Slashdot Mirror

← Back to Stories (view on slashdot.org)

Laser Communication System Sets Record With Data Transmissions From Moon

Posted by Soulskill on from the shoot-the-moon-with-lasers dept.

sighted writes "NASA reports that it has used a pulsed laser beam to transmit data over the 384,633 kilometers (239,000 miles) between the Moon and the Earth at a transfer rate of 622 megabits per second. The transmissions took place between a ground station in New Mexico and the LADEE robotic spacecraft now orbiting the moon. 'LLCD is NASA's first system for two-way communication using a laser instead of radio waves. It also has demonstrated an error-free data upload rate of 20 Mbps transmitted from the primary ground station in New Mexico to the spacecraft currently orbiting the moon. ... LLCD is a short-duration experiment and the precursor to NASA's long-duration demonstration, the Laser Communications Relay Demonstration (LCRD). LCRD is a part of the agency's Technology Demonstration Missions Program, which is working to develop crosscutting technology capable of operating in the rigors of space. It is scheduled to launch in 2017.'"

43 comments

  1. 20 mb between planets.. by lol_juice · · Score: 4, Funny

    Meanwhile, in the suburbs of Montreal, Canada, you may be lucky to get a 20 kb/s connection on an "ADSL" modem.

    1. Re:20 mb between planets.. by Cryacin · · Score: 3, Funny

      Yeah, but the latency! Forget playing BattleField 4 with those pings.

      --
      Science advances one funeral at a time- Max Planck
    2. Re:20 mb between planets.. by Rosco+P.+Coltrane · · Score: 3, Funny

      Yes, but weather conditions on the moon are much easier for cable workers to work on the infrastructure in than in Montreal.

      --
      "A door is what a dog is perpetually on the wrong side of" - Ogden Nash
    3. Re:20 mb between planets.. by VortexCortex · · Score: 3, Interesting

      Yeah, but the latency! Forget playing BattleField 4 with those pings.

      Well, yes, to the DRM server... But multiplayer should be fine over LAN (Lunar Area Networking). The store and forward DTN (delay tolerant networking) of the interstellar Internet will have to be supported eventually anyway. I've actually been experimenting with "games" that have persistent worlds that can support multiple planets worth of people via sparse information graphing, going so far as to use your "Network Simulator" on Debian to implement an aproximation of NASA's planned solar system wide DTN implementation. The laser bandwidth is going to be an awesome boon, much needed before any amount of populous can correspond interplanetarily in a practical manner.

      For slower-than-light interplanetary "gaming" the answer is to do like those beloved "BBS" classics, e.g., Tradewars, for the synch data. That way whenever more data becomes available it can appear, without the requirement for a real-time centralized server system. I still think that's a great way to play a game -- Get in, do your actions for that day, check messages and what not, then put it down and get to work, check back the next day -- Rather than the frantic skinner box, just make it part of the daily routine, ah those were the days. Mine has world building with quotas on vertex and texture amounts per volume, and is indexed via huge sparse octree -- Procedurally generating the unmodified nodes so folks who haven't staked a claim can still explore the same areas. For realtime gameplay atop the semi-synchronized user generated content, faction vs faction matchmaking only works in your latency neighborhood. So, ISS to other orbital platforms could work for a quick deathmatch if they weren't in too wildly different of an orbit, but otherwise they'd be limited to the secondary slower gameplay between Earth, its moon, and Mars, etc.

      DTN support would actually be friggin' awesome to have built in down here too. It's basically automatic caching w/ deduplication and free collocation. Methinks you'll have to ditch the "filename" idea though (at least in its current form) -- Eventually you'll realize those are only useful for display of a "region" specific designation, but what your mechano-electic slaves will request instead is the info-hash; So that renaming "Album03-0003.ogv" to "Moon-Cat-Leaps.ogv" or "QIp vIghro' pum.ogv" will end up being only one payload no matter which you request. That's also VERY MUCH NEEDED for mixed secure and insecure content display anyway, so that the secured page can specify the hash of the unencrypted external file to embed and be sure it wasn't tampered -- SSL that can be cached! What am I saying? That's crazy talk! The W3C HTML goons will never go for anything that logical, unless you grease their grubby little lobes, ugh, Ferengi...

      Oh, look at me just bubbling over about your species burgeoning potential progress. I'll just let you nudies get back to your exciting earth news... Nope, don't mind me, not socially engineering alien acclimation systems; No sir, not a violation of the prime directive at all... It's not like I need a vacation from watching all the depressing politics going on down here or anything.

    4. Re:20 mb between planets.. by Anonymous Coward · · Score: 0

      So that renaming "Album03-0003.ogv" to "Moon-Cat-Leaps.ogv" or "QIp vIghro' pum.ogv" will end up being only one payload no matter which you request.

