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NASA Achieves Laser Communication With Lunar Satellite

Soulskill posted about a year and a half ago | from the and-i-can't-even-shine-my-penlight-at-airplanes dept.

Moon 99

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.'"

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99 comments

where are the space sharks? (0)

Joe_Dragon (2206452) | about a year and a half ago | (#42635471)

where are the space sharks?

Re:where are the space sharks? (1)

Tablizer (95088) | about a year and a half ago | (#42636679)

Right next to your flying car.

This is awesome (0)

Anonymous Coward | about a year and a half ago | (#42635511)

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?

Re:This is awesome (4, Insightful)

K. S. Kyosuke (729550) | about a year and a half ago | (#42635595)

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.

I have an idea. What if, instead of this encoding, they used twelve time slots for each pixel and, by either sending or not sending a pulse, transmitted a small amount of information with each (non)pulse? Then, they could interpret the slots by repeatedly adding a one or zero and multiplying the whole thing by two. I think I've read about it somewhere...

Re:This is awesome (1)

click2005 (921437) | about a year and a half ago | (#42635661)

i can improve yours. one, zero or penguin allows for all possibilities.

Re:This is awesome (1)

Dekker3D (989692) | about a year and a half ago | (#42636223)

So you want to shoot laser penguins at the moon?

I like the way you think, but PETA might not.

Re:This is awesome (1)

evilviper (135110) | about a year and a half ago | (#42635885)

What if, instead of this encoding, they used twelve time slots for each pixel and, by either sending or not sending a pulse, transmitted a small amount of information with each (non)pulse?

Doesn't work that simply or easily over an unreliable medium... A BIRD flying by at the wrong time could turn a string of ones into zeros. Plus there are similar issues of clock-sync... With a long run of zeros, is your timing precise enough on both ends to ensure that you know EXACTLY how many zeros there were supposed to be in that time period of no signal? Maybe it was 200 zeros, maybe it was 199?

But it's probably more of an issue that sending "zeros" at all, ever, wasn't an option. They were piggy-backing on a laser being used for other purposes, they couldn't shut it off for however long they wanted... They could only modify the routine slightly, to test of a proof of concept. And with a proof of concept, a visual representation is a lot easier to comprehend (see the photo before reed-solomon ECC) than a lot of statistics...

Re:This is awesome (1)

Dekker3D (989692) | about a year and a half ago | (#42636239)

If you can't send zeroes, you could encode data in the length of a laser pulse instead. Use error correction techniques to reduce the chance of errors. A checksum should have very low overhead but decrease your chances of errors immensely. If you're feeling silly, you could even use differently coloured lasers and hope they all hit near the same spot. Disco SMS :D

Re:This is awesome (1)

pipatron (966506) | about a year and a half ago | (#42637627)

Uhm yeah, these are guys at NASA transmitting data to the moon. Maybe you should give them a call and tell them all you know about binary digits, checksums and error correction?

Re:This is awesome (0)

Anonymous Coward | about a year and a half ago | (#42646279)

If you're feeling silly, you could even use differently coloured lasers and hope they all hit near the same spot.

Umm, no. Chromatic aberration and all that.

Re:This is awesome (4, Informative)

AmiMoJo (196126) | about a year and a half ago | (#42635893)

Because they can't reliably send individual bits. If you RTFA (I know, I know...) it shows that there is a fair bit of error and quite a few lost pixels. Rather than sending bits they send a pulse of a certain length per pixel, and if the edge of that pulse is distorted somehow they just lose some intensity resolution and don't end up with totally corrupted digital data.

It's kind of analogue. The timing method they use is a bit like PWM with one cycle per pixel, and actually there are far fewer than 4096 shades reliably transmissible, that is just the range they measure.

Re:This is awesome (3, Informative)

WrecklessSandwich (1000139) | about a year and a half ago | (#42636169)

The timing method they use is a bit like PWM with one cycle per pixel, and actually there are far fewer than 4096 shades reliably transmissible, that is just the range they measure.

It would actually be PPM [wikipedia.org] (pulse-position modulation).

