News Space Station suffers Coolant loop issue

[tblaxland]

Tut tut tut, ESP-3 was relocated to the lower side of the S3 Truss in Jan. :facts:

Looking at the EVA briefing, they got the wrong ESP anyway. It looks the pump module is coming from ESP-2, which is attached to Quest. Here is an alternative view from the STS-114 fly-around (pump module in the bottom left hand corner of ESP-2 in this view):
http://upload.wikimedia.org/wikipedia/commons/9/96/STS-114_External_Storage_Platform_2_crop.jpg

 

[Orbinaut Pete]

Looking at the EVA briefing, they got the wrong ESP anyway. It looks the pump module is coming from ESP-2, which is attached to Quest. Here is an alternative view from the STS-114 fly-around (pump module in the bottom left hand corner of ESP-2 in this view):
http://upload.wikimedia.org/wikipedia/commons/9/96/STS-114_External_Storage_Platform_2_crop.jpg

Yes, the PM for this EVA is located on ESP-2 (PM launched on STS-121). However, PMs are also located on ESP-3 (PM launched on STS-127) and ELC-1 & ELC-2 (both launched on STS-129).

---------- Post added at 10:39 PM ---------- Previous post was at 12:51 PM ----------

From NASA's Main ISS Webpage:

Activities aboard the International Space Station remained focused on spacewalk preparations Tuesday as the Expedition 24 crew gets ready to replace a failed ammonia pump module that took down half the station’s cooling system over the weekend.

Expedition 24 astronauts Doug Wheelock and Tracy Caldwell Dyson, both flight engineers, currently are scheduled to start the repairs Friday during the first of two spacewalks. Mission managers, program managers, flight controllers, engineers, astronauts and spacewalk experts rescheduled the spacewalk, originally planned for Thursday, after continuing to analyze and refine engineering requirements, and reviewing the results of an underwater practice session.

Fellow astronauts Cady Coleman and Suni Williams spent Monday afternoon in the Johnson Space Center's Neutral Buoyancy Laboratory practicing underwater the tasks needed to restore the cooling loop over the course of two spacewalks.

› View video of practice spacewalk session

Meanwhile, robotics experts are continuing to refine the procedures that will be used by Flight Engineer Shannon Walker to guide the station's robotic arm, Canadarm2, as she moves Wheelock into position to swap the failed unit with a spare unit currently stored on External Stowage Platform 2. That spare parts carrier is attached to the Quest airlock that Wheelock and Caldwell Dyson will use to exit and reenter the station.

The station remains in a stable configuration. The crew is on a normal sleep shift, and supporting a normal workday, but most of the planned activities this week have been cancelled or deferred in order to support spacewalk preparations.

Wheelock, Caldwell Dyson and Walker reviewed spacewalk procedures Tuesday, taking a look at the activities to be performed during the excursion as well as familiarizing themselves with the steps needed to decontaminate the spacesuits should ammonia crystals seep out of the pump module connectors.

Also on Tuesday the station's Mobile Transporter was commanded to move to the Starboard 1 truss. With the Mobile Transporter in position, the ground team will be able to gather additional data to confirm power resources are sufficient for Canadarm2 to support the spacewalk.

Each pump module weighs 780 pounds and is 5 ½ feet long (69 inches) by 4 feet wide (50 inches), and is 3 feet tall (36 inches). The spacewalkers will need to disconnect and reconnect five electrical connectors, four fluid quick-disconnect devices, one fixed grapple bar and four bolts. The spare pump module that will be used to replace the failed unit was delivered to the station on the STS-121/Utilization Logistics Flight-1 mission in July 2006.

The pump failed Saturday night after a spike in electrical current tripped a circuit breaker. When the 780-pound pump failed, it shut down half of the station’s cooling system. Efforts to restart the pump, which feeds ammonia coolant into the cooling loops to maintain the proper temperature for the station’s electrical systems and avionics, were not successful. The station’s crew worked with Mission Control to put the station in a stable configuration.

NASA TV coverage will begin at 6 a.m. EDT Friday and Wheelock and Caldwell Dyson will begin the spacewalk at 6:55 a.m. In the first spacewalk, they will unbolt and remove the failed pump module, and install the spare. A second spacewalk to hook up a variety of electrical and fluid connections for the new pump module is targeted for Monday.

Wheelock, who will be designated as EV1, or extravehicular crew member 1, wearing the spacesuit bearing the red stripes, will be making the fourth spacewalk of his career, while Caldwell Dyson, designated as EV2, wearing the unmarked spacesuit, will be making her first spacewalk.

Wheelock and Caldwell Dyson originally were scheduled to perform a spacewalk to outfit the Russian Zarya module for future robotics work and prepare the station for the installation of a new U.S. permanent multipurpose module. However, because of the importance of restoring redundancy to the station's cooling and power systems, the two new spacewalks will be dedicated to the pump module replacement.

Read about the station's Thermal Control System on page 63 of the "Systems" section of the Reference Guide to the International Space Station. View the entire guide here.

