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Interplanetary Network (IPN) Tested

Posted by michael on from the token-ring dept.

CETS writes "Slim on detail but...USA Today reports of the first test of an Interplanetary Network. 'In a sign of cosmic communications to come, last week mission controllers sent signals to a Mars-orbiting European spacecraft, which relayed the instructions to NASA's Spirit rover on the surface, and a signal was returned to Earth back along the same path.'" NASA also has a press release.

32 of 138 comments (clear)

  1. Really bad pun - let's get it out of the way now by Anonymous Coward · · Score: 5, Funny
    Who's going to be the first to finger Uranus?

    Go ahead - mod this troll... :-)

  2. Isn't that a bit early? by locknloll · · Score: 5, Interesting

    I mean, good intentions, and kudos to NASA to get that infrastructure up and running, but it will probably take some more years before this really starts to make sense.

    I guess it won't be used for routing traffic to gameservers...

    --
    -- Power corrupts, but PowerPoint corrupts absolutely.
  3. Re:Really bad pun - let's get it out of the way no by Anonymous Coward · · Score: 5, Funny

    Does that come before or after pinging the Mons Venus?

  4. Try to catch me now... by Anonymous Coward · · Score: 3, Funny

    Hey, what is stopping us from using this as a proxy server? Could you just imagine the guy looking at where the signal is coming from? Hehe...

  5. Slashdotting Mars? by Big+Nothing · · Score: 5, Funny

    I'm looking forward to the day we can slashdot a website on another planet.

    --
    SIG: TAKE OFF EVERY 'CAPTAIN'!!
  6. With number of planets and stars out there... by SharpFang · · Score: 4, Funny

    they just MUST use IPv6

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    45 5F E1 04 22 CA 29 C4 93 3F 95 05 2B 79 2A B2
  7. What about subspace? by zonix · · Score: 4, Funny

    Wouldn't it be much faster to use a subspace frequency?

    z
    --
    What would an EWOULDBLOCK block, if an EWOULDBLOCK could block would? -- me
    1. Re:What about subspace? by Scoria · · Score: 5, Funny

      No, Wesley. Now rub my bald head.

      --
      Do you like German cars?
  8. oops by berkut1337 · · Score: 4, Funny

    let's see, we already have:

    PAN: Personal Area Network
    LAN: Local Area Network
    SAN: Storage Area Network
    WLAN: Wireless Local Area Network
    WAN: Wide Area Network
    MAN: Metro-something Area Network
    and now:
    IPN: Interplanetary Network

    can anyone add any more?

    1. Re:oops by Anonymous Coward · · Score: 5, Funny
      WOMAN - completely undecipherable network.

      Now I just hope that I remember to post this as AC ...

  9. NASA Contumues to ... by Zordas · · Score: 5, Insightful

    get people excited about space exploration. I for one am overwellmed by the string of success. Heck .. I even have NASA TV constantly running on my computer just so I don't miss a press release and to lean more about the rovers. Previously we were limited to bot's being in a "Direct line of sight" with Earth to transmit data. Now with the IPN we can get data faster and more often. KUDO's to NASA and the ESA for great job !

  10. Re:more network acronyms? by Cap'nCrunk · · Score: 3, Funny

    UPN: Unbearable Programming Network

  11. I'm kind of surprised... by TWX · · Score: 4, Interesting

    ...that they haven't implemented some form of relay satellite over Mars already. I'd think that one satellite in space would remain viable longer than a ground craft, and since it's in space it wouldn't have the dust-on-the-solar-panels problem, the atmospheric barrier problem, or the temperature variance problem. The ground craft wouldn't need to be built to transmit to Earth, just to an orbiting Mars satellite, which would handle the rest, so the landing craft could have engineering to make it more suited to its task rather than concentrate on radioing home.

    --
    Do not look into laser with remaining eye.
    1. Re:I'm kind of surprised... by Skyshadow · · Score: 4, Interesting
      that they haven't implemented some form of relay satellite over Mars already.

      Well, they *are* using existing orbiters to communicate with the current generation of orbiters. You know, just like the headline there says.

      I suspect that before any serious Mars exploration ramps up, a set of satellites in martian geosync would be a good idea. Not only would that facilitate communiation with anything actually on the planet, but it could also provide for a global positioning system.

      The real issue up to this point is that we just haven't needed that sort of thing yet. If/when we send people (especially if we follow Zubrin's advice and send them for 500+ day stays, or my advice and just build a colony and get on with it), that will change. If nothing else, just increasing the amount of bits you can push by sending a constant stream of lower-power 1's and 0's to a satellite instead of screaming data at the DSN here on earth a few hours a day would probably be a big benefit to future missions.

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    2. Re:I'm kind of surprised... by I+don't+want+to+spen · · Score: 5, Interesting

      Geostationary orbit satellites only last about 10-15 years before the satellites run out of fuel. I don't know if a Martian equivalent would need more or less fuel due to the lower gravity. The current orbiters can also do useful planetary observation as well as acting as a communication relay, precisely because they do orbit over the planet's surface and can see the whole of it from close range. I doubt that 3 aerostationary, or whatever the correct Martian term is, satellites would adequately perform observations for their much higher orbit as well as providing blanket comms coverage for the planet. Plus power considerations etc. I'm sure it will happen, but not for a good while yet.

