We Are Go For Launch!

Webb has been confirmed as being go for launch, and the countdown clock was started!  With weather reports looking favorable, the team authorized fueling of the Ariane 5, which began at 3 am EST.

Arianespace will measure winds at high altitude with the help of balloons to ensure absolute safety for the launch. Meanwhile the team continues to monitor Webb which is kept in a stable condition in the fairing. The team is monitoring temperatures, relative humidity, and cleanliness of the air entering the fairing – critical parameters to keep Webb cool, dry, and clean before liftoff.

Our broadcast of launch will begin at 6 am and can be watched on nasa.gov/live.  You can also follow along on the NASA app, and on social with the hashtag #unfoldtheuniverse.

Launch teams wearing Santa hats monitor the Webb telescope countdown from a control room.
Launch teams monitor the countdown to the launch of Arianespace’s Ariane 5 rocket carrying NASA’s James Webb Space Telescope, Saturday, Dec. 25, 2021, in the Jupiter Center at the Guiana Space Center in Kourou, French Guiana. The James Webb Space Telescope (sometimes called JWST or Webb) is a large infrared telescope with a 21.3 foot (6.5 meter) primary mirror. The observatory 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)