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Space The Internet

The 100-Million Mile Network 160

Posted by michael
from the long-ping-times dept.
mykepredko writes "eWeek has an article on the network and radio topography of the two Mars rovers and how they communicate with satellites in Mars' orbit as well as the Earth. The article ends by giving four rules for maintaining a space network, a) Automate processes, b) Bulletproof your gear, c) Be persistent and d) Simulate potential problems, which are probably good rules for any network."
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The 100-Million Mile Network

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  • e.) ... (Score:4, Funny)

    by jwthompson2 (749521) * <{moc.smargorpnialp} {ta} {semaj}> on Tuesday February 10, 2004 @04:30PM (#8241394) Homepage
    NEVER! BUT NEVER! Install Windows unless you want openly relayed spam from space!
  • Rule Z: (Score:5, Funny)

    by Anonymous Coward on Tuesday February 10, 2004 @04:32PM (#8241405)
    Never have a public webpage that can be linked to from Slashdot.
    • Re:Rule Z: (Score:2, Funny)

      by Anonymous Coward
      The latency is so bad, if you use port knocking and got the sequence wrong you'd be waiting days before you could try again!
  • Good tips (Score:5, Funny)

    by GlassUser (190787) <.slashdot. .at. .glassuser.net.> on Tuesday February 10, 2004 @04:32PM (#8241410) Homepage Journal
    b) Bulletproof your gear

    I'd think micrometeorite-proofing my gear would be more useful.
  • Yeah right (Score:5, Funny)

    by Deraj DeZine (726641) on Tuesday February 10, 2004 @04:32PM (#8241414)
    I didn't RTFA, but it sounds like they're just running ethernet cables (or OC12 or whatever) to Mars. Didn't they stop to think that the planets move? Ridiculous! The ESA and NASA really need to get their acts together.
  • by Beolach (518512) <{beolach} {at} {juno.com}> on Tuesday February 10, 2004 @04:33PM (#8241418) Homepage Journal
    Replace 'spacecraft' with 'child'...

    "The most difficult thing is to know how to talk to the spacecraft when you're getting no response from it," says Douglas J. Mudgway
  • wow thanks (Score:5, Funny)

    by Brahmastra (685988) on Tuesday February 10, 2004 @04:33PM (#8241429)
    The article ends by giving four rules for maintaining a space network, a) Automate processes, b) Bulletproof your gear, c) Be persistent and d) Simulate potential problems, which are probably good rules for any network."
    I'm going to try this out on my space network immediately
    • Re:wow thanks (Score:3, Insightful)

      by BuckaBooBob (635108)
      Bulletproof your gear... I was thinking that was a literal understatement :) After all Getting hit bya piece of anything at over 16,000 miles a huor + you should be alot more protetected than just Bullet proof.
  • by Munden (681257) on Tuesday February 10, 2004 @04:34PM (#8241430)
    MWAN - Multi-World Area Network i guess....
    • Well, "Area" really only applies to the surface of the Earth, so more likely it would be the IPSN - Inter Planetary Spacial Network. But how usefull can this really be? I mean Instant Messaging would be impossible. It would have to be renamed to Huge Lag Messaging.

  • Does anyone know which OS these things run? I heard that NASA really want 386 processors?

    Does this mean they run on Windows? That must SUCK.
  • by DanThe1Man (46872) on Tuesday February 10, 2004 @04:34PM (#8241439)
    b) Bulletproof your gear

    For what? Those pesky Martians?
  • by Anonymous Coward on Tuesday February 10, 2004 @04:35PM (#8241443)
    If only the Beagle 2 people had seen this article beforehand.
  • by mikeophile (647318) on Tuesday February 10, 2004 @04:35PM (#8241447)
    To enact all four rules at once, do the following.

    Persistantly empty clip after clip of rounds from an automatic rifle at your prototype. If it survives, begin production.

