The James Webb Space Telescope, touted as NASA's next great space observatory, has yet again been delayed following an incident during launch preparations, the US space agency said.

As technicians were preparing to attach the telescope to the launch vehicle adapter, "a sudden, unplanned release of a clamp band caused a vibration throughout the observatory", NASA said in a statement on Monday. The clamp band secures Webb to the launch vehicle adapter.

James Webb Space Telescope
James Webb Space

The incident occurred during operations at the satellite preparation facility in Kourou, French Guiana.

The launch vehicle adapter is used to integrate the observatory with the upper stage of the Arianespace's Ariane 5 rocket.

"The launch readiness date for the James Webb Space Telescope is moving to no earlier than December 22 to allow for additional testing of the observatory, following a recent incident that occurred during Webb's launch preparations," NASA said.

A NASA-led anomaly review board was immediately convened to investigate and instituted additional testing to determine with certainty that the incident did not damage any components.

NASA and its mission partners will provide an update when the testing is completed at the end of this week, the statement said.

The Webb Space Telescope is an international partnership with the European and Canadian space agencies. It has witnessed a set of delays.


Webb was first targeted to launch in March this year. It was later pushed back to October due to impacts from the ongoing Covid-19 pandemic, as well as technical challenges.

But in September NASA confirmed plans to launch the telescope into orbit on December 18.

Webb will launch on an Ariane 5 from Europe's Spaceport in French Guiana on the northeastern coast of South America. ESA is providing the Ariane 5.

The telescope will explore every phase of cosmic history -- from within our solar system to the most distant observable galaxies in the early universe, and everything in between. Webb will also reveal new and unexpected discoveries, and help humanity understand the origins of the universe and our place in it.