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Full-Text Articles in Engineering
Evaluation Of The Impact Of An Additive Manufacturing Enhanced Cubesat Architecture On The Cubesat Development Process, Rachel E. Sharples
Evaluation Of The Impact Of An Additive Manufacturing Enhanced Cubesat Architecture On The Cubesat Development Process, Rachel E. Sharples
Theses and Dissertations
Additive manufacturing (AM) is a fabrication method ideally suited to low-quantity, highly customized builds, leading to interest in its application to satellite development and manufacturing, where each build is unique. Due to the issues of long development schedules and high development and manufacturing costs, methods are needed in the CubeSat development process to reduce the weight and volume of subsystems and decrease integration time. The work develops an architecture for an AM-augmented CubeSat and examines the AM techniques of embedded electronics, embedded thrusters, and custom radiation-hardened materials can impact the subsystems of a CubeSat. The AM-augmented architecture shows a shift …
Operationally Responsive Space (Ors): An Architecture And Enterprise Model For Adaptive Integration, Test And Logistics, Jeff A. Alexander, Martha Charles-Vickers, Talbot L. Smith, Michael L. Vickers
Operationally Responsive Space (Ors): An Architecture And Enterprise Model For Adaptive Integration, Test And Logistics, Jeff A. Alexander, Martha Charles-Vickers, Talbot L. Smith, Michael L. Vickers
Theses and Dissertations
The capability to rapidly deploy tactical satellites to meet a Joint Force Commander's immediate battlespace requirements is a well-documented joint capability need. Key U.S. strategic documentation cites the need for the capability to maintain persistent surveillance or an "unblinking eye" over battlespace and to rapidly reconstitute critical space capabilities to preserve situational awareness. The warfighter requires a tactical space-based deployment capability which employs a request to launch and operational deployment window of 90 to 120 days. This master's thesis executed two (2) major areas of work: apply, and reinforce the Operationally Responsive Space (ORS) mission tasks using the Joint Capabilities …
Prioritizing Satellite Payload Selection Via Optimization, Benjamin S. Kallemyn
Prioritizing Satellite Payload Selection Via Optimization, Benjamin S. Kallemyn
Theses and Dissertations
This thesis develops optimization models for prioritizing payloads for inclusion on satellite buses with volume, power, weight and budget constraints. The first model considers a single satellite launch for which the budget is uncertain and constellation requirements are not considered. Subsequently, we include constellation requirements and provide a more enhanced model. Both single-launch models provide a prioritized list of payloads to include on the launch before the budget is realized. The single-launch models are subsequently extended to a sequence of multiple launches in two cases, both of which incorporate an explicit dependence on the constellation composition at each launch epoch. …
Optimizing Mean Mission Duration For Multiple-Payload Satellites, John A. Flory
Optimizing Mean Mission Duration For Multiple-Payload Satellites, John A. Flory
Theses and Dissertations
This thesis addresses the problem of optimally selecting and specifying satellite payloads for inclusion on a satellite bus to be launched into a constellation. The objective is to select and specify payloads so that the total lifetime utility of the constellation is maximized. The satellite bus is limited by finite power, weight, volume, and cost constraints. This problem is modeled as a classical knapsack problem in one and multiple dimensions, and dynamic programming and binary integer programming formulations are provided to solve the problem. Due to the computational complexity of the problem, the solution techniques include exact methods as well …
Optimal Maintenance For Stochastically Degrading Satellite Constellations, Timothy J. Cook
Optimal Maintenance For Stochastically Degrading Satellite Constellations, Timothy J. Cook
Theses and Dissertations
This thesis develops a methodology to determine an optimal policy for maintaining a satellite constellation that degrades over time. Previous work has developed a methodology to compute an optimal replacement policy for a satellite constellation in which satellites were viewed as binary entities, either operational or failed. This research extends the previous models by developing an optimal maintenance policy for satellite constellations in which each satellite may operate in a finite number of degraded states. The constellation is assumed to consist of a finite number of satellites, each with a finite number of functions with distinct failure mechanisms. Assuming each …
Optimal Replacement Policies For Satellite Constellations, Bradley R. Sumter
Optimal Replacement Policies For Satellite Constellations, Bradley R. Sumter
Theses and Dissertations
This work considers the problem of finding optimal replacement policies that minimize the expected total cost of maintaining a satellite constellation. The problem is modeled using discrete-time Markov decision processes to determine the replacement policy by allowing the satellite constellation to be in one of a finite number of states at each decision epoch. The constellation stochastically transitions at each time step from one state to another as determined by a set of transition probabilities. At each decision epoch, a decision maker chooses an action from a set of allowable actions for the current system state. A cost associated with …
Automating Satellite Range Scheduling, S. Michael Schalck
Automating Satellite Range Scheduling, S. Michael Schalck
Theses and Dissertations
The objective of this study was to develop a computer based satellite range scheduling SRS algorithm to create a 24 hour satellite support schedule. The algorithms goal was to schedule as many satellite support requests as possible. An iterative heuristic approach was used to schedule satellite support requests in three successive sub problems. The first sub problem involves scheduling low altitude satellite support requests using a mixed integer programming approach. The next two sub problems each involve scheduling 12 hour blocks of medium and high altitude satellite support requests, again using a mixed integer programming approach. Fourteen 24 hour schedules …