NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Optical Modeling Activities for NASA's James Webb Space Telescope (JWST)This is part three of a series describing the ongoing optical modeling activities for James Webb Space Telescope (JWST). The first two discussed modeling JWST on-orbit performance using wavefront sensitivities to predict line of sight motion induced blur, and stability during thermal transients. The work here investigates the aberrations resulting from alignment and figure compensation of the controllable degrees of freedom (primary and secondary mirrors), which may be encountered during ground alignment and on-orbit commissioning of the observatory. The optical design of the telescope is a three-mirror anastigmat, with an active fold mirror at the exit pupil for fine guiding. The primary mirror is over 6.5 meters in diameter, and is composed of 18 hexagonal segments that can individually positioned on hexapods, as well as compensated for radius of curvature. This effectively gives both alignment and figure control of the primary mirror. The secondary mirror can be moved in rigid body only, giving alignment control of the telescope. The tertiary mirror is fixed, however, as well as the location of the science instrumentation. Simulations are performed of various combinations of active alignment corrections of component figure errors, and of primary mirror figure corrections of alignment errors. Single field point and moderate field knowledge is assumed in the corrections. Aberrations over the field are reported for the varying cases, and examples presented.
Document ID
20080030118
Acquisition Source
Goddard Space Flight Center
Document Type
Conference Paper
Authors
Howard, Joseph
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
August 24, 2013
Publication Date
August 26, 2007
Subject Category
Optics
Meeting Information
Meeting: SPIE Optics and Phontonics
Location: San Diego, CA
Country: United States
Start Date: August 26, 2007
End Date: August 30, 2007
Sponsors: International Society for Optical Engineering
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

Available Downloads

There are no available downloads for this record.
No Preview Available