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NASA Laser Communication System Sets Record with Transmissions to and from Moon

nasa.gov

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Re: NASA Laser Communication System Sets Record with Transmissions to and from Moon

#41

Post by ck2 »

DanBC wrote: post #40
ck2 wrote: post #8

How 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? http://what-if.xkcd.com/13/ It doesn't talk about the size of the beam as it hits the moon, but it's interesting noodling none-the-less.

The end of that had me in tears. I think I like the "what-if" section more than the comics!

Gems like

Unfortunately, the laser energy flow would turn the atmosphere to plasma, instantly igniting the Earth’s surface and killing us all.

and another article

It's a shame humans wouldn't live this long, because at this point, something really neat would happen.

Re: NASA Laser Communication System Sets Record with Transmissions to and from Moon

#43

Post by VLM »

Kabacaru wrote: post #10

So fine for torrenting crappy for gaming?

I'm annoyed that gaming is defined solely as multi-player FPS twitch games. Astronauts / colonists into chess, go, poker, real role playing games, pretty much anything that happens in a casino, single player of any sort, wouldn't really notice.

Re: NASA Laser Communication System Sets Record with Transmissions to and from Moon

#45

Post by knowaveragejoe »

VLM wrote: post #43
Kabacaru wrote: post #10

So fine for torrenting crappy for gaming?

I'm annoyed that gaming is defined solely as multi-player FPS twitch games. Astronauts / colonists into chess, go, poker, real role playing games, pretty much anything that happens in a casino, single player of any sort, wouldn't really notice.

Besides, the speeds mentioned here would be more than enough for multi-player twitch FPS too.

Re: NASA Laser Communication System Sets Record with Transmissions to and from Moon

#46

Post by pilom »

peeters wrote: post #12

The 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.

Why is it easier to transmit from the moon to earth? Here we have more power and larger/better/faster/more tuned lasers than the space vehicle does. Seems like getting earth's transmit rate way up would be relatively easy while getting the vehicle's transmit rate up would be really really hard.

Re: NASA Laser Communication System Sets Record with Transmissions to and from Moon

#47

Post by 2close4comfort »

Ellipsis753 wrote: post #3
2close4comfort wrote: post #2

That is better than the connect at my house. I am moving there!

To NASA or the moon? I wouldn't think there's much good stuff to download from the moon but if you're on the moon then I'm sure there's plenty of cat videos you can download from Earth over that kind of connection.

With connectivity about 600x better than the average rural broadband connection. The direct application to purely to solve a problem it is great to see what we can do. That said it is kind of a bummer to see that once commerce gets involved that 1.5 dsl is good enough to claim your check from the FCC...but leaves a lot to be desired when trying to interact with the Modern world.

Re: NASA Laser Communication System Sets Record with Transmissions to and from Moon

#48

Post by zhouyunqing »

pilom wrote: post #46
peeters wrote: post #12

The 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.

Why is it easier to transmit from the moon to earth? Here we have more power and larger/better/faster/more tuned lasers than the space vehicle does. Seems like getting earth's transmit rate way up would be relatively easy while getting the vehicle's transmit rate up would be really really hard.

I think it's the problems of the receiver. On the earth, we can build more elegant noise reduction systems, larger amplifiers and larger antennas.

Re: NASA Laser Communication System Sets Record with Transmissions to and from Moon

#49

Post by bdegman »

VLM wrote: post #43
Kabacaru wrote: post #10

So fine for torrenting crappy for gaming?

I'm annoyed that gaming is defined solely as multi-player FPS twitch games. Astronauts / colonists into chess, go, poker, real role playing games, pretty much anything that happens in a casino, single player of any sort, wouldn't really notice.

Also once this is a real problem, hopefully there'll be enough people up there to fill up their own Battlefield servers with just moon players.
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