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A High-Bandwidth Interplanetary Connection 99

sciencehabit writes "A new study suggests that by twisting laser light, scientists could pack enough information into interplanetary beams to speed up extraterrestrial communications to the multi-gigabit level. The pulses would be passed through a hologram or multimode optical fiber, which twists the light. On the other side, a telescope would focus the light and a second hologram, or fiber would decode the signal. That could allow much more data-rich communication between, say, Earth and probes on Mars, the researchers say. Closer to home, the approach could provide Internet links of 100 gigabits per second."
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A High-Bandwidth Interplanetary Connection

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  • by RandomFactor ( 22447 ) on Saturday July 16, 2011 @08:43AM (#36784974)

    > Hemmati and his colleagues estimate that receiving OAM data from a transmitter as distant as the sun would require a kilometer-wide telescope.

    Sounds like even someplace closer like Mars is going to take an impractically large receiver.

    • Re: (Score:2, Informative)

      by Anonymous Coward

      That's huge. Arecibo [] is only 0.3 km.

    • by Anonymous Coward

      More than 50% of the time mars is not closer to earth than sun.

    • by Olix ( 812847 )
      If you don't have to worry about gravity, making really big receivers and transmitters isn't much of an issue.
      • But at a size like stuff like statics is on a completely different level. Imagine the stresses on such a huge networked frame during something as unseemingly as a fine-adjustment of the array's rotation. Ass ume a decade of use and these things develop into a serious factor.

    • Is a relay via the moon not possible ?

      We'd not have so much of a problem with size up there, and the link from here to the moon would require smaller telescopes, with at least one at each pole.
      • by HiThere ( 15173 )

        I think an Lagrange point would be a better choice than the moon. The moon has too much gravity. But, as was pointed out earlier, rotating the antenna (telescope) would be a bit problem, even there. The lighter the structure, the less twist it could take.

    • Sounds like even someplace closer like Mars is going to take an impractically large receiver.

      The Sun is roughly the same distance from Earth all the time, because we have a roughly circular orbit around it.

      Mars is sometimes closer to us when our orbital position around the Sun is on the same side as Mars, however due to the different year lengths on Mars and Earth, sometimes it's much further away on the far side of the Sun to us.

  • We need faster speeds here down on earth before we think of these "multi gigabit" speeds for interplanetary communications..
    • Re:You serious? (Score:4, Insightful)

      by John Hasler ( 414242 ) on Saturday July 16, 2011 @08:50AM (#36785018) Homepage

      Why? How does thinking about "multi gigabit" speeds for interplanetary communications conflict with you getting a faster connection to Pirate Bay?

      • by Osgeld ( 1900440 )

        cause they are not thinking about how to do it here, which is totally different than a line of site irda bullshit idea (which is fucking stupid in the first place, a laser will diffuse to be larger than the planet you want to aim for)

        its a simple matter of quit wasting our time and money for these mankind space cloud ideas and lets fucking finish something down here

      • by slick7 ( 1703596 )

        Why? How does thinking about "multi gigabit" speeds for interplanetary communications conflict with you getting a faster connection to Pirate Bay?

        (sarcasm) Since the government refuses to confirm or deny the existence of alien life forms, this is just a waste of money that should be going to the war effort. (/sarcasm)

    • We need faster speeds here down on earth before we think of these "multi gigabit" speeds for interplanetary communications..

      We HAVE faster speeds here on Earth. Blame your ISP for not utilizing what their network is capable of, preferring to intentionally cripple their services so they can charge through the nose for faster connections. But all that is really totally irrelevant because this Earth-Mars link is not in any way intended for consumer use.

    • by Idbar ( 1034346 )
      I'm crossing my fingers. Hopefully, I'd be able to get 100G first from a martian ISP than the crappy US ISPs. And furthermore, I hope is not going to be capped by the ISP and government regulations or tapped **IA.
    • If they send people to Mars, they better still be able to play in multiplayer with their friends on Earth! Not to mention Youtube.

      • Of course you're joking, but it's not an all-around impossible idea.

        Bandwidth? Check. Ping? Not so much. Or rather, too much. Or something. The bandwidth being high doesn't lower the latency any of course.

        "The communications delay between Earth and Mars can vary between five and twenty minutes depending upon the relative positions of the two planets. As a consequence of this, if a robot on the surface of Mars were to encounter a problem, its human controllers would not be aware of it until at least five min

        • I would imagine if we had serious computing business in Mars we would have some sort of caching running there :) Like, full replication... :) Just an idea, of course...
          • Sending people to Mars does not imply large-scale long-term colonization.Serious business wouldn't be built to keep a handful of researchers connected to the homeworld. If there was sufficient demand for content, though, sure you could expect both caching much of Earth's content on Mars as well as a large cache on Earth of content from Mars.

