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Re: ISS Packet Turned Off?



> Why does HAM radio need to be turned off during spacewalks?

Well, its a long story...  As you recall, it didn't used to be...

But when PCSAT2 was planned as a Ham Radio experiment
on the outside of the Space Station, to be installed by
a crew member during an EVA, from  day one, there were
very stringent safety requirements that must be met
in the vicinity of a space suit.

PCSAT2 had to have FOUR independelty controllable "INHIBITS"
to prevent transmission (could survive 3 failures and still not
TX and endanger the spacesuit).  An indavertant transmission
was considered a "Catastrophic Hazard" to the crew.  And all
of this circuitry down to each transistor had to be briefed,
reviewed, documented, approved and then re-briefed, re-reviewd,
re-documented, and re-approved at 4 different levels over a
span of 3 years at Space Station Safety Meetings which include 
dozens of skeptical NASA Safety engineers around a BIG table, 
taking a full day at a time.

And this had to be coordinated with ARISS which coordinates
all HAM activities on the space station...

Well, with this scruitny and visibility to "ham radio" on the
space station, it didnt take long for them to realize that there
might not be such a paper trail in the NASA system for operating
the other radios on board too.  

So, in the end, ARISS was also forced to shut down during
all EVA's.  So unfortunately, it was PCSAT2 that brought on
this new requirement.  But sooner or later, it was going
to come up probably anyway...

de Wb4APR, Bob
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