Earlier quoted context omitted.
The latency would probably kill you though.
Or the cold.
Or lack of atmosphere...but I digress. Plus I am sure that latency would be better than earth based sat transmissions
NASA Laser Communication System Sets Record with Transmissions to and from Moon
31–40 of 84 posts
Re: NASA Laser Communication System Sets Record with Transmissions to and from Moon
#32Re: NASA Laser Communication System Sets Record with Transmissions to and from Moon
#33How huge is a 1mm beam when it hits the moon (and visa-versa) ? I wonder if wolframalpha can tell me... Actually, I don't even know how to ask it the proper question. Can anyone make this formula work in wolfram? http://laserpointerforums.com/attachments/f51/17952-calculat... update: I think I figured this out as ((λ * L) / d)* 2 (((630nm in meters)*(380000km in meters)) / (1mm in meters)) * 2 Which would be a nearly…
Even if the laser is extremely low divergence (maybe NASA is using some huge gas laser or something), atmospheric effects will still cause significant widening of the beam.
Re: NASA Laser Communication System Sets Record with Transmissions to and from Moon
#34Re: NASA Laser Communication System Sets Record with Transmissions to and from Moon
#35The article cites 622 Mbps down, 20 Mbps error-free up. Is the implication that the 622 Mbps down is before error correction? Either way, it's pretty incredible. Even if the 622 Mbps down isn't completely error free, but maybe 99%, you just need to use a video compression algorithm that is error tolerant.
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Re: NASA Laser Communication System Sets Record with Transmissions to and from Moon
#36The article cites 622 Mbps down, 20 Mbps error-free up. Is the implication that the 622 Mbps down is before error correction? Either way, it's pretty incredible. Even if the 622 Mbps down isn't completely error free, but maybe 99%, you just need to use a video compression algorithm that is error tolerant.
Or FEC, and optionally reliable re-transmission. TCP won't work well due to the huge latencies involved.
TCP can work decently with high latency, it just needs bigger buffers and to be tuned for the delay. FEC is awesome.
Re: NASA Laser Communication System Sets Record with Transmissions to and from Moon
#37How huge is a 1mm beam when it hits the moon (and visa-versa) ? I wonder if wolframalpha can tell me... Actually, I don't even know how to ask it the proper question. Can anyone make this formula work in wolfram? http://laserpointerforums.com/attachments/f51/17952-calculat... update: I think I figured this out as ((λ * L) / d)* 2 (((630nm in meters)*(380000km in meters)) / (1mm in meters)) * 2 Which would be a nearly…
Even if the laser is extremely low divergence (maybe NASA is using some huge gas laser or something), atmospheric effects will still cause significant widening of the beam.
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Re: NASA Laser Communication System Sets Record with Transmissions to and from Moon
#38Earlier quoted context omitted.
Or we figure out how to use quantum entanglement or gravity as information transfer mechanisms.
Gravity propagates at the speed of light, too.
I think that's a debatable topic.
Some say it is just a pure geometric effect of curved space (and thus instantaneous), not a force of nature that propagates.
Re: NASA Laser Communication System Sets Record with Transmissions to and from Moon
#39There is an xkcd that seems awfully appropriate here - http://what-if.xkcd.com/13/ - shooting lasers at the moon.
Re: NASA Laser Communication System Sets Record with Transmissions to and from Moon
#40How huge is a 1mm beam when it hits the moon (and visa-versa) ? I wonder if wolframalpha can tell me... Actually, I don't even know how to ask it the proper question. Can anyone make this formula work in wolfram? http://laserpointerforums.com/attachments/f51/17952-calculat... update: I think I figured this out as ((λ * L) / d)* 2 (((630nm in meters)*(380000km in meters)) / (1mm in meters)) * 2 Which would be a nearly…
Have you seen this "What If?" post by xkcd?
It doesn't talk about the size of the beam as it hits the moon, but it's interesting noodling none-the-less.