Re:This is awesome (0)

Anonymous Coward | about a year and a half ago | (#42652313)

Because they can't reliably send individual bits. If you RTFA (I know, I know...) it shows that there is a fair bit of error and quite a few lost pixels. Rather than sending bits they send a pulse of a certain length per pixel, and if the edge of that pulse is distorted somehow they just lose some intensity resolution and don't end up with totally corrupted digital data.

It's kind of analogue. The timing method they use is a bit like PWM with one cycle per pixel, and actually there are far fewer than 4096 shades reliably transmissible, that is just the range they measure.

They will be able to use symbol-correction techniques later on to transmit higher bit-rates.

Re:This is awesome (1)

milkmage (795746) | about a year and a half ago | (#42636129)

"transmitted a small amount of information with each (non)pulse?" ...non pulse? so the absence of light is data too?
doesn't that mean the image would have to be transmitted in momchrome (vs greyscale)

  "Every pixel was converted into a shade of gray, represented by a number between zero and 4,095" ..whatever. this whole thing is kind of over my head /woosh

Re:This is awesome (1)

Dekker3D (989692) | about a year and a half ago | (#42636245)

Duration of the pulse or nonpulse. That's how you get 0-4095

Re:This is awesome (2)

Tom Womack (8005) | about a year and a half ago | (#42642493)

The laser-tracking protocol is defined to run at 25 pulses a second; pulling them back and forward by tiny amounts, to take advantage of the electronics in the orbiter that are designed to measure tiny time differences in order to do the LIDAR altimetry, is a really nifty classic NASA hack.

But the press release did not make a good job of pointing out that NASA were working under that restriction. Obviously if you were trying to do laser communication you'd do something else; ESA have done 50Mbit/second laser communication from low-Earth orbit to geostationary and from geostationary back to Earth, with their Artemis satellite.

300 bits per second? (3, Interesting)

SternisheFan (2529412) | about a year and a half ago | (#42635531)

No budget left over to get FIOS?

Re:300 bits per second? (1)

davester666 (731373) | about a year and a half ago | (#42635953)

Verizon isn't bringing it to, well, anywhere else anymore.

Re:300 bits per second? (1)

hackertourist (2202674) | about a year and a half ago | (#42638827)

They tried that, but the spacecraft has been in lunar orbit for a while now and the cable got all tangled up.

Re:300 bits per second? (1)

SternisheFan (2529412) | about a year and a half ago | (#42639051)

They tried that, but the spacecraft has been in lunar orbit for a while now and the cable got all tangled up.

Well, see, that explains why they decided to go with wireless. :)

300 bits per second? (4, Funny)

Ardeaem (625311) | about a year and a half ago | (#42635545)

My dream of running a BBS on the moon grows ever closer! Who wants to play tw2002 on my moon server?

Re:300 bits per second? (3, Funny)

VortexCortex (1117377) | about a year and a half ago | (#42635687)

Who wants to play tw2002 on my moon server?

I do. 300 Baud is a nice reading speed...
But First!...

He who would negotiateth a handshake of that breadth must answer me these questions three, Ere the ATDT ye see...
0. What is your FidoNet node address?
1. What number of in & out dials have you?
2. What is the land area coverage of an unladen local call?

Re:300 bits per second? (3, Interesting)

dissy (172727) | about a year and a half ago | (#42636833)

Would you like to play a game?

0. What is your FidoNet node address?
1:226/201

1. What number of in & out dials have you?
7 / 1 (8 chans of a frac pri)

2. What is the land area coverage of an unladen local call?
About half of the area code, guessing 100 square miles?

I never understood why some parts of 614 were local but others were long distance, while at the same time a small part of 740 was local to me yet a different area code.
I had to route mail to another board across town in 614, where he could reach the other half of 614 locally, just to avoid minutely charges.

My 8 PRI channels were to my home (well, to my parents home at the time) and mostly for dialin. I rocked Oblivion/X by the time I was on fido. One line floated for scheduled callouts, but none dedicated to that.
Once I discovered the Internet in '89, first one then later two channels were dedicated to PPP.
By '92 I was getting less than 5 calls a day to the board, and shortly converted my whole frac PRI to be dedicated Internet, and I pretty much gave up the sysop role for good in exchange for EFnet as things turned out. Even ran an efnet server for a short time back in '95 i think it was.

While I can say for certain that communications have only changed for the better as far as the Internet goes, there is still a lot I miss from those days, even though I wouldn't want to go back to that for anything.