      This, so much. Get that in bittorrent, STAT.

      Also, heh: "QIp vIghro' pum" is Klingon.

    5. Re:20 mb between planets.. by Anonymous Coward · · Score: 0

      ? That's crazy talk! ...

      your news is unlikely under direct propangandizing via Rupert Murdereroch, as the Fishman`s undermine israeli cellular-phone-freedumb, and the Gillman`s launder money and evade taxes through their shipping empire.

      Seriously though, are you down`unda, did the Australian Navy subs kick the pants off the yanks in the naval drills, did the Cheonan sinking actually point towards israeli nuclear attack submarines in the Pacific, and WHEN WILL THE ISRAELI SATELLITE FLEET BE DISABLED FOR THEIR ILLEGAL EAVESDROPPING (not to mention the malicious israeli weaponisation of space)?

    6. Re:20 mb between planets.. by Kjella · · Score: 2

      The laser bandwidth is going to be an awesome boon, much needed before any amount of populous can correspond interplanetarily in a practical manner.

      The closest planet would be Mars and it's 4-20 light minutes away, which means 8-40 minutes round trip. At that rate, you'll be playing postal chess no matter what. The moon is somewhat more practical with 1.3 light seconds so 2.6 seconds round trip but it's probably still way too high for FPS, RTS, car races (did we crash?), fighting games (did the kick hit?) or MMORPGs (did you slay that monster?), you're probably looking at turn-based games of various sorts from chess to TBS. At least it's not intersteller, that 8.4 year round trip means you wouldn't finish one chess game in your life time (unless it's the fool's mate).

      --
      Live today, because you never know what tomorrow brings
    7. Re:20 mb between planets.. by K.+S.+Kyosuke · · Score: 1

      Also, heh: "QIp vIghro' pum" is Klingon.

      (fetches Okrand from the shelf...)

      Hah...I get it now. I knew it! Thirteen years ago, when I bought the damned book, I knew it would come handy one day! Thank you so much.

      --
      Ezekiel 23:20
    8. Re:20 mb between planets.. by jimmydevice · · Score: 1

      Go back to dialup. I'm getting 45kb/s.
      In Wa state USA. It's that or $150/month
      for 10GB cap satellite

    9. Re:20 mb between planets.. by rednip · · Score: 1

      Also, heh: "QIp vIghro' pum" is Klingon.

      (fetches Okrand from the shelf...)

      Hah...I get it now. I knew it! Thirteen years ago, when I bought the damned book, I knew it would come handy one day! Thank you so much.

      (looks up 'Klingon translator' on google, finds oddly enough that Bing translator is the first hit)

      "QIp vIghro' pum" translates to "stupid cat falls" without a 'investment' and braving more than a decade of dust.

      --
      The force that blew the Big Bang continues to accelerate.
    10. Re:20 mb between planets.. by K.+S.+Kyosuke · · Score: 1

      "QIp vIghro' pum" translates to "stupid cat falls" without a 'investment' and braving more than a decade of dust.

      Actually, it translates to "fall cat stupid". "Stupid cat falls" would be "pum vIghro' QIp". (Perhaps on the Moon, it should have been "pumlI' vIghro' QIp", but I digress...)

      --
      Ezekiel 23:20
    11. Re:20 mb between planets.. by Anonymous Coward · · Score: 0

      How about the suburbs of San Jose, California?

      There's an engineer on the LADEE team that can't get DSL or Cable.(less than a mile from the major fiber trunk lines that run south out of the Bay Area). Yep, literally 4 orders of magnitude slower speed, with similar ping times (65kb/sec at 1 second ping ).

      Thank you sooo much, AT&T!

  2. Mooncast will be throttling I presume? by Anonymous Coward · · Score: 0

    And sharing your browsing behavior with the government and perhaps even blocking torrent ports / reporting them to the MAFIAA?

  3. meanwhile by Bite+The+Pillow · · Score: 0

    meanwhile, Sprint is trying to match pace with cheap vibrators. Go science!

  4. You ain't seen nothing yet... by ls671 · · Score: 0

    BTO song:
    https://www.youtube.com/watch?v=7miRCLeFSJo

    on topic: I can easily set world records for transmission to Jupiter with a relatively cheap LASER.

    --
    Everything I write is lies, read between the lines.
    1. Re:You ain't seen nothing yet... by Anonymous Coward · · Score: 0

      on topic: I can easily set world records for transmission to Jupiter with a relatively cheap LASER.

      And your transmission rate would've been verified too, but the Jovians logged off when you kept sending "pics or GTFO"...

  5. Error-corrected* by Anonymous Coward · · Score: 1

    I very much doubt the end to end was error free, just good enough to correct.

