The International Space Station has a potentialy very serious problem.

ynotdu

NASA TV has just gone live with coverage of todays third emergency Spacewalk.The Astronauts are about 35 minutes ahead of the expected start time of Midday for the beginning of the Spacewalk.
All going well this EVA will install the replacement pump module and will be started up during the spacewalk to make sure it works,but it will be a few further days before the Loop A cooling will be back to full function.
If time permits a powerline needed to be hooked up before a new section called Leanardo to be carried on a Shuttle due to launch on November 1st can be fitted.Leanardo will act as storage space.One of the Astronauts jokingly called it a wardrobe that she can keep her shoes in.:)

The two Astronauts are called Doug Wheelock and Tracey Caldwell Dyson.
Tracey whose first ever Spacewalk was the first of these emergency is seeing some milestones for a rookie! This will be the 150th EVA in support of the construction of the ISS since its construction began in 1998.Her Rookie spacewalk was the longest ever from Astronauts onboard the ISS,the first emergency one and the eight longest in Spaceflight history!

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Meanwhile i have found some sketchy information on what the 'BIG 14' list is that will always require emergency Spacewalks should they happen:

The so-called Big 14 all relate to the station’s electrical power system. (Critical life-support functions have more levels of redundancy, so they don’t have to be fixed as quickly.) Ten involve keeping the primary electrical power system running, by replacing switching units, distribution hubs, and controller assemblies for power generation, storage, and distribution units. The other four breakdowns, including the one that did occur, keep the station’s thermal control system working, which in the vacuum of space is the only way the ISS can dump waste heat from consumed electricity.

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The Spacewalk is now in progress and its official start time was 11.20AM.
They estimate it will be a six hour thirty minutes EVA.

Turtwig

Finger's crossed it's third time lucky.

Ghost Train

looks like the first (bump) test of the new pump shows its working

ynotdu

The Newly fitted Amonia tank assembly is now installed,bolted.electricly connected and has been powered up for a test of the pump!!! and HEY guess what it is all working despite the fact that this is the oldest of the four spares,It has been stored on the spare part section of the ISS since July 10th 2006 when a Shuttle Mission delivered it!

as it was being fitted NASA Commentry said "Try to imagine fitting a Fridge Freezer back into its box while weightless and not being able to lie the box it came in on its side":)
The Amonia lines can shortly be fitted when Nitrogen that was being used to keep the spare pump assembly pressurised is purged.

This is a picture of the first Orbital sunrise they had at the beginning of this EVA, Ya Could say a ray of sunshine has well and truely entered this crisis:)



woops Ghostrain i missed Your post confirming the 'BUMP Test sucess,SOZ

ynotdu

Job Done!:)
The spare tank assembly has been filled with Amonia,The Quick disconnects have been fitted and valves opened with NO leakage of Amonia.
even if some Amonia did get on their suits there is no need to extend the planned time of this EVA.
At the moment they are finishing up the installation of the new pump,covering parts with thermal protection etc.

They are still go to finish the final bonus task of connecting a lead[for future use] between the Quest airlock and the Unity Module in preperation for Leanardo's delivery by STS-131 NOV 1st.
The only outstanding issue then will be removing the failed pump module from its temporary grave to its permanent grave on the ISS which NASA have said can be done at its leisure.

Since this All began there has been an argument on the NSF forums as to whether the HTV ressupply could deliver more spare Tank assemblys.
It has only flown once.
ATV ressuply[also only flown once]has been ruled out and Progress ressuply could not.
So there is still three spares left of what was replaced today,that might sound like a lot but the pump that runs loop B is as old and has been used as much as the one replaced today!!

NASA it is said are planning the Cargo for that extra Shuttle flight without waiting for Congress's approval,So if that goes ahead it might help and will proably become a priority for spares now.

Can ANYBODY confirm or deny that the HTV could deliver these spare tank assembly's?

The hope now is to extend the ISS until 2028 so one nearly fully used Amonia pump and two spares will not see them through based on there life expectancy!

ynotdu

Hee hee Astronaut Doug wheelock had a message ready if all went well on the installation to his buddy and NASA's Chief fluid Engineer Tim Bond.
Pity i can't enlarge it, It says GAME OVER!:)



Aww well,the bonus task of fitting the extension cable[called the J612 extension cable] has been deferred.
any DIY's would empathise with what the delay was,It was making sure all tools used over the 3 emergency EVA's were safely back in there toolbox

The J612 cable would only have had to be used if the Quest airlock needed power from the Unity module in a future emergency.
Once Leanardo is in place as NASA put it, "It would have been like putting a hugh heavy wardrobe in front of Your wall sockets without first plugging in an extension lead"

It will still happen before Sts-133 Launch on NOV 1st barring something weird.

The ISS will be back to doing what it does best on Thursday, Lighting up the Night Sky for us,and conducting Science!

Yayyyyyyyy for NASA!!!! beat that Augustine, Space-x or any other pretenders to the Crown!!!!!!

Ghost Train

good summary of the various ways the iis can be supplied
http://www.nasa.gov/pdf/167126main_Transportation_Logistics.pdf

looks like htv has a certain amount of space for external components in it unpressureized cargo section

lord lucan

Great work by Wheelock and Tracy Caldwell-Dyson. Everything seems to be going well so far. A few more tests and another shut down and re-start and everything should be back to normal.