Systems Concept Optimization Technology (DISCO-Tech) methodology. DISCO-Tech is a modular space system design tool that focuses on the optimization of disaggregated and non-traditional space systems. It uses a variable-length genetic algorithm to simultaneously optimize orbital parameters, payload parameters, and payload distribution for space systems. The solutions produced by the genetic algorithm are evaluated using cost estimation, coverage analysis, and spacecraft sizing modules. A set of validation cases are presented. DISCO-Tech is then applied to three representative space mission design problems. The first problem is the design of a resilient rideshare-manifested fire detection system. This analysis uses a novel framework for evaluating constellation resilience to threats using mixed integer linear programming. A solution is identified where revisit times of under four hours are achievable for $10.5 million, one quarter of the cost of a system manifested using dedicated launches. The second problem applies the same resilience techniques to the design of an expanded GPS monitor station network. Nine additional monitor stations are identified that allow the network to continuously monitor the GPS satellites even when five of the monitor stations are inoperable. The third problem is the design of a formation of satellites for performing sea surface height detection using interferometric synthetic aperture radar techniques. A solution is chosen that meets the performance requirements of an upcoming monolithic system at 70% of the cost of the monolithic system.
General Audience Abstract
Civilians, businesses, and the government all rely on space-based resources for their daily operations. For example, the signal provided by GPS satellites is used by drivers, commercial pilots, soldiers, and more. Communications satellites provide phone and internet to users in remote areas. Weather satellites provide short-term forecasting and measure climate change. Because of the importance of these and other space systems, it is necessary that they are designed in an efficient, reliable, and cost-effective manner. The Disaggregated Integral Systems Concept Optimization Technology (DISCO-Tech) is introduced as a means of designing these space systems. DISCO-Tech optimizes various aspects of the space mission, including the number of satellites needed to complete the mission, the location of the satellites, and the sensors that each satellite needs to accomplish its mission. This dissertation describes how DISCO-Tech works, then applies DISCO-Tech to several example missions. The first mission uses satellites to monitor forest fires in California. In order to reduce the cost of this mission, the satellites share launch vehicles with satellites from other, unrelated missions. Next, DISCO-Tech is used to choose the placement of new ground stations for GPS satellites. Because GPS is an important asset, this study also assesses the performance of the network of ground stations when some of the stations are inoperable. Finally, DISCO-Tech is used to design a group of satellites that measure sea level, since sea level is important for climatology research. A design is presented for a group of satellites that perform these measurements at a lower cost than a planned mission that uses a single satellite.
- Doctoral Dissertations