    • Afaict we have 10 gigabit (maybe more now) through a single optical transciver and we can combine multiple such links on a single fiber through WDM and a typical cable contains many fibers.

      The big issue with end user connections is not technical it's financial, upgrading all the connections to end users is very expensive and most users probablly aren't prepared to pay all that much more for a faster connection. So the incentive for providers to upgrade is low. Further any sensible last mile communications p

  • Ping times (Score:4, Informative)

    by s_p_oneil ( 795792 ) on Saturday July 16, 2011 @08:48AM (#36785008) Homepage

    They're going to have to do something about the terrible ping times. Its orbit is about 1.5AU, so when it's close to the Earth, the round-trip ping time will be about 8 minutes. When it's on the opposite side of the sun, it'll be about 40 minutes.

    • by Anonymous Coward

      After they're done with this, I'm sure they'll start working on getting around that pesky ole' theory of relativity...

    • Bit more than that - the sun would blind any attempts at communication when mars is directly opposite. You're going to have to either settle for being out of contact for a short time, or bounce the signal from somewhere else. The other inner planets arn't very suited to building a communication station, so probably a router at earth-sun L4/5 point.

      Eight minutes means we'd have to dump this 'stream everything' internet and start actually downloading files before watching them again.
    • by pushing-robot ( 1037830 ) on Saturday July 16, 2011 @10:37AM (#36785748)

      Yeah, the latency on wireless connections always sucks. If we plan on being on Mars a lot, we should just go ahead and string a cable.

      • the spins of earth and mars should present no problem just as long as we remember to unwind the cable periodically, I see no big obstacles to your idea. We can save money by only unwinding the Mars end and giving the cable a big up and down shake to undue the earth end.
    • I was going to say, "Yeah but latency would S.....U.....C.....K."

    • I might be wrong, but surely it's a 4 SECOND ping time ?

      Earth to Mars furthest distance 401 million km.

      Speed of light 299 million km per second.

      Round trip time 4 SECONDS.

      Ok so at this distance the sun is smack bang in the way, but from all other viable viewing points the distance is less than the 401 million km used above.
    • I'm surprised no one has discussed TCP window size. The TCP stack on both ends will need a huge amount of RAM, and even with that, I'm not sure how they are actually going to get the throughput needed if we're talking TCP/IP.

      Perhaps UDP or some non-IP method. Remember, bandwidth != throughput.

      • Any high speed interplanetary connection is going to either have to put up with occasional data loss (how occasional can be influenced to some extent by forward error correction but that comes at a price in bandwidth and still doesn't really provide a soloution for block outages) or have lots of storage for retransmissions.

        TCP is not appropriate, it was designed to deal with connections of relatively low latency and unknown bandwidth by slow-starting. On a high latency connection of known bandwidth that is

    • Seems like DSL with Bell.

    • by Dadoo ( 899435 )

      They're going to have to do something about the terrible ping times.

      I'm guessing IP is out, since the latency will be horrendous. They'll probably have to bring back a mechanism like UUCP, where your files get dropped off in a temporary storage server. There, they'll be placed in a queue to be transmitted to another planet, and you'll be emailed, once transmission is complete.

  • The farthest away people are is in LEO (the ISS) So why do we need to develop faster links to other planets.

    • Article: That could allow much more data-rich communication between, say, Earth and probes on Mars, the researchers say.
    • by mbone ( 558574 )

      Because most space probes now-a-days are data rate limited. LRO, MRO, Dawn, etc., all could take more data, if we could get it back.

  • There is as yet no interplanetary communication by Laser. It's all done by radio at present. The first flight demonstration [] of Laser communication will be on the LADEE [] Lunar Orbiter. That's scheduled to be launched in 2012. I am sure that optical communications will eventually be used, though. Using reasonably sized telescopes, gigabit per second communication across interplanetary distances should be possible using conventional techniques, even if OAM is not actually practical. (Of course, the weather wou

    • Is there that much demand for higher bandwidth, outside of earth-sats? The only machines further out than that are scientific probes, and all they need to send back is telemetry and the occasional photograph.
      • by mbone ( 558574 )

        As I posted above, most scientific probes now are data-rate limited. They could acquire more data, but they can't send it back, due to data-rate and Earth-side antenna-availability limitations. So, yes, there is a strong demand for higher bandwidth.

      • if they are trying to send us a new video of their greatest pop star, how will we be able to download it in a reasonable amount of time?

      • Well... if they had more bandwith, they could send more than the occasional photo.

        Those landers on titan only could send 10Mbyte or so during the decent.

        New horizons has a multi-GB solid state drive. It will fill it up during Pluto flyby (limiting the amount of data it can aquire), and will then spend _months_ transmitting it back a modem speeds.

