[time-nuts] Bicentennial GOES satellite clock

David I. Emery die at dieconsulting.com
Mon Aug 13 01:36:12 UTC 2018


On Sun, Aug 12, 2018 at 07:48:52PM -0400, Bob kb8tq wrote:
> Hi
> 
> Well???. there???s also the solar flare that vaporizes the planet earth :) 
> 
> A flare big enough to take out all the sat systems would disrupt a lot more than just navigation.
> It also probably is big enough to take out HF radio gear as well. It takes a *lot* of energy to 
> permanently take out a sat system. Hour or two disruptions ??? sure ??? total destruction, that???s 
> getting into crazy levels.

	Not so clear, big events can cause satellites to fail due to
large charges and voltages on induced on surfaces of the bird that cause
arcs - and also bombardment by energetic particles that can cause logic
states in chips to get tweaked (SEDs) and crash the control electronics
and CPUS and/or confuse vital sensors..  causing the bird to enter modes
that may not be safe for it or recoverable - more than a few satellites
have died of these kinds of things.

	Whether ENOUGH GPS/Galileo/Glonnass/Baideu birds would fail to
eliminate them as a functioning constellation is probably somewhat
unlikely... however.

	But It is much more likely that orbits would be less accurately
known for a while due to atmospheric heating and increased drag and
maybe also due to disturbances in satellite orientation and power and
thermal status during the event that could both change drag and perhaps
even induce slight impulses if gas jets or similar means were required 
to recover the bird and make it stable again.   And the power and
thermal perturbations in emergency mode shutdown configurations might
well impact the on board clock performance and accuracy (even maybe just
from the extra radiation as the magnetopause moved inside the satellite
orbits in an extreme event).

	So in addition to the disturbed propagation through the
ionosphere causing degraded performance there well could be significant
errors in ephemerides (basic bird position) that would do so too for a
while.

	And recovering a whole constellation of confused, sick and 
dangerously misconfigured satellites during a massive world wide event
might be less easy than one might first imagine as the resources
required on the ground would probably be damaged and disabled by other
effects (massive nation wide power grid collapses and the like) and
would certainly be stretched thin by all the urgent problems to get
under control before individual  satellites started to become nearly or
completely unrecoverable.

	And there are certainly positive feedback vicious spiral effects
here - such as lack of time and position accuracy caused secondary
problems such as  sync failures in fiber rings and the like that might
take out parts of the Internet and cell systems) and make it much harder
to recover the satellites due to lack of effective communications on the
ground.

	I'd expect that decently designed HF and LF radio time and
positioning systems would be VERY much more resistant to lethal damage
by flare EMPs... hard to see how massive earth magnetic events could
kill LF or HF receivers that were even modestly hardened against EMP
simply because otherwise local lightning would be frying them regularly.

	And the HF and LF transmitters involved should be pretty self
protecting too... maybe their power supply would be the weak point as
the grid collapsed but this is a problem that can be cheaply handled
with well known and proved diesel generator technology.



-- 
  Dave Emery N1PRE/AE, die at dieconsulting.com  DIE Consulting, Weston, Mass 02493
"An empty zombie mind with a forlorn barely readable weatherbeaten
'For Rent' sign still vainly flapping outside on the weed encrusted pole - in 
celebration of what could have been, but wasn't and is not to be now either."





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