MS thesis abstract - Lamassoure, Elisabeth
| Author: | Lamassoure, Elisabeth |
| Degree: | Masters of Science |
| SERC #: | 7-01 |
| File type: | PDF, 2382 kB |
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A Framework to Account for Flexibility in Modeling the Value of On-Orbit Servicing for Space Systems
The traditional method for maintenance of space systems consists in building reliable satellites through redundancy and replacing them in case of failure, or whenever an upgrade is necessary. On-orbit servicing could change this paradigm. What would be the missions for which servicing would be most interesting, and what price would they be willing to pay for the capability to be serviced? The answer to these questions would provide valuable guidelines as to which servicing technologies to develop, and at what cost. Assuming that the technologies enabling automated servicing are available, traditional metrics and models are first proposed to systematically evaluate servicing cost-effectiveness within a representative trade space of serviceable missions and servicing infrastructures. It is shown that though it can capture some elements of cost-effectiveness, the traditional approach tends to underestimate the value of servicing and demonstrate cost advantages smaller than the cost uncertainty.
This issue is solved by then proposing a new approach to on-orbit servicing. First, the intrinsic value of servicing is studied separately from its cost. Furthermore, a first framework to evaluate the flexibility provided by on-orbit servicing to space systems is developed. This framework is used to define models of the value of servicing for two families of space systems faced with different types of uncertainty: commercial systems with uncertain market and military missions with dynamic requirements.
For commercial missions with uncertain market, modeling servicing as an option on life extension shows that space systems should not systematically be designed for the longest possible lifetime. Instead, the optimal design life decreases with increasing uncertainty. The maximum servicing price that would make servicing economically interesting is evaluated as a function of uncertainty and the value of flexibility is illustrated on two current examples. For military missions, a small number of satellites with the option to maneuver is considered as an alternative to global coverage for flexibility with respect to contingency location. It is shown that while this alternative has little value in the case of a low Earth orbit radar constellation, it has interesting potential for geostationary communication satellites.