    On another note, this could have applications with mirror satellites for high throughput medium-hight latency links between continents/islands, instead of laying more undersea cable.

    1. Re:Error-corrected* by ls671 · · Score: 1

      On another note, this could have applications with mirror satellites for high throughput medium-hight latency links between continents/islands, instead of laying more undersea cable.

      Nothing feels better than being hooked by a physical cable, despite what I have said here:
      http://slashdot.org/comments.pl?sid=4366737&cid=45209721

      --
      Everything I write is lies, read between the lines.
  6. Not all bad news by bobstreo · · Score: 3, Funny

    Netflix will probably suck until they build some caching servers on the Moon.

    Usenet on the other hand will be fine.

     

    1. Re:Not all bad news by SeaFox · · Score: 1

      So, no streaming video until Netflix makes a trip to the moon?

    2. Re:Not all bad news by Sockatume · · Score: 1

      If there's one thing that The Excession taught me, it's that interstellar communications will be more like newsgroups than video chat.

      That and never make assumptions when you're dealing with a perfect blackbody sphere from higher dimensions.

      --
      No kidding!!! What do you say at this point?
    3. Re:Not all bad news by MightyYar · · Score: 2

      interstellar communications will be more like newsgroups than video chat.

      A flame war is more disturbing when the guy on the other end can hurl an asteroid at you...

      --
      W..w..W - Willy Waterloo washes Warren Wiggins who is washing Waldo Woo.
  7. Question by Anonymous Coward · · Score: 0

    Am I correct in assuming that lasers can't be jammed, as is the case with EM waves.

    1. Re:Question by sugar+and+acid · · Score: 2

      I think a free air/vacuum laser transmission could be intentionally jammed. It is simply a matter of aiming a laser at the same target. Obviously the satellite and ground transmission must have some sophisticated tracking that maintains the laser link, and anybody attempting to jam will need very precise knowledge of the position of the satellite. But if you can send a signal with a laser from the ground, another laser can send a spoiler signal from the ground as well.

    2. Re:Question by newcastlejon · · Score: 2

      Am I correct in assuming that lasers can't be jammed, as is the case with EM waves.

      No, all you need is a teapot, although you might have to wait for quite a while for it to pass into the beam's path.

      --
      If God forks the Universe every time you roll a die, he'd better have a damned good memory.
    3. Re:Question by Anonymous Coward · · Score: 0

      You are correct. The israelis have been jamming with lasers for nearly 3 decades, but not as long as they have been working with polonium.

      As with the Litvinenko case, its ILLEGAL ISRAELI WMD, and malicious intent; thats why the israeli space-program needs to be disabled, and their agents and moles found and uprooted.
      "Diamonds are of value for cutting tools, until the laser-monopoly came about" -Yitzak "Rabin" Pearlman

  8. Your Verizon bill is now available by paiute · · Score: 4, Funny

    Unfortunately, NASA went over their 7 gigabyte data limit with this experiment and owes Verizon $50 per additional megabyte, a total of $4,573,994.01.

    --
    If Slashdot were chemistry it would look like this:Cadaverine
    1. Re:Your Verizon bill is now available by Anonymous Coward · · Score: 0

      juST WAIT TILL AIPAC HEARS ABOUT THIS!everything MUST go through PRISM, or else......
      AMDOCS projected profits just went through the Capitol Buildings roof!

    2. Re:Your Verizon bill is now available by MightyYar · · Score: 1

      The space station is just a front for the NSA. Actually, NASA is involved too. Didn't you notice that they are only one letter apart?

      --
      W..w..W - Willy Waterloo washes Warren Wiggins who is washing Waldo Woo.
    3. Re:Your Verizon bill is now available by Anonymous Coward · · Score: 0

      And it was you who said israeli terrorists at NASA caused the explosion over Palestine, Texas.....
      Or was that the King David Hotel Bombing?
      Whatever the case may be, could you clear up how AMDOCS is connected to metadata at Verizon?

      "ohh, look at all the pretty colours!" - anonymous civil-liberty supporter, and vocal PRISM-related laser-microphone splitter
      "I didn`t hear the PIN drop" - Sprint grenade-operator
      "Data, that sounded like the torque-wrench glancing off Kirk`s brow. Confirm." -Scottie

  9. great news... by Connie_Lingus · · Score: 2

    i, for one, am happy to know that our future astronauts will be able to stream Game of Thrones and porn from their moonbase without having to wait too long.

    its a good day.

    --
    never bring a twinkie to a food fight.
    1. Re:great news... by bob_super · · Score: 1

      I think if you're on a one-way trip to Mars, you should get to stream all the porn you want, cap-free.
      That's pretty fair.

