Mr. Duncan M. Shields Profile

Duncan M. Shields

P & V Techn Program Director at BAE Systems Inc

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Publications (6)

Proceedings Article | 20 September 2007 Paper

TRL-6 for JWST wavefront sensing and control

Lee Feinberg, Bruce Dean, David Aronstein, Charles Bowers, William Hayden, Richard Lyon, Ron Shiri, J. Scott Smith, D. Scott Acton, Larkin Carey, Adam Contos, Erin Sabatke, John Schwenker, Duncan Shields, Tim Towell, Fang Shi, Luis Meza

Proceedings Volume 6687, 668708 (2007) https://doi.org/10.1117/12.736059

KEYWORDS: Image segmentation, James Webb Space Telescope, Wavefronts, Phase retrieval, Mirrors, Telescopes, Wavefront sensors, Sensors, Cameras, Phase modulation

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Proceedings Article | 20 September 2007 Paper

Using multifield measurements to eliminate alignment degeneracies in the JWST testbed telescope

Erin Sabatke, Scott Acton, John Schwenker, Tim Towell, Larkin Carey, Duncan Shields, Adam Contos, Doug Leviton

Proceedings Volume 6687, 668707 (2007) https://doi.org/10.1117/12.736309

KEYWORDS: Mirrors, James Webb Space Telescope, Wavefronts, Space telescopes, Telescopes, Image segmentation, Monochromatic aberrations, Phase retrieval, Matrix multiplication, Wavefront sensors

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Proceedings Article | 20 September 2007 Paper

End-to-end commissioning demonstration of the James Webb Space Telescope

D. Scott Acton, Timothy Towell, John Schwenker, Duncan Shields, Erin Sabatke, Adam Contos, Karl Hansen, Fang Shi, Bruce Dean, Scott Smith

Proceedings Volume 6687, 668706 (2007) https://doi.org/10.1117/12.731653

KEYWORDS: Image segmentation, James Webb Space Telescope, Image processing, Phase modulation, Space telescopes, Wavefronts, Telescopes, Mirrors, Aerospace engineering, Imaging arrays

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Proceedings Article | 6 July 2006 Paper

Demonstration of the James Webb Space Telescope commissioning on the JWST testbed telescope

D. Scott Acton, Timothy Towell, John Schwenker, John Swensen, Duncan Shields, Erin Sabatke, Lana Klingemann, Adam Contos, Brian Bauer, Karl Hansen, Paul Atcheson, David Redding, Fang Shi, Scott Basinger, Bruce Dean, Laura Burns

Proceedings Volume 6265, 62650R (2006) https://doi.org/10.1117/12.672133

KEYWORDS: Image segmentation, James Webb Space Telescope, Space telescopes, Phase modulation, Telescopes, Wavefronts, Algorithm development, Image processing algorithms and systems, Sensors, Aerospace engineering

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Proceedings Article | 23 June 2006 Paper

Bringing it all together: a unique approach to requirements for wavefront sensing and control on the James Webb Space Telescope (JWST)

Adam Contos, D. Scott Acton, Paul Atcheson, Allison Barto, Paul Lightsey, Duncan Shields

Proceedings Volume 6271, 62710Z (2006) https://doi.org/10.1117/12.669072

KEYWORDS: James Webb Space Telescope, Mirrors, Wavefront sensors, Observatories, Space operations, Databases, Optical components, Cameras, Wavefronts, Error control coding

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The opto-mechanical design of the 6.6 meter James Webb Space Telescope (JWST), with its actively-controlled secondary and 18-segment primary mirror, presents unique challenges from a system engineering perspective. To maintain the optical alignment of the telescope on-orbit, a process called wavefront sensing and control (WFS&C) is employed to determine the current state of the mirrors and calculate the optimal mirror move updates. The needed imagery is downloaded to the ground, where the WFS&C algorithms to process the images reside, and the appropriate commands are uploaded to the observatory. Rather than use a dedicated wavefront sensor for the imagery as is done in most other applications, a science camera is used instead. For the success of the mission, WFS&C needs to perform flawlessly using the assets available among the combination of separate elements (ground operations, spacecraft, science instruments, optical telescope, etc.) that cross institutional as well as geographic borders. Rather than be yet another distinct element with its own set of requirements to flow to the other elements as was originally planned, a novel approach was selected. This approach entails reviewing and auditing other documents for the requirements needed to satisfy the needs of WFS&C. Three actions are taken: (1) when appropriate requirements exist, they are tracked by WFS&C ; (2) when an existing requirement is insufficient to meet the need, a requirement change is initiated; and finally (3) when a needed requirement is missing, a new requirement is established in the corresponding document. This approach, deemed a "best practice" at the customer's independent audit, allows for program confidence that the necessary requirements are complete, while still maintaining the responsibility for the requirement with the most appropriate entity. This paper describes the details and execution of the approach; the associated WFS&C requirements and verification documentation; and the implementation of the primary database tool for the project, DOORS (Dynamic Object-Oriented Requirements System).

Proceedings Article | 10 June 2006 Paper

Aligning and maintaining the optics for the James Webb Space Telescope (JWST) on-orbit: the wavefront sensing and control concept of operations

Adam Contos, D. Scott Acton, Paul Atcheson, Allison Barto, Paul Lightsey, Duncan Shields

Proceedings Volume 6265, 62650X (2006) https://doi.org/10.1117/12.669067

KEYWORDS: Image segmentation, Mirrors, Image processing, James Webb Space Telescope, Wavefronts, Observatories, Telescopes, Space telescopes, Image processing algorithms and systems, Actuators

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Showing 5 of 6 publications

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