Welcome to the fifth issue of the Webb Update, a newsletter to update
the community about the James Webb Space Telescope. Webb will be the
next flagship astrophysics mission for NASA and is planned for launch in
2013. A web version of this newsletter is available at
http://www.jwst.nasa.gov/newsletter5.html
In this issue:
(1) Webb Confirmed For Implementation
(2) Webb Primary Mirror Engineering Design Unit in Final Stages of Testing
(3) Hubble Postdoctoral Fellowship Program to include Webb
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(1) Webb Confirmed for Implementation
-- Mark Clampin, Observatory Scientist and Peter Stockman, STScI Deputy
Project Scientist
On July 10, 2008, NASA confirmed the James Webb Space Telescope, marking
the project’s formal transition from the formulation phase to the
implementation phase. Confirmation initiates monitoring of the project
by Congress. NASA’s decision followed two intensive reviews of the Webb
project, the Preliminary Design Review (PDR) in March, and, several
weeks later, a second Non-Advocate Review (NAR). The first NAR, dealing
specifically with Webb’s new technologies, was held in January 2007.
The Webb design evolved considerably in the run-up to the PDR. While the
telescope optics and their deployment structures remain the same, the
sunshield size and shape have been optimized. For protection during
launch, the sunshield will now be stowed on two folding pallets. After
launch, booms will extend the sunshield from the pallets. Located at the
rear of the sunshield, to neutralize the generated solar-radiation
torque, a trim tab will help manage the momentum in the spacecraft’s
reaction wheels. The design of the spacecraft bus—which provides support
functions, such as avionics, power, and computers—has also evolved, due
to the decision to employ a single, long solar array.
The next 12 months will present exciting challenges for the Webb
project. Before their final cryo-polishing, the first mirrors intended
for flight will be delivered to the Marshall Space Flight Center for
testing. The last of the science instruments will complete their
Critical Design Reviews (CDRs), and the fabrication of the flight
instruments will begin. The CDR for the entire Webb mission will take
place in 2009.
The project schedule shows readiness for launch in mid 2013, when an
Arianne 5 rocket will lift the Webb observatory into space from the
European Space Agency spaceport at Kourou, French Guiana. Science
operations—the fun part!—will begin after instrument checkout and the
cruise to Webb’s station at L2, the second Earth-Sun Lagrange point.
(2) Webb Primary Mirror Engineering Design Unit in Final Stages of Testing
-- Lee Feinberg, Optical Telescope Element Manager
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. 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 its cryogenic operating temperature. Once cryogenic polishing is
completed to final specifications, the mirror will be coated and sent
for final cryogenic testing.
(3) Hubble Postdoctoral Fellowship Program to include Webb
NASA has announced the launch of a new postdoctoral fellowship program,
which is an amalgamation of the pre-existing Hubble and Spitzer
Fellowship programs. This new program, to be called the Hubble
Postdoctoral Fellowship program, will support outstanding postdoctoral
scientists whose research is broadly related to NASA Cosmic Origins
scientific goals as addressed by ANY of the missions in this program:
the Herschel Space Observatory, Hubble Space Telescope, James Webb Space
Telescope, Stratospheric Observatory for Infrared Astronomy (SOFIA), and
the Spitzer Space Telescope.
Applications are solicited for fellowships to begin in the fall of 2009.
The Announcement of Opportunity, which includes detailed program
policies and application instructions, is available at the web site:
http://www.stsci.edu/institute/org/spd/hubble-fellowship/ao-2009
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Much more information is available on our website at
http://www.jwst.nasa.gov <http://www.jwst.nasa.gov/> including
presentations, cool animations, images of technology development in
progress, exposure time calculators and much more. STScI also maintains
an archive of the HST newsletters, which have regular discussions of the
progress on Webb. These are available at http://sco.stsci.edu/newsletter/
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