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Space

Web Enabled Spacecraft 236

gilgsn writes "Yahoo has an article from space.com about a satellite which will be operated by FTP over TCP/IP on the Internet! The CHIP (Cosmic Hot Interstellar Plasma Spectrometer) spacecraft will examine the stuff between stars, the so-called void of space that is actually rich with hot gas. The choice of protocol was dictated by economics. I wonder what OS it will run and if communications will be encrypted?"
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Web Enabled Spacecraft

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  • by garbs ( 121069 ) on Thursday December 19, 2002 @07:53AM (#4921991)
    Though they may have anticpated the slashdot effect.
  • by Anonymous Coward on Thursday December 19, 2002 @07:54AM (#4921999)
    Watch out: the RIAA will shut down the first Mp3 pirate server in space!
    • by lscotte ( 450259 )
      I know this was meant to be funny, but it's a very interesting thought. Sort of like the off-shore hosting companies, but taken several steps further.

      Of course latency would always be an issue for something in space, but for a streaming protocol...
  • Windows... (Score:2, Funny)

    by Anonymous Coward
    Oh no, that was MIR and yes, it crashed nicely after relatively long uptime (at least for Windows).
  • by SmurfButcher Bob ( 313810 ) on Thursday December 19, 2002 @07:57AM (#4922010) Journal
    Windows SPACE! Service Pack 12.

    In other news, a satellite was taken over by a 5 year old...
  • I can see the headlines now, "new satellite lauched and it is controlled from a windows 95 workstation at www.h4x0r-R-t0yz.com"
  • FTP? (Score:2, Funny)

    Surely they could've hacked together something better than that? If that's a question of economy, their budget must be extremely small.

    I didn't read the article btw.

  • called Cosmic Orbital Discovery (COD) is planned to go along with CHIPS
    • No no no. They'll be sending DIP, the digital interstellar plasmotromiter.
      • Re:Wacky brit! (Score:3, Informative)

        by wackybrit ( 321117 )
        Hmm, did I hear my name called? :-)

        ~~

        By the way, this story is a dupe, and I don't think anyone else has called on it yet. It was posted several months ago under a topic of something like '.mars is coming.' and talked about how satellites around Mars would use TCP/IP.. just like, er, this article.
  • We were asked to come up with a fast cheap solution for getting two servers to keep in touch, and not have to change the company's firewall setup. Our solution was to use SOAP and JAXM, but our backup plan was to do everything via FTP...who knew we were in the same league as NASA?
  • by selderrr ( 523988 )
    Why, it will run WindowsCE offcourse.

    MS is working hard on the C_CHIP ActiveX control. Once that's done, for NASA it's just a matter of a simple drag&drop and 3 lines of VB code.

    Who said space exploration was difficult ?
  • Why FTP? (Score:5, Interesting)

    by drunkmonk ( 241978 ) on Thursday December 19, 2002 @08:01AM (#4922032) Homepage
    Maybe it's just me, but doesn't it seem strange that it would be operated by FTP? I mean, one would think that being able to SSH to it and having a command prompt would be a lot more useful...

    Unless it's actually a cover and NASA is creating the first orbiting pr0n server :)
    • Re:Why FTP? (Score:3, Interesting)

      by Bostik ( 92589 )

      one would think that being able to SSH to it and having a command prompt

      Did you give that thought any consideration whatsoever? SSH2, while secure and neat protocol, is not the leanest you could do. Try to think about it. We're talking about control channel to a moving, non-terrestrial body with probably not too much CPU cycles to spare.

      To establish an SSH connection, both the client and server need to exchange public keys. After that, they need to negotiate the session key(s) over public-key cryptography. This alone is slow. Then, to have any kind of real control, the latency between SSH endpoints needs to be rather small. The symmetric encryption wouldn't take that much cycles, so I'm leaving that out of the equation.

      So while FTP sounds like a really weird and unortohodox solution, it is after all a trivial protocol to transfer sets of batch commands.

      USER control
      PASS *********
      PUT batch
      QUIT

      Just a thought...

      • Re:Why FTP? (Score:2, Funny)

        by Anonymous Coward
        So while FTP sounds like a really weird and unortohodox solution, it is after all a trivial protocol to transfer sets of batch commands.

