Precise Ariane 5 launch likely to extend Webb’s expected lifetime

Webb’s precise launch on an ESA-provided Ariane 5 rocket was performed by Arianespace on behalf of ESA from Europe’s Spaceport in French Guiana – photo: ESA ©

After a successful launch of the NASA/ESA/CSA James Webb Space Telescope on 25 December, and completion of two mid-course correction manoeuvres, the Webb team has analysed its initial trajectory and determined the observatory should have enough propellant to allow support of science operations in orbit for significantly more than a ten-year lifetime (the minimum baseline for the mission is five years). This was reported by the European Space Agency (ESA) on 29 December.

The analysis shows that less propellant than originally planned is needed to correct Webb’s trajectory toward its final orbit around the second Lagrange point known as L2, a point of gravitational balance on the far side of Earth away from the Sun. Consequently, Webb will have much more than the baseline estimate of propellant – though many factors could ultimately affect Webb’s duration of operation.

The accuracy of the launch trajectory had another result: the timing of the solar array deployment. That deployment was executed automatically after separation from the Ariane 5 based on a stored command to deploy either when Webb reached a certain attitude toward the Sun, ideal for capturing sunlight to power the observatory, or automatically at 33 minutes after launch.

Because Webb was already in the correct attitude after separation from the Ariane second stage, the solar array was able to deploy about a minute and a half after separation, approximately 29 minutes after launch.