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Ham Hears Mars Orbiter 45 Million Miles From Earth

Posted by Zonk on from the that's-quite-a-commute dept.

Richard L. James writes "As reported on the Mars-net email list Flight Refuelling Amateur Radio Society's resident satcom + WLAN guru Paul J. Marsh (M0EYT) has managed to detect and receive NASA's Mars Reconnaissance Orbiter on X band at a staggering range of 45 million miles from Earth using a home made receiver setup and a RFspace SDR-14 software radio."

13 of 239 comments (clear)

  1. Re:Security risk? by user9918277462 · · Score: 5, Interesting
    All NASA communications are encrypted. One of the highest priorities during recovery of the Columbia wreckage was to find and secure the NSA "black box" that encrypted radio traffic between the shuttle and ground control.

    Can you imagine the damage some antisocial radio vandal could do to the Mars Rovers, for instance, if the command traffic was sent in the clear?

  2. Yay for Amateurs! by drwho · · Score: 3, Interesting

    I think this is great. It shows what's possible, even without a huge budget. I wish I could read more about it, but the sites have all been slashDOSed.

    But just because they guy isn't paid to do this, and didn't spend a million dollars on the equipment, doesn't mean that anyone can do it -- setups like these are tricky. I imagine he had ot capture a lot of data, and use some really powerful computer for signal processing.

    Now, if he can send signals BACK to mars, and have them interpreted by beings or equipment there, I'd be even further impressed.

    I'd like to claim that this is a victory for ham radio. In a way it is, as it is a radio accomplishment and the fellow is not paid for this. But as it doesn't involve any transmission, it's more of an SWL (ShortWave Listener) accomplishment than an Amateur Radio accomplishment.

  3. Not quite by slightlyspacey · · Score: 5, Interesting

    As with most things in life, the correct answer is "it depends". All NASA communcations to/from the shuttle are NOT necessarily encrypted but can be. Uplink from the ground to the shuttle always is encrypted (we don't want someone sending bogus commands). In addition, the crew has the option of disabling all commands coming from the ground. Direct downlink from the shuttle to the ground can be encrypted but that is not always done. It depends on the mission configuration. DOD-based classified missions back in the 80s always were encrypted on both the uplink and downlink.

    There are also other communications paths between the shuttle and the ground. Indirect communications, known as forward and return links via, TDRSS are always encrypted.

    1. Re:Not quite by slightlyspacey · · Score: 2, Interesting

      You are correct of course. In the case of the space shuttle, it's just easier, cheaper, and safer to encrypt the entire uplink using the existing crytographic device and its corresponding hardware key. The cost of the integration of a command authentication mechanism using a crypto signature with the existing shuttle hardware and software would be prohibitive.

  4. Power being wasted? by Ruff_ilb · · Score: 2, Interesting

    If we're broadcasting a signal so strong that some random dude can pick it up at home with homemade equipment, isn't that an unnecessary amount of power being wasted on transmissions? I don't know about the actual power consumption, but seriously, when your launch costs are in terms of millions (if not billions) of dollars, you shouldn't have this sort of ineffeciency.

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    1. Re:Power being wasted? by NixieBunny · · Score: 5, Interesting
      Perhaps you meant to say "some random microwave receiver expert", not "some random dude". This is not everyday work - I build stuff like this for radiotelescopes. But I'm surprised that he used a tiny 1 meter diameter dish to receive the signal - I was expecting at least a standard old-fashioned 3 meter satellite dish to have been used to improve the signal level at the receiver.

      I am waiting patiently for the equipment webpage to load so that I can see what sort of filters he used. That's the main tricky part for doing such an experiment - you need to build a custom filter to reject everything that isn't in the spacecraft's frequency band. The rest of the equipment is apparently a modified satellite TV receiver and a generic software radio.

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  5. Communication mode by earthstar · · Score: 2, Interesting

    I have always wondered,what type of commmunication is to communicate with far far away missions like Hubble? How does the signal reach earth?When signals are travelling through millions of miles through space ,wont it weaken to nothing?

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  6. Re:Security risk? by mwilliamson · · Score: 2, Interesting

    You'd think they'd be using some form of PKI, not simply relying on a symmetric cipher. Revoke keys...

  7. Further details from the southgate ARC website by Anonymous Coward · · Score: 1, Interesting

    The following text is from this article Amateur station hears MRO at 45 million miles on the southgate ARC website:

    Amateur station hears MRO at 45 million miles
    This week the Mars-Net e-mail list reported that Paul Marsh, an amateur observer, has detected Mars Reconnaissance Orbiter at X band at a range of 45 million miles from Earth.

    The MRO transmits on Deep Space Network channel 32 which is 8439.444444 MHz.
    By the time that reaches Earth, due to doppler the frequency has dropped to around 8439.031 MHz. The MRO has a 3 meter diameter dish antenna driven by a 100 Watt X-band TWTA to transmit signals to Earth. The signal coming in our direction is of the order of 4.2 mega watts of RF.

    The signal was clearly visible in the FFT display of an SDR-14 software radio, and was just audible in SSB bandwidth of a communications receiver. The signal was consistently about 6 to 8 dB above the noise floor.
    More details can seen at:
    http://www.uhf-satcom.com/mro/

    Thanks to Joe, KM1P, the Mars-net list, and
    Uhf-satcom.com for the above information

  8. Re:Security risk? by bombadier_beetle · · Score: 2, Interesting

    As someone who consulted at JPL and helped develop a good amount of DSN protocols, I can second this.

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  9. Re:the interesting stage.... by Anonymous Coward · · Score: 1, Interesting

    But honestly, if the person is an UBER hacker and can get through the encryption, what makes you think he has to have his OWN huge array to transmit with. He could just as easily get into and hijack NASA's.

  10. Betting time again.... by Moggie68 · · Score: 2, Interesting

    How long until this guy receives more than the Mars orbiter signal...a visit from FBI? I give it 14 days, tops.

  11. Re:Just like Apollo by John+Hasler · · Score: 2, Interesting

    > "How many of you remember the articles in QST and Ham Radio from
    > the 1970's about..."

    > I'm willing to wager: not many.

    At least one.

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