  • Persistency is not as important on an earth-bound LAN. Most of the time, bringing it back up is not an issue of "try, try again", but of just doing it right in the first place.
  • by butane_bob2003 (632007) on Tuesday February 10, 2004 @04:38PM (#8241477) Homepage
    ...Starfleet can communicate over extremely long distances with out an lag. Apparently, the lag is encountered occasionally when it is necessary to fill plot holes. But otherwise, not at all. The laws governing subspace communication elude me.
    • That's because there are complete copies of the script at both ends. So long as Starfleet's responses are completely predictable, they can travel infinitely fast. If someone is slightly unpredictable... however... they have a short... lag... in their communications... due to the information... in the signal.

  • Just a few peices of bailin' war oughta do it...
  • by blair1q (305137) on Tuesday February 10, 2004 @04:39PM (#8241497) Journal
    e) submit your URL to /. and start up the benchmark server.
  • by slashname3 (739398) on Tuesday February 10, 2004 @04:39PM (#8241498)
    They are just perpetuating the myth that the rovers are really on mars. Everyone knows that it is all done in a Hollywood sound stage. The problem a few weeks ago with the the first rover was traced to someone using the mircowave oven and causing interference with their radios on the set. Anyone want another burrito heated up?
  • Doh (Score:3, Funny)

    by TechnologyX (743745) on Tuesday February 10, 2004 @04:40PM (#8241507) Journal
    Here I thought they just had a reeeeeeally long cable.
  • by chow_mein (750728) on Tuesday February 10, 2004 @04:40PM (#8241512)
    and I can't even get a cable/DSL modem yet!!! new slogan... Earth First, We'll Network the Other Planets Later
  • by GoodNicsTken (688415) on Tuesday February 10, 2004 @04:43PM (#8241543)
    "The orbiter then uses its more-powerful antenna to send as many as one million bits of data per second back to Earth. While fairly fast for an attenuated radio connection, that's only about a tenth of the speed of a cable-modem connection for the average home-computer user." Unless they are using Commcast, such high bandwidth usage would violate the vauge acceptable use policy, putting the rover in the top 10% of Mars bandwidth users. Ah, maybe that's what happened. NASA ignored the first warning letter, and got cut off.
    • Re:Unless . . . (Score:3, Informative)

      Well, actually it's right, and it implies that the average house internet connection is 1.0mbps.

      Do the math...
      1000000 bits / 8 = 125000 bytes/s 125000 bytes / 1024 = 122.0703125 kb/s 122.0703125 / 1024 = 0.1192092mb/s That means it's a 0.1192092mb/s line to mars, and probably with brutal latency. Let's just hope that they're not serving up warez from it...or that slashdot doesn't link to a webserver hosted on it...
      • No. In bandwidth measurements, "Mbps" with a small "b" refers to megabits per second. So the rover has a roughly 1 Mbps (0.119 MB/s) line to mars, and the article therefore implies that the average house has a 10 Mbps (1.25 MB/s) connection, which is quite untrue. 1 Mbps is quite acceptable for warez (roughly 10 minutes for an average ISO) and could probably handle a minor slashdotting as well (assuming the page was low on images).

        How do they get that much bandwidth over a satellite link? My satellite
        • How do they get that much bandwidth over a satellite link?

          At this point you need to be extremely careful with terminology. The question is not how they get bandwidth, but how they achieve the data rate. Bandwidth and data rate are proportional to each other only if the signal to noise ratio is a constant. People commonly use "bandwidth" when what they are actually referring to is "data rate."

          Shannon's theorem states that the data rate of a channel is equal to the bandwidth times the logarithm of (1+SNR

    • When reached for comment, Comcast Vice President of Public Relations, Craven Dick had this to say:

