1993 — Space Telescope Institute Council appoints a committee to study 21st century space-astronomy missions.

1995-1996 — The committee recommends, as a successor to Hubble, a significantly larger telescope capable of seeing infrared light. NASA selects Goddard Space Flight Center and the Space Telescope Science Institute to study its feasibility. Three independent government and aerospace teams determine that such an observatory is feasible.

1997 — NASA selects teams from the Goddard Space Flight Center, TRW, and Ball Aerospace to fine-tune the telescope's technical and financial requirements.

1999 — NASA chooses Lockheed Martin and TRW (which in 2002 became Northrop Grumman Space Technology/Ball Aerospace) to conduct "Phase A" mission studies, preliminary analysis of the design and cost.

2002 — Based on two "Phase A" studies, NASA selects the design of TRW/Ball Aerospace to continue in "Phase B" detailed design studies, which examine the performance and cost of the chosen design. The telescope is renamed from the Next Generation Space Telescope to the James Webb Space Telescope. TRW, bought by Northrop Grumman, becomes Northrop Grumman Space Technology. NASA selects the flight science working group and the team responsible for developing the Near Infrared Camera.

2004 — Construction begins on certain telescope parts that require extensive, long-term work -- in particular, Webb's science instruments and the 18 segments of the primary mirror.

2005 — NASA approves the use of the European Space Agency-provided Ariane 5 rocket to launch Webb into its operating orbit. This completes the contributions of the ESA and the Canadian Space Agency in the Webb program.

2006 — The science instrument teams for the Near Infrared Camera (NIRCam) and the Mid-Infrared Instrument (MIRI) pass their critical design reviews and initiate construction of the flight instruments. All Webb's essential technologies are tested successfully under flight conditions.

2007-2008 — NASA will have the mission reviewed by internal and external groups. The internal "preliminary design review" and external "non-advocate review" will take place before NASA commits to phases C and D . Phases C and D entail detailed design, procurement, testing and assembly of telescope components. Construction begins in earnest.

2009 — The primary mirror will be completed. The telescope’s science instruments will be delivered to NASA.

2012 — The assembled telescope and its instruments will be tested in a giant cryogenic vacuum to see if they function properly in the frigid temperatures of space.

2013 — Scheduled launch of the James Webb Space Telescope.

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