The James Webb Space Telescope will be launched on an Ariane 5 rocket, one of the world's most reliable launch vehicles.


Webb Launch

Ariane 5 Launch
Webb will be launched on an Ariane 5 Launch Vehicle.Credit:

Launch Date

Webb's launch date is set for December 18, 2021 07:20 EST.

Launch Vehicle

The James Webb Space Telescope will be launched on an Ariane 5 rocket. The launch vehicle is part of the European contribution to the mission. The Ariane 5 is one of the world's most reliable launch vehicles capable of delivering Webb to its destination in space. The European Space Agency (ESA) has agreed to provide an Ariane 5 launcher and associated launch services to NASA for Webb. The Ariane 5's record for successful consecutive launches is 80 (as of June 28, 2017).

Launch Location

image of the earth showing French Guiana

Webb will be launched from Arianespace's ELA-3 launch complex at European Spaceport located near Kourou, French Guiana. It is beneficial for launch sites to be located near the equator - the spin of the Earth can help give an additional push. The surface of the Earth at the equator is moving at 1670 km/hr.

Additional Details

The Launch Segment has 3 primary components:

1. Launch Vehicle: an Ariane 5 with the cryogenic upper stage. It will be provided in the single launch configuration, with a long payload fairing providing a maximum 4.57 meter static diameter and useable length of 16.19 meters.

2. Payload Adapter, comprising the Cone 3936 plus ACU 2624 lower cylinder and clamp-band, which provides the separating mechanical and electrical interface between the Webb Observatory and the Launch Vehicle.

3. Launch campaign preparation and launch campaign. The launch campaign preparation and launch campaign is the mutual responsibility of NASA, ESA, NGAS, and Arianespace.

Webb Launch Configuration

For the telescope to fit into the rocket, it must fold up. These images show how it fits into the rocket fairing. Images courtesy of

Ariane 3
Ariane 4
Ariane 2

Post Launch Deployment

After launch, the telescope will deploy on its 30-day, million-mile journey out to the second Lagrange point (L2). This video shows the deployment procedure, timeline, and location of the satellite during deployment. More about the telescope's final orbit around L2.

Related Content

Watch an Ariane 5 rocket launch!

More Information

Read more about the Ariane 5.

Read more about the launch site.

launch site