Re:300 bits per second? (0)

Anonymous Coward | about a year and a half ago | (#42639153)

My 8 PRI channels were to my home (well, to my parents home at the time)

surprise, surprise.

Re:300 bits per second? (1)

dissy (172727) | about a year and a half ago | (#42642749)

I have yet to personally meet any 14 year olds NOT living with their parents.

Let me guess, your parents gave up on you before you became a teen and you've been living under a bridge in the park ever since?

Re:300 bits per second? (1)

drinkypoo (153816) | about a year and a half ago | (#42637055)

I do. 300 Baud is a nice reading speed...

150 cps isn't even a good typing speed. I've often outtyped 1200 bps modems and I can definitely outread them. I used to hang out on a five-liner with all 1200bps USRs in scruz called XBBS and the modems were agonizing.

Re:300 bits per second? (1)

pipatron (966506) | about a year and a half ago | (#42637657)

Cool. Maybe you should contact the Guinness Book of World Records, because you're typing five times faster than the fastest typist in the world!

Re:300 bits per second? (1)

Electricity Likes Me (1098643) | about a year and a half ago | (#42642029)

Divide by 2 if he's not using local echo though, plus add in latency for the round trip of waiting for your characters to appear.

Business alert, mod parent up! (0)

Anonymous Coward | about a year and a half ago | (#42635699)

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

Re:Business alert, mod parent up! (1)

lord_mike (567148) | about a year and a half ago | (#42637207)

At 300 baud, that movie download is going to take one heck of a long time!

Re:300 bits per second? (0)

Anonymous Coward | about a year and a half ago | (#42635785)

You're gonna have to get me drunk first.

Re:300 bits per second? (0)

Anonymous Coward | about a year and a half ago | (#42636249)

It depends. How many moves per day are you set ? :)

Overkill on detail? (4, Funny)

CodeheadUK (2717911) | about a year and a half ago | (#42635559)

> 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..

Re:Overkill on detail? (0)

Anonymous Coward | about a year and a half ago | (#42635899)

So a twelve bit grayscale image, with a transmit rate of 0.036KBps using light? I think we were better back when we owned 14.4kbps modems.

Re:Overkill on detail? (2, Funny)

Anonymous Coward | about a year and a half ago | (#42635965)

50 shades ought to be enough for anybody

They could have just sent a message... (1)

InterestingX (930362) | about a year and a half ago | (#42635975)

"Do not look at laser with remaining eye"

Re:Overkill on detail? (1)

Tablizer (95088) | about a year and a half ago | (#42636671)

Bill Gates insists 640 shades should be good enough for anyone.

300 bits per second is pretty damn good (4, Insightful)

The Living Fractal (162153) | about a year and a half ago | (#42635581)

...considering how tight this beam was, and that you'd have to be pretty much directly in its path to intercept the transmission.

Re:300 bits per second is pretty damn good (1)

schnits0r (633893) | about a year and a half ago | (#42635605)

Still a faster upload speed than Crashplan.

Re:300 bits per second is pretty damn good (0)

Anonymous Coward | about a year and a half ago | (#42635645)

I was thinking the opposite. This sounds to me like "Look! Using current technology, we tried this and actually managed to get this to work".

While i'm not denying its a great leap from "point a laser at the moon to measure the distance" this really doesn't seem to be that big of a leap over current communications. Is this supposed to lead to a new more reliable method of communicating over distances because it seems like a backwards step at best.
If this is just to say they did more with a laser beam than some other people.. whoop-de-doo.

Re:300 bits per second is pretty damn good (0)

Anonymous Coward | about a year and a half ago | (#42636791)

I was thinking the opposite. This sounds to me like "Look! Using current technology, we tried this and actually managed to get this to work".

While i'm not denying its a great leap from "point a laser at the moon to measure the distance" this really doesn't seem to be that big of a leap over current communications. Is this supposed to lead to a new more reliable method of communicating over distances because it seems like a backwards step at best.
If this is just to say they did more with a laser beam than some other people.. whoop-de-doo.

"Hey, we've managed to send 100 Gb/s over 100 feet!"

"Meh, sorry. Some guy on Slashdot pointed out that it's not such a big leap over current communications. I mean, you can already send information for miles at a fraction of that speed."

