What launch vehicle carried JWST into space?

The James Webb Space Telescope was carried into space by an Ariane 5 rocket. It launched on December 25, 2021, from Europe’s Spaceport in Kourou, French Guiana.

Ariane 5 was operated by Arianespace and supplied as a major European contribution to the NASA-ESA-CSA mission. Its reliability and precise launch performance were especially valuable because Webb was an exceptionally large, delicate spacecraft with no realistic option for astronauts to repair it after launch.

The rocket’s upper stage placed Webb on an extremely accurate trajectory toward the Sun-Earth Lagrange point L2, about 1.5 million kilometres from Earth. That precision mattered: a good launch reduced the amount of fuel Webb needed for its trajectory correction and helped preserve fuel for station-keeping and attitude control throughout the mission.

Ariane 5 separated from Webb roughly 27 minutes after liftoff. The observatory then began a demanding sequence of deployments, including its solar array, antenna, mirror, and five-layer sunshield. Falcon Heavy, Atlas V, and the Space Shuttle were not involved in Webb’s launch.