Take the 2-minute tour ×
Server Fault is a question and answer site for professional system and network administrators. It's 100% free, no registration required.

Aside form the "buy really costly NASA stuff" solution, what can be done about running a system in high radiation environments like space? (This is mostly a thought experiment.)

Known Issues primarily amount to data errors:

  1. main memory
  2. cache ram and CPU internal state
  3. HDD

What can be done about these?

My thoughts include

  • Use EEC Ram
  • Shield the CPU and cache with tungsten because it's a good conductor and IIRC a good radiation shield.
  • Use RAID 5 (or RAID 6) disks with some sort of hacked setup to correct errors in place rather than just writing off the whole disk as bad.
  • Use ROM disks built out of sold state HDDs with the flash chips replaced with ROMs or just a stack of CD/DVD/HDDVD drives.


Note: I'm not just thinking of embedded system. I'm also interested in high end system right on up to supercomputers if anyone has any info of them.

share|improve this question
1  
haev you tried tiny tinfoil hats? ;-) –  Steven A. Lowe May 25 '09 at 20:13
1  
@Steven A. Lowe: IIRC aluminum is good shielding from EM but not other forms of radiation . –  BCS May 25 '09 at 20:31
add comment

2 Answers

up vote 6 down vote accepted

For "on the cheap", meaning "relatively economical", I turned my search to Amateur Radio. They fly satellites at a fraction of the cost. Put "AMSAT" in your search. I found this in an article at codec.org.

  • "AMSAT satellites are generally firmware-free, lacking even a boot ROM! They use a hardware circuit, without the assistance of software, to initially load their computer RAM from a ground data stream."

  • Certain RAM technologies cannot be used. Those with charge pumps, for example.

  • Error-correcting systems (extra bits and CRC's)

  • "They continuously "wash" the RAM by reading it, checking it against the CRC, and writing the information back to correct for radiation-induced errors. Without this activity, the computer onboard a space vehicle would not survive."

  • "Many modern microprocessors would not execute reliably in the radiation environment. AMSAT uses a special radiation-hard silicon-on-sapphire version of the CDP-1802 CPU designed in the late 1970's as its main control computer. They experimented with the StrongARM SA-1100 chip" (but it doesn't state results of that experiment).

Don't forget that an "HDD" is going to have a CPU and RAM on its own controller!

share|improve this answer
    
Right to the point. Nice. –  dmckee May 25 '09 at 19:21
    
Do you have the link for the article its self? Points 2-5 are good, but #1 only applies to booting, and if you need to reboot in space you have Problems (at least under the type of use I'm thinking of)! –  BCS May 25 '09 at 19:45
add comment

If you're talking about a fairly accessible environment (like an accelerator end-station hall) and a fairly low impact system, you just do lots of verification and complain when it fails, then you try a reboot followed by a field circus.

If it is a little less accessible, you add redundancy and fail-over.

After that it starts to get expensive.


The problem with shielding is that for high energy gamma and electron progenitors a little shielding can make things worse! And neutrons are generally hard to shield. You don't even want to talk about muons.

A space environment means cosmic rays which means multi GeV protons. Yuck.

share|improve this answer
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.