9 ms·
The ¬NED pin goes low on detection of a nuclear detonation [pdf]
- fleitz 15y agowhile(ned_pin) {}; party_like_its_1999();
- pjscott 15y agoRemember to declare ned_pin volatile. (Sorry to be pedantic, but I was getting physically uncomfortable about the possibility that it might not have been declared volatile.)
- sjwright 15y agoYou're physically uncomfortable about indefinite 1999-esque partying? Do you have something better to do when !ned_pin?
- pjscott 15y agoOf course! When the !NED pin goes low, duck and cover like it's 1959. (Fun fact: in a fairly large portion of the blast radius of a nuclear bomb, the main danger for people indoors is falling debris and broken glass from the pressure waves. Duck and cover actually works.)
- elliottkember 15y agoSo hiding in a fridge might actually save you?
- vidarh 15y agoGiven how close to ground zero in Hiroshima and Nagasaki people actually survived just by virtue of being slightly more shielded than people around them: Yes, it'd probably at least increase your odds. And it's not like the Indy movies aren't full of situations where his odds of survival would've been ludicrously low.
- pjscott 15y agoHiding in a fridge protects from debris and direct radiative heat from the blast, both major killers. So yes, the Indiana Jones approach could help. A more practical variant, of course, is the time-honored "hide in the basement" approach, which doesn't require you to compete for space with hastily-evicted perishable food and plastic racks.
- saalweachter 15y agoThe TED talk on surviving a nuclear blast: http://www.ted.com/talks/irwin_redlener_warns_of_nuclear_terrorism.html http://www.ted.com/talks/irwin_redlener_warns_of_nuclear_ter... Instructions start at around minute 18.
- geuis 15y agoHere's a link to the product page, http://www.maxwell.com/products/microelectronics/product.aspx?PID=SPACE-NUCLEAR-EVENT http://www.maxwell.com/products/microelectronics/product.asp.... Maxwell makes an entire array of microelectronics components. These are generally meant for use in devices that are deployed into space environments.
- JonnieCache 15y ago"FOR SPACE" Holy shit. So this is to protect your orbital weapons platform from EMP blasts?
- pjscott 15y agoOr anything you feel like putting in space, that you worry might be near a nuclear explosion or other source of intense ionizing radiation at some point. Be prepared, as the boy scouts say. I assume that maxim goes double in space, considering how expensive it is to put things up there in the first place.
- sliverstorm 15y agoNo kidding. I believe NASA had something like 3 dual-redundant flight computers on the Voyager probes.
- pjscott 15y agoJust think how much redundancy you could get, cheaply, with the advances that have been made with Moore's Law over the years. Computers for space probes don't need to be that fancy. It's totally feasible to build processors that use error-correcting codes in their entire datapaths, have tri-modular redundancy for all their functional units, and then are arranged alongside several other identical processors for ridiculous amounts of redundancy. This sounds silly, but the vast majority of the cost is non-recurring engineering cost. Manufacturing it would be a relatively cheap matter of sending the design to a fab like TSMC along with a bundle of money. Transistors are dirt cheap.
- idoh 15y agoSo, my mom is a former Maxwell employee who now does her own defense contracting, and makes this same type of part. As I understand it, when there is a nuclear event, it generates x-rays followed by the EMP. The goal is to have warheads in flight to be able to continue to their target, so the strategy is to employ an NED. When an event is detected, the warhead shuts down its electronics for the duration of the EMP, and then powers back up. With her NED, she uses an ASIC for detection. I might get some details wrong, but the ASIC has a physical array in it, and the x-rays flip bits in the array. When enough bits get flipped, one can infer a nuclear event. Because it is an ASIC it is really small, which has important advantages for space-born avionics.
- kprobst 15y agoI thought EMP affected electronics regardless of whether they are powered at the time of the burst or not?
- ynniv 15y agoYou can harden your circuits against EMP, it's just expensive and almost universally unnecessary. Almost.
- burgerbrain 15y agoPerhaps the idea is to disengage delicate circuitry from long potentially antenna like circuits.
- Daniel_Newby 15y agoEMP generally refers to the radio-frequency flash. This device is for the ionizing radiation flash -- gamma rays, x-rays, and neutrons -- that can be extremely damaging to devices that are powered on. For example, the ionizing radiation can cause power transistors to turn on unconditionally, which can fire rockets, burn out power converters, and so forth.