      "Well with three users on Mars, even a 6th grader could figure out one of them is going to be amoung the high bandwidth users. We told NASA to either cut back or encourage the EU to send more probes. Comcast would be delighted to provide service to further EU Space Agency probes."
  • by Anonymous Coward on Tuesday February 10, 2004 @04:43PM (#8241546)
    It appears that one of the direct results of NASA research will be better networks, both on Earth and elsewhere. Just about anything and everything applied to a deep space network can be applied right here at home. I'm also wondering about wireless network tech resulting from all of this.
  • Use OLD technology (Score:5, Insightful)

    by NineNine (235196) on Tuesday February 10, 2004 @04:43PM (#8241551)
    The article seemed to fail to point out that these things are using OLD technologies... UFH? Jesus, that's been around for ages. Their basic data transmission seems to be just that... basic. . No bells and whistles. No wireless garbage. Not super fast. I see failures when people use cutting edge stuff. My business computers need to be ROCK SOLID. I don't use wireless. My hardware uses serial and parallel ports instead of USB/firewire/whatever. I use W2K as a platform. I use an external modem through a parallel port for important credit card stuff.

    I use what has worked reliably for years and years. I'm not gonna risk my business being down because of some stupid gee-whiz technology that's only been out for a few years. Engineers that build solid, reliable, critical systems (financial, medical, avionics) do the same thing.
    • Type UFH into Google. It says what I was going to say, right at the top.

    • by dsci (658278) on Tuesday February 10, 2004 @05:10PM (#8241780) Homepage
      I use W2K as a platform.

      I use what has worked reliably for years and years.


      Isn't that a contradiction in terms?
    • Hmm, interesting. I help run our business on the technologies that do the job best at the time we're buying. We have 802.11b connecting the machines around facility. As they are all Apple, I have not seen a serial or parallel port in some time. USB works quite well for our tasks. I use OSX a a platform. I use an external cable modem through a business class router for all data.

      As long as one avoids the bleeding edge, I don't think there is any reason to not take advantage of technologies as they come
    • by nick0909 (721613) on Tuesday February 10, 2004 @05:39PM (#8242156)
      UHF is not that old... most public service (save the boomtowns like LA and NYC) are still on VHF-lo/hi. My county fire (in CA) does digital telemtry over a 159mhz (VHF) freq to track all the apparatuses around the county. With the low bandwidth allowed and general problems that come with VHF, it is a fight. A good thing about UHF is its relative line of sight path while still penetrating/bending around slight obstructions and keeping a good digital signal. Higher frequency signals coming from an omni-directional antenna would die out pretty quick if anything more than dust was in the way. To get around really big obstructions lowband is the way to go... there is a reason CA Dept. of Forrestry and CA Highway Patrol still maintain their 30mhz radio nets around the state. But to go digital you need clean signals, so 800+mhz is the way to go there. What, you want both? Oh, UHF-T band then, 400mhz. Enjoy.
    • by Anonymous Coward
      UHF? Old technology (as opposed to "new whiz-bang technology"? Yeah.
      So check it, I'm using OLD, super reliable technology... it's called "copper". Yeah, everyone seems to miss the fact that I'm using OLD technology, this copper stuff has been around FOREVER. Why golly jee, I'm using several twisted wires of this stuff inside a plastic sheath to transmit my slashdot posts over old reliable printed circuit boards into something that uses LIGHT, a REALLY old technology, to transmit my slashdot post over an
    • by Fastolfe (1470)
      While I don't disagree with you, suggesting that UHF was chosen because it's "old" and proven isn't really accurate. There are only so many ways you can communicate with a lander on another planet (that we know of), and things like whiz-bang 802.11 aren't really appropriate.

      Incidentally, the real "technology" decisions here would probably revolve around the data protocols themselves, not necessarily the choice of the radio band. Lots of new technologies use the same radio bands we've used for years. Hig
    • There's a long testing cycle to get hardware certified for space operations.

      Radiation hardening isn't the first thing Intel or AMD puts onto a bleeding-edge chip.

      Missions are planned years in advance, often most of a decade.

      Where I'm going with this is, even if they chose a barely-working new technology, it would be old by the time it got there.

      Your point is well taken -- for example, composites have been around for decades, Boeing is still building planes out of aluminum, and it's because they're not g
  • by egomaniac (105476) on Tuesday February 10, 2004 @04:46PM (#8241579) Homepage
    The orbiter then uses its more-powerful antenna to send as many as one million bits of data per second back to Earth. While fairly fast for an attenuated radio connection, that's only about a tenth of the speed of a cable-modem connection for the average home-computer user.

