The L2 Lagrange point, one of the equilibrium points in the Earth-Sun system, is located 1.5 million kilometres from the Earth on the side opposite the Sun. This distance corresponds to one hundredth of the distance from the Earth to the Sun. Although the trip to L2 will only take about a month, the JWST will not be operational for another six months while the mirrors are aligned and calibrated.
During the first month of the mission, many steps will have to be successfully completed. First of all, it should be noted that the launch is a very short stage in the life of a satellite. Ariane 5 will operate for about ten minutes and the JWST will separate from the rocket after 30 minutes and set off on a direct trajectory towards L2. From that moment on, what is probably the most complicated deployment in the history of satellites will begin.
First, the 6-metre solar panels will be deployed immediately to provide the electrical power needed for the satellite to function properly, followed by the deployment of the telecommunication antenna. On the first day, the first of three small propulsive manoeuvres, known as mid-course correction manoeuvres, will take place to ensure that the satellite is in the correct orbit on arrival. The other deployment operations will start 2.5 days after launch and will take place over several days. The critical point will be the deployment of the JWST's solar shield, which consists of five layers of Kapton, each a few hundredths of a millimetre thick and the size of a tennis court. As the telescope observes in the infrared, it will have to be cooled to extremely low temperatures (-220 degrees Celsius) and the role of the solar shield will be to protect it from external light sources such as the sun, the earth and the moon, but also from the heat emitted by the satellite itself. The telescope with its primary and secondary mirrors can then be deployed.