Image Caption
Engineering Design Unit Primary Mirror Segment
Caption: The James Webb Space Telescope Primary Mirror
Engineering Design Unit (EDU) recently demonstrated the final manufacturing
process at L-3-SSG/Tinsley in Richmond, California. Shown in the
picture below, the EDU is a prototype 1.4 meter diameter Beryllium mirror
that is identical to the 18 flight mirror segments and is used to check out
all mirror manufacturing processes prior to the actual flight mirror
processing. This recent result gives confidence that all
manufacturing processes are in place to figure the 18 flight mirrors.
Lessons learned from the EDU have been applied to the flight mirrors
improving the performance and processing time and all 18 flight mirrors are
well along in their processing at L3-SSG/Tinsley. As a result of
completing the final manufacturing demonstration, the EDU mirror was sent
to Ball Aerospace in Boulder, Colorado where it is now undergoing
integration with the hexapod mount assembly and optical testing
checkout. After integration to mount assemblies, flight mirrors will
be sent for cryogenic (50 degrees Kelvin) optical testing where the
cryogenic distortions will be measured. After cryogenic testing,
mirrors will eventually be returned to Tinsley for final cryogenic
polishing. During final cryogenic polishing, the inverse of the
measured cryogenic distortions will be polished into the mirror to assure
the mirror works at it’s cryogenic operating temperature. Once
cryogenic polishing is completed to final specifications, the mirror will
be coated and sent for final cryogenic testing.
The people shown from left to right are: Chris Alongi (L3-SSG/Tinsley), Amber Zertuche (L-3-SSG/Tinsley), Scott Texter (NGST), Patrick Johnson (L3-SSG/Tinsley), Michael Hirsch (NGST), Lee Feinberg (NASA GSFC), Ben Gallagher (Ball Aerospace).