        That would be TFTP.. Hence the T

      • Re:Why FTP? (Score:3, Interesting)

        by sketerpot ( 454020 )
        Perhaps FTP over an encrypted connection with symmetric keys exchanged before the thing goes into space? There are even special purpose chips to do such things if you want negligible CPU time expended. Check out OpenCores [opencores.org]
      • Re:Why FTP? (Score:3, Interesting)

        by Cujo ( 19106 )

        They don't just use FTP. That's just one port for getting data to and from the spacecraft in batches (which is usually a perfectly acceptable way to get data in and out). See their whitepaper [spacedev.com]. They can also telnet to the 750, and hve other services as well.

    • Re:Why FTP? (Score:2, Insightful)

      by Tolleman ( 606762 )
      Because SSH with giant ping isnt to nice. While if they make so that it runs the scripts that they ftp to it. They wont realy notice the lag.
    • Well assuming that your primary reason for communicating with the thing is to transfer data to/from it, ftp would be the minimum protocol required (i.e. you'd want ftp anyway even if you did have telnet/rsh/ssh). It would be simple on the sat side to have it respond to commands that were say in a specific file (text file at that). So they could upload '/commands' and the sat would then execute whatever was there. Another way would be to use the normal authentication to do some command processing. If communications were over a secure channel (as one would assume it would be), then you could have various username/password combos be meaningful. I.E. you could login as EngineControl and anything you upload would then be assumed to be for the engine controller (I have a dye sub printer that works sorta like this).

      So out of all the "standard" protocols out there, ftp would be the most flexible while still being very light weight.
    • SSH is the protocol they kept using to open and close the doors on the moon base. :-D
    • Re:Why FTP? (Score:3, Interesting)

      by medcalf ( 68293 )

      That would be really bad. Leaving aside the practical implications of attempting an interactive encrypted session with the kind of lag that comes from the physical distance, there is the simple matter of mistakes. You don't want someone to make a mistake typing an interactive command, which could leave the satellite useless and nonresponsive. Instead, you create and test the heck out of your control files, and once they are perfect, just transfer them.

      What actually surprises me is that they are using TCP/IP, rather than UUCP, which seems more appropriate to this kind of latency and simple file transfer need.

    • US export laws forbid the export of strong crypto from earth. I mean, we wouldn't want passing aliens to get a hold of the all-American Made AES! Who knows what they could do with it! It could mean the end of American civilization as we know it!

  • FTP? (Score:5, Funny)

    by praedor ( 218403 ) on Thursday December 19, 2002 @08:01AM (#4922034) Homepage

    It wont take long for someone to crack the satellite. They will download images thinking to collect nice data about deep space but instead will find that some h@X0R has redirected their satellite to take a good close look at Natalie Portman.


    Or...the first DDoS initiated from space will soon be in the headlines.


    FTP? C'mon!

    • FTP? C'mon!

      FTP is perfectly secure if you run it over IPSec.

      I doubt they're actually using IPSec here, but I'm sure they have some form of encryption built into the lower protocol layers.
  • FTP!? (Score:5, Insightful)

    by autopr0n ( 534291 ) on Thursday December 19, 2002 @08:02AM (#4922035) Homepage Journal
    Wow, I've never heard of FTP being used as a control protocol. Sure, HTTP might have been a bit much (although I doubt it. people have run webservers computers the size of matchheads. Even HTTP over a serial connection on an apple2). Why not use straight telnet with no options?

    And I wonder how this control works, do you CD into a spesifc cordinate of space to examine? Can you DIR the stars it can see to find which ones to look more closely at, and then GET the acual data?

    Hrm, actualy that would be kind of cool.
    • Re:FTP!? (Score:3, Informative)

      by AaronLuz ( 559686 )

      FTP is used as a control protocol in plenty of environments. It's really quite simple. You upload one or more files with instructions in it. Then you upload a semaphore file to say your message is complete. The receiving end reads the directory every 10 seconds or so and starts processing when it sees the last file. I imagine that the satellite would return data instead of instructions, and then the process would repeat. The FTP protocol per se has nothing to do with controlling the satellite; it's all about using files as messages.

      I've seen credit card authorizations go through this way. UNIX and mainframe machines often exchange data this way when turn-around time is not important. I would assume NASA doesn't need to control the satellite second-by-second.

    • Why not use straight telnet with no options?

