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Comment by huijzer | Hacker News Reader

Eliminate deep sea cables? How are they going to send the lasers in a curve from one base station to the next?

Starlink is already working on a backhaul from satellite to satellite. Interestingly, they claim that they can speed up data transfers by 50% over long distances. Musk said that in a Tweet which I cannot find now. I looked a bit into it and the reason seems to be that light trough a cable can only reach 70% of the speed of light while lasers through the vacuum of space can reach the speed of light.

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> Eliminate deep sea cables? How are they going to send the lasers in a curve from one base station to the next?

They use a special laser that gives the photons a bit of topspin.

> Eliminate deep sea cables? How are they going to send the lasers in a curve from one base station to the next?

Multiple satellites. The ISS can see about a thousand miles in each direction to the horizon, so you'd only need to bounce across a couple to cross the Atlantic.

Sending lasers in a curve should be easy if you use circular polarization. /s

You would send to a satellite in view; my orbital dynamics are poor, but I think with the LEO orbits, you may need to relay in space for a cross ocean link, as it seems unlikely one satelite would have a view of both sides. But Telstar 1 and 2 were used for cross-Atlantic microwave relay with a single satellite in view at a time. Future Telstars were geostationary, because satellite tracking was a lot of work (and with only two satellites, service was intermittent as they were only in view for a portion of their orbits). I imagine satellite tracking for lasers is going to be very difficult as well.

How hard can it be

To be clear, Starlink is already doing this. Their satellites have laser links that connect them to each other.

They’ve launched satellites with laser links, but I don’t think they’ve got the satellite-to-satellite links active yet. https://www.starlink.com/technology says “testing” for that feature.

The website is out of date.

They are already providing service over open ocean out of reach of one hop to base station.

> How are they going to send the lasers in a curve from one base station to the next?

All you need is a well-placed black hole in Earth’s atmosphere.

> Musk said that in a Tweet

This gives me negative confidence in the claim

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