    Uhhh ... did I miss something? My DSL line peaks at 1.5Mb on a good day. Where can I get a ten-megabit cable modem? And "average home-computer users" have them? I thought average home-computer users were still using 56K modems.

    Oh, I get it now. According to this calendar, it's 2008. Damn, that was a nice nap. Need to catch up on the last four years of news. Hope something horrible happened to Microsoft.

    What? SCOSoft? Oh, shit.
    • Uhhh ... did I miss something? My DSL line peaks at 1.5Mb on a good day. Where can I get a ten-megabit cable modem? And "average home-computer users" have them? I thought average home-computer users were still using 56K modems.
      Yeah, no doubt, I was wondering that myself. My cable line used to get about 3mbit, which was nice, but that's not not the speeds they were talking about.
    • Well, actually it's right, and it implies that the average house internet connection is 1.0mbps. Do the math... 1000000 bits / 8 = 125000 bytes/s 125000 bytes / 1024 = 122.0703125 kb/s 122.0703125 / 1024 = 0.1192092mb/s That means it's a 0.1192092mb/s line to mars, and probably with brutal latency. Let's just hope that they're not serving up warez from it...or that slashdot doesn't link to a webserver hosted on it...
      • by egomaniac (105476) on Tuesday February 10, 2004 @06:22PM (#8242747) Homepage
        Well, actually it's right, and it implies that the average house internet connection is 1.0mbps. Do the math... 1000000 bits / 8 = 125000 bytes/s 125000 bytes / 1024 = 122.0703125 kb/s 122.0703125 / 1024 = 0.1192092mb/s That means it's a 0.1192092mb/s line to mars, and probably with brutal latency. Let's just hope that they're not serving up warez from it...or that slashdot doesn't link to a webserver hosted on it...

        You have confused your units. Network speeds are reported in bits, not bytes -- an average cable modem is around 1.5Mbps, not 1.5MBps.
  • Why not repeaters? (Score:3, Interesting)

    by dacarr (562277) on Tuesday February 10, 2004 @04:46PM (#8241584) Homepage Journal
    Look, when we get to the other side of the sun, we're not going to get very good communications between here and there. Isn't there some way to place some sort of sattelite in solar orbit to act as a repeater network, or for that matter, is there some really good reason why we can't do this?

    Considering how enthralled we are about seeing Mars up close and personal now, I'd think this would be a Really Good Idea.

    • by GPLDAN (732269)
      A satellite that could bounce signals to the far side of the sun at Mars orbit would have to be much bigger than the International Space Station, be somewhere in the orbit of Jupiter and have enough fuel to reposition itself hundreds of millions of miles for several years to be economically viable.
      • by Anonymous Coward
        be somewhere in the orbit of Jupiter

        Couldn't it just be located at earth's L4 or L5 Lagrange point around the sun. It would need to expend little or no station-keeping effort and would always have line of sight both to earth and the backside of the sun (from earth's perspective). Also, why would it need a transmitter stronger than those on the various other orbiters that already transmit and receive signals across the solar system.

        • It wouldn't, that guy is retarded. We could put a satelite in either l4 or l5 and it would do the job nicely, we just don't have a need for it yet, so why would we?
  • The router analogy (Score:5, Insightful)

    by GPLDAN (732269) on Tuesday February 10, 2004 @04:46PM (#8241585)
    I think that Spirit should be considered a big win for NASA. They patched a software bug on a platform that had corrupted flash, basically having to reinstall portions of operating code.
    Something about the repairing a 747 while it is in flight analogy.
    It may not be as dramatic as the rescue of Apollo 13, but they should be commended for well though out design principles, instead of just taking cheap shots at them when something fails as most people are wont to do.
    • by BookRead (610258)
      Yes, indeed. I was struck at how similiar to a garden-variety remote system administration problem it was and how well they had designed the rover and planned its fallbacks to solve it. Very, very nicely done NASA. I'm beginning to believe the robot guys can do it better than the human spaceflight guys. I'm also hoping it trickles down to the hardware we have to manage everyday.
    • When I upgraded my bios on one of my Intel motherboards, it took about 7 minutes - and the system provided no feedback whatsoever that it was working or not. I planned on pulling the plug at the 15 minute mark if it didn't come back...then investigate how to flash a new bios without an operating bios...not fun. Needless to say I was on pins and needles.