- bisrig 15y agoThat ASIC idea is pretty neat - it kind of sounds like taking the problem of single event upset and turning it into a solution, pretty clever.
- marshray 15y agoI like how the logo on the package is the M from *Monsters, Inc." Something else they make there, I suppose?
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- JonnieCache 15y agoThey also sell something called the SCS750 which is apparently like a BeagleBoard IN SPAAAACE... http://www.maxwell.com/products/microelectronics/product.aspx?PID=SPACE-SBC http://www.maxwell.com/products/microelectronics/product.asp... Datasheet: http://www.maxwell.com/products/microelectronics/docs/SCS750_REV7.PDF http://www.maxwell.com/products/microelectronics/docs/SCS750... Its CPU is in fact triply-redundant, like pjscott was saying. They run in lockstep, and they do some fancy stuff that involves dumping the CPU registers to memory, "scrubbing" the registers and then restoring them. I recommend having a look. Space is cool. Even when it does have nuclear weapons in it.
- kabdib 15y agoI've wondered about the following: The firmware controlling a nuke has to have, at some point, a bit or control register it sets that causes the explosion to go off: *pKaboom = true; or something like that. My question is: What is the line of code after that? *pKaboom = true; /*NOTREACHED*/ I suspect it's more complicated than that (there's an infinite loop of some kind that keeps retrying the command sequence). I also suspect I will never know, short of some very hush-hush software being open-sourced someday. :)
- deleted 15y ago[deleted]
- tdicola 15y agoI doubt the warhead has code to control its activation--more likely it's something like an altitude sensor that controls detonation.
- kabdib 15y agoThink cruise missile. Some code looks at a map, looks at GPS, looks at altitude and velocity, and decides "Yup, this is the spot." It's probably a lot more prosaic than I imagine.
- samfoo 15y agoI'm fairly certain that ICBM's use inertial guidance with predefined/computed coordinates (http://en.wikipedia.org/wiki/Inertial_guidance http://en.wikipedia.org/wiki/Inertial_guidance). There's no software involved, its all physical. Detonation is (probably) trigged by a combination of altimeter, accelerometer and other telemetry systems.
- InclinedPlane 15y agoYeah, GPS doesn't work so well through the plasma sheath around a reentry vehicle. And you don't have a whole lot of time to acquire GPS lock, or steer, when you're still traveling at hypersonic speeds and it takes maybe half a minute to hit the ground after first encountering the upper atmosphere.
- tdicola 15y agoGuaranteed to operate in ionizing radiation of 10^12 rad/s. Yikes, that's like 10 billion sieverts/s. Since a dose of something like 10+ sieverts is fatal I'm guessing a human would be turned to a puddle of goo around that much radiation.
- Daniel_Newby 15y agoA nuclear bomb emits a fast flash of radiation over about 50 nanoseconds. Even if the total dose is small, it arrives fast enough to spuriously turn on transistors.
- kmm 15y ago1e12 rad/s is 10e9 Gray/s. Sieverts measure something else, dose equivalence. Interestingly, in this radiation field, every kilogram of mammalian tissue absorbs 10 GW. If this blasts lasts for more than a few nanoseconds, your puddle of goo would be a good guess.
- jeffreymcmanus 15y agothe unit test for this thing must be awesome
- linuxlizard 15y ago"not authorized for use as critical components in life support devices" Now try to imagine something using this part in such a way. /* NED low. Turn off life support. Insurance companies now vapor."
- jrockway 15y agoYou, sir, have just voided the warranty.
- gnu6 15y agoWhat's the pricing on those chips?
- illamint 15y agoWell, this is certainly cooler than anything I work on, nuclear destruction or not.
- JoeAltmaier 15y ago"Tested and Guaranteed" Really? I would like to have seen that.
- nobody31 15y agoMoney back if not entirely satisfied!
- jwallaceparker 15y agoWow. Great article. This is big.
- bravesirrobin 15y agoI just love this bullet point: * Maxwell Technologies Specified, Controlled, Tested and Guaranteed So, I suppose if you experience a nuclear detonation and the chip doesn't go off, you get your money back?!
- dimitar 15y agoI think you can physically model the ionizing radiation of a nuclear event, without actually detonating a weapon, just condoms are tested for elasticity by filling them with pressured air and water. The detector may have been tested before the discontinuation of underground testing in the US in '92
- rphlx 15y agoHopefully the Built-In Test pin doesn't trigger a nuclear event.