* To be useful to science, the telescope needs a huge diameter which is more than can be launched so they had to make a folding telescope that can be later unfolded.
* We only get a single chance for success so testing becomes critical. Lot of testing was needed to make sure everything would work out in the end.
* The technology needed was pushing the limits of what we are capable of so lot of R&D needed.
* To be useful to science, the telescope needs a huge diameter which is more than can be launched so they had to make a folding telescope that can be later unfolded.
* We only get a single chance for success so testing becomes critical. Lot of testing was needed to make sure everything would work out in the end.
* The technology needed was pushing the limits of what we are capable of so lot of R&D needed.