      I can only imagine how these engineers felt when the system came back online...
      • A "friend" of mine one time was trying to flash the bios on his scsi card, and the flash failed. He couldn't boot the computer with the card in, but he needed the card to access his boot drive as a temporary measure, so he booted the computer with the card out, then once the bios had passed the stage where it would try to initialize the scsi card, he jammed it into a pci slot (note, this was most definitely not a hot-swappable part). The first two times he didn't get the timing right, but the third time h
  • by gumbysworld (470849) on Tuesday February 10, 2004 @04:48PM (#8241594) Homepage Journal
    Just wait till spam starts to relay from Mars

    Them crafty spamers have spoofed every other network. Just wait till the IP trace routes through Mars.

    Martian Viagra pills 25% off
    Order now and save on shipping.
  • Thinking of the NASA DSN as a LAN type network like I'm used to, makes me wonder if they take into account someone attacking it. How hard would it be for someone to broadcast messages to reach and try to take over the rovers? Something tells me that the communications aren't encrypted or authenticated. Are the frequencies and protocols publically available?

    If someone did manage to DoS or somehow log in to the rover and damage the software it could be the most damaging single-target attack (dollar wise

    • Re:Hack Attack? (Score:3, Interesting)

      by Graelin (309958)
      Something tells me that the communications aren't encrypted or authenticated.

      Your last paragraph should tell you otherwise.

      If someone did manage to DoS or somehow log in to the rover and damage the software it could be the most damaging single-target attack (dollar wise - at over $400 million per rover) of all time. I think that's kind of scary.
  • by ryanvm (247662) on Tuesday February 10, 2004 @04:52PM (#8241631)
    c) Be persistent

    Do they really need that in the handbook? What did they use to do when they had a problem?

    Engineer 1: "Shit Fred, I can't ping it."
    Engineer 2: "Oh well, cest la vie. You wanna grab a beer?"
    • Good stuff :) And true enough. But basically all four of the rules are pretty straight forward and don't have to be said. The problem is in an organization like that, they have to be said. Otherwise there's no accountability. If something goes wrong and they did no simulations then they can just say "Well, we never had that in our guidelines so we didn't do it". With it written down, now there is a accountability.
  • by dekashizl (663505) on Tuesday February 10, 2004 @05:00PM (#8241702) Journal
    More info on communications between Mars/Earth and the DSN (Deep Space Network):
    - NASA's MER2004 Communications with Earth Overview [nasa.gov]
    - DSN (Deep Space Network) Main Page [nasa.gov]
    - Wikipedia entry on Deep Space Network [wikipedia.org]

    --
    For news, status, updates, scientific info, images, video, and more, check out:
    (AXCH) 2004 Mars Exploration Rovers - News, Status, Technical Info, History [axonchisel.net].
  • by DR SoB (749180) on Tuesday February 10, 2004 @05:02PM (#8241713) Journal
    Bulletproofing your gear is extremely important. The old IBM XT's were up for that, I took one camping once (just the case and CPU) and we set up it and took shot's at it with .22's. Only 1 shot pierced the 1/4 inch thick steel case, and the only actual damage done was a really noisy fan afterwards. Think martians have more firepower then .22's, though? d'oh!
  • by hesiod (111176) on Tuesday February 10, 2004 @05:07PM (#8241751)
    To hell with bulletproofing, that's only useful on Earth. If they make it ASTEROID-PROOF... now THAT would be impressive.
  • DSN (Score:4, Informative)

    by Malk-a-mite (134774) on Tuesday February 10, 2004 @05:12PM (#8241802) Journal
    Deep Space Network website:
    http://deepspace.jpl.nasa.gov/dsn/ [nasa.gov]

    Not very detailed but a nice overview of the setup.

