Author Topic: Using commercial off the shelf electronics in space  (Read 8135 times)

Offline tnphysics

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Can one use commercial off the shelf electronics in space? I imagine shielding would be required, but how much? I am referring to parts used in PCs, etc.

Offline TyMoore

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Re: Using commercial off the shelf electronics in space
« Reply #1 on: 05/21/2010 02:50 PM »
The short answer is no--w/regards to computers and solid state memories. The amount of shielding needed to prevent single-event upsets is pretty substantial: meters of regolith, for instance.

Rad hard electronics is pretty expensive and also 'dumbs down' CPU's so the typical Space rated CPU is only a fraction of the speed and computing power of a typical ground rated CPU. I believe that this has to do with the necessity of having extra electronics on the chips to do real-time parity checking and correcting, and to detect and bleed off anomalous charge depositions caused by cosmic-ray strikes...


There is also the need to make the components more robust because of the inherent need for radiation damage resistance.

I really don't know how it is done, but rad hard electronics is a real art aparently.

Offline cozmicray

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Re: Using commercial off the shelf electronics in space
« Reply #2 on: 05/21/2010 05:13 PM »
There are many laptop PCs on ISS with little change to them?

How much COTs have really been tested in space?

Without a way up and down to ISS we can't do that now?

OK  how about 16 commercial CPUs/memory in all different orientations to mitigate radiation hits?

The Solid state recorder on Terra is a 600 pound box packed with 4MB DRAM  --  could be replaced with an 10 lb array of SATA Solid state drives with Error Detection and Correction software?

Reliability--  does COTS have the reliability?
Why do ISS batteries have to be replaced after 6 years
and other spacecraft are using batteries for 10, 20, 25 years

NASA now doesn't know how to write requirements to allow COTs
and risk aversion paramount.

At times I believe some of the Wall street firms have better fault tollerant and reliable data systems than spacecraft.  Lose a computer for 10 min on a trading day lose billions?

Online Robotbeat

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Re: Using commercial off the shelf electronics in space
« Reply #3 on: 05/21/2010 06:05 PM »
The short answer is no--w/regards to computers and solid state memories. The amount of shielding needed to prevent single-event upsets is pretty substantial: meters of regolith, for instance.

Rad hard electronics is pretty expensive and also 'dumbs down' CPU's so the typical Space rated CPU is only a fraction of the speed and computing power of a typical ground rated CPU. I believe that this has to do with the necessity of having extra electronics on the chips to do real-time parity checking and correcting, and to detect and bleed off anomalous charge depositions caused by cosmic-ray strikes...


There is also the need to make the components more robust because of the inherent need for radiation damage resistance.

I really don't know how it is done, but rad hard electronics is a real art aparently.

This isn't necessarily true at all. Off-the-shelf electronics are used all the time on University cubesats.

There are ways to use commercial electronics in ways which are resilient to radiation but without requiring rad-hard chips. ST-8 was one such mission to test such ideas... of course, it was canceled to pay for the PoR boondoggle:
http://nmp.nasa.gov/st8/tech/eaftc_tech1.html
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Offline A_M_Swallow

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Re: Using commercial off the shelf electronics in space
« Reply #4 on: 05/21/2010 06:25 PM »
Electronic components only works within a temperature range.  Use of COTS components requires temperature controls.  Military components have a wider range than civilian components and normally are better at resisting radiation.

Online Robotbeat

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Re: Using commercial off the shelf electronics in space
« Reply #5 on: 05/21/2010 06:37 PM »
Electronic components only works within a temperature range.  Use of COTS components requires temperature controls.  Military components have a wider range than civilian components and normally are better at resisting radiation.
Right, but even Mil-spec components are relatively "off-the-shelf" compared to rad-hardened chips.

And besides, space electronics still are designed only for certain temperature ranges...

Which brings me to another point: there should be a way to design components for an even greater temp range so that failure of those temp controls doesn't necessarily mean end-of-the-line.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline Patchouli

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Re: Using commercial off the shelf electronics in space
« Reply #6 on: 05/21/2010 07:01 PM »
The biggest thing I'd worry about with most off the shelf IC's is latchup.
http://en.wikipedia.org/wiki/Latchup

But silicon on insulator makes them more resistant.
http://en.wikipedia.org/wiki/Silicon_on_insulator

Certain off the shelf PPCs and AMD chips may do just fine in a space environment with the addition of a watch dog and error checking memory.

One big irony a Wii or PS3 might be able to deal with space radiation better then an expensive laptop simply because their CPUs are SOI based.

It probably would be a good idea to steer clear of any process smaller then 90nm.
« Last Edit: 05/21/2010 07:03 PM by Patchouli »

Online Robotbeat

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Re: Using commercial off the shelf electronics in space
« Reply #7 on: 05/21/2010 07:08 PM »
Right, end-to-end ECC (and multi-bit ECC in some places) could certainly be done to help allow commercial off-the-shelf components to be used. No sane person runs a production server nowadays without ECC. ECC helps a lot with avoiding problems like what happened to Voyager lately (flipped bit).

Another thing is the extreme temperature range. One of the most difficult problems with spacecraft design is thermal control. If the components themselves are designed for a very high temperature range, this difficulty can be substantially relaxed.

See here for more info on using COTS components at extreme temperatures:
http://www.extremetemperatureelectronics.com/tutorial2.html
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To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline Patchouli

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Re: Using commercial off the shelf electronics in space
« Reply #8 on: 05/21/2010 09:22 PM »
You might want ECC in the cpu cache as well fortunately many off the shelf CPUs have this.

