Slashdot Mirror

← Back to Stories (view on slashdot.org)

Web Enabled Spacecraft

Posted by michael on from the fluffy-bunny-to-the-rescue dept.

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?"

3 of 236 comments (clear)

  1. FTP!? by autopr0n · · Score: 5, Insightful

    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.

    --
    autopr0n is like, down and stuff.
  2. TCP/IP is TERRIBLE in space by cheesedog · · Score: 3, Insightful
    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.

  3. Re:FTP and TCP/IP???? by g4dget · · Score: 3, Insightful
    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.