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NASA Achieves Laser Communication With Lunar Satellite
New submitter EngnrFrmrlyKnownAsAC writes "Communicating with lasers has become the hot new thing. While most researchers are seeking faster throughput, NASA set its sights in a different direction: the moon. They recently announced the first successful one-way laser communication 'at planetary distances.' What did they send? An image of the Mona Lisa, of course. 'Precise timing was the key to transmitting the image. Sun and colleagues divided the Mona Lisa image into an array of 152 pixels by 200 pixels. Every pixel was converted into a shade of gray, represented by a number between zero and 4,095. Each pixel was transmitted by a laser pulse, with the pulse being fired in one of 4,096 possible time slots during a brief time window allotted for laser tracking. The complete image was transmitted at a data rate of about 300 bits per second.'"
where are the space sharks?
With stronger, cleaner signal they can obviously get better speed.
But how much room for improvement here, with better signal processing? Does someone here know about such things?
No budget left over to get FIOS?
My dream of running a BBS on the moon grows ever closer! Who wants to play tw2002 on my moon server?
> Every pixel was converted into a shade of gray, represented by a number between zero and 4,095.
Obviously 50 shades of gray wasn't enough..
...considering how tight this beam was, and that you'd have to be pretty much directly in its path to intercept the transmission.
I do not respond to cowards. Especially anonymous ones.
The Mona Lisa? Are you serious? Way to break tradition NASA, my heart weeps for Lenna:
http://www.cs.cmu.edu/~chuck/lennapg/lenna.shtml
Shouldn't have been Lena?
Wow, sent an e-mail as suggested when clicking on "use classic" banner, and got a fast response that addressed my msg
This is no joke. Anyone providing a BBS on the moon has a ready customer here.
It's also worth pointing out that the MPAA/RIAA aren't bribing the FBI enough yet to finance server seizures on the moon. There's a clear business opportunity there until they tighten their belts, sell off a few limos, and spend a lot more cocaine money on decent quality bribes.. :P
We can send and receive messages to rovers on Mars.
I seem to remember having a V.21 300 baud modem attached to my C64 about 30 years ago.
They have mirrors on the moon, that we routinely bounce lasers off of to measure distances and do Relativity experiments with. It's suddenly difficult to transmit information via laser? Why so slow? Why was this an accomplishment?
"Do not look at laser with remaining eye"
If laser communication overtakes radio for our own space equipment, it might explain the Fermi paradox - we cannot detect alien civilizations because the communicate with lasers (emitting no radio signals at all), making them undetectable to those not in the path of the beam.
"That's either incredibly asinine or the most brilliant troll I've ever read. Not sure which." -Anonymous Coward
Friggin sharks communicating with friggin laser beams on their heads.
So that's Pulse Position Modulation, yeah?
Why not use 2 different wavelength lasers (Or even 3 or more)
For two lasers (let it be greeen and blue) it would be binary transmission,
"4096" fits into 13 bits. Image transmission would be 315 times faster.
As I've been saying for years SETI doesn't have a hope in h**l finding the aliens because they use the much more efficient point to point message casting as opposed to the broadcasting in every direction used here on earth. Why use the inefficient method sending your message/data/... everywhere when it is really only destined for 1 place.
I think in 100 years we'll look back and see that the use or radio and the inefficient broadcasting methods was a short segment in our history. It will likely be the same for other developing races.
I recall a few years back they actually found something that looked like real alien communication. It couldn't be captured again. Of course it coul'n't be found again. We were no longer behind the target of the message beam.
not bad for moon to earth communications
They want their Hayes Smart Modem 300 back.
If you disagree with me on social issues, then it's pretty clear that you are a narrow-minded bigot.
So, the moon, which is 409,073 kilometers away at its furthest is "planetary distances"? What does that make the distance to Venus, which is 41 million kilometers at its closest or Mars, which is 56 million kilometers at its closest. Seems to me that this is only over about 1% of the shortest distance you could actually consider "planetary distances".
not 300. 30 baud is roughly 30 characters per second, or close to 8 words per second. 480 words per minute.
Nobody types that fast. Even the fastest typists won't go over about 100 words per minute (and then, not for very long).
You just know when you click it, it's gonna be a lame banana store site or something.
Defining Statistics and Social Research
who is completely underwhelmed by this "feat"?
They way they're doing it is too damned easy. I'd throw a little challenge into it by requiring that low bits must transmitted by bouncing them off the Apollo laser reflectors. Might require spinning up LRO to about 3000 rps unless it has two sensors.
"You must try to forget all you have learned. You must begin to dream." -- Sherwood Anderson
How wide is the beam when it reaches the craft? What are the theoretical limits of the width per distance?
Table-ized A.I.
This has been going on for a long time, and it has never offered anything meaningful to the ordinary guy.
What they're really doing is ejecting our paychecks into space.
We could see laser flashes just as easily as hear radio waves from parabolic dishes. http://www.cusabio.com/pro_11.html