On Falcon, and in the future with conventional Starship, Starlink launches are volume-limited, not mass-limited. Thus, a Starship with more interior space would allow them to send up many more satellites per launch.
When they get their production line up, we might see them launch Starlink in disposable second stages, dispensing with heat shielding and landing engines, and with substantially smaller fuel tanks, leaving room for more Starlink cargo. They could park the carriers in orbit, and gather up the Raptor engines to bring home once enough have piled up there; and maybe turn the empty hulls into a fuel depot.
Launching, say, 150 satellites at a time, that's more than a hundred launches to fill out the constellation. It should not be hard to find a use for some fraction of those hulls given they have already been boosted to orbit.
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.
> 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.
I don't think people are talking about changing Super Heavy.
> 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.
You'd have to build an entire new stage0 system, for starters, even if you've built a new one for starship 2.0 as it wouldn't accomodate the larger fairing size.