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Moon Communications NASA Shark

Laser Communication System Sets Record With Data Transmissions From Moon 43

Posted by Soulskill
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.'"
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Laser Communication System Sets Record With Data Transmissions From Moon

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  • by lol_juice (3377467) on Wednesday October 23, 2013 @01:21AM (#45209625)
    Meanwhile, in the suburbs of Montreal, Canada, you may be lucky to get a 20 kb/s connection on an "ADSL" modem.
    • by Cryacin (657549) on Wednesday October 23, 2013 @01:24AM (#45209631)
      Yeah, but the latency! Forget playing BattleField 4 with those pings.
      • by VortexCortex (1117377) <VortexCortex@pro ... ICAGOcom minus c> on Wednesday October 23, 2013 @02:19AM (#45209825)

        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.

        • by Kjella (173770)

          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 interstell

    • by Rosco P. Coltrane (209368) on Wednesday October 23, 2013 @01:25AM (#45209641)

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

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

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

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

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

  • by Anonymous Coward
    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.
  • by bobstreo (1320787) on Wednesday October 23, 2013 @02:27AM (#45209847)

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

    Usenet on the other hand will be fine.

     

    • by SeaFox (739806)

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

    • by Sockatume (732728)

      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.

      • by MightyYar (622222)

        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...

  • by paiute (550198) on Wednesday October 23, 2013 @05:41AM (#45210607)
    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.
  • by Connie_Lingus (317691) on Wednesday October 23, 2013 @06:57AM (#45210937) Homepage

    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.

    • 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.

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

  • 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 !
    • by Anonymous Coward

      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.

  • by ortholattice (175065) on Wednesday October 23, 2013 @08:39AM (#45211611)

    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?

    • 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.
  • 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 ra
    • 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.

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