[mncharity]

> getting a telescope the size of the Keck telescopes into space probably won't be feasible for a long time

SpaceX is said to be discussing making a telescope out of a dedicated Starship. To simplify the telescope, and periodically return for maintenance. Like the telescopes of NASA's Scientific Balloon Program.

Except... Starship User Guide gives a payload envelope of 8 m diameter, and "100+" metric tons to LEO. Launch cost is TBD, but $30M would be failure (similar to Falcon 9 internal cost), and $2M is said to be an aspirational goal. Which is what a balloon flight costs, for a day or so, a few tons, and couple of meters of mirror.

So 8 m to Keck's 10 m. Half the area. But with balloon speed-tape (aerospace gaffers tape) pragmatics, not Webb insanity. Although... how about a "simple" pivot-out-to-hex of 20+ m diameter?

Starship changes the constraint envelope by multiple orders of magnitude. And that's starting to be reflected in strawman project sketches. Which seem low visibility for now. But unless something goes seriously wrong, very won't be in not a long time. (Edit: removed a misleading sentence).

[mr_toad]

> So 8 m to Keck's 10 m

No need to stop at one. Build hundreds, put them in orbit around the sun and turn them into an array capable of imaging exoplanets.

[mncharity]

> hundreds [...] into an array

Or even just a few. :) A constraint is that optical-frequency interferometry arrays need to directly combine the input light, rather than being able to sample and simply combine data, as with radio frequencies. So optical telescopes would need to be docked. But yes, if both launch and instrument costs dramatically decline, "can I have two? four? eight? more?" becomes a fun question. At a minimum, as launch and recovery becomes inexpensive, there's less point in leaving a backup instrument warehoused on the ground.

[justaguy88]

> reflected in strawman project sketches

Do you have a link to some of them?

[mncharity]

Sorry, I don't. It's not something I follow, and with access to campuses still restricted, I've only the occasional stumbled-on gossip to go on. That last "Monster submarine surfacing" sentence was excessive. And calling $30M failure, given the difference in payload mass, was just silly. I was tired, and should have punted or pruned the comment.