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From ISS On-Orbit Status Report for 02/08/2010:

Following a teleconference with ISS Program Management at ~02:00 PM GMT, Tracy Caldwell-Dyson, Doug Wheelock & Shannon Walker joined up for a 3 hour 25 minute review of uplinked instructions & procedures for the Tracy's & Doug's two new spacewalks, intended to remove & replace the failed ETCS (External Thermal Control System) loop A Pump Module. The EVAs will take the place of the originally scheduled single EVA-15 on 05/08, one on 06/08 (Friday), the second on 09/08 (Monday). [As reported yesterday, at 11:48 PM GMT on 31/07 (Saturday), RPC 1 (Remote Power Controller 1) in RPCM (RPC Module) S11A_D tripped, powering off the S1 ETCS loop A PM (Pump Module). Necessary thermal loop A powerdowns were immediately executed, and the ISS crew installed two jumpers to maintain maximum available power redundancy. A ground-commanded attempt to repower the Loop A PM saw a repeat of the trip when the pump motor was commanded to spin-up. Activities related to the earlier planned EVA for installing a PDGF (Power & Data Grapple Fixture) on the FGB have been put on hold. R&R of the PM will require 2 EVAs: the first for setup, removal & temporary stowage of the failed PM, retrieval & partially installation (structural/heater power) of the spare PM, the second to complete the spare PM installation (activation), stow failed PM, and clean up. With one half of the station's cooling capability gone, the ISS is currently largely single-string, i.e., zero fault-tolerant, due to thermal constraints. With the Lab Contingency Truss Jumper installed by the crew on Sunday, the following DDCUs (DC-to-DC Converter Units) and their associated loads had to be unpowered: DDCU S04B, DDCU S14B, DDCU N2D1B, DDCU N2D4B, DDCU N2S1B, and DDCU N2S4A. A PM R&R is the only available option to recover ETCS Loop A. Tracy & Doug will perform the spacewalks, and Shannon would operate the SSRMS (Space Station Remote Maneuvering System), but plans for the EVA without SSRMS are also being made, just in case.]

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From ISS On-Orbit Status Report for 03/08/2010:

In preparation for the two emergency EVAs on 06/08 & 09/08 to replace the failed ETCS (External Thermal Control System) Loop-A NH3 (ammonia) pump module, Caldwell-Dyson, Wheelock & Walker jointly conducted a 1 hour review of NH3 decontamination procedures uplinked overnight. [NH3, a toxic substance, in vapor form will not stick to the EMU (Extravehicular Mobility Unit) spacesuits; solid contamination will likely bounce off, but may be caught in fabric folds; liquid contamination freezes on the EMUs. Mechanical removal (i.e., brushing off) is useless for ammonia. Instead, sublimation through conductive heat transfer is the most effective way to eliminate NH3 contamination. A heated tool pressed against a contaminated EMU surface area, then removed, will allow NH3 to sublimate. After removal of all visible ammonia, the EMU must be "baked out" for the equivalent of 30 minutes in the C/L (Crewlock). Sometime after the bakeout, the crewmember must ingress the A/L (Airlock) again for about 2 hours 20 minutes to allow for testing and an additional A/L depress/repress cycle, if the contamination test in the C/L indicates more bakeout is needed.]

Afterwards, Tracy & Wheels prepared the A/L for the spacewalks and also worked on the EVA tools, reconfiguring/restowing the equipment originally intended for EVA-15 and unstowing tools needed for the PM R&Rs.

---------- Post added at 11:07 PM ---------- Previous post was at 10:39 PM ----------

SPACE.com: "NASA Scrambling to Plan Vital Space Station Repairs".

SPACE.com: "NASA Delays Start of Major Space Station Repairs to Friday".

SPACE.com: "Graphic: NASA's Space Station Cooling System Malfunction Explained".

SPACE.com: "International Space Station: By the Numbers".

BBC News: "Urgent spacewalks to fix ISS pump".

Orlando Sentinel: "NASA prepares for spacewalks to fix space station's cooling system".

Florida Today: "Astronauts trained for space station repair".

Florida Today's "The Flame Trench" Blog: "Astronauts hope to tackle one of "big 14" repairs on Friday".

Houston Chronicle: "Astronauts above, below plot repair of cooling unit".

 

[Orbinaut Pete]

Going through my files last night, I managed to find some good images of the PM on ESP-2.

 

[Orbinaut Pete]

From NASA's Main ISS Webpage:

Crew Prepares for Spacewalks.

Video: Astronauts Robert Satcher Jr. and Rick Sturckow conduct an underwater practice spacewalk session at Johnson Space Center’s Neutral Buoyancy Laboratory. The session was used to help International Space Station team members identify challenges that will need to be addressed when Expedition 24 astronauts Doug Wheelock and Tracy Caldwell Dyson perform the first of two planned spacewalks to replace a failed ammonia pump module. Credit: NASA TV

Spacewalk preparations continue to preoccupy the Expedition 24 crew aboard the International Space Station as it gets ready to conduct a pair of spacewalks aimed at replacing a failed ammonia pump module. The pump failed Saturday night after a spike in electrical current tripped a circuit breaker. When the 780-pound pump failed, it shut down half of the station’s cooling system.

› Read more about the cooling loop loss

Flight Engineers Doug Wheelock and Tracy Caldwell Dyson are scheduled to start the first spacewalk at 6:55 AM EDT Friday to unbolt and remove the failed pump module, and install the spare. NASA TV coverage will begin at 6 AM.

