[Starlink] Re: AI IN SPACE: Post from Elon Musk (@elonmusk)

[David Lang <david@lang.hm>]

sun synchronous orbits are in sunlight 100% of the time at any altitude.

David Lang

On Thu, 20 Nov 2025, Kenneth Porter via Starlink wrote:

> Date: Thu, 20 Nov 2025 09:03:00 -0800
> From: Kenneth Porter via Starlink <starlink@lists.bufferbloat.net>
> Reply-To: Kenneth Porter <shiva@sewingwitch.com>
> To: starlink@lists.bufferbloat.net
> Subject: [Starlink] Re: AI IN SPACE: Post from Elon Musk (@elonmusk)
> 
> It's all geometry. Recall that the Earth is 8000 miles in diameter. LEO is 
> just a few hundred  miles above the surface, so you'll spend half your orbit 
> in shadow. If you put the satellite much higher and in a tilted orbit, it 
> spends much less time in shadow. Much like how the Earth and Moon rarely 
> eclipse each other.
>
> Lagrange points L4 and L5 are advantageous because the orbits are stable, 
> compared to the other Lagrange points. The downside is that they're 250,000 
> miles away, in the same orbit as the moon. One leads the moon by 60 degrees 
> while the other lags it. They'd be good if you used lunar material to build 
> your satellites, but bad if you raise the material from the Earth. A geosync 
> orbit is about 22,000 miles above sea level (26,000 radius) but do you need 
> to maintain position over the same point on the surface?
>
> A medium Earth orbit (MEO) is probably a good compromise for Earth-sourced 
> materials.
>
> Low Earth orbit is crowded but cheap and suffers the shadow problem. Probably 
> not a good place.
>
> https://en.wikipedia.org/wiki/Medium_Earth_orbit
>
> https://en.wikipedia.org/wiki/Lagrange_point
>
> https://en.wikipedia.org/wiki/Geosynchronous_orbit
>
> https://en.wikipedia.org/wiki/Low_Earth_orbit
>
>
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