How Do We Make Future Space Astronomy Missions Happen?

The James Webb Space Telescope is the successor to the Hubble Space Telescope. How was that mission chosen over all the others?
NASA has begun four concept studies of exciting major space observatories that could launch sometime in the coming couple decades. Who will determine what astronomy science goals will be the highest priorities for the 2020s? How is this done and how are the missions chosen to achieve those goals?
Please join our regular hosts, Tony Darnell, Alberto Conti, and Harley Thronson, as they discuss with Drs. John O’Meara (Saint Michael’s College) and Joel Parriott and Ashlee Wilkins (both at the American Astronomical Society) which among many alternatives the most exciting science and most capable space astronomy missions are identified and, eventually, chosen.