Just to add more data points to the discussion. The first Mexican cubesat
which launched today, aztec-sat is using a beagle black board
<https://beagleboard.org/black/> for it's primary computer. That's a
decidedly terrestrial design. About $65 USD from digi-key.
I wonder if those of you with the experience could elaborate about the
memory error correction software being flown routinely. Given that
radiation effecting a spacecraft is measured as a function of time, when we
talk about radiation correction software, are we really just talking about
multiple CPUs with their own short term memory that are constantly running
basic arithmetic equations 1+2=3. If one of the cpu's results don't match
the other two for a given instance of time, the computer that produced the
faulty results has it's own influence on the satellites
subsystems(guidance, communication, etc) thrown out for that period of
time. That computer is restarted which resets it's pins to their default
state and the process repeats. The other computers take over responsibility
while the faulty computer is restarting.
Is this pretty much what you mean when people talk about radiation
hardening through software only? If I'm grasping the concept fully, is
there a specific framework on github that's popular among professionals and
student sat groups or are they all righting their own code to duplicate
this functionality?
Thanks
On Thu, Dec 5, 2019 at 4:03 PM Henry Spencer <hspencer@xxxxxxxxxxxxx> wrote:
On Thu, 5 Dec 2019, I wrote:
...Not only is lead awkwardly soft (although some lead alloys are
stronger), but it's not nearly as dense as tungsten...
A minor elaboration here: Tungsten is about the densest thing you can buy
at a sane price. Its density is similar to gold or uranium, and the only
things that are significantly denser are grossly-expensive platinum-group
metals. It's unfortunately difficult to work with -- terribly hard,
somewhat brittle, so heat-resistant that welding is impractical, etc.
Tantalum isn't quite as dense, but rather more tractable, and still denser
than lead.
Henry