CLEARANCE: Top Secret
- Sep 26, 2008
- Reaction score
The original WFIRST mission proposal was for a much smaller mirror, the whole thing built from scratch. This would have been cheaper, according to just about everybody.The Wikipedia link says using a spare NRO telescope mirror
“.... provided important political momentum to the project, even though the telescope represents only a modest fraction of the cost of the mission and the boundary conditions from the NRO design may push the total cost over that of a fresh design.”
which was my point. I don’t think (or at least hope) nobody would propose a follow on Hubble just because a spare primary exists. WFIRST proposals may have sidetracked themselves using the spare mirror argument rather than sticking with a telescope design optimized for the requirements. If mapping dark energy effects is important, it can compete directly on that basis.
Former NASA Associate Administrator for the Science Mission Directorate John Grunsfeld (essentially the guy at NASA who was then in charge of all the science stuff) said a number of times in public that he could not find political support to fund that proposal. It was not until after the NRO mirror became available that the political leadership (White House, Congress) became interested in WFIRST. So, according to Grunsfeld, it was the case of do you want the original proposal, which nobody is going to fund, or do you want this new one, which is different, and will cost more, but which people will fund?
Now there are people who disagreed with Grunsfeld and argued that NASA should have stuck to the original specifications, but they were not in the position that he was. He saw the funding situation differently.
The new much larger WFIRST mirror does some different science than the original proposal. Essentially, it trades off looking farther into the infrared (because the mirror cannot get colder) in return for much larger collection area. So some scientists are unhappy with the loss of the farther IR, and some scientists are happy with the greater collecting power.
It's common to simply heap scorn on NASA and say that they cannot manage anything and keep it on cost. But who else does this stuff? Who is better at doing these things than NASA? These things are not easy to do. And this is a case where, at least according to a senior NASA official, the cheaper WFIRST option simply was not exciting enough to get funded. So do you want 100% of nothing or 80% of something? That was apparently the choice in this case.
(Oh, there are a lot more complicated aspects to this as well, like the number of instruments and how the astrophysics community uses these big telescopes. These are just the basic ones.)