"Gosh, you're right. Cancel the project. I guess we've learned everything we can."

Re:300 bits per second is pretty damn good (1)

fikx (704101) | about a year and a half ago | (#42637003)

lasers used for communication in space is very important/useful due to the distances involved. the more focused you can send, the less energy needed to compensate for signal spread...probably not the right terms, but in general terms that's the first thing I thought of. The distances involved in space take some real work to deal with...Everything gets harder to do when you talk about these kinds of distances....
You may think a trip down to the corner store is a long way to go, but that's just peanuts to space...

Re:300 bits per second is pretty damn good (0)

Anonymous Coward | about a year and a half ago | (#42641533)

I just meant that radio is already used for two-way communications at far greater distances. While this seems a case of using existing equipment and doing something different with it I'd think that they'd look for more useful things to do with the limited their resources they get these days.

Re:300 bits per second is pretty damn good (1)

Electricity Likes Me (1098643) | about a year and a half ago | (#42642057)

I believe the current theory on laser communication in space is that it could get up to some serious bandwidth at inter-planetary distances - think 100 mbit/s to 1 Gbit/s - but obviously it's not really been tried yet. Curiosity is only sustaining something like 1.5 mbit/s even even with help from the Mars orbiters.

I'm guessing the real benefit of this type of work was getting some actual data on the types of things which affect tracking and receiving lasers in space, even if only at very low bitrates.

Re:300 bits per second is pretty damn good (1)

AbrasiveCat (999190) | about a year and a half ago | (#42635777)

I think I would hold out for at least 1,200 baud.

What about Lenna? (5, Interesting)

ericcc65 (2663835) | about a year and a half ago | (#42635623)

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 [cmu.edu]

Re:What about Lenna? (1)

Impy the Impiuos Imp (442658) | about a year and a half ago | (#42635817)

Ya! Aren't technological advancements driven by porn anyway?

Re:What about Lenna? (0)

Anonymous Coward | about a year and a half ago | (#42637907)

Ya! Aren't technological advancements driven by porn anyway?

Not necessarily, but typically first utilized by/for...

Re:What about Lenna? (0)

Anonymous Coward | about a year and a half ago | (#42636059)

Yeah, obviously those rocket scientists have never read any graphics papers.

Re:What about Lenna? (1)

GodfatherofSoul (174979) | about a year and a half ago | (#42636501)

I imagine that an environment that isn't all-male wouldn't be so pleased with the idea of "tradition."

Re:What about Lenna? (1)

Anonymous Coward | about a year and a half ago | (#42636885)

I imagine that an environment that isn't all-male wouldn't be so pleased with the idea of "tradition."

If a person has a problem with the image of a woman from the shoulders up, I'm certain they would also have issues with the current image of a woman from the shoulders up.

Besides, I doubt anything you could do would please a person who is offended by a picture of a female face, no matter which face it happens to be. They would also likely be offended by just about anything else, including squiggly lines in a stock 60's TV test pattern.

There's really nothing you can do about such people, they will be offended by anything and everything. No sense in putting effort into changing your own habits when you will get equally bitched out no matter what.

Re:What about Lenna? (0)

Anonymous Coward | about a year and a half ago | (#42637839)

I've attended image processing lectures which had about 30% female students.
Everyone seemed to approve of that particular tradition :P

Re:What about Lenna? (1)

khallow (566160) | about a year and a half ago | (#42637937)

Indeed. Who is this upstart, Mona? Has anyone even heard of her before?

Re:What about Lenna? (1)

cellocgw (617879) | about a year and a half ago | (#42638617)

Who is this upstart, Mona? Has anyone even heard of her before?

I think she was a White House intern or something.

({[ yes I know that's not the right name. Go away, silly nitpickers ]})

Re:What about Lenna? (1)

RivenAleem (1590553) | about a year and a half ago | (#42655483)

Very Simple.

If they missed the moon, and it instead went straight on out into space to be picked up at random by an alien species. I suspect they want to display a false front.

lena (1)

AvitarX (172628) | about a year and a half ago | (#42635635)

Shouldn't have been Lena?

300 bps (-1)

Anonymous Coward | about a year and a half ago | (#42635657)

300 bps. Fuck-ing great. What is the point? To show they are idiots? Can anyone explain??? Geez....

