Webb is optimized to view the heavens in infrared light, and its instruments must therefore be kept quite cool. So the telescope will sport a giant sunshield the size of a tennis court, which will unfold after Webb reaches its final destination, a gravitationally stable spot about 930,000 miles (1.5 million kilometers) from Earth.
The road to that destination has been quite bumpy to date. Webb is a very complex observatory that has proved difficult for primary contractor Northrop Grumman to build and test, as the repeated delays attest.
Until relatively recently, NASA had been targeting an October 2018 launch. In September of last year, however, NASA announced that spacecraft-integration issues had delayed the launch until spring 2019. Then, this past March, the agency pushed the scheduled liftoff date back again, to May 2020. More time was needed to test Webb's intricate systems and to deal with setbacks, such as small tears in the sunshield, NASA officials said at the time.
The agency also set up an independent review board (IRB) in March to monitor the observatory's progress and develop recommendations. The IRB submitted its report to NASA on May 31, and the agency wrapped up its response to that report June 26. (You can read both the report and NASA's response here.)
The IRB traced the 29-month delay (from a targeted launch date of October 2018 to March 2021) to five factors: human error, "embedded problems," excessive optimism, systems complexity, and a lack of experience in key areas, such as sunshade development.
IRB Chairman Tom Young laid out some of the most significant human errors during today's news conference. Technicians used the wrong solvent to clean propulsion valves, employed improper wiring that caused excessive voltage to be applied to transducers, and improperly installed sunshield-cover fasteners ahead of a key test, he said.
"All simple fixes that were not implemented resulted in approximately a 1.5-year schedule delay, at a cost of about $600 million," said Young, the former director of NASA's Goddard Space Flight Center in Greenbelt, Maryland, and the former president and chief operating officer of aerospace company Martin Marietta, which merged with Lockheed Corporation in 1995, forming Lockheed Martin.
The IRB report was key in NASA's latest plan for Webb, agency officials said. Indeed, the review panel made 32 separate recommendations for the observatory's development going forward, 30 of which NASA fully agrees with, Zurbuchen said. The agency is still considering the other two, he added.
Crucially, the IRB did not recommend pulling the plug on the telescope.
"With all the factors that I've discussed considered, the IRB believes that JWST should continue, because of the compelling science, and because of JWST's national importance," Young said.
The bump in the mission's development cost from $8 billion to $8.8 billion may complicate that vision, however. The former number was a cap imposed by Congress, meaning that Webb needs another signoff from Capitol Hill to proceed.
"We submit our final 'breach report' to Congress this week," NASA Associate Administrator Steve Jurczyk said during today's news conference. "And then, it is true that Congress will have to reauthorize Webb through this next cycle of appropriations."
Originally published on Space.com.
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