Author Topic: Expedition 35 thread (March 15 - May 14, 2013) (Read 110820 times)

Targeteer · « **Reply #180 on:** 05/09/2013 06:51 pm »

They are discussing the 2B PFCS...

DaveS · « **Reply #181 on:** 05/09/2013 06:51 pm »

Quote from: Targeteer on 05/09/2013 06:49 pm

The crew is asking for a hardware reference (EVA planning tool, DUG) to identify the area...

I think that should be DOUG (Dynamic Onboard Ubiquitous Graphics).

Targeteer · « **Reply #182 on:** 05/09/2013 06:55 pm »

Copy... Houston is talking about the a cold plate of the cooling loop. Leak is being described as between two boxes in front of the batteries. The good view from the Kibo is not on the ISS feed. This definitely sounds like a coolant (ammonia?) leak...

Targeteer · « **Reply #183 on:** 05/09/2013 06:58 pm »

Crew has identified the source of the leak using DOUG...

Targeteer · « **Reply #184 on:** 05/09/2013 07:09 pm »

The US DPC was skipped due to current events. The Russian DPC is droning on as usual...

Targeteer · « **Reply #185 on:** 05/09/2013 07:17 pm »

Crew advised to close the shutters on all windows not being used for observation

Targeteer · « **Reply #186 on:** 05/09/2013 07:21 pm »

Crew has downloaded photos of the leak for Houston viewing with 400 and 180 (mm lenses?)

Ian · « **Reply #187 on:** 05/09/2013 07:24 pm »

Does anyone know if that is Loop A or B that is leaking there right now?

Targeteer · « **Reply #188 on:** 05/09/2013 07:47 pm »

Comm loop has been quiet for a while--during a nighttime pass.

Targeteer · « **Reply #189 on:** 05/09/2013 08:01 pm »

Houston confirms images are on the ground and will have more words for the crew shortly...

paycom · « **Reply #190 on:** 05/09/2013 08:03 pm »

Quote from: Ian on 05/09/2013 07:24 pm

Does anyone know if that is Loop A or B that is leaking there right now?

It's the cooling system of the photovoltaic system on P6. The photovoltaic systems have their own cooling loops, which are not connected to the main loops in normal operation, but can be refilled from the tanks of the main loops if neccessary.

Targeteer · « **Reply #191 on:** 05/09/2013 08:06 pm »

Houston is considering moving the mobile transporter and the SSRMS to the port side overnight for viewing. The P4 array may be moved to clear the view of the P6 array.

Targeteer · « **Reply #192 on:** 05/09/2013 08:13 pm »

Leak rate now is slow but has increased before as the array rotates

Targeteer · « **Reply #193 on:** 05/09/2013 08:18 pm »

CDR asked Houston for something (procedures?) just in case but my feed took a hit. Houston said they would have it. Crew reports leak rate has increased with array rotation

Targeteer · « **Reply #194 on:** 05/09/2013 08:22 pm »

The P4 array may be turning edge on to improve the view of P6

Targeteer · « **Reply #195 on:** 05/09/2013 08:37 pm »

For those with L2 access, check the ISS thread for details from Jester and Space Pete.

DaveS · « **Reply #196 on:** 05/09/2013 08:40 pm »

Could anyone detail what the PFCS is?

Squid.erau · « **Reply #197 on:** 05/09/2013 08:41 pm »

Some stills taken from one of the downlink video channels.

anik · « **Reply #198 on:** 05/09/2013 08:47 pm »

Ammonia Leak Observed Outside Station
http://www.nasa.gov/mission_pages/station/expeditions/expedition35/e35_050913.html

At around 10:30 a.m. CDT on Thursday, the Expedition 35 crew reported seeing small white flakes floating away from an area of the International Space Station’s P6 truss structure. The crew used handheld cameras and Mission Control used external television cameras to gain additional imagery in an attempt to narrow down the leak’s location.

The crew reports, along with imagery and data received by flight controllers in Mission Control in Houston, confirmed that the rate of the ammonia leaking from this section of the cooling system has increased. Ammonia is used to cool the station’s power channels that provide electricity to station systems. Each solar array has its own independent cooling loop. This ammonia loop is the same one that spacewalkers attempted to troubleshoot a leak on during a spacewalk on Nov. 1, 2012. It is not yet known whether this increased ammonia flow is from the same leak, which at the time, was not visible.

The station continues to operate normally otherwise and the crew is in no danger.

Plans are being developed to reroute other power channels to maintain full operation of those and other systems normally controlled by the solar array that is cooled by this loop.

The early analysis by thermal control systems specialists indicates that the leak rate could result in a shutdown of this one cooling loop in about 48 hours. The team is looking at whether any additional imagery is needed to isolate the leak’s location.

Space Pete · « **Reply #199 on:** 05/09/2013 08:47 pm »

So, what we're looking at is an ammonia leak, which looks to be in the PFCS (Pump Flow Control System) in the PVTCS (Photo Voltaic Thermal Control System) cooling loop of Power channel 2B on the P6 Truss.

This is the same channel that has been leaking for a while, which is what prompted US EVA-20 in November last year to connect the spare radiator to stop the leak (which didn't work). Obviously the leak just got a whole lot worse.

So, in order to stop the leak they'll need to shut down the 2B PVTCS, which means they'll need to power down the entire 2B channel - meaning ISS will lose 12.5% of its power. I imagine we'll be looking at an imminent US EVA to R&R the 2B PFCS - and probably a delayed Soyuz TMA-07M landing as a result.