        With a real time data link, those probes could have / would be able to transfer orders of magnitude more data back home.

  • Throttling (Score:5, Funny)

    by Rik Sweeney ( 471717 ) on Saturday July 16, 2011 @09:09AM (#36785112) Homepage

    Closer to home, the approach could provide Internet links of 100 gigabits per second

    Throttled down by your ISP to 24 megabits per second

  • They'll be able to stay occupied downloading music and porn quicker.
  • by craznar ( 710808 ) on Saturday July 16, 2011 @09:23AM (#36785188) Homepage

    Should give limitless bandwidth.

    Latency of course is the factor here.

  • by Anonymous Coward

    That's great, but the roaming charges will kill you.

  • It's the latency that's the real killer.

    If you want to just talk bandwidth... which is how much data can be sent from one location to another within a unit of time, then the bandwidth of a cargo van hauling a truckload of flash ram sticks across the country has, by many orders of magnitude, a higher bandwidth than any sort of technology that is built on electronic communication infrastructure.

    When it becomes possible to, from earth, ping an orbiter around mars in under a second... *THEN* we will have r

    • by ffejie ( 779512 )
      I love the dumptruck analogy, but I'm not convinced of the math. Let's see if we can work it out:

      A dumptruck has a volume of approximately 722 cubic feet (17 x 8.5 x 5) source []. Converting that gets us 1,247,616 cubic inches.

      A harddrive is 3.5" x 102 mm x 25.4 mm source []. Or about 14 cubic inches.

      This means that roughly, we can fit about 89,115 hard drives into a dumptruck, assuming everything fits perfectly.

      The largest commercially available 3.5" harddrive is 3 TB. This means that we're going to
      • by xkuehn ( 2202854 )

        Assumption fail. Volume is not necessarily a limiting constraint. Hard drives are dense.

        According to this [] a dump truck can typically hold 13T. I've googled the weight of a 3.5" hard drive and I get values between 400g and over 1kg. So I weighed an old one, and got a bit over 400g. The 400g drives are those with fewer platters, but I'll go with it for simplicity.

        13,000kg / 0.4kg gives you 32,500 hard drives. Continuing with your calculations, 3T

      • by PlazMan ( 40335 )

        Driving across the country takes 26 hours assuming no stopping. Source []

        I think you meant 50 hours.

  • 100 gigabit connections will open up the vast unexplored market for molecular biology porn!
    On a 15 inch monitor, you'd be able to fit enough pixels to make out ribosomes and cell walls, not to mention viruses and bacteria.
    Pervs all over the world would devote entire discussion forums to their favorite STDs in porn stars.

    • of course a slashdot reader would think anything of the "molecular biology" type of sexual entertainment would involve high bandwidth and looking at a monitor. I could think of another way that involves another person.....
  • by Anonymous Coward

    They'll just cap it anyway. :( I wish i was joking.

  • by GooberToo ( 74388 ) on Saturday July 16, 2011 @09:54AM (#36785426)

    Isn't the limiting factor for current bandwidth power rather than speed anyways? My understanding they've long had the technology for much high bandwidth but the limitations are always power demands.

    Secondary to power is usability. There's a big difference between pointing an antenna in the general direction of home and precisely aiming a laser million of miles away. Several orders of magnitude more accuracy is required.

    Personally I don't find anything practical about this project. At least not today.


      Picard: Mr. LaForge, we're having trouble receiving the signal from the Very Far Away Observatory. Can you boost the signal.
      LaForge (v.o.): Sir, we're already using a holographic multi-modal optical receiver.We're operating near the theoretical limit.
      Picard: Prehaps you could route secondary power through the replicators in the galley on deck 12.
      LaForge (v.o.): Uhm ... yeah ... I'll get right on that. LaForge out.

      Power v. Bandwidth is always one of the spacecraft design tr
  • Interplanetary IRDA is just as dumb and useless as it is here for the exact same reasons

  • Sounds like inter-planetary multi-player Quake is still out of reach.
  • by retroworks ( 652802 ) on Saturday July 16, 2011 @03:36PM (#36788010) Homepage Journal
    Rather than actually doing it, couldn't we just auction the interstellar bandwidth to Google, Verizon, ATT, Sprint, etc.? Then we'd close the federal deficit! Centuries from now, they'd make the money back on roaming charges. We've been passing the buck to our kids, time to exploit the great-great-great-grandkids.
  • OK, maybe bandwidth is an issue but latency is still a bear.

  • Obviously, this doesn't "solve" the latency issue, but the concept does help bandwidth. Also, it doesn't replace RF links, but merely would relegate them to the failover for the IPN [] version of the BGP.

Syntactic sugar causes cancer of the semicolon. -- Epigrams in Programming, ACM SIGPLAN Sept. 1982