The  ARM Cortex R4 has this feature so it can be safely used in automotive applications.
http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0363e/Chdgfjac.html

http://www.arm.com/products/processors/cortex-r/cortex-r4.php

So do sever processors such as the Opteron and Xeon.

Though the cortex has much more advanced error trapping since it's aimed at embedded applications.

A server can reboot but an airbag controller or engine management computer does not have this option.

Another nice thing automotive applications are already close to mil-spec requirements in that the device must operate at extremes of temperature and vibration that would cause a typical PC processor to fail.

The chip die also is much smaller then an X86 cpu and will present a smaller target to high energy cosmic rays.
« Last Edit: 05/21/2010 09:34 PM by Patchouli »

Offline GreenGlow

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Re: Using commercial off the shelf electronics in space
« Reply #9 on: 05/21/2010 10:14 PM »
The short answer is no--w/regards to computers and solid state memories. The amount of shielding needed to prevent single-event upsets is pretty substantial: meters of regolith, for instance.

I really don't know how it is done, but rad hard electronics is a real art aparently.


Polar and GEO orbits do experience more radiation and likely require rad-hard components.  A bio-science payload I worked on (electronics and software design) was on the MIR space station for a few years.  I made inquiries as to whether rad-hard components were needed.  We were considering using lead shielding or something like that.   I was told radiation was not a problem we needed to worry about with a low inclination LEO orbit.  Our payload didn't have any electronic failures during its time on MIR.  It burned up with MIR when the space station was de-orbited.   Any radiation effects that do occur can be mitigated by the use of a "watchdog" circuit or software function.  Electronic hardware that is left on continuously with no power down cycling may be more susceptible to radiation effects if it causes latchup.  Radiation hits, even by alpha particles, does not usually cause permanent damage; if the flux is low.
« Last Edit: 05/21/2010 10:14 PM by GreenGlow »

Online Robotbeat

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Re: Using commercial off the shelf electronics in space
« Reply #10 on: 05/21/2010 10:24 PM »
The short answer is no--w/regards to computers and solid state memories. The amount of shielding needed to prevent single-event upsets is pretty substantial: meters of regolith, for instance.

I really don't know how it is done, but rad hard electronics is a real art aparently.


Polar and GEO orbits do experience more radiation and likely require rad-hard components.  A bio-science payload I worked on (electronics and software design) was on the MIR space station for a few years.  I made inquiries as to whether rad-hard components were needed.  We were considering using lead shielding or something like that.   I was told radiation was not a problem we needed to worry about with a low inclination LEO orbit.  Our payload didn't have any electronic failures during its time on MIR.  It burned up with MIR when the space station was de-orbited.   Any radiation effects that do occur can be mitigated by the use of a "watchdog" circuit or software function.  Electronic hardware that is left on continuously with no power down cycling may be more susceptible to radiation effects if it causes latchup.  Radiation hits, even by alpha particles, does not usually cause permanent damage; if the flux is low.
Very interesting. I know that the probability of a memory error here on Earth for non-ECC-protected computers with lots of memory is roughly once every few months, and a good portion of those are caused by cosmic rays (most?), evident by the fact that memory error rate increases greatly with altitude (Denver has more errors than LA, for instance). That's why servers all have ECC and why that's what you use if you want stability. Also, basically all of the errors produced by cosmic rays on the Earth's surface are produced by the shower of secondary particles produced when a cosmic ray interacts with the atmosphere, not by the cosmic ray itself (which may be why you could actually have a lower error rate in LEO than on the surface since the shower of secondary particles only occurs when a cosmic ray hits something first).

Welcome to NASASpaceflight, BTW!
« Last Edit: 05/21/2010 10:25 PM by Robotbeat »
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Offline MKremer

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Re: Using commercial off the shelf electronics in space
« Reply #11 on: 05/21/2010 11:13 PM »
Sure, you can use commercial electronics and digital hardware for spaceflight. The main question is - what are you going to do when they glitch or have a hard failure? Because they will, absolutely 100% encounter one of those two possibilities within their mission lifetime. (high-energy cosmic rays, high-energy Van Allen belt particles, sudden solar flare/CME eruptions)

Even expensive, purpose-manufactured and shielded spaceflight electronics encounter glitches and total failures. And they're designed to resist and survive the environment they're in as much as possible.
Consumer-grade equivalents are much, much more vulnerable to that sort of environment, even with heavy external shielding.

« Last Edit: 05/21/2010 11:14 PM by MKremer »

Offline Downix

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Re: Using commercial off the shelf electronics in space
« Reply #12 on: 05/22/2010 12:51 AM »
there is also a rAD-hardened SPARC processor on the market, which i've used before to good effect. 
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Offline kraisee

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Re: Using commercial off the shelf electronics in space
« Reply #13 on: 05/22/2010 01:08 AM »
I've always wondered, just how different are the requirements between human habitation and electronics protection, in terms of space radiation?

Which is the more demanding requirement, and by how much?   Can somebody help quantify it for me?

Ross.
« Last Edit: 05/22/2010 01:09 AM by kraisee »
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Offline Downix

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Re: Using commercial off the shelf electronics in space
« Reply #14 on: 05/22/2010 01:10 AM »
I've always wondered, just how different are the requirements between human habitation and electronics protection, in terms of space radiation?

Which is the more demanding requirement, and by how much?   Can somebody help quantify it for me?

Ross.
Electronics, if a single rad slips through with people, it won't kill them.  But I have delt with some electronic designs which, if they got hit by a single alpha particle, would have a cascade effect killing the whole house of cards.
chuck - Toilet paper has no real value? Try living with 5 other adults for 6 months in a can with no toilet paper. Man oh man. Toilet paper would be worth it's weight in gold!

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