You'd need to build an entirely new stage0 system. How would a 15m fairing fit onto the current orbital launch pad?
Not saying it can't be done, just that it's not as simple as just whacking a larger fairing on, there are lots of considerarations to deal with. Perhaps it's worth it for 15m, but then again even a 9m would be a vast improvement from 2.4m
> For a relatively trivial fraction of the overall telescope budget, non-recurring engineering costs could weld together an expendable Starship variant (no TPS, no flaps, no landing legs) with a 15 meter diameter payload fairing. Almost overnight, endless gnashing of teeth about the relative mirror diameters of Luvoir or Habex, or the relative difficulty of performing coronography with a segmented, non circular mirror, go away.
As I've noted in other replies, you'd need an entire new stage0 to accomodate this. Even larger than the 2.0 planned. It'd be have to be made especially for this.
> The post mentions an expendable version at 15m d but that can't be done on either the current iteration (9m) or v2.0 (12m). The original plan was for 15m but that would require around 100 raptors to get it off the ground!
However, that's not obviously true. This is just a fairing. The fairing can be made wider w/o adding engines or making the booster (or the bottom of starship) wider.
Then you mentioned the stage zero issues, but if an expendable starship with a wider fairing doesn't need to be reused then there's plenty of space right now between starship's nose and the launch tower for a wider fairing, and a crane can be used to stack it instead of the chopsticks if the wider fairing makes using the chopsticks impossible. Even if modifications to stage 0 are needed -or a new one altogether-, if SpaceX ends up building more stage zeros elsewhere (like, say, at Cape Canaveral), they'll have a chance to accommodate larger fairings then.
Certainly. First things first. They have a year's worth of testing ahead of them just to make 100t to LEO reusable launch vehicle a thing. Once they've done that they'll be able to build a new stage zero, work on larger and smaller launch vehicles (smaller because why let others take the by then obsolete Falcon 9's business?) (larger only for large telescopes and such).
Not saying it can't be done, just that it's not as simple as just whacking a larger fairing on, there are lots of considerarations to deal with. Perhaps it's worth it for 15m, but then again even a 9m would be a vast improvement from 2.4m