      I thought using FTP on the satellite sounded dumb, but this would be far worse.
    • Re:FTP!? (Score:3, Funny)

      by macshit ( 157376 )
      Wow, I've never heard of FTP being used as a control protocol.

      When I worked in the MIT AI lab, the coke machine used FTP as a `control protocol'.

      You'd ftp to the machine, log in (you had to have a coke account), and type:

      get coke

      ... and a can of coke would drop, deducting coke-money from your coke account.

      The thing is, most people just use a normal FTP client, and the above command will actually transfer a file called `coke,' so I suppose it's better to type "get coke -".

      But I always forgot about that, and as it happens, I usually drank Dr. Pepper, so to this day, in random directories on that system, I'll find little files called `drpepper'...

    • Wow, I've never heard of FTP being used as a control protocol. Sure, HTTP might have been a bit much (although I doubt it. people have run webservers computers the size of matchheads

      Having implemented FTP and HTTP I find the choice bizare but not suprising. There are a lot of people who incorrectly belive that FTP is more efficient than HTTP. If you do an actual packet trace there are practically no circumstances in which FTP is more efficient, and all the cases where FTP wins are contrived (padding out the headers etc.)

      HTTP is simply a bunch of RFC822 headers on top of a raw TCP socket. FTP has two channels, a control channel layered on telnet - if you don't believe me go read the specs. Data has a separate channel. That means that you have two sets of stream setup and maintenance. If you have a large file the control channel acks continuously to keep itself alive.

      I would not be worried so much by the inefficiency here as the unnecessary fragility over a lossy channel. Twice as many moving parts means twice the chance of failure.

      Reusing FTP because it is twenty five years old does not seem to me to be a good strategy. FTP has not progressed in the time since. It was never designed to serve this use.

    • So, in college, I worked with some astrophysicists at the Enrico Fermi Institute [uchicago.edu], which is where they build nuclear powered satellites, and took some classes from professors at at The Laboratory for Advanced Space Research [uchicago.edu], which is responsible for building such satellites/spacecraft as Ulysses, Pioneer 10 & 11, Cassini, StarDust, and Argos.

      Anyhow, from talking with folks at the EFI and LASR, the general answer to everybody's questions is: latency and noise. Remember, this is a Cosmic Hot Interstellar Plasma Spectrometer, which means that it's going to be sent away from the earth, and eventually be millions and billions and trillions + miles away. The longer that it works, the more latency is going to build up... So, the programming needs a very non-interactive protocol. If this thing goes interstellar, it could take days and weeks for packets to travel from Earth to CHIPS and back.

      Remember, it takes 4 minutes for light from our closest neighboring star to reach earth, traveling at, well, the speed of light. In all probability, this CHIPS will be using radio frequencies which are much, much slower. (I could be wrong, but I would be surprised if they had hacked some type of interstellar laser guidance system... )

      Anyhow, they write scripts for this kind of mission, and generally operate with a big time lag, to the extent that it's sort of like typing with your computer monitor turned 'off'. That is, they'll figure out what they want the satellite to do for the next week or next month, type up a script, and 'submit' it to CHIPS. A couple of hours/days/weeks later, CHIPS will receive the script and start working. This kind of astrophysics programming generally involves being able to project into the future (temporally), and to know that in {x} days, the satellite will be past Mars, in {x+a} days, it'll be past the asteroid belt, in (x+a+b} days, past Jupiter, in {x+a+b+c} days, past Saturn, and so forth. It also requires good file keeping and record keeping, so that you know how many days {n} into the project you are, so you can calculate {n-x}, which gives you the time window for submiting an FTP control sequence.

      Other than that, yeah... they can dir things and get thing. Depends on the exact implementation, but you have the concept.
      • it takes 4 minutes for light from our closest neighboring star to reach earth, traveling at, well, the speed of light. In all probability, this CHIPS will be using radio frequencies which are much, much slower

        You know, I could almost believe your comment about the Enrico Fermi institute, until I read this. I guess nobody's ever told you about 299,792,458m/s.

        It's not just a good idea, it's the law.

        • Well, it's the truth about the EFI and LASR. I am not, however, an astrophysicist. There are many things about astrophysics I don't know.

