NASA Statement on James Webb Space Telescope Launch Readiness
NASA’s James Webb Space Telescope, which will be the premier observatory of the next decade, remains on schedule for a launch readiness date no earlier than Oct. 31, 2021.
Webb will ship to the launch site in August with little to no schedule margin; launch processing will take two months. The observatory has completed all the post-environmental testing deployments, and it is in its final integration and folding stages. Final stow, closeout, and pack and ship are imminent. We are working closely with the European Space Agency (ESA) and Arianespace on establishing the launch date. We will launch approximately four months after the first launch of the Ariane 5 this year, which is scheduled for late July. Webb has no launch date constraints; hence, it can launch almost any day of the year.
Webb will study every phase in the history of our universe, including the first luminous glows after the creation of the cosmos, the formation of solar systems capable of supporting life on planets like Earth, and the evolution of our own solar system.
Source: NASA – James Webb Space Telescope