Wheelock, who will be designated as EV1, or extravehicular crew member 1, wearing the spacesuit bearing the red stripes, will be making the fourth spacewalk of his career. Caldwell Dyson, designated as EV2, wearing the unmarked spacesuit, will be making her first spacewalk.

The second spacewalk to hook up a variety of electrical and fluid connections for the new pump module is targeted for Monday.

Wheelock and Caldwell Dyson originally were scheduled to perform a spacewalk to outfit the Russian Zarya module for future robotics work and prepare the station for the installation of a new U.S. permanent multipurpose module. However, because of the importance of restoring redundancy to the station's cooling and power systems, the two new spacewalks will be dedicated to the pump module replacement.

Wednesday aboard the station, Wheelock, Caldwell Dyson and Flight Engineer Shannon Walker participated in conferences with Mission Control to review spacewalk procedures.

Meanwhile back on Earth, fellow astronauts Robert Satcher Jr. and Rick Sturckow were underwater, practicing the spacewalking tasks in the Johnson Space Center’s Neutral Buoyancy Laboratory (NBL). Astronauts Cady Coleman and Suni Williams spent Monday afternoon in the NBL to help prepare for the spacewalks as well.

› View video of Wednesday spacewalk practice session
› View video of Monday spacewalk practice session

Robotics experts are continuing to refine the procedures that will be used by Flight Engineer Shannon Walker to guide the station’s robotic arm, Canadarm2, as she moves Wheelock into position to swap the failed unit with a spare unit currently stored on External Stowage Platform 2. That spare parts carrier is attached to the Quest airlock that Wheelock and Caldwell Dyson will use to exit and reenter the station.

The station's Mobile Transporter was commanded to move to the Starboard 1 truss on Tuesday. With the Mobile Transporter in position, the ground team will be able to gather additional data to confirm power resources are sufficient for Canadarm2 to support the spacewalk.

Each pump module weighs 780 pounds and is 5 ½ feet long (69 inches) by 4 feet wide (50 inches), and is 3 feet tall (36 inches). The spacewalkers will need to disconnect and reconnect five electrical connectors, four fluid quick-disconnect devices, one fixed grapple bar and four bolts. The spare pump module that will be used to replace the failed unit was delivered to the station on the STS-121/Utilization Logistics Flight-1 mission in July 2006.

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From ISS On-Orbit Status Report for 04/08/2010:

Loop A PM Update:
Yesterday, a second test of the Pump Module was performed by the ground. The intent was to close the RPC (Remote Power Controller) that powers the PM and send a "bump start" command to the PM (the "bump start" commands the pump on for 10 seconds). The RPC was expected to trip when the command was sent; however, it tripped before that, immediately as it was being closed (powered on). The implications of this test result are under discussion.

MT & SSRMS EVA Preparation:
The MT (Mobile Transporter) was moved on its rails to WS-2 (Worksite-2) yesterday for supporting the EVAs. Manual mode had to be used for the MT translation UMA (Umbilical Mechanism Assembly) mating operations due to the current power limitations. No issues were encountered in manual mode. Also in preparation for the EVAs, the SSRMS (Space Station Remote Manipulator System) was walked off from MBS (Mobile Base System) PDGF-3 (Power & Data Grapple Fixture-3) to PDGF-1.

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Florida Today's "The Flame Trench" Blog: "Preparations for critical station repairs continue".

SPACE.com: "Giant Swimming Pool Helps NASA Plan Emergency Spacewalks".

Aviation Week: "ISS Managers Rethink Sparing Strategy".

---------- Post added 5th Aug 2010 at 04:28 PM ---------- Previous post was 4th Aug 2010 at 11:58 PM ----------

First EVA now pushed back to Saturday 07/08.

---------- Post added at 05:28 PM ---------- Previous post was at 04:28 PM ----------

From NASA's Main ISS Webpage:

Spacewalks Delayed to Saturday and Wednesday

NASA International Space Station managers have delayed two spacewalks to replace a faulty cooling system component to Saturday and Wednesday.

Saturday's spacewalk now is officially scheduled to begin at 6:55 AM EDT/10:55 AM GMT, and will be followed by a second spacewalk Wednesday to complete replacement of the ammonia pump module that failed last Saturday.

Teams of flight controllers, engineers, and spacewalk and robotics experts have made significant progress in preparing for the spacewalk, but need an additional day to finish working out all the details.

The additional time to prepare for the first spacewalk allows for the final procedures to be uplinked late today and gives the station crew one full day to review the plans that have been developed by Mission Control. Managers also moved the second spacewalk to Wednesday to give the crew additional time to rest and prepare.

During the first spacewalk the pump module will be removed and replaced. The crew will complete connecting fluid ammonia lines to the replacement pump during the second excursion Wednesday.

The spacewalks are challenging because the crew will be handling ammonia lines at full operating pressure, which makes the lines stiff during reconnection and mating. The timeline for the spacewalk will require numerous "off ramps" to ensure there is enough time to complete decontamination procedures if the crew comes in contact with ammonia.

