JWST components emerging from a testing chamber. Photo: NASA.

In September, NASA announced that the launch of the James Webb Space Telescope (JWST) on an Arianespace Ariane 5 rocket had been delayed from October 2018 to June 2019. Now, it’s likely that launch date will be pushed back again, says the U.S. Government Accountability Office (GAO).

According to a Feb. 28 GAO report, given the remaining integration and test work ahead, NASA expects additional delays for the Hubble Space Telescope successor. If that happens, JWST will be at risk of “breaching its $8 billion cost cap” set by Congress in 2011, GAO stated. Over the past few months, NASA has run into numerous technical challenges, including a test anomaly on the telescope, issues with the sunshield hardware and leaks in the spacecraft’s propulsion system thruster modules.

“With the project’s current low level of schedule reserves, even a relatively minor disruption could cause the project to miss its revised launch window. According to program officials, [Northrop Grumman] has increased its daily work shifts from two to three and is now working 24 hours per day on spacecraft integration, which further limits schedule flexibility,” GAO noted in the report.