re: #5 Hal_10000

Because the JWST has been sucking up all the funds several other proposed, second tier (much less expensive) space based astronomy assets have been put on hold. Thus there has been some grousing in the astro community over the JWST.

In fairness to the JWST team, they are attempting to build a cutting edge satellite and telescope. Think of this - a folding mirror, a design to work in the infra-red which means active cooling in space, on a platform that is located far enough away from Earth that it will not be reachable to be repaired (unlike the HST) so it has to work without any further tinkering when launched.

The infra-red capability is important - being able to detect the infra-red portion of the spectrum is what will tell scientists the composition of planetary atmospheres as well as early stars/galaxies. The JWST will be able to see portions of the spectrum that ground-based telescopes can only do so poorly because of the Earth’s atmosphere.

If the JWST is cancelled, though, it might free up some money for a couple of the less expensive proposed satellites, which can be built for substantially less than a billion dollars.