Posted on 01/14/2016 7:35:24 PM PST by BenLurkin
Two space station astronauts are gearing up for a planned six-and-a-half-hour spacewalk Friday to replace a presumably shorted out solar array voltage regulator that knocked one of the lab's eight power channels out of action late last year. They also plan to finish up ongoing work to route power and data cables needed for new docking mechanisms that will be installed later.
The voltage regulator, a 200-pound box known as a sequential shunt unit, or SSU, is one of eight at the base of each of the station's solar power wings that serve to relay regulated 160-volt DC current to downstream components that then step the power down to the 124 volts used by station equipment.
The SSUs also send, or shunt, excess power back to the arrays where it is dissipated as heat.
The SSU in question failed last November, knocking out power channel 1B, one of the space station's eight primary sources of electricity. Flight controllers tied systems normally powered by channel 1B to other channels, and station operation continued without any major impact.
But an additional SSU failure would take down another power channel and that would force flight controllers to shut down equipment on the station, impacting research and other work, until a replacement could be installed. Friday's spacewalk is intended to restore the lost power channel to normal operation and to restore full redundancy.
(Excerpt) Read more at cbsnews.com ...
“The voltage regulator, a 200-pound box known as a sequential shunt unit”
It is so funny that they should mention the weight since it does not weigh anything up there.
Mynocks chewing on the power couplings.
“This is Ground Control to Major Tom.....”
There should be a VW beetle-shaped shuttle for the geek squad to arrive and fix it. Thanks BenLurkin.
It has mass ... mass is more important than weight in space ... but weight gives an indication of mass.
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