Comment by lxgr

4 hours ago

> Starlink’s special sauce is the low earth orbit.

Arguably Starlink's special sauce is quantity of satellites and massively higher bandwidths combined with high-gain, electronically steered beams on both sides (i.e. terminal and satellite).

None of these are net-new as technologies: We've had LEO based telecommunications satellites for over two decades now (Iridium and Globalstar, the former of which even has in-space forwarding as well), as well as directional beams on both sides, but rarely all in one system and never at this scale.

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lxgr

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mbreese  2 hours ago

In my opinion, the quantity of satellites needed is a function of the height of the satellites. You only need a large constellation because they are moving so fast relative to the earth. This means that each satellite can only see a limited arc at a time. So, in order to cover a large enough area, you have to have multiple satellites following after each other.

The phased array antenna is also a function of this. Each satellite is moving so much that you need to have an antenna following the satellite across the sky.

So, once Starlink decided to have a low earth orbiting constellation (for better latency and bandwidth), the other features (quantity and a steerable antenna) became requirements to have a functional system.

  • lxgr  33 minutes ago

    Altitude does impose a lower bound for the number required for global coverage but they have much, much more than geometrically needed. Iridium gets by with about 70 and is only marginally higher.

    As for steered terminals, you actually only really need these once you have more than one satellite visible in the sky at the same time. Without that, they’re purely a power efficiency feature.