JWST History: 2005
2005 The First Major Reviews and a Financial Shock
As is typical in major NASA developments, the element, systems and subsystems teams proceeded
ahead of the overall mission reviews. All the science instrument teams, except for the
NIRSpec team, passed their preliminary design reviews in 2005 and began development of
their long lead items and engineering models. In May, Brush Wellman had delivered all 20
Be segments to Axsys for light-weighting.
NASA administrator signed off on the use of the Ariane 5 on February 2005. Despite
this good news, which formalized the contributions of ESA to the mission, the
Project discovered both technical and financial difficulties that forced another
schedule and technical replan. With the better defined observatory and system designs,
the overall observatory mass estimate had become too high for the phase of the project
(before PDR and Critical Design Review – CDR). To reduce mass, particularly in the area
of the ISIM and optics, the Project and MIRI changed from a cryostat to a cryocooler.
Fortunately, the cryocooler technology development had progressed to the point where
this posed little risk to the MIRI and observatory design. NASA and CSA agreed to reduce
and simplify the Tunable Filter Imager.
Financial problems were more difficult to address. NASA received new estimates on the
cost-to-complete from Northrop Grumman and the NASA ISIM team (science instruments and
their support). Along with the reserves required to cover unknown difficulties in development,
the estimated overall development cost almost doubled, from about 2B to 3.5B. This led to
a major re-planning exercise and the chartering of the Science Assessment Team. Their
report prioritized the scientific capabilities of Webb and endorsed relaxation of several
driving performance requirements. The SAT also recommended that the I&T tests be simplified
to take advantage of the adjustable optics.
Following a number of reviews and the recommendations of the SAT and Independent Program
Assessment Office (IPAO), the JWST Project re-baselined the project for a launch date no
earlier than June 2013. The Project team identified significant savings and risk reductions.
Using a "cup-up" configuration for the final optical testing of JWST at the Johnson Space
Center would save more than $100M and significantly reduce the costs of additional testing, if
required. The SAT's recommendation to relax the optical requirements at 1 micron also significantly
reduced the cost of additional cryo-polishing cycles for the Be primary mirror segments
(the individual segment quality is relaxed).
While many areas in the program have slowed down due to lower funding levels, the Project
is maintaining schedule on the manufacture of mirror segments and in reaching the appropriate
flight qualification of new technologies. The System Definition Review (SDR) would be held in
January 2006. The mission PDR and Non-Advocate Review (NAR) were to occur a year later.
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