  • is it me... (Score:3, Interesting)

    by ricochet81 (707864) on Tuesday February 10, 2004 @05:18PM (#8241863)
    or did they not talk much about space networking? I want to know what protocols they use, how data is buffered on the sats orbiting mars, etc. Where are the technical details?
  • Channel 25? (Score:5, Funny)

    by Unnngh! (731758) on Tuesday February 10, 2004 @05:18PM (#8241868)
    The rover-to-orbiter link uses UHF radio-the same basic technology used for broadcasting channels 14 and higher to television sets in the United States

    Clearly, Mars Channel 25 caused the original Spirit communication breakdown by interrupting it with an episode of Days of our red, dreary lives.

  • As Murphy and others have pointed out, it's the flaw you don't test for that gets you every time. There are an infinite number of things that can go wrong, and a finite number of things you can test. The idea that you could somehow plan for every contingency is what stops many a promising project.
  • by Alsee (515537) on Tuesday February 10, 2004 @05:41PM (#8242195) Homepage
    Rules for maintining a space network:
    a) Automate processes
    b) Bulletproof your gear
    c) Be persistent
    d) Simulate potential problems
    e) Don't crash into the damn planet
    f) Don't confuse feet and meters
    g) Don't "misplace" quarter-billion dollar probes
    h) Don't let probes explode because you left out the fuel-check valve
    i) Don't press the big red shiny button (Narf!)
    j) ???
    k) PROFIT!

    -
  • I have to say, that's the first thing that popped into my head when I read the title. "Hundred million mile? MILE? Didn't they learn anything the last time?"
  • I was surprised to see no mention of Vint Cerf's InterPlaNetary Internet Project. [ipnsig.org]
  • by femtoguy (751223)
    Just think about how many cans of pringles those guys at NASA had to eat to get 100,000,000 miles out of their link.
  • by tiger_omega (704487) on Tuesday February 10, 2004 @08:56PM (#8244237)
    I was wondering if NASA has actually disclosed the details of what they believe was the malfunction of the Spirit rover?

    As someone who has developed backup and recovery systems for embedded systems using vxWorks and flash memory I have my own theory of what could have gone wrong.

    There is an intermitant problem that can occur when using a combination of vxWorks 5.5, dosFs2 and flash memory.

    The problem goes like this : When file A is written to flash memory formatted with a FAT16 table the FAT table is updated to say which disk clusters are occupied by file A, and hence no longer available as free disk space. So when file B starts writing to the hard disk it checks what clusters are free to write to.

    Now a timing problem can occur when a process writing files in a sequential order closes the file handle to A and opens a new handle for B and starts writting to B. The problem exists because the clusters used by A have not been updated to the FAT in time before file B starts writing. The consequence of this is that some of the data belonging to A is overwritten hence breaking the chain. Once this has occurred the FAT and file A cluster chain are corrupt. Once this corruption occurs more corruptions occur with rate of corruption errors growing expotentially until the flash memory can longer function for disk I/O.

    Now as the problem only occurs rarely it is very hard to reproduce in a lab. Also as the rate of corruption is expotential then catching the orginal culprit is even harder. I have spent weeks just trying to catch and diagnosis the problem before eventually catching it.

    Unfortunately once the flash had started to become corrupt the only way to correct it was to reformat the flash memory.

    As for solving the problem, before closing the handle of a file that had been written to flash memory was done an ioctl call would be made to the dosFs2 library to write the size of the file to the disk. Once this solution was is in place the problem never raised its head again.
    • I was wondering if NASA has actually disclosed the details of what they believe was the malfunction of the Spirit rover?

      Space.com [space.com] quoting Glenn Reeves, the JPL Flight Software Architect for the project, on Feb. 6:

      "The first problem is that we ran out of memory. A subsequent problem after that is we managed to corrupt the file system."

      My understanding is that the memory problem occurred because they were trying to load the FAT into memory, and it had grown too large from files accumulated during the

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