Scientists (-1)

Anonymous Coward | about a year and a half ago | (#42635669)

They do great things but cannot send the image digitally in a jpeg with forward error correction at fraction of bits.

What's wrong with radio waves? (0)

Anonymous Coward | about a year and a half ago | (#42635751)

We can send and receive messages to rovers on Mars.

Re:What's wrong with radio waves? (1)

profplump (309017) | about a year and a half ago | (#42635827)

The inverse square law

Re:What's wrong with radio waves? (0)

Anonymous Coward | about a year and a half ago | (#42635989)

The inverse square law

applies to lasers too.

Re: What's wrong with radio waves? (0)

Anonymous Coward | about a year and a half ago | (#42635833)

Think security. This would be the interplanetary equivalent of a closed circuit network.

Hello world (-1)

Anonymous Coward | about a year and a half ago | (#42635801)

Might have been more appropriate...

30 years of progress, and we're back to 300 baud (0)

Anonymous Coward | about a year and a half ago | (#42635901)

I seem to remember having a V.21 300 baud modem attached to my C64 about 30 years ago.

I don't get it... (1, Interesting)

Charliemopps (1157495) | about a year and a half ago | (#42635919)

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?

Re:I don't get it... (2)

tyrione (134248) | about a year and a half ago | (#42636081)

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?

To demonstrate a line of sight transmission, from any possible point of orbit? Think about it. They are developing towards a true subspace solution.

Re:I don't get it... (1)

Anonymous Coward | about a year and a half ago | (#42636285)

Because with lunar ranging, you have a big receiver antenna (telescope) on the ground, which is impractically large to put on a spacecraft.

Re:I don't get it... (0)

Anonymous Coward | about a year and a half ago | (#42636653)

Because you don't have to aim a corner reflector? [wikipedia.org] Not to mention that its position is known and static.

As where this is a moving satellite.

Fermi Paradox (5, Interesting)

yanom (2512780) | about a year and a half ago | (#42636291)

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.

Re:Fermi Paradox (3, Informative)

doublebackslash (702979) | about a year and a half ago | (#42637255)

https://en.wikipedia.org/wiki/Diffraction-limited_system [wikipedia.org]

It doesn't matter. Laser. Radio. Gama ray.Doesn't matter. At these distance the systems are, no matter how well focused, diffraction limited. Just like we can't build a mircoscope to see infinitely deep into the smal we cannot build a laser com with perfect focus. Diffraction wins. We can cheat a little, but not over these distances.

We could see laser flashes just as easily as hear radio waves from parabolic dishes.

Re:Fermi Paradox (1)

Sigg3.net (886486) | about a year and a half ago | (#42638741)

Or they stared right into it and reversed their spaceship into a sun..

The Blind Ones will have revenge!

Just what we need (1)

retaj (1020999) | about a year and a half ago | (#42636301)

Friggin sharks communicating with friggin laser beams on their heads.

PPM? (2)

dohzer (867770) | about a year and a half ago | (#42636311)

So that's Pulse Position Modulation, yeah?

Why time based modulation ? (1)

sseymour1978 (939809) | about a year and a half ago | (#42636511)

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.

Re:Why time based modulation ? (0)

Anonymous Coward | about a year and a half ago | (#42636547)

The resolution would likely be lower, given the adjustments that would be required by the doppler effect. Wavelengths change with differences in relative velocity.

Re:Why time based modulation ? (0)

Anonymous Coward | about a year and a half ago | (#42636599)

Because this experiment used already in place hardware without disrupting the normal usage too much.
Using multiple wavelengths is a multi-million dollar experiment, using every 4096th pulse of the positioning laser already there to transmit information is a much cheaper software fix.

Re:Why time based modulation ? (1)

sseymour1978 (939809) | about a year and a half ago | (#42636743)

Use one laser. Actually there is no need for second wavelength for binary transmission.
I assume that actual cause of "analog" data transfer is that there is some possibility that
their data transfer is not very precize on receiving side. They could send for example
0,0,10,10,4095 and receive 0,0,11,9,4094
That still would be ok for "analog" image, but not for binary transmission.

And that's why SETI will never find the aliens (3, Interesting)

Anonymous Coward | about a year and a half ago | (#42636519)

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.