      --
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    3. Re:I'm kind of surprised... by Helvick · · Score: 5, Informative
      Simple - the primary mission objectives for Orbiters is remote imaging and a low altitude polar orbit is ideal for that because it gives almost total planetary coverage. It means that communications windows with landers are very short (8-12 minutes a day for Odyssey, MGS and Mars Express) but they can cover landers anywhere on the planet at high bandwidth for those communication windows.

      This will be the case for the next Orbiter (Mars Reconnaissance Orbiter 2005) and any others prior to the Mars Telecommunications Orbiter which has a primary objetive of being a proper telecoms relay. MTO will provide at least 10x the current bandwidth, communication windows up to 8 hours in duration and will use optical as well as S-Band\X-Band radio links.

    4. Re:I'm kind of surprised... by RayBender · · Score: 3, Informative
      Geostationary orbit satellites only last about 10-15 years before the satellites run out of fuel. I don't know if a Martian equivalent would need more or less fuel due to the lower gravity.

      Likely somewhat less. Geostationary comsats spend much of their fuel counteracting the effects of the Moon, which tends to pull them out of place. There is no moon around Mars that's large enough to cause problems. On the other hand, Mars os far enough away that it take s bunch of fuel just to get there.

      By the way, the GPS network does NOT use geostationary staellites - they are in "half-Geo" orbits; the problem with getting the equivalent of a GPS network around Mars is that you'd need ~24 satellites. The GPS net is a big constellation.

      --
      Human genome = 3 billion base pairs = 6 GBit. Windows + Office = 20 Gbit. Which is more impressive?
  12. See naked little green women at SpiritRover.com by BenJeremy · · Score: 3, Funny

    ...Yeah, I told my wife I meant to type SpiritRover.org - Doh!

  13. Not really by mlyle · · Score: 4, Insightful

    The bulk of data coming back from the Mars Exploration Rovers comes back through relay sessions through the Mars Odyssey and the Mars Global Surveyor satellites. The orbiters are simply much closer to the rovers than Earth is, the path loss is less, and so the data rates are much higher... and the satellites have direct visibility of earth for much longer and much higher EIRPs to talk to earth with.

    A couple of weeks ago they tried the first "interplanetary network" where the sessions were up "live", rather than store and forward.

    The really big advantage of this is they'll be able to command the rovers in near-realtime and get answers back right away for much more of the day than direct to earth communications is possible. And with 3 communications satellites above Mars, they are likely to have quite a few communications windows. Expect them to be fairly risk adverse, though, and for it to be several weeks before this is included in their operations.

  14. Re:USATODAY.com for all your science needs... by AeroIllini · · Score: 5, Interesting

    USA Today, is right, though. The lag time between Earth and Mars is anywhere between 3 and 22 minutes when Earth and Mars are clostest and farthest away from each other in their orbits.

    And I think NASA has had plans to incorporate signal relay satellites for some time. Of course, NASA plans to build many more probes/satellites than actually get launched, so we're just now seeing satellites with relay capabilities. There were plans as far back as 1997 to launch a series of satellites whose only purpose was to relay signals from other spacecraft. Interplanetary routers, if you will. However, due to budget cuts, the capability was instead built into satellites with otherwise scientific payloads.

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  15. IPN not like TCP/IP by Anonymous Coward · · Score: 5, Informative

    The IPN and the Internet are two different things.

    The IPN does not use TCP or another transmission control protocol because it is simply not possible to acknowledge data/rerequest data if the latency is that big (minutes to days in the solar system).

    1. Re:IPN not like TCP/IP by Anonymous Coward · · Score: 3, Informative

      Quite the contrary, the IPN and our terrestrial Internet are rather closely related. Don't think a lot of the lessons of a best-attempt network have been ignored.

      http://www.ipnsig.org/

      I recommend reading there about the entire suite of protocols, *all* based on terrestial Internet equivalents.

  16. Re:more network acronyms? by FrostedWheat · · Score: 3, Funny

    ISN: Inter-Stellar Network

    For all the latest fair and balanced news from the Bu.. Clarke government.

  17. Things we can look forward to by cyranoVR · · Score: 4, Funny

    Martian Email Scam ("my recently deposed president Marvin...")

    Movie hax0rz routing their connection "through Mars" to avoid detection

    RIAA supoenas Spirit rover

  18. Ping thread by eap · · Score: 3, Redundant

    Please place all ping mars with time=(large number) jokes under this thread.

    Thank you

  19. KA9Q by bigattichouse · · Score: 3, Interesting

    Just a dressed up store-and-forward packet radio, right? KA9Q was written well over 10 years ago, and can route IPv4 traffic over such a connection.

    --
    meh
  20. Re:Really bad pun - let's get it out of the way no by gertsenl · · Score: 5, Funny
    What I want to know is, did they store a hard copy of their public key fingerprint on the spacecraft and rover?

    You know, to prevent a Little Green Man-in-the-Middle Attack?

