The rocket family that launched the James Webb Space Telescope in 2021 was Ariane 5.
The European Space Agency launched Webb aboard an Ariane 5 ECA from Europe’s Spaceport in Kourou, French Guiana, on 25 December 2021. The launch vehicle placed the observatory on a precise trajectory toward the Sun–Earth L2 point, reducing the fuel Webb needed for its journey and operations.
Ariane 5 was chosen for its strong launch record and accurate orbital insertion. Webb then unfolded its solar array, antenna, sunshield and segmented primary mirror during a complex sequence of deployments. The observatory reached its operational halo orbit around L2 roughly 1.5 million kilometres from Earth.
Webb’s 6.5-metre primary mirror observes mainly infrared light. Its sunshield keeps the telescope and instruments extremely cold, allowing them to detect faint heat from distant galaxies, stars and planets.