[amsat-bb] Digital Satellites Question

Bryce Salmi bstguitarist at gmail.com
Tue Jul 22 16:56:47 UTC 2014

You don't necessarily need to do the processing on the satellite. There
still is concern over radiation and power for all Fox-1 satellites. To run
the FM transponder, IHU, experiments, etc. all on 1.9W to 2.5W (varies)
from the solar cells is extremely difficult. That's less power on average
than most HTs. It's all an interesting problem as software can be
safegaurded to a degree by using FRAM memory (instead of voltages you store
data in piezoelectric/magnetic states) and having several copies of memory
you compare with each other as radiation is random and it's highly unlikely
the same bit will be flipped in three different copies. Periodically
checking and correcting bits (with the voted 2/3 majority) is one way to
mitigate many errors.

Truth is, AMSAT needs a really good foundation. FM/Telemetry
communications, IHU (computer), Battery system, solar cell power system
(MPPT or other form of management, etc. Once these systems stabilize and
gain heritage then they can be relied upon and not really worried about.
Volunteer hours had be focused on other areas.


On Tue, Jul 22, 2014 at 8:41 AM, Dave Marthouse <dmarthouse at gmail.com>

> I have been following the digital satellite discussion with great
> interest.  Both sides have valid points.
> I would like to pose a strictly engineering question.  Keep in mind that
> I'm not an engineer but consider myself reasonably well read on the amateur
> satellite
> world.
> A digital satellite would imply loads of processing power on the
> satellite.  I would assume that with this additional activity that there
> will be more
> hardware on the bird with more complexity as this won't be a bent pipe
> system.
> With more physical hardware of much more complexity in orbit what about
> the radiation hazards to this more complex and physical hardware heavier
> system?  Wouldn't a software based system be prone to radiation induced
> hardware and software glitches?
> What about shielding etc?
> Dave Marthouse N2AAM
> dmarthouse at gmail.com
> --
> Dave Marthouse
> dmarthouse at gmail.com
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