          Please enlighten myself and other slashdot readers about 299,792,458m/s. Have I erred in saying that CHIPS will be using radio frequencies? Have I erred in regards to the time it takes for light from the next star over to reach earth?

          Be more specific, if you're going to critique. I would like to know your opinion regarding this matter, and what about 299,792,458m/s do I apparently not know.
      • In all probability, this CHIPS will be using radio frequencies which are much, much slower. (I could be wrong, but I would be surprised if they had hacked some type of interstellar laser guidance system... )

        Sorry for replying to my own post, however, I stand corrected. I was describing 'Radio Waves' in terms of accustic sound waves; which, in this case, does not apply. Ignore this comment regarding radiowaves being slower...

  • ...now all that stuff the US government keeps telling us about the danger of crackers and how they can cause millions of dollars worth of damage is TRUE!
  • FTP and TCP/IP???? (Score:4, Interesting)

    by amithv ( 233062 ) on Thursday December 19, 2002 @08:05AM (#4922045)
    Couldn't they have picked better protocols? It seems to be me for reliability and performance that isn't the best of choices. There are alot of other protocols (XTP [sandia.gov] for example) that the government could have used instead. Although TCP/IP is so commonplace I wouldn't want my 15 million dollar satellite to depend on it.
    • There are computers worth more then $15m hooked up to the internet, I'm sure.
    • by sploxx ( 622853 ) on Thursday December 19, 2002 @08:14AM (#4922073)
      There'is actually a proposal for a "space internet" where long ping times, high data loss etc. occur.

      It is called "Interplanetary Internet SIG":
      http://www.ipnsig.org/home.htm

      So... they do not use the common TCP/IP things, but their networking principle is closely related to IP.
    • by g4dget ( 579145 )
      Couldn't they have picked better protocols? It seems to be me for reliability and performance that isn't the best of choices.

      And what, specifically, do you think is wrong with TCP/IP? It's pretty minimal and simple.

      Although TCP/IP is so commonplace I wouldn't want my 15 million dollar satellite to depend on it.

      Even if TCP/IP had some technical drawbacks relative to some alternative protocol, software implementation errors and engineering mistakes are likely much bigger risks than some theoretical limitations of the protocol.

      In different words, I'd much rather bet $15 million on a proven, debugged, mature TCP/IP implementation than on some implementation nobody has ever used for a protocol nobody has ever heard of.

  • Got r00t? (Score:5, Funny)

    by RAMMS+EIN ( 578166 ) on Thursday December 19, 2002 @08:07AM (#4922050) Homepage Journal
    What? No security through obscurity? I can hear the 5kr1p7 k1dd13z rejoicing...

    J. |_337 H4x0r: D00d$$$ I took control of da satelite man! See hoe |337 I am!!!
    J. |_3373r H4x0r: L00se, sux0r! I can make her spin round! Wheee! Wheeee!
    J. |_337 H4x0r: What are you doing idiot you're taking her down!!!
    J. |_3373r H4x0r: No way man. I'm much to |337 for that!! DAMMIT Windows crashed again! sux0rzzz!!!###

    [Sattelite falls down to Earth]
  • "Web Enabled"? (Score:2, Insightful)

    by ovideon ( 634144 )
    I'm probably missing something, but when did FTP mean that it was "web enabled"? Aren't ftp and http intended for different purposes etc?
    • Thank you, Ovidian. I'm glad someone brought this up first. I was going to mention it, but didn't want to seem like I was nit-picking. Since when does an FTP server make something "web enabled"?

      Seriously, just because modern web browsers can issue a limited subset of the commands defined in the FTP protocol doesn't mean that FTP is part of "the web". I was using FTP long before there was ever a "Web". If you upload anything via FTP on a regular basis, the difference is readily apparent.

  • Windows (Score:3, Funny)

    by m00nun1t ( 588082 ) on Thursday December 19, 2002 @08:13AM (#4922069) Homepage
    Ok, satellite running windows, yada yada, service pack yada yada, hacked by 12 year old, yada yada, Microsoft Windows for Space yada yada.

    Ok, now I've gotten all the blindingly predictable jokes out of the way, can we move to something more interesting?
    • They'll need the 30+ mile long poles to hit Ctrl+Alt+Del...

      On the Unix side -
      That "No route to host" error becomes more meaningful.

