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The main mirror of NASA’s James Webb Space Telescope being tested at Goddard Space Flight Center in Greenbelt, Maryland, in 2017.

NASA/Desiree Stover/Flickr (CC BY-NC-ND 2.0)

NASA announces more delays for giant space telescope

Delays in the testing and integration of NASA’s next space observatory, the James Webb Space Telescope (JWST), will push its launch back to May 2020, the agency announced today. NASA’s acting administrator, Robert Lightfoot, also admitted in a press briefing that the project’s cost may exceed the ceiling of $8 billion imposed by Congress in 2011. The agency expects to provide a confirmed schedule and cost estimate this summer. Congress will have to give its approval for extra spending if the cost cap has been breached.  

The two parts of the spacecraft—the telescope and instrument package and the spacecraft bus with sunshield—are waiting to be melded together at the facility of prime contractor Northrop Grumman in Redondo Beach, California. The JWST was originally planned to launch in October, but last September NASA pushed back the launch to the second quarter of 2019.

Delays in testing the sunshield and problems with the in-space propulsion system have slowed work. NASA science chief Thomas Zurbuchen said during the briefing that, during testing, the cables that tension the craft’s tennis court–size sunshield became unexpectedly slack during deployment and risked tangling. He also said the deployment tests had produced some tears in the superthin fabric of the sunshield that are now repaired and some changes had to be made to stem leaks in the propulsion system. “Webb is a really complex machine and rigorous testing is required to have a high confidence of success,” Zurbuchen said. “We have one shot to get this into space. Failure is not an option.”

A review board suggested that testing of the completed spacecraft will take longer than predicted, and calculated that there is a 70% probability the JWST would be ready for a May 2020 launch. In response, NASA will increase its engineering oversight, make some personnel changes, and institute new management reporting structures that will involve daily progress reports from Northrop Grumman. NASA has also commissioned an independent review of the project led by NASA veteran Thomas Young. That panel’s recommendations and NASA’s own findings will be combined in a report to be delivered to Congress this summer.

The JWST is the largest science mission NASA has ever attempted and is expected to make great discoveries everywhere from the dawning of the universe to nearby exoplanets.