[threeseed]

There is a 3GPP standard for satellite to phone connectivity which Iridium is adopting:

https://www.iridium.com/project-stardust/

[toomuchtodo]

Their 66 satellites are going to support a much lower aggregate constellation throughput and spot beam count vs StarLink. They’re fundamentally constrained by lift costs and low constellation satellite count.

Iridium has 48 spot beams per satellite each covering 250 miles. Each StarLink cell covers ~15 miles with a similar spot beam count, with 5,442 satellites currently operational (as of this comment).

https://planet4589.org/space/con/star/stats.html

(Disclosure: StarLink customer, no other affiliation)

[wkat4242]

Most of those sats don't support direct to cell though. But more will come of course.

And are the spot beams for direct to cell the same in size and quantity?

[toomuchtodo]

Good question. I could not find the cell size specifically for the LTE coverage, and agree it will take time for the constellation to turn over to maximize the direct to phone capability. Regardless, SpaceX launches more StarLink satellites in three flights (~69) than Iridium has in its entire constellation.