NASA managers have stored spare pumps on the station for just this purpose, because hardware will periodically need to be replaced throughout the station's lifetime. There are four replacement pumps on the station, delivered during previous space shuttle missions. These spares are attached to storage platforms at various locations on the station’s structure. Both the Japan Aerospace Exploration Agency’s H-II Transfer Vehicle and future commercial resupply craft will be able to deliver additional spare parts as needed.

Aboard the station, Wheelock, Caldwell Dyson and Flight Engineer Shannon Walker participated in conferences with Mission Control to review spacewalk procedures.

On Wednesday, fellow astronauts Robert Satcher Jr. and Rick Sturckow were underwater, practicing the spacewalking tasks in the Johnson Space Center's Neutral Buoyancy Laboratory (NBL). Astronauts Cady Coleman and Suni Williams spent Monday afternoon in the NBL helping to prepare for the spacewalks as well.

Robotics experts continue to refine the procedures that will be used by Walker to guide the station's robotic arm, Canadarm2, as she moves Wheelock into position to swap the failed unit with the spare unit, stored on External Stowage Platform-2. That spare parts carrier is attached to the Quest airlock that Wheelock and Caldwell Dyson will use to exit and reenter the station.

The station's Mobile Transporter was moved to the Starboard 1 truss on Tuesday. With the Mobile Transporter in position, the ground team will be able to gather additional data to confirm power resources are sufficient for Canadarm2 to support the spacewalk.

Each pump module weighs 780 pounds and is 5 ½ feet long (69 inches) by 4 feet wide (50 inches), and is 3 feet tall (36 inches). The spacewalkers will need to disconnect and reconnect five electrical connectors, four fluid quick-disconnect devices, one fixed grapple bar and four bolts. The spare pump module that will be used to replace the failed unit was delivered to the station on the STS-121/Utilization Logistics Flight-1 mission in July 2006.

Wheelock, who will be designated as EV1, or extravehicular crew member 1, wearing the spacesuit bearing the red stripes, will be making the fourth spacewalk of his career. Caldwell Dyson, designated as EV2, wearing the unmarked spacesuit, will be making her first spacewalk.

 

[Orbinaut Pete]

Spaceflight Now: "Station EVAs delayed".

SPACE.com: "NASA Delays Critical Space Station Repairs to Saturday".

Florida Today's "The Flame Trench" Blog: "Spacewalking station repairs moved to Saturday".

NASA TV Video: "Practice Makes Perfect EVAs".​

NASA TV Video: "Spacewalk Preview Briefing".​

Tracy and I in the 'Quest' Airlock, preparing our equipment for two very challenging spacewalks scheduled for Friday and Monday. The Space Station had a critical failure last Saturday, and we'll attempt to bring it back to life. A 'shout out' and tremendous thanks to our support team on Earth! "When one voice falls silent…there are hundreds of voices that will begin to sing…"

 

[Orbinaut Pete]

From ISS On-Orbit Status Report for 05/08/2010:

FE-2 Tracy Caldwell-Dyson & FE-4 Doug Wheelock jointly continued preparations for their EVAs, configuring tools needed during the spacewalks not yet deployed in the A/L (Airlock) and readying numerous tethers (e.g., one 55-ft & three 85-ft safety tethers, four waist tethers & four D-ring extenders).

FE-6 Shannon Walker also had about one hour set aside for EVA tool building support.

Later, Tracy & Doug, joined in part by FE-5 Fyodor Yurchikhin, conducted a 2.5 hour review of the latest uplinked EVA procedures. EVA-15, the first of two spacewalks, is expected to last ~7 hours. Wheelock (EV1) will "fly" with the PM on the SSRMS (Space Station Remote Manipulator System) operated by Shannon (suited as IV (Intravehicular) Crewmember), Tracy will free-float.
Objectives for EVA-15 will be to:
• Demate connections and QDs (Quick Disconnects) on the old PM (Pump Module).
• Install PM jumper (to bypass PM and connect ATA (Ammonia Tank Assembly) at S1 to Loop-A).
• Install AGB (Adjustable Grapple Bar), currently on ESP-2 (External Stowage Platform 2), on old PM.
• Remove old PM at S1 and stow on POA (Payload ORU Accommodation) on the MT (Mobile Transporter) at WS2 (Worksite 2).
• Prepare spare PM (on ESP-2) for installation.
• Install spare PM at S1 and make electrical & data connections.

Afterwards, Tracy & Wheels worked in the A/L to continue preparing its EL (Equipment Lock) compartment for the first spacewalk.

Activities by Shannon, who will be operating the SSRMS, included:
• A ~2.5 hour in-depth review of EVA Robotics procedures, including DOUG (Dynamic Onboard Ubiquitous Graphics) files.
• Preparing RWS (Robotic Workstation) SSC (Station Support Computer) monitors in the US Lab to provide additional views during EVA.
• Updating SODF (Station Operations Data File) EVA Systems procedures with P&I (Pen & Ink) changes to include ammonia decontamination procedures plus an ammonia contamination cue card.
• Tying in the DOUG application for SSRMS EVA support by connecting the DOUG SSC at the Lab RWS to the networked PCS (Portable Computer System). [DOUG is a frequently updated special software program running on the MSS (Mobile Service System) RWS laptops that provides a graphical birdseye-view image of the external station configuration and the SSRMS arm, showing its real-time location and configuration on a laptop during its operation.]

