James Webb Space Telescope Post-Launch Deployment Timeline

1ST HOUR: Starting at liftoff, the Ariane rocket will provide thrust for a little over 8 minutes. Webb will separate from the Ariane V launch vehicle a half hour after launch and we will deploy the solar array immediately afterward. We will also release several systems that were locked for launch.

1ST DAY: Two hours after launch we will deploy the high gain antenna. About ten and a half hours after launch, Webb will pass the Moon’s orbit, nearly a quarter of the way to L2. Twelve hours after launch there will be the first trajectory correction maneuver by small rocket engines aboard Webb itself.

1ST WEEK: The second trajectory correction maneuver will take place at 2.5 days after launch. We will start the sequence of major deployment just after that. The first deployments are the fore and aft sunshield pallets, followed by the release of remaining sub-system launch locks. The next deployment is the telescope in which the telescope and the spacecraft bus move apart from each other by about 2 meters when the deployable tower assembly extends. The full sunshield deployment with unfolding and tensioning of the membranes can then be initiated. At 6 days we deploy the secondary mirror, followed by the side wings of the primary mirror.

1ST MONTH: As the telescope cools down in the shade of the deployed sunshield, we will turn on the warm electronics and initialize the flight software. At the end of the first month, we will do the mid-course correction that ensures that Webb will achieve its final orbit around L2. Although the telescope cools to near its operating temperature, the Integrated Science Instrument Module (ISIM) is warmed with electric heaters to prevent condensation on the instruments as residual water trapped in the materials making up the observatory escapes to the vacuum of space.