      "Uptime" will relate to orbit, not system.
  • I guess you can't expect most people nowadays to 'get' it, but come on, I'm sure most people on slashdot know the difference between the 'web' and the 'internet'. When something is web enabled that means you can access and control it using a web browser over HTTP. (although I suppose most browsers can use FTP these days).
  • I hope they choose something else than the infamous wuftpd, or else the satellite might be doing other things then intended by the owners...
  • PING (Score:5, Interesting)

    by del_ctrl_alt ( 602455 ) <paulsd@@@skiing8...freeserve...co...uk> on Thursday December 19, 2002 @08:16AM (#4922083)
    Hope it has an IP address, It would be cool to ping something not on earth.
    • Re:PING (Score:2, Funny)

      by tigress ( 48157 )
      Ping my boss. That should qualify. =)
    • That would be very cool...

      You could watch the latency gradually shrink and grow as it constantly changed distances from its receiver. If you could ping it directly, pinging it from 4 different non-planar sources would allow you to quadrangualte its exact position at any time.
    • Re:PING (Score:5, Informative)

      by Lumpy ( 12016 ) on Thursday December 19, 2002 @10:06AM (#4922688) Homepage
      amateur radio operatros can do this daily.

      I have "pinged" the dove sattelite at least 20 times in my life, Pinged and sent email to MIR, had a kind-of IRC chat with 2 different Space shuttle missions and have listened to my ping come back from the moon.

      ham radio, you get to do things that other only wish they could do.

      all of this was done at 144-148mhz with standard radio equipment and radio modem called a TNC. MIR was the easiest to contact.... moonbounce requires a friend with no wife and lots of money.
  • by Effugas ( 2378 ) on Thursday December 19, 2002 @08:20AM (#4922101) Homepage
    Serious kudos to these guys for the work they're doing! From what it sounds like, they're using FTP inside of either a IPSec or custom layer 2 encrypted tunnel -- once you've been wrapped by that, you're mostly OK (though FTP servers in general have had some pretty nasty growing pains).

    Some may be wondering why the use of FTP, instead of HTTP. Indeed, HTTP is a unified protocol capable of elegantly handling both (moderately) interactive command exchange and bulk data transfer. The problem is latency -- if this beast is going anywhere, there's going to be some significant (5-10 second, minimum) lag between issuing commands and receiving responses. In such an environment, you don't *want* interactive access; you want an elegant way of providing a series of commands and receiving a series of responses. FTP provides that -- among other things, while HTTP's capacity for downloading files is quite mature, anything more is asking a bit more of HTTP than it was designed.

    FTP has specific commands for machine interaction w/ the file server -- NLST provides a standard formatted directory of files, independent of the underlying implementation. By contrast, Apache dumps some HTML.

    WebDAV ("Web Folders) was meant to address complex file system operations under the rubrick of HTTP. Thus far, it hasn't been much of a success. It most likely never will be. Thus, FTP is used.

    But FTP is built on TCP, and this introduces a problem: The affects of latency upon the underlying TCP error handling protocol. TCP implementations are notoriously untuned for the case of high bandwidth, high latency. They're built to assume the lack of a response implies either congestion on the line or packets being dropped; either way, implementations tend to scale back. Significant work has been done to address this case, mostly on the behalf of Satellite systems (the ultimate in high latency, high bandwidth access). Mostly, the idea is to expand window size (the amount of data that each side is allowed to send before it must receive an acknowledgement) to match the amount of data that's literally hanging amidst space and time on its way to its receiver. But this is a very hard problem, one of the few that the architecture of TCP has quite a bit of trouble scaling to handle.

    NASA went to a bulk transfer protocol, partially because interactive performance across large distances is problematic. But the bulk transfer protocol itself is based upon an interactive error management protocol. It'd be interesting to repurpose an established protocol for error-handled bulk transfers for just this use...I'm certain one of the "reliable multicast" architectures out there would be an astonishingly elegant solution.

    That's not to say they made the wrong choice with FTP -- particularly if they tuned their stacks well, and encapsulated themselves amidst lower layer security, great job! Just that there's lots of work in this arena left to do.