At ~4:25 PM GMT, Doug, Tracy & Shannon held a teleconference with ground specialists at MCC-Houston to discuss spacewalk particulars.

---------- Post added at 11:07 PM ---------- Previous post was at 10:56 PM ----------

Timeline for EVA-1 (in EDT and Elapsed Time (ET)):

---EDT---|--ET--|EVENT
06:55 AM | 00:00 | Spacesuits to battery power.
07:00 AM | 00:05 | Post depress/airlock egress.
07:25 AM | 00:30 | Tools/tether setup.
07:45 AM | 00:50 | EV-1: PM removal preps.
07:55 AM | 01:00 | EV-2: CETA cart preps.
08:35 AM | 01:40 | EV-1: SSRMS prep and ingress.
08:45 AM | 01:50 | EV-2: PM jumper vent.
09:00 AM | 02:05 | Initial PM quick-disconnect ops.
10:05 AM | 03:10 | EV-1: Retrieve AGB (Adjustable Grapple Bar).
10:05 AM | 03:10 | EV-2: Prep failed PM for removal.
10:50 AM | 03:55 | Remove failed PM.
11:10 AM | 04:15 | EV-1: Move failed PM to POA fixture.
11:10 AM | 04:15 | EV-2: Spare PM preps.
11:30 AM | 04:35 | EV-1: Spare PM preps.
11:50 AM | 04:55 | BINGO for spare PM removal.
12:20 PM | 05:25 | Remove spare PM from ESP-2.
12:50 PM | 05:55 | Install spare PM in S1 Truss.
01:25 PM | 06:30 | Cleanup and ingress.
01:50 PM | 06:55 | Pre-airlock repress.
01:55 PM | 07:00 | Airlock repress.

Source.

---------- Post added 6th Aug 2010 at 10:05 PM ---------- Previous post was 5th Aug 2010 at 11:07 PM ----------

From ISS On-Orbit Status Report for 06/08/2010:

FE-2 Tracy Caldwell-Dyson & FE-4 Doug Wheelock continued preparations for their EVAs. [Activities included configuring tools needed during the spacewalks such as equipment tethers, wire ties, etc. and making further preparations in the A/L (Airlock) EL (Equipment Lock), checking on EMU (Extravehicular Mobility Unit) DIDBs (Disposable In-suit Drink Bags) filled from PWD (Potable Water Dispenser), confirming the presence of emergency provisions in the A/L, taking O2 (Oxygen) readings with the CSA-O2 units 1041 & 1045 for notifying MCC-Houston and verifying proper function of the vacuum manometer for pressure readings.]

Tracy & Doug also spent ~1 hour 45 minutes on reviewing latest EVA procedures. [The review included uplinked PM (Pump Module) supplemental information, PM R&R cuff checklist pages, workaround crib sheets for bolt removal problems and FQD (Fluid Quick Disconnect) malfunction cases, plans for PM tie-down on the S1 Truss, P-clamp tie-down, etc.]

A teleconference by Doug, Tracy & FE-6 Shannon Walker with EVA specialists at MCC-Houston wrapped up the preps at ~5:30 PM GMT.

Today, Shannon:
• Closed the protective shutters of the windows in the US Lab, the JPM, and Cupola.
• Powered up the Cupola RWS (Robotic Workstation) DCP (Display & Control Panel) for additional video coverage of her SSRMS (Space Station Remote Manipulator System) ops. tomorrow.
• Studied uplinked briefing material on NH3 (Ammonia) decontamination procedures and hardware.
• Reviewed Robotics procedures and DOUG (Dynamic Onboard Ubiquitous Graphics) setup for supporting the EVA-15.
• Configured the low pressure O2 tank of the ACS (Atmospheric Control System) to supply O2 to the high pressure oxygen system.

After completing preparations of A/L EL for tonight's lockout, Doug (EV1) and (EV2) will begin their "campout" (nachalo desaturatsiy = desaturation start) in the A/L with hatch closure and depressurization of the CL (Crewlock) from 14.7 to 10.2 psi, followed by mask prebreathe (~7:55 PM to 9:00 PM GMT) and sleep from 9:30 PM to 6:00 AM GMT. The CL hatch will then be cracked (i.e., temporarily repressurized to 14.7 psi) for a hygiene break/with mask prebreathe for Tracy & Doug at 6:35 AM to 7:45 AM GMT. Shannon will provide suited support in the A/L Around 7:45 AM GMT, the hatch will be closed again for EVA preps in 10.2 psi (7:45 AM to 9:15 AM GMT), followed by EMU purge (~9:15 AM to 9:30 AM GMT) & prebreathe (~9:30 AM to 10:20 AM GMT). Afterwards, Shannon will support CL depressurization until egress at ~10:55 AM GMT.]

---------- Post added at 10:44 PM ---------- Previous post was at 10:05 PM ----------

IEEE Spectrum: "ISS Repair Space Walk: A Glimpse Into the Station's Future".

SPACE.com: "FAQ: International Space Station Cooling System Pump Failure".

