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{
    "url": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/OHFZNJ3JZDC7Q76Q2BWJLGMQG5MR7MNO/",
    "mailinglist": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/",
    "message_id": "[email protected]",
    "message_id_hash": "OHFZNJ3JZDC7Q76Q2BWJLGMQG5MR7MNO",
    "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/OHFZNJ3JZDC7Q76Q2BWJLGMQG5MR7MNO/",
    "sender": {
        "address": "rjc53 (a) cornell.edu",
        "mailman_id": null,
        "emails": null
    },
    "sender_name": "Robert Christ",
    "subject": "[amsat-bb]  Since there's been a lot of ISS chatter recently,\tI thought this \tmight be a good time to post",
    "date": "2010-07-14T16:40:53Z",
    "parent": null,
    "children": [],
    "votes": {
        "likes": 0,
        "dislikes": 0,
        "status": "neutral"
    },
    "content": "Hey everyone.  I'm a researcher at Cornell, and this fall, our\nexperimental, 1 inch diameter, “chip satellites” are scheduled to be\nlaunched on the final space shuttle flight, STS-134.  They're going to\nbe mounted on the exterior of the ISS structure, and will be set to\ntransmit a 902 MHz signal.  Unfortunately, we do not yet have an\nantenna for receiving this transmission.  After talking with Bob -\nWb4APR for a while, it was suggested that the fine members of the\nAMSAT – BB might be able to help us.\n\nWhat we’re looking for is a digital capture of this 902MHz frequency\n(with a bandwidth of about 200KHz), during at least one ISS pass (only\na few gigs of data, we believe).  No decommutation or other analysis\nof the signal will be required, but actually capturing the signal will\nrequire at least a 20 dbB gain receive antenna (more details in a\nminute).\n\nIf any of you can help us in this experiment, or are able to\nsuccessfully capture the signal, not only would we be incredibly\ngrateful, but we would also be prepared to add your names and\ncontributions to all of the published papers that will result from\nthis mission.  It goes without saying, though, that we’d also be\nentirely open to suggestions if the community, or a member, were aware\nof some manner by which Cornell might be able to better avail itself\nto the both those who help us on this project and the community as a\nwhole.\n\nSo here are the technical details.  There are 3 transmitting antennas,\nall tiny, center-fed dipoles: two of them use wires separated by 180\ndegrees, and one has wires separated by 90 degrees.  Each of these\ndipoles is mounted a few mm from large metal panels on the ISS.  The\nChipSats will transmit for approximately 10ms every 1-2 seconds, but\nthe signal is going to be beneath the noise floor.  Detecting the\nsignal requires a pseudorandom noise (PRN) code, which Cornell will\nhandle once the dataset is in hand.  Since we can/will take care of\nthe post processing, and capture isn’t guaranteed on every ISS pass\n(attitude alignment problems still TBD) so anyone who can take a\nrecording of this frequency at this bandwidth for us, of any ISS pass,\nwould be incredibly helpful.\n\nThe good news is that the chips will be live and transmitting almost\nimmediately after they are installed from STS-134, and they will\ntransmit continuously whenever the ISS is in sunlight.  Additionally,\nshould they survive in their environment, they are set to transmit for\nup to two years, which should give us many chances to receive the data\nand confirm that the ChipSats are functioning.\n\nThanks for your time, everyone,\nRobert Christ\nhttp://www.spacecraftresearch.com/\n\nP.S. a little extra information:  Our website is\nhttp://www.spacecraftresearch.com/projects.html if you're interested.\nThis mission isn't explicitly mentioned there yet, but is rather a\nproof of feasibility study for most of the projects listed on that\nsite.  Ah and lastly, the ERP of the transmitter is expected to be ~10\ndBm, though it will almost certainly be facing in a poor orientation,\ngiving us only a fraction of that power.  We won't know the exact\namount for a few more days.  Thanks all!\n\n",
    "attachments": []
}