STScI Logo

James Webb Space Telescope

JWST will be launched into a large halo orbit at the Sun-Earth L2 point. During transfer to L2 the different elements of JWST will be deployed and commissioning will start.

The observatory has five deployment stages involving the following elements: 1) spacecraft appendages (solar arrays, high gain antenna), 2) sunshield, 3) extend tower, 4) secondary mirror, and 5) primary mirror. All critical deployment points have heaters and can be unlatched and re-latched to relieve any residual long term stress in the structure, even in the cold of outer space.

L2 position SPIE orbit/trajectory

Deployment of the observatory will start fairly soon after launch, with the sunshade unfolding after 2 days and the secondary and primary mirror deploying after approximately 4 days. First light will occur at about 28 days after launch, initiating wavefront sensing and control activities to align the mirror segments. Instrument checkout will start 37 days after launch, well before the final L2 orbit insertion is obtained after 106 days. Hereafter the full commissioning starts and the observatory will be ready for normal science operations approximately 6 months after launch.

OTE deployment