SPACE.com: "Space Station Astronauts Set for Dramatic Spacewalk Repairs".

Florida Today's "The Flame Trench" Blog: "Astronauts Make Final Preps For Station Spacewalks".

Spaceflight Now: "'Go for EVA' on Saturday".

Spaceflight Now's EVA Mission Status Center.

EVA Checklist (PDF, 894 KB).

 

[Orbinaut Pete]

Our first spacewalk is now on Saturday, to allow some time for our procedures and safing steps to mature a bit. The airlock, and our equipment are ready. We're anxious to get started and get the Space Station back up and running. Here is a glimpse into the airlock with our spacesuits staged. This won't be easy, but our team is ready…

 

[Orbinaut Pete]

The EVA has begun!

I'll be providing updates when major milestones are met.

SPACE.com's Live EVA Updates.

---------- Post added at 12:54 PM ---------- Previous post was at 12:37 PM ----------

NASA TV in HD.

NASASpaceFlight: "LIVE: Critical ISS spacewalk to replace coolant pump begins".

Live updates from NASASpaceFlight Forum.

 

[N_Molson]

Live EVA video... amazing !

Tracy sounds a little under stress, though it's easy to understand.

The EVA duration is planned for 7 hours... That must be completely exhausting !

---------- Post added at 12:34 PM ---------- Previous post was at 12:16 PM ----------

Ground asked Tracy for a "gloves check", then she looked at the palm of her's gloves. I didn't knew such a procedure existed

 

[Orbinaut Pete]

All is going well so far. :thumbup:

Spaceflight Now: "Station repair EVA underway".

SPACE.com: "Spacewalking Astronauts Tackle Major Space Station Repair".

BBC News: "Astronauts begin key space station repairs".

BBC News: "Astronauts tackle urgent International Space Station repair".

---------- Post added at 04:17 PM ---------- Previous post was at 03:18 PM ----------

The Ammonia line QDs (Quick Disconnects) on the faulty PM won't budge....

 

[N_Molson]

Looks like they had a problem with an ammonia leak that prevented them to remove the pump has scheduled.

http://www.spaceflightnow.com/station/exp24

Tracy & Douglas are safe but had to shorten the EVA. They will have to spend time in the airlock to make sure their spacesuits are decontaminated from ammonia that could pollute the station.

 

[DaveS]

Looks like they had a problem with an ammonia leak that prevented them to remove the pump has scheduled.

http://www.spaceflightnow.com/station/exp24

Not quite correct. They got behind schedule trying to remove one of the NH3 1.5" QDs(M3). By the time they had gotten it removed they were well past the "bingo" time for starting the PM R&R. The NH3 leak just put them even more behind the schedule and for time being it will remain mated to the failed PM.

Tracy & Douglas are safe but had to shorten the EVA. They will have to spend time in the airlock to make sure their spacesuits are decontaminated from ammonia that could pollute the station.

The EVA was not shortened. It was planned for a duration of 7 hours.

 

[SiberianTiger]

Is there a chance they'll get everything done through the next EVA, or one more EVA might become necessary?

 

[DaveS]

Is there a chance they'll get everything done through the next EVA, or one more EVA might become necessary?

For now the remaining tasks are on the next EVA. More information will be available during the post-EVA press conference at 5 pm EDT(2100 UTC).

 

[Orbinaut Pete]

EVA Completed! Some facts:
• Total duration was 8 hours and 3 minutes!
• It was the 6th longest EVA in history!
• It was the 2nd longest EVA at the ISS!
• It was the longest ever EVA without a Space Shuttle present!

There will likely be two more EVAs to finish up this PM R&R, and per NASASpaceflight, maybe even a third to R&R an RPCM. But we'll have to wait & see.


Spaceflight Now: "Ammonia leak delays space station repair work".

Spaceflight Now: "Astronauts run into problems with second umbilical".

Florida Today's "The Flame Trench" Blog: "Spacewalkers wrestle with ammonia lines as repair work continues".

Florida Today's "The Flame Trench" Blog: "Spacewalk behind due to stuck ammonia coolant line".

Florida Today's "The Flame Trench" Blog: "Spacewalk wrapping up with failed coolant pump still in place".

Florida Today's "The Flame Trench" Blog: "Sixth-longest spacewalk complete, but repair job is not".

NASASpaceFlight: "Opening ISS spacewalk to replace coolant pump completed".

Houston Chronicle's/Eric Berger's "SciGuy" Blog: "Astronauts complete long spacewalk with mixed success".

 

[N_Molson]

Wow. If the same two astronauts perform all the EVA, there will become spacewalk veterans in a few days !

---------- Post added at 10:20 PM ---------- Previous post was at 10:14 PM ----------

Though they willl still be far from the records (16 EVAs & 82h ! :blink

Russian [ame="http://en.wikipedia.org/wiki/Anatoly_Solovyev"]Anatoly Solovyev[/ame] holds both the [ame="http://en.wikipedia.org/wiki/List_of_cumulative_spacewalk_records"]record for most EVAs and for the greatest cumulative duration spent in EVA[/ame] (16 EVAs; 82 hr and 22 min).