Re:And that's why SETI will never find the aliens (1)

Tablizer (95088) | about a year and a half ago | (#42636723)

But aren't laser pulses that coincidentally point our way detectable? If you have gajillion satellites and spaceships all about, then every now and then one will line up with Earth.

Re:And that's why SETI will never find the aliens (1)

QQBoss (2527196) | about a year and a half ago | (#42637415)

Are you assuming that the satellites are transparent, or that such a sufficiently advanced civilization will miss their target so frequently?

Re:And that's why SETI will never find the aliens (1)

Tablizer (95088) | about a year and a half ago | (#42643657)

It's not a point source when it reaches the craft.

Re:And that's why SETI will never find the aliens (1)

Jeremi (14640) | about a year and a half ago | (#42637431)

But aren't laser pulses that coincidentally point our way detectable? If you have gajillion satellites and spaceships all about, then every now and then one will line up with Earth.

Will the aliens' laser have spread out enough to cover a significant part (or all) of Earth by that point, or will it still be pretty small? It's no good having the laser light land in New Zealand if your receiving equipment is in Australia, after all...

Re:And that's why SETI will never find the aliens (1)

cusco (717999) | about a year and a half ago | (#42644373)

Only if you're looking for them. Optical SETI has barely begun, and only with a fraction of the (miniscule) resources that radio SETI has. We at least *think* we know how to do radio search, but there are so many bizarre natural sources in the optical range that I don't think they're sure what to look for.

Re:And that's why SETI will never find the aliens (1)

ericcc65 (2663835) | about a year and a half ago | (#42682627)

Why use the inefficient method sending your message/data/... everywhere when it is really only destined for 1 place.

I think you're forgetting about broadcast transmissions. You know, TV, trunked mobile communications...messages that will reach multiple locations simultaneously. Now the distances involved and the spreading loss, that's another issue. There is only so much coherent integration that can be done usually.

4096 times 300 = 1.2 megabits/sec (0)

Anonymous Coward | about a year and a half ago | (#42636595)

not bad for moon to earth communications

Re:4096 times 300 = 1.2 megabits/sec (1)

jklovanc (1603149) | about a year and a half ago | (#42636705)

Fist it is not 4096 bits. It takes 12 bits to make up 4096 possibilities. Also, don't you think that the scientists factored the 12 bits into their 300bps calculation? If there were only 300/12= 25 slots per second the data rate would be 300 bps.

1982 called. (1)

n6kuy (172098) | about a year and a half ago | (#42637325)

They want their Hayes Smart Modem 300 back.

Planetary distances? (1)

tragedy (27079) | about a year and a half ago | (#42637335)

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".

Re:Planetary distances? (1)

maxwell demon (590494) | about a year and a half ago | (#42637843)

No. Planetary distances are distances as found on planets. Like, from New York to Moscow. From Earth to Venus would be an interplanetary distance.

Of course, laser communication on planetary distances is not new, as there are tons of fiber used for exactly that.

Re:Planetary distances? (1)

tragedy (27079) | about a year and a half ago | (#42640777)

Either way, the term "planetary distances" that was used is clearly not accurate, whether it's two orders of magnitude too small or two orders of magnitude too big.

300 bits per second is about 30 baud... (0)

Anonymous Coward | about a year and a half ago | (#42638429)

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).

oh no, QR codes (1)

Sigg3.net (886486) | about a year and a half ago | (#42638719)

You just know when you click it, it's gonna be a lame banana store site or something.

Am I the only one.... (1)

Bartles (1198017) | about a year and a half ago | (#42638883)

who is completely underwhelmed by this "feat"?

Too easy. (1)

yusing (216625) | about a year and a half ago | (#42643149)

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.

How wide? (1)

Tablizer (95088) | about a year and a half ago | (#42643675)

How wide is the beam when it reaches the craft? What are the theoretical limits of the width per distance?

so ... ? (1)

micahraleigh (2600457) | about a year and a half ago | (#42649173)

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 (1)

cusabiozdy (2818117) | about a year and a half ago | (#42653163)

We could see laser flashes just as easily as hear radio waves from parabolic dishes. http://www.cusabio.com/pro_11.html [cusabio.com]
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