NASA's James Webb Space Telescope


It’s easy to forget how long the James Webb Space Telescope has been in development.

Garth Illingworth, the former Deputy Director of the  Space Telescope Science Institute (STScI),  notes that work on the James Webb Space Telescope began over 30 years ago at STScI with a challenge to “think about the next major mission beyond Hubble.” The development of a mission concept came in September 1989, with a workshop held at STScI. The workshop, titled The Next Generation: A 10 m Class UV-Visible-IR Successor to HST, covered the scientific opportunities and technological challenges of such a mission and built on earlier research by key individuals.

The UV-Optical in Space Panel of the 1990 Decadal Survey pushed the concept along by recommending a 6-m cooled space telescope as a successor to Hubble. Development of the 8-m concept over the next two years focused on a cooled visible and infra-red telescope since it had become clear that it was technically impractical to include the UV capabilities. In 1993, the Space Telescope Institute Council appointed a committee to study 21st-century space-astronomy missions and two years later, the committee recommended a 4-m telescope — smaller than the 8- to 10-m NGST initially discussed, but retaining the very important capability of seeing infrared light. The eventual restoration of the NGST to 8-m was due to NASA Administrator Dan Goldin, who noted that a 4-m telescope was "such a modest thing".

For more about the early history of JWST, refer to Garth Illingworth’s article, NGST: The Early Days of JWST, in the STScI newsletter (2016, Volume 33, Issue 01).

The timeline below outlines key milestones in the history of the James Webb Space Telescope, starting with the NGST workshop at STScI in 1989 and followed by the formation of the committee in 1993.