Welcome to the fourth issue of the Webb Update, a newsletter to update
the community about the James Webb Space Telescope (JWST). JWST 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/newsletter4.html
In this issue:
(1) Astrophysics in the Next Decade: JWST and Concurrent Facilities -
Meeting Summary
(2) JWST at the Austin AAS Meeting
(3) ISIM Component Completes Cryo-Thermal Distortion Test
(4) Preliminary Design Review held for the JWST Telescope
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(1) Astrophysics in the Next Decade: JWST and Concurrent Facilities -
Meeting Summary
-- Peter Stockman, STScI, Science Organizing Committee Secretary
The conference, held September 24-27, drew almost 200 participants to
Tucson to hear forty speakers and moderators discuss the prospects for
their fields in the next decade and how the Webb and future facilities
would advance them. The subjects ranged from the theory of the very
first stars (Tom Abel) to the origins of our Solar System (David
Jewitt). Over 40 posters expanded on these themes, with many describing
new instruments or new mission concepts. Representatives from most of
the major funding agencies described their plans for the upcoming
decade: Guy Monnet (ESO), Eric Smith (NASA), Hiroshi Karoji (NOAJ), and
Gillian Wright (representing ESA).
The Science Organizing Committee organized the conference such that each
40-minute presentation was followed by a 20-minute moderated discussion.
The order of topics was mixed to provide a wide range of science fields
every day. Both these experiments were successful in captivating and
engaging the participants.
We will publish the conference proceedings, including summaries of the
discussions and poster abstracts in mid-2008. In the meantime, we are
posting presentations and posters on the conference web site. For more
information on the conference see
http://www.stsci.edu/institute/conference/jwst2007
(2) JWST at the Austin AAS Meeting
-- Peter Stockman, STScI
The JWST project will have a major presence at the upcoming winter AAS
meeting in Austin, TX, January 8-11. Northrop Grumman will unveil
updates to the JWST sunshield and display samples of the sunshield
membrane. Ball Aerospace will bring a full-scale aluminum version of a
primary mirror segment. The STScI and GSFC booths will feature pictures
of the observatory, brochures and Webb DVDs.
The Science Working Group has organized a JWST Technology Town Hall
meeting on January 9 at 12:30pm. The topics will be the new JWST
technologies that enable the science instruments: the HgCdTe and Si:As
detectors and ASICs, and the NIRSpec Micro-Shutter Array. In addition to
addressing the current project status and the upcoming Preliminary
Design and Non-Advocate Reviews, the speakers will answer questions from
the AAS members.
(3) ISIM Component Completes Cryo-Thermal Distortion Test
-- Eric Johnson, ISIM Structure Manager
The JWST project recently completed the cryo-thermal distortion test of
the Integrated Science Instrument Module (ISIM) Breadbox structure at
the Marshall Space Flight Center (MSFC). This test, which took place in
the X-Ray Calibration Facility (XRCF), is a critical part of the ISIM
structure verification and validation. The test was complex and
challenging, requiring interferometric measurements of thermal
distortions at the micron level over five thermal cycles from room
temperature to 40K. Teams from GSFC, ATK, Ball Aerospace, University of
Alabama Huntsville, and the Space Telescope Science Institute worked
on-site at MSFC, in close cooperation with the XRCF staff, for about 134
days during the period April-August 2007, 62 days of which required
round-the-clock support for test operations.
The Breadbox, designed to simulate the ISIM structure, is a composite
tube truss structure, 1.2m by 1.4m in size, and is fabricated using the
same design details, materials, and fabrication techniques as ISIM. The
test of the Breadbox leveraged the Backplane Stability Test Article test
in 2006 to the greatest extent possible by utilizing modified BSTA
support structures, test and handling procedures, instrumentation, and
support teams. However, unlike the backplane test, both in-plane and
out-of-plane distortions of the Breadbox were measured. The in-plane
distortions were measured by distance measuring interferometers, while
the out-of-plane distortions were measured by an electronic speckle
pattern interferometer.
Based on preliminary data reduction and analysis, the Breadbox test was
highly successful. Data quality, coverage, and cycle-to-cycle
repeatability were good to excellent. Final data processing is underway
in support of Breadbox finite element model correlation. Ultimately,
this will be a major element in the verification of the accuracy of the
ISIM finite element models used to analytically predict thermal
distortions of the structure during various mission phases.
(4) Preliminary Design Review held for the JWST telescope
-- Bill Hayden, JWST Systems Engineer
From Nov 27 to Nov 29, the JWST Optical Telescope Element (OTE) held
its Preliminary Design Review (PDR) at Northrop Grumman in Los Angeles.
The joint review team included a panel of independent experts from both
Goddard and Northrop Grumman. Review participants also included members
of the NASA Headquarters-chartered JWST Standing Review Board, and
members of the Project's Optical Product Integrity Team, which is an
advisory group of independent experts in large optical systems. The OTE
passed its PDR with no liens which is the official gate that authorizes
the project to proceed to the OTE Critical Design Review (CDR) scheduled
for early 2009.
Many of the OTE subsystems had previously passed their individual
critical design reviews, such as the Primary Mirror Segment Assemblies,
because they include long-lead items that are critical schedule drivers.
Hence the quality of the OTE PDR reflected the unusually high maturity
of the OTE design. As with all NASA design reviews, a formal process was
in place so that the review panels could submit requests for action
which will be systematically addressed by Northrop Grumman before the
OTE CDR. The OTE PDR predates the Mission PDR by 4 months, which is
scheduled in April 2008.
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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 on JWST, 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 JWST progress. These are available at
http://sco.stsci.edu/newsletter/
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