Michael Lopez-Alegria holds the American records (10 EVAs; 67 hr and 40 min);

[ame="http://en.wikipedia.org/wiki/Christer_Fuglesang"]Christer Fuglesang[/ame], the European (non-Russian) (5 EVAs; 31 hr and 55 min).

 

[Orbinaut Pete]

From ISS On-Orbit Status Report for 07/08/2010:

US EVA-15 by EV-1 Doug Wheelock & EV-2 Tracy Caldwell-Dyson was terminated without Loop A PM (Pump Module) removal because of a leak at one (M3) of the four QDs (Quick Disconnects) connecting the ammonia lines to the failed PM of the starboard EATCS (External Active Thermal Control System) during demate activities. Torque on the 4 PM bolts remains unbroken. [After Wheelock reconnected the M3 QD on the PM to stop the leak, not enough suit time remained to allow further PM work, due to the time necessary for the crew's cleanup procedures for assuring than no ammonia was introduced into the pressurized volume of the ISS. EV-1 & EV-2 began their "campout" last night in the US A/L (Airlock) with hatch closure and depressurization of the Crewlock (CL) from 14.7 to 10.2 psi, followed by mask prebreathe. Following the usual hygiene break/with mask prebreathe for Caldwell-Dyson & Wheelock at 6:35 AM to 7:45 AM GMT, the A/L hatch was closed again by Shannon Walker & Fyodor Yurchikhin for EVA preps in 10.2 psi, followed by EMU purge (~9:15 AM to 9:30 AM GMT) and prebreathe in the EMUs (~9:30 AM to 10:20 AM GMT). Afterwards, with CL depressurization and EV-1/EV-2 switching to suit power, EVA-15 began at 11:19 AM GMT. It ended at 7:22 PM GMT, lasting 8 hours 3 minutes – the longest ISS-EVA and the sixth-longest EVA in history. It was the 148th spacewalk for ISS assembly & maintenance, and the 240th for US astronauts, with a total time of 929 hours 38 minutes.]

Before the EVA, FE-6 Shannon Walker:
• Printed out instructions for actions to be taken in case of occurrence of a "next worst failure", e.g. MBSU-2 (Main Bus Switching Unit-2) failure, ETCS Loop B failure, File Server crash, etc.
• Completed the IV (Intravehicular) portion of the EVA "inhibit pad", i.e., the list of temporary external deactivations in support of the EVA.
• Set up the RWS (Robotic Workstation) and DOUG (Dynamic Onboard Ubiquitous Graphics) peripherals with the IPV (International Procedures Viewer) laptop to support SSRMS (Space Station Remote Manipulator System) ops.
• Operated the SSRMS, "flying" Doug Wheelock during the EVA.

During the spacewalk, CDR Alexander Skvortsov assisted Walker on the SSRMS, and FE-5 Fyodor Yurchikhin worked with her supporting the Campout, prebreathe, EVA prep & post-EVA activities.

---------- Post added at 12:13 AM ---------- Previous post was at 12:03 AM ----------

BBC News: "Space station repairs 'only partial success'".

Orlando Sentinel: "Spacewalk fails to remove broken cooling pump".

Orlando Sentinel's "The Write Stuff" Blog: "NASA sets spacewalk record during repair mission".

EVA coverage from collectSPACE.


Post-EVA Briefing.

Florida Today's "The Flame Trench" Blog: "NASA expects three spacewalks to fix station pump".

---------- Post added at 06:15 PM ---------- Previous post was at 12:13 AM ----------

Spaceflight Now: "Troubles stall replacement of space station coolant pump".

SPACE.com: "Record-Setting Spacewalk at Space Station Falls Short on Repairs".

Florida Today: "Stubborn valve adds snarl to space station fix".

SPACE.com: "NASA: Third Spacewalk Required to Fix Space Station Cooling System".

Space Travel: "Third spacewalk needed to fix station cooling system: NASA".

NASA TV Video: "Astronauts' Make Progress on Spacewalk" - in HD!​

[ame="http://www.youtube.com/watch?v=DIYYUuP-jKs"]YouTube- ‪Astronauts' Make Progress on Spacewalk‬‎[/ame]

---------- Post added at 08:40 PM ---------- Previous post was at 06:15 PM ----------

From ISS On-Orbit Status Report for 08/08/2010:

FE-2 Tracy Caldwell-Dyson completed the usual post-EVA activities in the US A/L (Airlock), including:
• Recharging the EMUs (Extravehicular Mobility Units) with water, using PWR (Payload Water Reservoir) #1023, #1027 (backup, may have required degassing) & CWC (Contingency Water Container) #1059.
• Initiating recharge of EVA batteries in the BSA (Battery Stowage Assembly) for EVA-16 – i.e., EMU batteries #2086 & #2088 plus 4 HL (Helmet Light), 2 PGT (Pistol Grip Tool) & 2 REBA (Rechargeable EVA Battery Assembly) units.
• Deconfiguring the A/L after the spacewalk.

Doug Wheelock meanwhile had ~90 minutes to go through an uplinked listing to verify EVA tools left at various sites outside or brought inside after the excursion, such as tethers. The review included an inspection of the tethers brought back.

