WASHINGTON – U.S. and European officials acknowledged on June 1 that the launch of the James Webb Space Telescope will likely slide from late October to at least mid-November due to Ariane 5 delays.

During a European Space Agency briefing on the space telescope, representatives from the agency and Arianespace said they were finalizing reviews to correct a payload shroud issue found on two Ariane launches 5 last year who had grounded the rocket since August. Arianespace described the problem last month as “less than fully nominal separation of the fairing” on these two launches.

“The origin of the problem has been found. Corrective actions have been taken ”, declared Daniel de Chambure, interim manager of Ariane 5 adaptations and future missions at ESA. “The qualifying review has started, so we should be able to confirm all of this within a few days or weeks.”

He did not give details of the problem or of these corrective actions, beyond stating that the problem occurred during the separation of the fairing from the payload. Industry sources said in May that during both launches, the separation system transmitted vibrations to the payload above acceptable limits, but did not damage the payloads.

The issue is not related to a change in the payload shroud required for JWST. Arianespace has tested new vents on the fairing intended to reduce the pressure differential once the fairing has been separated and thus reduce the loads on the spacecraft. “The issue of modifying the ventilation system and the fairing anomaly are different,” said de Chambure.

The Ariane 5 is expected to make its next launch, the first since the August 2020 launch that featured the payload shroud anomaly, in the second half of July, said Beatriz Romero, JWST project manager at Arianespace. This launch will be the first of two Ariane 5 commercial launches before the launch of JWST.

In a media event on May 11, Greg Robinson, director of the JWST program at NASA Headquarters, said the launch of JWST would take place about four months after the first of two commercial Ariane 5 launches that precede it. That would postpone the launch, currently scheduled for October 31 at the earliest, to at least mid-November.

During the ESA briefing, Thomas Zurbuchen, NASA’s associate administrator for science, offered a similar timeline. When asked if a mid-November launch is likely, based on a 10-week launch processing schedule that begins with the shipment of JWST from California to the launch site in French Guiana in late August , he said the timing was “approximately correct”.

“We want to be sure to launch exactly when we’re ready, not a day sooner,” he said. “That is, when the spaceship is ready and when the rocket and the fairing and everything is ready.”

Romero said several factors will come into play in setting an official launch date, including the readiness of the rocket, payload and spaceport. “We are currently consolidating all of this information for the definition of the launch date,” she said. Arianespace has reserved a “launch period” for JWST which begins October 31st and ends in early December.

A NASA-commissioned independent review of JWST in 2018, when technical issues with the telescope sparked a new round of delays and cost increases, recommended that NASA increase surveillance of Ariane 5 to the same level as the The agency does this for launch missions in the United States. Vehicles. Although NASA improved its surveillance, it fell short of the level recommended by this independent review.

Zurbuchen said NASA has had no problem obtaining information from its European partners on the condition of Ariadne 5. “We have had all the information we need. We have had in-depth technical discussions with all parties aligned with one goal, which is the success of the mission, ”he said.

The briefing was primarily intended to provide an overview of the upcoming launch of JWST and the science the observatory will perform once in space, highlighting the roles that partners NASA, ESA and the Canadian Space Agency, play in the mission. Günther Hasinger, Scientific Director of ESA, estimated that Europe’s contributions to JWST, in the form of instruments and the launch of Ariane 5, would amount to around 700 million euros (850 million euros). dollars), roughly the same amount as an ESA “class M” science mission. .

Gilles Leclerc, director general of space exploration at the Canadian Space Agency, said Canada’s contribution of a fine guidance instrument and sensors cost the agency about C $ 200 million (C $ 165 million dollars) over 20 years. “It is an investment in the discoveries of the universe,” he said.

NASA now estimates that it will spend $ 8.8 billion on JWST when the spacecraft is launched.