Conversation so far:
what's the most powerful telescope in the world
The James Webb Space Telescope is the largest, most powerful and most technologically challenging space telescope ever built.
what does the james webb space telescope do
The JWST will provide improved infrared resolution and sensitivity over the Hubble Space Telescope, and will enable a broad range of investigations across the fields of astronomy and cosmology.

Question: when did development begin
Self-contained rewrite: when did development begin for the james webb space telescope