[amsat-bb] SuitsSat battery life?

["John P. Toscano" <tosca005@xxxxxxxxxx>]

I was curious to know how the power is configured to the radio.  If the 
handheld being used is anything like those I own, it requires a battery 
voltage somewhare between 6 and 12 volts, yet the spacesuit batteries 
are providing far more than double that.

Is there a voltage regulator between the batteries and the handheld to 
drop the voltage to what the handheld requires?  If so, at what 
spacesuit battery voltage is the regulator likely to "run out of 
headroom" and stop regulating?  (Depends on the output voltage selected, 
and the regulator design.)  Below that, I suppose that the delivered 
voltage would be approximately equal to the battery voltage, and then 
the question becomes "how low of a battery voltage will still operate 
the handheld?"

I suppose this could all be moot, if the battery voltage drops extremely 
fast once the cells are mostly depleted, and the delivered voltage to 
the radio abruptly goes from "plenty" to "not enough".

But if we continue to accumulate battery voltage telemetry data, it 
would be interesting to plot the falloff rate and estimate how much 
longer SuitSat will likely transmit.  (Oh, yeah, does anyone have an 
estimate of how long until SuitSat starts its final re-entry?  If the 
battery consumption is slow enough, I suppose that could be the 
rate-limiting step in the process!)

73 de W0JT
AMSAT Life Member #2292
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