Re: CDRA suffers another failure

OK, if I have this right the situation was that the heater main circuit
failed during the Shuttle docked period. Then the software refused to start
the bed up because of the heater problem, or so they thought. Saving time
they switched to the back up heater, and controlled it manually from the
ground. Remember this is only one of two alternating systems. One is gassing
while the other scrubs.

However, after some days, the thing gave indications of the controller
failing, which put that channel completely off line. Thinking logically, the
ground thought.. PSU has been damaged and it is why the heater and
controller are acting up. So the plan, as I gather it is to firstly check
for shorts or funny values of resistance in the system, then probably patch
in a spare supply. However, if the controller and heater are knackered, then
they would need to change the hardware in that channel out.

I've not heard the result of the resistance checks, but methinks that the
psu may well have totalled the heater and the controller in some way and
thus a new supply and assembly is going to be needed.

Does not sound awfully reliable to me, one would have thought psus and other
control equipment would be designed to fail safe.

Brian

--
Brian Gaff - briang1@xxxxxxxxxxxxxxxx
Note:- In order to reduce spam, any email without 'Brian Gaff'
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Blind user, so no pictures please!
"Craig" <WeBeGood@xxxxxxxxx> wrote in message
news:V5-dnRuJq_ZuVOzXnZ2dnUVZ_qqdnZ2d@xxxxxxxxxxxxxxxx
John Doe wrote:

NASA TV is currently showing 2 station crewmembers trying to fix the
CDRA (Carbon Dioxide Removal Assembly). Ground generated a plan to fix
it which will take about 6 hours of work.

The CDRA is much bigger than I had imagined it to be.

NASA TV commentator mentioned something about a heater controller, so
I assume this would have something to do with the "cleaning phase" to
outgas the accumulated CO2 to space.


What is the backup plan if it cannot be fixed ? Can they use EVA LiOH
filters into the station's ventilation system to clean the air ?

While the Shuttle was there it overheated and they were controlling it
from the ground, I guess they though a software patch could fix it.
Probably the backup plan is to use the Russian scrubber. I think they
said they have around a month of backup LiOH.

Can the Russian scrubber keep up?



.

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