Test challenges blamed for James Webb Space Telescope delay


The James Webb Space Telescope’s mirror section

The US Government Accountability Office has blamed delays to the launch of the James Webb Space Telescope on problems with testing and integrating components and has said more delays and costs are likely.

The James Webb Space Telescope (JWST) is the planned successor to the Hubble Telescope and is one of NASA’s most complex and expensive projects.

The infrared telescope was due to be launched in October 2018 on an Ariane 5 rocket, but was rescheduled in September last year by NASA to be launched between March and June 2019.

A recent assessment by the Government Accountability Office (GAO) of the work left to complete on the project has found that the launch date is likely to be delayed again and that the project will break a US government-set US$8bn cost cap it if that happens.

According to a report issued by the GAO the James Webb Space Telescope has made considerable progress with its integration and test activities in the last year. However, it found that the project has already used all of the time set aside for unforeseen problems dealing with technical issues.

These issues include an anomaly on the telescope found on the optical mirror during vibration testing that would have affected image quality. Additional testing determined that the anomaly was caused by a test equipment setup issue and not related to the flight hardware itself.

Issues were also found with the folding and deployment of the observatory’s sunshield, when several tears in the sunshield membrane layers. The spacecraft’s thruster modules also have to be replaced, after valves in the propulsion system were found to be leaking during tests.

Issues also have to be solved that were found during the cryovacuum test.

Most of the remaining work is being done by Northrop Grumman, which is developing JWST’s sunshield, the Optical Telescope Element, the spacecraft, and the mid-infrared instrument’s cryo-cooler, in addition to integrating and testing the observatory.

A complete update on JWST’s status from NASA is expected in early 2018 in a Standing Review Board report to program and project management regarding JWST’s schedule and feasibility for meeting its new launch window.

March 6, 2018

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Ben has worked as a journalist and editor, covering technology, engineering and industry for the last 20 years. Initially writing about subjects from nuclear submarines to autonomous cars to future design and manufacturing technologies, he was editor of a leading UK-based engineering magazine before becoming editor of Aerospace Testing in 2017.

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