NASA plans to launch the James Webb Space Telescope into orbit Dec. 18, 2021, to serve as the premier deep space observatory for the next decade.
Webb's development cost and time was vastly underestimated, and it's finished a rigourous testing phase. (Unlike Hubble, which has remained in service longer than expected, there will be no astronaut repair missions for Webb, which will orbit the sun rather than the Earth.)
NASA JPL used to provide webcam feeds on the clean room where Webb was being constructed, and I have good memories of glancing at them, I now realize. Here's a quick video that conveys the telescope's stature and majesty.