  10. Nice by coofercat · · Score: 1

    As a not-American, I'm always impressed with NASA for stuff like this. I just wish the ESA would do more like it :-)

  11. time ? by fluffythedestroyer · · Score: 2

    This might be an idiot question but how much time did it take from the earth station to the moon to receive the transmission ? I know it's 75.9Mb seconds but the time that took for point A to point B. Were talking about around 384,633 kilometers. I would guess a couple of seconds here !

    1. Re:time ? by Anonymous Coward · · Score: 1

      This might be an idiot question but how much time did it take from the earth station to the moon to receive the transmission ? I know it's 75.9Mb seconds but the time that took for point A to point B. Were talking about around 384,633 kilometers. I would guess a couple of seconds here !

      The speed of light is ~300,000km per second.

      Unlike radio (where transmitting tends to desensitize your receiver), it is fairly easy to support full duplex for this system. So the overhead caused by the latency for the entire transmission was likely only 1 or two round trips or somewhere in the neighborhood of 3-5 additional seconds.

  12. Bandwidth of early space missions by ortholattice · · Score: 2

    One thing that still puzzles me about the early space explorations is the extremely poor quality of the audio. When I see film clips of those days, I often cannot understand what they are saying at all; "Houston, we have a problem" would be like "Hous-acch w-cch acch a pracch-acch". At first I thought it might be that the extra bandwidth needed for clean audio would be prohibitively expensive in those days, yet they were able to transmit live video very early on, which of course uses far more bandwidth.

    Wouldn't the barely intelligible audio be a safety issue, or is it just that I'm not trained to understand it? Does anyone with historical knowledge know what the deal with this was?

    1. Re:Bandwidth of early space missions by josiahgould · · Score: 2

      I believe the live video that was transmitted early, like from the Moon landing, was slow-scan TV. Which is very low bandwidth when compared to a standard television signal. The good video that most people think about was shot on a 16mm film camera then delivered back to earth.

    2. Re:Bandwidth of early space missions by Anonymous Coward · · Score: 0

      back in the day, using radio for regular voice traffic over 200K miles was very difficult. In fact, Chris Kraft in a interview about when Kennedy announced the challenge to go to the moon, Chris recalled his first thoughts how can they even talk over a distance of quarter million miles? They had to build the deep space network and also add telemetry data along with voice. An interesting article about Apollo communications is described in a 1969 issue of 73 (or QST) magazine. It has diagrams and frequencies used. 2100 MHz was used between spacecraft and earth. 296 MHz was used between moon walking astronauts and LM.

  13. One Photon Return Per Laser Pulse? by Fleetie · · Score: 1

    Conventional wisdom was that the lunar distance ranging, using the lunar retroreflector arrays, averaged 1 photon or less returned to the Earth detector, per outbound laser pulse.

    Now presumably, this 622 Mbit/sec was outbound only (Earth to Moon) and not a return trip. So that will help quite a lot.

    But to get these remarkable bandwidths, the Earth-based laser and beam expander/collimator must be pretty special.

    Does anyone know the juicy figures like: Laser wavelength, energy per pulse, pulse rep rate, and so on? Oh, and the strength of the signal received at the moon, in (I dunno) photons-per-bit or something?

    --
    "Absorbing your worst..."
    1. Re:One Photon Return Per Laser Pulse? by Neil+Boekend · · Score: 1

      It's not 1 photon per pulse. It's 1 photon per x trillion photons. If you send 100,000 * x trillion photons you'll probably get around 100,000 photons back. This is one of the cases where more power actually works.
      I'd hazard a guess that NASA has more powerful lasers than a backyard setup like in one the one in one of the first seasons of The Big Bang Theory.
      I'd also hazard a bet that the NASA lasers have better focus, which means a higher percentage of the photons actually reach the receiver.

      --
      Well, I might have a way, but it only works on a semi spherical planet in a vacuum.
    2. Re:One Photon Return Per Laser Pulse? by Anonymous Coward · · Score: 0

      Lasers used for range finding are much stronger than those used for communicating, since, one, it gets more difficult to modulate a laser the more powerful it is, and two, it is a lot easier to make a very strong pulse than to provide a CW laser. The inefficiency comes from a large amount of the light missing the retro-reflector, which is only on the order of a square meter (not all of which is reflective), the reflector not perfectly reflecting light, then most of the reflective light missing the receiving telescope. So whatever one-way loss you experience, you get that loss roughly squared for round trip. So with the loss factor of about 10^17 to one, a one watt average power laser would get back about 50 photons a second, whereas one way would be several to many nanowatts which is much easier to measure.

  14. Paradox Resolved by Anonymous Coward · · Score: 0

    And thus, the Fermi Paradox is resolved.