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{
    "url": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/OQF6OF7T76R2GA7AJ3SH7JDVVJ3FNXYM/",
    "mailinglist": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/",
    "message_id": "C29742C3.669%[email protected]",
    "message_id_hash": "OQF6OF7T76R2GA7AJ3SH7JDVVJ3FNXYM",
    "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/OABE3MIGX3YDWBRWF3CV6DOFYWJA7UJG/",
    "sender": {
        "address": "n7hpr (a) tapr.org",
        "mailman_id": "9201f906e43e4b99b01dc50a5cd003f5",
        "emails": "https://mailman.amsat.org/hyperkitty/api/sender/9201f906e43e4b99b01dc50a5cd003f5/emails/"
    },
    "sender_name": "Steven Bible",
    "subject": "[eagle] Re: CAN-Do noise abatement plan and questions",
    "date": "2007-06-15T02:08:51Z",
    "parent": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/V6F62CNIX5VFDWBTCKIXJ5B4JLONLKJG/",
    "children": [],
    "votes": {
        "likes": 0,
        "dislikes": 0,
        "status": "neutral"
    },
    "content": "And is someone who happens to know a lot about radiation :-)\n\nDid somebody ring?\n\n- Steve N7HPR\n\n\nOn 6/14/07 2:15 PM, \"Chuck Green\" <[email protected]> wrote:\n\n> Hi Guys,\n> \n> This is the first time I have seen something written about radiation\n> where I came away believing that the author actually understood what he\n> was talking about!\n> \n> If you want the inside information regarding PICs and radiation, I'd\n> suggest contacting Steve Bible.  But keep in mind that he is an employee\n> of the company that makes PICs.\n> \n> Chuck\n> \n> Howard Long wrote:\n>> Hi John\n>> \n>>   \n>>> OK. The PIC MCU that I'm considering should be safe. It's\n>>> rated for 40 years data retention in an automotive\n>>> temperature range. Most parts guarantee only 10 year data\n>>> retention or say nothing on the data sheet.\n>>>     \n>> \n>> On ESEO, we have avoided PLLs because of the requirement to program them at\n>> power on, although I have used them often before for programming PLLs on the\n>> ground: those PIC10F SOT23 packages are really neat! ESEO has a default mode\n>> of a traditional analog linear transponder. PICs have not faired\n>> particularly well in radiation tests, and I'd suggest that it may be wise to\n>> consider both SELs/SEBs as well as total dose.\n>> \n>> You can shield against TID to a large extent by depending on tantalum as\n>> previously described, as well as the spacecraft's aluminum structure and\n>> enclosures, but this will not prevent SEEs from happening. After shielding,\n>> SEEs that are predominently caused by high energy protons. You may well need\n>> to consider other mitigation efforts against these high energy inner Van\n>> Allen (proton) belt effects.\n>> \n>> On designs with PICs, I have implemented over current protection using\n>> INA200 devices that cut the power for about 30s as soon as a preset current\n>> is passed. This is an attempt to reduce the chance of an SEB, when a FET\n>> effectively turns into an SCR clamping VSS and VDD.\n>> \n>> Care should be taken when setting the current trip - not only do you not\n>> want to power down the device if it genuinely wants extra current, but\n>> equally TID (total ionising dose) means that over time the FETs will take\n>> gradually more current anyway.\n>> \n>> Achim Volhardt DH2VA already did some radiation tests on a PIC12F device\n>> programming an SPI DDS (AD9834) at CERN when the CANDo's were done also. I\n>> attach his notes. As well as the CREME96 simultations that Achim describes,\n>> there is also SPENVIS: unlike CREME96, SPENVIS can include both the electron\n>> and the proton belts in its analyses. I cannot stress enough the effect that\n>> the orbit has on the amount of ionizing radiation that a spacecraft is\n>> subjected to! Indeed, the AO-10 IHU's early demise is due to its low\n>> inclination HEO orbit, spending inordinate amounts of unplanned time within\n>> the Van Allen belts. By increasing the inclination, significantly reducing\n>> the time spent in the Van Allen belts during an elliptic HEO orbit, ionising\n>> radiation can be reduced by orders of magnitude.\n>> \n>> Although there is some science in this, it's a fairly subjective risk\n>> analysis that guides the tradeoff between the complexity of mitigation\n>> circuitry against the KISS principal. After all, if the planned propulsion\n>> fails, you're left in a near equatorial orbit and a big dose of radiation!\n>> \n>> 73, Howard G6LVB\n>>   \n> _______________________________________________\n> Via the Eagle mailing list courtesy of AMSAT-NA\n> [email protected]\n> http://amsat.org/mailman/listinfo/eagle\n\n\n",
    "attachments": []
}