    If I remember right, Vint Cerf and a couple of his colleagues were working on IP protocols suited for communication between Earth and Mars. We're talking *minutes* of latency! Now that'll be a hell of a hack :-)

    Yours Truly,

    Dan Kaminsky
    DoxPara Research
    http://www.doxpara.com
    • NASA already uses multicast UDP for transferring telemetry and command data between ground stations and control centers/experimenters. Congestion control is handled by scheduling the bandwidth of the data lines. This is on a private NASA Internet that is not connected to the public Internet. The air/ground communications links use the CCSDS [ccsds.org] standards.
      • Telemetry's pretty error resilient; even if I drop a packet, I can usually interpolate without too much threat. Batches of instructions are another matter; if a packet's dropped, it needs to be replaced, in line, or the entire transfer fails. Thus me mentioning the tech used for reliable multicast -- it works by broadcasting to everyone, then letting individuals ask the central server (or eachother) for retransmissions. In this case, there's as few as one host to speak to -- but it may request retransmissions without even interrupting the primary link.

        You mentioned multicast UDP for commands. I can see this for something like, "Everyone, point their dishes at this quadrant of space"...but managing error control and responses must not be fun. :-) I'm curious if you know any more about the work involved on this.

        Thanks!

        Yours Truly,

        Dan Kaminsky
        DoxPara Research
        http://www.doxpara.com

        --Dan
        • Control centers handle their own retransmission of lost/corrupted commands. They transmit a command and check the telemetry to see if it was received by the spacecraft. If it was lost, they retransmit the command. The details are very spacecraft dependent. Commands may execute immediately upon receipt or they may be split into two phases, load command and execute command. Some commands are time tagged for execution at a later time. A set of commands can be uplinked into a command buffer on the spacecraft, verified by a memory dump in the telemetry stream, and executed after the control center has verified that they got a good load of the command list.
          • Cool! This makes total sense -- any manuever that's time sensitive would be loaded and verified long in advance.

            Are sats constantly dumping their buffers and status to RF?

            --Dan
            • Status information is usually being continually downlinked in the telemetry. This includes things like the status of the command receiver and decoder. Memory dumps are usually only transmitted in the telemetry when the control center sends a command for a memory dump.
  • ipinspace (Score:2, Informative)

    by Anonymous Coward
    This project has been going on for quite sometime and has already been repeatedly demonstrated for low earth orbit satellites. For details please see:http://ipinspace.gsfc.nasa.gov/
  • Pedantic, I know, but FTP != web. HTTP == web. I know a lot of people don't grasp the difference between the internet and the world-wide-web, but you'd have thought someone writing web content might have got it right.

    Also, ethernet != internet (the program manager for the project got that one wrong).

  • by Goonie ( 8651 ) <.robert.merkel. .at. .benambra.org.> on Thursday December 19, 2002 @08:21AM (#4922109) Homepage
    I think the point is that they're going to use TCP/IP as the basic communication protocol between the satellite and the ground. I think FTP was basically a "for-instance" they were using to describethe type of thing they would use - but, then again, there's no reason why they couldn't run an FTP server on the satellite for retrieving data (though I'd run SCP methinks...)

    Conceivably, you could even control the satellite by ssh'ing into it and running various command-line apps. If you wanted to be really cute, run a web server on the satellite and make it controllable with web forms... but that strikes me as just a little over-elaborate :)

    For security purposes, they mention using "standard commercial applications" to encrypt the link. Presumably that means they're running a VPN of some description. As an additional security measure, you'd presumably want to hide the thing behind a firewall and give it a non-global IP address (somewhere in the 192.168.*.*'s, presumably) so that it simply can't be reached from the wider internet, and then (if it was *really* necessary) set the firewall up so that the appropriate people can tunnel through.

    Actually, it would be interesting if we could get a /. interview with one of the people behind this satellite (and grill them about their security measures). Roblimo, are you listening?

  • Protocol choice (Score:5, Interesting)

    by tigress ( 48157 ) <rot13.fcnzgenc03@8in.net> on Thursday December 19, 2002 @08:24AM (#4922120)
    Personally, I find it very intriguing that they've chosen FTP as the protocol, though it does make a lot of sense. Most of what the sattelite is intended to do will be done in a pre-determined manner. Very little will be done in real-time. As a result, most instructions will be able to be scripted, and FTP is an excellent way of uploading scripted instructions to the sattelite. TFTP would've been even better, had it not been for the lack of access controls.

