NASA, Partners Confirm Webb Launch on Dec. 25

NASA, ESA (European Space Agency), and Arianespace confirmed a targeted launch date of Saturday, Dec. 25, for the James Webb Space Telescope. A 32-minute launch window opens at 7:20 a.m. EST in Kourou, French Guiana (9:20 a.m. GFT/12:20 UTC).

An Ariane 5 rocket will lift off from Europe’s Spaceport carrying NASA’s next-generation space observatory.

white mockup of Ariane 5 rocket
A mockup of Arianespace’s Ariane 5 rocket is seen at the entrance to the Guiana Space Center in Kourou, French Guiana, Tuesday, Dec. 21, 2021. The James Webb Space Telescope is a large infrared telescope with a 21.3 foot (6.5 meter) primary mirror. The observatory is scheduled to launch Dec. 25 and will study every phase of cosmic history—from within our solar system to the most distant observable galaxies in the early universe. Photo Credit: (NASA/Bill Ingalls)

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Ahead of Webb Launch, NASA is Watching the Weather in Space

Webb Moved to Meet its Rocket

On Dec. 7, NASA’s James Webb Space Telescope was transferred to the final assembly building at Europe’s Spaceport in French Guiana to meet its Ariane 5 launch vehicle.

Stowed inside a special transport container and mobile clean room, Webb’s vitals were meticulously monitored throughout the entire process of moving between buildings.

Credit: © ESA-CNES-Arianespace; used with permission

The Ariane 5 rocket Webb will ride to space was moved to the same building on Nov. 29. Here, adjustable platforms allow engineers to access the launch vehicle and its payload.

The next steps ahead are to safely lift Webb to an upper platform which has been prepared so that Webb can be connected to the Ariane 5’s upper stage. After being connected to the rocket, technicians will move forward to encapsulate Webb inside Ariane 5’s specially adapted fairing.

Credit: © ESA-CNES-Arianespace; used with permission

In preparation for a Dec. 22 launch, ground teams have already successfully completed the delicate operation of loading the spacecraft with the propellant it will use to steer itself while in space.

Webb will be the largest, most powerful telescope ever launched into space. As part of an international collaboration agreement, ESA (the European Space Agency) is providing the telescope’s launch service. Working with partners, ESA was responsible for the development and qualification of Ariane 5 adaptations for the Webb mission.

Credit: © ESA-CNES-Arianespace; used with permission

Webb is an international partnership between NASA, ESA and the Canadian Space Agency (CSA).

Find out more about Webb here:

By Thaddeus Cesari, Webb science writer, NASA’s Goddard Space Flight Center, Greenbelt, Md.

Introducing the Webb Blog

This is it! It is less than two months until the Webb telescope finally launches, and we couldn’t be more excited. Webb is NASA’s next flagship observatory and a technological marvel, more than twenty years in the making. It has just arrived in Kourou, French Guiana – home to Europe’s Spaceport facility and our upcoming launch site. (More on that next week, including some amazing photos and video footage!)

We are starting a blog to keep you abreast of what is happening during the telescope’s launch and commissioning timeframe. The first science from the observatory won’t be available until next summer, but there are many exciting things along the way. We’ll also use this space to hear firsthand from some of the mission’s top scientists and engineers about the technical processes that are happening, their experiences with the mission, and the exciting discoveries that await us!

To begin, we asked the mission’s senior project scientist and Nobel laureate, John Mather, to reflect upon the mission that will define the next decade of astronomy:

“On behalf of all scientists and all curious people everywhere, thank you to the team who made the Webb telescope possible! It represents decades of work by over 10,000 of us, putting our hearts and minds and fingers together through troubles, nights, weekends, and COVID.

“Now we’re near launch, and everyone wants to know if I’m worried – will it work? My opinion has no effect on the hardware, but we did what it takes to win. We sketched, we argued, we worried, we analyzed, we made a plan, we wrote down everything, we made checklists, we built the parts, we put them together, we tested as though our lives depend on it. We have backup electronic systems for everything where we can. Everyone on the team knows how much this mission matters to the world.

“Our scientific colleagues are ready to go. We’ve decided where we’re going to look for the whole first year of scientific observations. We’ll be hunting for the first objects that grew out of the primordial big bang material, we’ll be looking at distant galaxies to see back in time, we’ll be looking inside dust clouds to see stars and planets being born today, we’ll be looking at planets around other stars to see if they have atmospheres, and we’ll be looking close to home at everything in the solar system from Mars on out.

“But before we do that, we have to set up the equipment. We’ve got an hour-by-hour plan, and it takes 6 months. First, we unfold the observatory by remote command, then we wait for its plastic sunshield to dry out, then we let the telescope cool down, then we focus it, then finally we check out the four instruments. They come from the U.S., Europe, and Canada, and they will make images and spectra, spreading out the light into rainbows that tell us what’s happening inside the stars and galaxies – what’s their chemistry, how hot are they, how are they moving? The data will come back by radio to the computers and scientists around the world. We’ll be asking and trying to answer: Where did we come from? How is life possible here on Earth?

“It will be worth the wait.”

—John Mather, Webb senior project scientist


By Alexandra Lockwood, project scientist for Webb science communications, Space Telescope Science Institute

And Jonathan Gardner, Webb deputy senior project scientist, NASA’s Goddard Space Flight Center