So they're going to go from basically no maritime coverage to having the world's oceans fully covered within the next two quarters? That's pretty impressive, if they can actually pull it off.
That is, that reflects a leap in technology, not an incremental growth from putting more satellites in orbit.
Nope, all v1.5 sats have them, so everything launched since January 2021. They experimented with them earlier for polar orbit sats. At this point that's by far the majority of the constellation and either approaching or at critical mass for the mesh. They're probably testing it globally now.
To sibling: they definitely need Starship, but not so much for pure launch numbers as the ability to launch v2.0 at all. F9 fairing isn't big enough. 2.0 will let them shrink cell sizes and improve density and performance which they need too (obviously now more in light of yesterday's announcement). More 1.5 sats wouldn't help as much with that, though the mesh will help relieve ground station chokes as well as ilenabling beyond station service.
Inter satellite links are basically fiber, just without the fiber (instead they just point the laser in the right direction and rely on the fact that space is empty). Up and down has to use valuable radio spectrum, handle interference and atmospheric effects, etc.
Right now Starlink is a bent pipe model. The customer's station connects to a satellite which relays data to the closest ground station. Therefore, the satellite must be in contact with both the customer station and a ground station at the same time. This is not possible over oceans.
Newer Starlink satellites also have a satellite to satellite laser link which is intended to allow relay from consumer station -> satellite -> other satellite -> ground station to provide coverage over oceans, but this functionality has not yet been enabled and relies on enough satellite density that each satellite can see a neighbor.
It will mainly depend on having enough marine subscriber terminals in place, scattered around the world on shipping routes, to ping-pong the packets through. Presumably they already have authority to route other subscribers' traffic through "your" terminal.
You know, sharks with frickin' laser beams attached to their heads.
I understand you are enamored with the idea of using ground repeaters. It is, however, not what SpaceX is doing. They have been very open from the start that they intend to move the entire transport layer to orbit, and they have launched more than a thousand satellites capable of doing that with laser links. That's what they are using.
Starlink can get full ocean-wide coverage with software today, or hardware after they have lofted enough of it, their choice. Immediate practicality depends on how fast they deploy marine and aircraft terminals. Full coverage of course depends on having lots of such terminals. They could speed that up if they care to.