    Now, that much said, when do you think we'll see the first DDoS of zombie spaceprobes? =)
    • TFTP is based on UDP--that's not the kind of protocol you want to use over a long-haul, noisy connection.

      A TCP-based protocol is exactly the right thing for this application. The only thing they have to watch out for is that they need to increase timeouts and other parameters that have been adjusted downwards in consumer machines for "performance reasons". FTP's use of separate control and data connections also makes it a little more attractive than alternatives.

      I doubt authentication was a consideration--FTP is insecure anyway. They probably use firewalls.

  • The CHIP (Cosmic Hot Interstellar Plasma Spectrometer) spacecraft will examine the stuff between stars

    "Calling Seven-Mary-Three and Four"
  • Ask Slashdot? (Score:2, Informative)

    by drouse ( 34156 )
    There is a page at berkeley.edu that talks in more depth about the satellite (http://chips.ssl.berkeley.edu/index.html) but doesn't really cover command/control and software issues. Maybe an Ask Slashdot for the maintainer of the page is in order?
  • Remember this infamous bit of commenting?

    /* Increase the timeout each time we retransmit. Note that
    * we do not increase the rtt estimate. rto is initialized
    * from rtt, but increases here. Jacobson (SIGCOMM 88) suggests
    * that doubling rto each time is the least we can get away with.
    * In KA9Q, Karn uses this for the first few times, and then
    * goes to quadratic. netBSD doubles, but only goes up to *64,
    * and clamps at 1 to 64 sec afterwards. 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!
    */
    in linux/net/ipv4/tcp_timer.c
  • FTP, eh? Commercial software, eh? Low budget, eh? This is gonna be so easy.

  • by cheesedog ( 603990 ) on Thursday December 19, 2002 @08:59AM (#4922271)
    There is a reason satellites don't commonly use TCP/IP: it performs HORRIBLY over high latency, high BER links. This is because TCP makes the assumption that ALL data corruption is due to congestion, and thus its backoff algorithm throttles way back when errors are actually caused by a noisy link. Likewise, the high latency of a satellite link (rougly around 500 ms RTT) causes TCP to send unneccessary retransmits, etc.

    And, this isn't the first satellite to use TCP/IP, by the way. TCP/IP has been run over satellite links numerous times, most often to demonstrate TCP's shortcomings in relation to better methods.

    note: that's not to say that TCP/IP isn't a fine protocol -- it's a perfectly reasonable way to do things on a low BER, low latency network (i.e., the majority of networks we commonly use). I'd have the same criticisms of someone trying to run, for example, SCPS on a terrestrial network. It's the wrong tool for the wrong job.

    • "And, this isn't the first satellite to use TCP/IP, by the way"


      No, it's not. However it IS the first satellite to ONLY use TCP/IP to communicate.


      From the spacedev website [spacedev.com]:

      "The Cosmic Hot Interstellar Plasma Spectrometer Satellite (CHIPSat) will be the first mission to use end-to-end satellite operations with TCP/IP and FTP. This concept has been analyzed and demonstrated by the NASA OMNI team via UoSAT-12; however, CHIPSat will be the first to implement the concept as the primary means of satellite communication."

    • > It's the wrong tool for the wrong job.

      Nah, a default TTL of 60 is perfect for sending packets through space...
  • Ok, I read the article, but I can't see how it relates to Ponch and Baker [imdb.com]?

  • Would this be the only way to legally host a file server for MP3's? Or does the RIAA presume its jurisdiction (and yes, I do believe it has elevated itself to an enforcement entity) now extends to outer space?
  • Web-enabled vs. FTP (Score:2, Interesting)

    by Peter_Pork ( 627313 )
    Let's get this straight. The web uses the HTTP protocol, not FTP, so this web-enabled spacecraft headline is misleading. Browsers include an anonymous FTP client, so you can navigate and download from FTP servers, but that doesn't mean FTP is part of the web. The piece of news is the use of out-of-the-box Internet protocols in a spacecraft. It is great news. Save money by using solid, well-known technologies. This is part of the agenda of the new NASA, and it is basically good. You cannot reinvent the wheel in every mission. BTW, you still need a deep space antenna to contact the spacecraft, so it cannot be hacked unless the attacker breaks into a well-protected NASA site.
  • The technical paper [spacedev.com] is on the SpaceDev website [spacedev.com].
    They are using VxWorks, PSOS, OS-9, and Linux. Looks like VxWorks is what will be running on the satellite, with less than 20 lines of code in the actual communication routines...

