So most LEO cubesats are not radiation hardened...at all. That said,
most LEO missions are pretty short duration comparatively(less than a
year). There is some component selection where some types of equipment
are better than others , but typically not much is done for extra
shielding. If you look at some COTS cubesat parts like radios they
will be in their own aluminum shells or whatever, but that is about
it.
The electronics and software are all designed so that if there are
some bit flips or something the system will or can be easily rebooted
or deal with dead memory blocks.
I think the duration for most of the lunar and mars missions have been
pretty short as well. NASA may do a but more there in electronics
design and fault handling, but still I don't think you see much
physical shielding.
Also, be really careful about plastics selection regarding outgassing
properties. You don't want to poop on other spacecraft
electronics(especially the primes on a launch) or any chambers you
test in.
On Thu, Dec 5, 2019 at 9:03 AM Ian M. Garcia <ian@xxxxxxxxxxxxx> wrote:
Does anybody here have experience with Cubesat (or any satellite) electronics
in LEO? I’m starting to look at this and comparing rad hard vs COTS with and
without shielding. Rad hard options are crazy expensive and low performance
compare to COTS, but I am worried about radiation for a satellite that could
be out there for a while.
Our joke used to be that in the worst case we’d just drop the boards in a
lead block and flight that, but now I am reading that lead is actually not
used that much because it’s too soft, so instead they use tantalum, tungsten,
or just thicker aluminum. But then I continue reading and it turns out that
materials high in hydrogen are better, so they are starting to recommend
polyethylene (HDPE) instead of metals? And then the latest is that HDPE
combined with a metal liner is actually even better because the metal
captures secondary radiation. What the hell? This is all very confusing.
Cheers,
Ian
--
Ian M Garcia