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Executive Summary
Pages 1-7

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From page 1...
... In keeping with its statement of task (Appendix A) , the Committee on the Assessment of Options for Extending the Life of the Hubble Space Telescope assessed the scientific value of continued HST operation, issues of safety in using the space shuttle for servicing HST with an astronaut crew, the feasibility of robotic servicing, the impacts of servicing options on HST's science capability, and risk/benefit relationships between those servicing options deemed acceptable.
From page 2...
... Based on its examination of data and numerous technical reports on Hubble component operations, as well as discussions held with Hubble project personnel, the committee developed the following findings predicated on an estimated SM-4 earliest launch date of July 2006 and a most likely robotic mission launch date of February 2010. FINDING: The projected termination in mid to late 2007 of HST science operations due to gyroscope failure and the projected readiness in early 2010 to execute the planned NASA robotic mission result in a projected 29-month interruption of science operations.
From page 3...
... The four key advantages that Hubble provides over most other optical astronomical facilities are unprecedented angular resolution over a large field, spectral coverage from the visible and the near infrared to the far ultraviolet, access to an extremely dark sky, and highly stable images that enable precision photometry. Hubble's imaging fields of view are also considerable, permitting mapping of extended objects and significant regions of sky.
From page 4...
... These data sets will be archived to serve astronomers for decades to come, given that there are no foreseeable plans to replace Hubble with a telescope of comparable size, wavelength coverage, and high resolution. The key findings of the committee related to the benefits of future servicing of Hubble are as follows: FINDING: The Hubble Space Telescope is a uniquely powerful observing platform in terms of its high angular optical resolution, broad wavelength coverage from the ultraviolet to the near infrared, low sky background, stable images, exquisite precision in flux determination, and significant field of view.
From page 5...
... The components of schedule risk examined by the committee included the readiness levels of such technologies as the sensors, software and control algorithms, and vision-based closed-loop support for autonomous docking operations, as well as NASA's relevant programmatic and technical expertise, resources, and specific development plans for a robotic servicing mission. From the risk mitigation viewpoint, the committee judged that the planned use of the mature International Space Station robotic arm and robotic operational ground system helps reduce both the schedule risk and the development risk for the robotic mission.
From page 6...
... Based on extensive analysis, the committee concluded that the very aggressive schedule for development of a viable robotic servicing mission, the commitment to development of individual elements with incomplete systems engineering, the complexity of the mission design, the current low level of technology maturity, the magnitude of the risk-reduction efforts required, and the inability of a robotic servicing mission to respond to unforeseen failures that may well occur on Hubble between now and the mission, together make it highly unlikely that NASA will be able to extend the science life of HST through robotic servicing. THE RISKS OF SHUTTLE SERVICING The risks that must be considered in making a decision to service Hubble with the shuttle are the risk to the safety of the crew and the shuttle, as well as the risk of failing to accomplish the servicing objectives.
From page 7...
... The very aggressive schedule, the complexity of the mission design, the current low level of technology maturity, and the inability of a robotic servicing mission to respond to unforeseen failures that may well occur on Hubble between now and a servicing mission make it unlikely that the science life of HST will be extended through robotic servicing. A shuttle astronaut servicing mission is the best option for extending the life of Hubble and preparing the observatory for eventual robotic de-orbit by, for example, attaching targets to Hubble.


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