LIVE: Expedition 35 US Spacewalk (EVA-21) - May 11, 2013

[DMeader]

OP was wondering if  leak had potential still to be severe/ongoing, hence a refill would be "good after bad". At least that's what I understood him to ask.

[rdale]

I don't think they are still adding to the system. In any event, there is no sign of a leak so no indication that a refill would be bad.

[psloss]

OP was wondering if  leak had potential still to be severe/ongoing, hence a refill would be "good after bad". At least that's what I understood him to ask.

Maybe in a narrow sense, but there could be other "benefits", such as the possibility of eliminating a leak path candidate (the old PFCS).  Given the availability of ammonia reserves, the (IIRC) ~20 lbs in the replacement PFCS might have been worth risking.

I would recommend to anyone that is interested in some of the thinking going into the EVA to watch the status briefing beforehand (the one on May 10th).

[John44]

Expedition 35 - Post-Landing Activities
http://www.space-multimedia.nl.eu.org/index.php?option=com_content&view=article&id=8264

[Prober]

OP was wondering if  leak had potential still to be severe/ongoing, hence a refill would be "good after bad". At least that's what I understood him to ask.

Maybe in a narrow sense, but there could be other "benefits", such as the possibility of eliminating a leak path candidate (the old PFCS).  Given the availability of ammonia reserves, the (IIRC) ~20 lbs in the replacement PFCS might have been worth risking.

I would recommend to anyone that is interested in some of the thinking going into the EVA to watch the status briefing beforehand (the one on May 10th).

from what I gathered on L2 we gained maybe a tad better then 1/2 of a full charge?
 
would be worth the investment to add some more cams with the next EVA or as part of an upgrade.
 

[psloss]

from what I gathered on L2 we gained maybe a tad better then 1/2 of a full charge?
 
would be worth the investment to add some more cams with the next EVA or as part of an upgrade.

Not sure what the full quantity would be for that loop/isolated part of the loop.

Like a lot of things, upgrades are easier said than done.

[russianhalo117]

From the NASA ISS Section main page: Station Status:
LINK: http://www.nasa.gov/mission_pages/station/expeditions/expedition36/e36_051413.html

The following is an excerpt regarding today's (14 May 2013) status of the 2B power channel:
Following the Soyuz TMA-07M undocking, thermal systems specialists in Mission Control Houston detected a drop in the International Space Station’s P6 truss ammonia accumulators consistent with the ammonia leak last Thursday. The 2B power channel that had been activated following Saturday’s spacewalk (but not yet integrated back into accepting loads from systems) was shut down in a preventative measure. Throughout the night, however, no leakage has been observed in the newly installed Pump and Flow Control Subassembly box on the P6 truss nor is there any data suggesting a leak. Thermal system specialists speculate this could be a function of fluids settling down within the pump’s plumbing and shifting from one internal tank to another from the forces imparted on the component from the Soyuz undocking. More data is being acquired but thermal experts seem to be comfortable that we still have an air-tight system.

[Targeteer]

CAPCOM just passed the news of the suspected leak indication cause during the evening DPC.  Chris Cassidey was relieved because he must have heard news of the leak return. The pump has been reactivated and some suppressed temp operating warnings are possible/likely.

[gfagley]

.

(still wishing we had shuttle to bring it down for analysis)

If they wanted to, couldn't they jury rig something with the bolts (which apparently open/close the valves) to vent the unit in space sufficiently long to drain all the ammonia thus allowing the unit to be brought inside and returned by Dragon?

What if it was bagged in several layers of bagging and sealed in that before bringing it in-station?

As the wouldn't want to bring it inside, I was thinking that if space-X could configure a compartment where there side hatch is in the dragon capsule, the could do an EVA and put the PFCS in there.   
the bad part about doing that is that no early retrieval of goods would be available as they couldn't gain access to the capsule through the side hatch once the landed.

[Chris Bergin]

Good news on it not being a real leak. Article covering the L2 coverage showing how they worked on it:

http://www.nasaspaceflight.com/2013/05/no-return-leak-iss-teams-clear-concern-false-signature/

[Prober]

Any idea when some of the power available on 2B will be used?
Wouldn't a low load be good for a proper test?

[robertross]

Wouldn't a low load be good for a proper test?

Not if another shadowing event causes the fluid levels to drop again (to fill voids/the accumulators).

[erioladastra]

Any idea when some of the power available on 2B will be used?
Wouldn't a low load be good for a proper test?

Still need some update calibration curves to be loaded.  Probably start moving things over next weekish.