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0 pointsshaklee33y ago0 comments

are you really comparing the moon to the earth with two satellites at much closer distances moving rapidly?

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> are you really comparing the moon to the earth with two satellites at much closer distances moving rapidly?

I'm comparing to LEO to ground, which has a higher rate of angular movement (e.g. harder to point at) than LEO-to-LEO in the same shell, among other things.

I've built systems that point to sub-arcsecond precision at satellites in LEO. It's not quite an off-the-shelf controls problem (e.g. good luck getting a COTS motion controller to hit-a-fast-moving-target-at-a-chosen-time, rather than follow a track and not care about time) but it's not super hard, either.

shaklee3OP3y ago

you should probably have worked for Facebook a few years back when they threw billions at the problem and couldn't solve it.

mlyle3y ago

Citation needed, for Facebook: A) spent billions of dollars on this specific problem (free space optical links in space), and B) couldn't solve it.

Given that there's systems that have successfully flown doing links from GEO to LEO (e.g. high angular rates again), using several year old conservative technology, it's not so bad.

There's a million little details, of course. Just conduction cooling for fast optical transceivers is going to be annoying in space, for instance.

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mlyle3y ago

> are you really comparing the moon to the earth with two satellites at much closer distances moving rapidly?

I'm comparing to LEO to ground, which has a higher rate of angular movement (e.g. harder to point at) than LEO-to-LEO in the same shell, among other things.

shaklee3OP3y ago

you should probably have worked for Facebook a few years back when they threw billions at the problem and couldn't solve it.

mlyle3y ago

Citation needed, for Facebook: A) spent billions of dollars on this specific problem (free space optical links in space), and B) couldn't solve it.

Given that there's systems that have successfully flown doing links from GEO to LEO (e.g. high angular rates again), using several year old conservative technology, it's not so bad.

There's a million little details, of course. Just conduction cooling for fast optical transceivers is going to be annoying in space, for instance.

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j / k navigate · click thread line to collapse