    --
    --Leo
  21. Not even that good. by Civil_Disobedient · · Score: 4, Interesting

    The lag time between Earth and Mars is anywhere between 3 and 22 minutes when Earth and Mars are clostest and farthest away from each other in their orbits

    And just to make matters worse, you've got to deal with some serious high-gain amplification to "dial them up". Beaming cable over a satellite's easy -- sending it millions of miles away means a lot more power (a scarce commodity on a satellite to begin with) or a much more sensitive antenna on the recieving end. I don't know what the current data transmission rates with the things we sent to Mars, but for reference, the Magellan probe back in the 90's had a transmission rate of 115 - 268.9 kilobits/sec.

    It is really amazing to consider that we now have a "spy" satellite orbitting Mars relaying images of the surface back to us on Earth, and that it's sensors are good enough to show us photos of the landing of the rover on the surface. Just incredible. But this technology is still in its infancy -- we've still got decades before we land a man on the planet. This is an amazing page about the Soviet exploration of Venus that may also be of interest.

    1. Re:Not even that good. by dvd_tude · · Score: 5, Interesting

      They do have one thing that helps (as it turns out, quite a bit): no in-band background noise to interfere with the communication.

      Anyway, yes their data rates are lower than diect broadcast TV satellite. It's all about the relative S/N owing to inverse square law and the greater distance to the deep space vehicle. The rover and orbiter link rates are on par with Magellan's - 128~256 kb/s, compared with about 30mb/s for a DTV satellite transponder channel.

      Read this chapter in JPL's Space Flight Primer for more information about how their space vehicle comms work. A tidbit I found in there: they use coherent (phase-locked) transmission and Doppler to very accurately measure the remote vehicle's position. That's a neat hack.

      Both things are amazing when you look at them, for different reasons. Deep space communication is amazing because it's possible. Direct broadcast satellite is amazing because it's so cheap!

      A nitpick: the 'milestone' stated in the article, which was apparently overlooked by many of the posters here is the fact that, for the first time, a non-NASA spacecraft (in this case the ESA's Mars Express Orbiter) got into the act as a data relay for the rovers. This is more a statement about cooperation than it is about outright technical achievement. It is a political milestone, much the same as our (America's) cooperation with Russia in the ISS and in developing new rocket booster technology. Yet while it is political, it is a good thing in that it's another step toward recognizing that for space exploration to be fully realized it needs to be global endeavor, not a national one.

      This is very much at odds with Bush's election-year 'man to the moon' pipe dream that serves no real scientific end and is more about beating the collective American wiener on the table with China.

  22. Re:Communications Relays by Detritus · · Score: 4, Informative
    Phased array antenna systems are used for applications like air defense radar, where you need to track multiple inbound targets, and satellite communications where the satellite transmits to multiple stations on the ground. The difference between a phased array and a parabolic dish is that the parabolic dish is mechanically aimed and can only point at one target at a time, while a phased array is electronically steered and can simultaneously track multiple targets.

    A phased array is composed of a large number of simple antennas in a regular pattern. Each of the simple antennas is connected to a phase controlling element, usually controlled by a computer. By adjusting the phase of each simple antenna, the array's radiation pattern can be manipulated to form one or more directional beams, without having to move any mechanical parts.

    For NASA's application on TDRS, it allows them to simultaneously track and communicate with multiple satellites in low-Earth orbit, with a single electronically steered antenna system.

    The trick NASA pulled with the phased array antenna on TDRS was to take the phase controllers off the spacecraft and put them at the TDRS ground station. The TDRS spacecraft takes the output of all the simple antenna elements and retransmits each one to the ground station. The ground station has a magic phasing/combiner box that takes the outputs of all the simple antennas and adjusts the phase of each signal and combines them under computer control. This splits the phased array into two parts, with part in space (simple antenna array) and part on the ground (phasing/combiner/control computer). This removes a big chunk of hardware and complexity from the spacecraft and relocates it to the ground station.

    Looking at the TDRS web page, the latest series of TDRS spacecraft (TDRS-H, I, J) have the beam-forming hardware on board the spacecraft, instead of doing it on the ground.

    --
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  23. Reminds me of... by Beolach · · Score: 4, Informative
    A comment in the Linux kernel:
    /*
    * [...] Note that 120 sec is
    * defined in the protocol as the maximum possible RTT. I guess
    * we'll have to use something other than TCP to talk to the
    * University of Mars.
    *
    * PAWS allows us longer timeouts and large windows, so once
    * implemented ftp to mars will work nicely. We will have to fix
    * the 120 second clamps though!
    */
    --(from /usr/src/linux-2.6.2/net/ipv4/tcp_timer.c, concerning RTT [round trip time])
    --
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  24. Submitter misread news article and release by benh57 · · Score: 3, Insightful
    The news article and the press release noted that this was the first INTERNATIONAL interplanetary network, IE, NASA Rover -> ESA Satellite -> NASA ground station. Read it again, guys. That was the whole point, that ESA was involved for the first time.

    Orbiting networks via NASA Rover -> NASA Sat -> NASA ground have been done repeatedly since the rovers landed well over a month ago.