WASHINGTON – NASA announced on Nov. 22 that it was delaying the launch of the James Webb Space Telescope for at least four days to investigate an incident that occurred while the spacecraft was preparing for launch in French Guiana.
NASA said it, working with the European Space Agency and Arianespace, has postponed the launch of JWST on an Ariane 5 from December 18 to no earlier than December 22 in order to conduct additional testing of the spacecraft after the incident.
In that incident, according to the NASA statement, a “sudden, unplanned release of a clamp strap” that JWST attached to its launcher adapter caused “a vibration throughout the observatory”. Arianespace is responsible for these activities, the statement said.
It is not known exactly when the incident occurred, except in the last few days. NASA officials did not mention this during two briefings on November 18 about the science and instruments of the JWST, saying at the time that the mission was still on schedule for a Dec. 18 launch.
“When you’re working on a $ 10 billion telescope, conservatism is of course the order of the day,” said Thomas Zurbuchen, NASA’s assistant science administrator, when speaking at a November 22 press conference about the upcoming launch of the Double Asteroid Redirection Test mission (DART).
He said that since the JWST is so close to launch, it did not have sensors that were present when it was transported to French Guiana to measure the effect of the clamp release on the spacecraft, only calculations to estimate the force exerted on it left over. “As a precaution, we used a small number of subsystems after these calculations and only performed the functional tests to ensure that, despite all this conservatism, nothing happened.”
“It is the right thing to do these tests now to make sure everything is set up as we hope it is,” he said. “I hope that in a few days we will be in good shape here.”