    LR
    • Not sure why I'm not being modded up, but the link [spacedev.com] details all of the technical specs of OS and hardware, as well as the code and networking info. Shines quite a bit of light on the story... Surprised the original poster didn't look this far...

      LR
  • by cybrpnk2 ( 579066 ) on Thursday December 19, 2002 @09:26AM (#4922410) Homepage
    The Ground Systems Department [nasa.gov] at NASA Marshall Space Flight Center has a "new" system called Telescience Resource Kit (TReK) [nasa.gov] that allows experimenters to hook personal computers in their home labs up to experiments they are running aboard the International Space Station. The main entrance page is here [nasa.gov], but most of the links are password protected...
  • it's at this link [lcarscom.net]

    RickTheWizKid
    Lightening Slashdot users' days since 2001!
  • Woot! (Score:2, Funny)

    by DjMd ( 541962 )
    Alright, lets here it for War-orbiting!
  • Looking forward to the first CPAN mirror in orbit.
  • Am I the only one having a hard time swallowing that bit?

    Sounds like some clueness reporter pulled a TLA out of a hat or something...

    Unless the FTP is being used as a sort of batch command transmission vehicle... A little like the IPN [slashdot.org] protocol specifies. A sort of connectionless command line over a connected protocol.
  • Phew (Score:2, Funny)

    by parad0x01 ( 549533 )
    Phew! After that RS-232 fiasco I guess the FTP protocol would be the next logical choice! Aren't FTP commands transmitted unencrypted as plain text. Looking to impress a girl, hack the satellite and have a shooting star at your command.
  • Here are some website links:
    Spacedev is (duh)
    www.spacedev.com [spacedev.com]
    CHIPSat can be found under Missions.
    Spacedev's stock price can be found at:
    finance.yahoo.com [yahoo.com]
    The Space Sciences Laboratory at UC Berkeley
    chips.ssl.berkeley.edu [berkeley.edu]
  • The CHiPs spacecraft will be ground controlled by Officers 'Ponch' Poncherello and Jon Baker.
  • TCP/IP notorously bad for high latency/high error rate connection.
    Hacking together a special use protocol with a push stream with ton of error corrections is not a big deal.
    Or, what they are talking about is a connection up to the uplink station?
  • oh dear... (Score:2, Funny)

    by monkey_jam ( 557265 )
    kind of misread that as

    'WEP enabled spacecraft '

    I can imagine loads of script kiddies aiming Pringles cans into the sky....
  • SpaceDev, the company that constructed CHIPSat, today sent out an email announcement that the launch of CHIPSat was delayed due to problems with the launch vehicle.

    The announcement is reproduced below:

    eAnnouncement

    CHIPSat Launch Delayed
    December 19, 2002

    Due to circumstances beyond our control, the CHIPSat launch scheduled for Thursday, December 19, 2002 on a Delta II rocket from Vandenberg Air Force Base has been delayed and is now targeted for January 8, 2003.

    The launch was delayed due to a technical glitch in the Boeing-manufactured launch vehicle. The technical problem is associated with the signal the ordnance box provides for launch vehicle devices to unlatch and separate the payload fairing. NASA is expecting the replacement of this unit to take approximately two weeks.

    SpaceDev designed and built the CHIPS (Cosmic Hot Interstellar Plasma Spectrometer) spacecraft and associated subsystem products (e.g. Miniature Flight Computer) for the University of California, Berkeley under a NASA-funded contract. The CHIPS mission is designed to study the formation of stars, and will have a life span of about one year.

    CHIPSat will be the first mission ever to use end-to-end satellite operations over the Internet with TCP/IP and FTP. This concept was analyzed and demonstrated by the OMNI team via UoSat-12; however, SpaceDev will be the first to implement the concept as the only means of satellite communication.

    SpaceDev has overall responsibility for the design of the mission, the design, assembly, integration and testing of the microsatellite, and mission control and operations from Spacedev's Mission Control Center.

    If there are any further delays, we will send out an update immediately.

It was kinda like stuffing the wrong card in a computer, when you're stickin' those artificial stimulants in your arm. -- Dion, noted computer scientist

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