At ~3:45 PM GMT, Tracy, FE-6 Shannon Walker & FE-4 Doug Wheelock joined for a one-hour debrief on yesterday's EVA-15 with ground specialists, answering & discussing a number of questions on the balky & leaky M3 QD (Quick Disconnect), EVA suit fit, socks/boot fit & comm. cap issues, etc.

Current Station Status:
The Loop A PCVP (Pump & Control Valve Package) of the ETCS (External Thermal Control System) is "hard" failed, requiring replacement (four spares are on orbit). Loop B continues to function nominally, at zero fault tolerance (i.e., no backup). The Lab Contingency Truss Jumper is installed, and a number of DDCUs (DC-to-DC Converter Units) and their associated loads continue to be unpowered to prevent overheating. This especially impacts the science program. [Note: While the ETCS is using toxic NH3 (ammonia) as coolant, no NH3 is used inside the station. Instead, ITCS (Internal TCS) cooling consists of nine separate water-based fluid circuits, each with an LTL (Low Temperature Loop) and an MTL (Moderate Temperature Loop), that circulate in the station’s interior to collect excess heat from the electronic & experiment equipment and carry this heat to IFHX (Interface Heat Exchangers) units which transfer the heat to the ETCS and its two ammonia loops. There are ten IFHXs, located on the Lab, Node 2 & Node 3. The pump-driven heated ammonia circulates through huge radiator panels located on the exterior of the ISS, releasing the heat as infrared radiation and cooling as it flows. It high-pressure ammonia then returns to the heat exchangers.]

 

[Orbinaut Pete]

Florida Today's "The Flame Trench" Blog: "Second station repair spacewalk targeted for Wednesday".

SPACE.com: "NASA Targets Wednesday For Next Space Station Repair Attempt".

Spaceflight Now: "NASA changes spacewalk strategy for station repair".

---------- Post added at 11:37 PM ---------- Previous post was at 11:20 PM ----------

From ISS On-Orbit Status Report for 09/08/2010:

In preparation for the next spacewalk, EVA-16, on 11/08 (Wednesday), FE-2 Tracy Caldwell-Dyson resized her EMU (Extravehicular Mobility Unit) #3009 by adding ~1 inch to its torso length to lessen suit pressure on her shoulders while working outside.

FE-4 Doug Wheelock terminated METOX (Metal Oxide) canister regeneration in the US A/L (Airlock) bakeout oven, and FE-6 Shannon Walker finished recharging the EMU batteries in the BSA (Battery Stowage Assembly).

Then, Doug & Tracy re-equipped their spacesuits with the METOX CO2 absorber cans and freshly charged EMU batteries, while Shannon re-installed the charged HL (Helmet Light) batteries and the PGT (Pistol Grip Tool) batteries. [EMU #3005: METOX #5 & Battery #2088; EMU #3009: METOX #15 & EMU Batt #2086.]

Afterwards, Tracy, Doug & Shannon joined in a 2 hour review & discussion of preliminary details of EVA-16, followed by an EVA teleconference with ground support personnel.

Activities completed by Shannon included preparing MELFI-1 (Minus Eighty Laboratory Freezer for ISS-1) for reactivation by wiping down internal surfaces and leaving Dewar 2 trays out to dry, replacing them with trays from MELFI-3 (MELFI-1 Dewar 2 to be activated later).

ETCS Loop A Pump Module Update:
EVA-16 is being extensively & thoroughly replanned as a result of the disappointing outcome of EVA-15 which failed to get the nonfunctional ETCS (External Thermal Control System) Loop A PM (Pump Module) out and start work on the new pump. Spacewalkers Tracy Caldwell-Dyson & Doug Wheelock ended up short of that, due to a balky and leaky QD (Quick Disconnect, M3) at the old PM (losing about 3 lbs of NH3 (ammonia) in the process). Re-attaching the QD and re-opening the valve stopped the leak. For EVA-16, the plan is to lower Loop A NH3 pressure (from 370 psi to ~200 psi), close two additional QDs (one each at each end of the S1 Truss) to isolate/minimize the line segment to be vented, and then vent that coolant piping in the zenith direction (NH3 to be lost from the pipe: ~ 15lbs, later from the PM: ~22 lbs, i.e., a total just under 40 lbs of ammonia). M3 should then be "dry" (without pressure), allowing straight-forward valve closing and demating. Next, 5 power/data cables will have to be removed, followed by four attachment bolts of the PM. The latter will then be attached to the MBS (Mobile Base System) POA (Payload ORU Accommodation) via a grapple bar and vented, to be left on the POA for an extended period of time. Replacing the PM and making all necessary connections will very likely require a third EVA (tentatively scheduled for 15/08, (Sunday)). If at all necessary, a fourth EVA is also possible.

 

[Orbinaut Pete]

For future reference, I have produced this image showing unused PM locations on the ISS following EVA-16/17.

 

[Orbinaut Pete]

From ISS On-Orbit Status Report for 10/08/2010:

FE-2 Tracy Caldwell-Dyson & FE-4 Doug Wheelock completed final preparations for tomorrow's EVA-16. [Activities included configuring tools needed during the spacewalk such as equipment tethers, wire ties, etc., and making further preparations in the A/L (Airlock) EL (Equipment Lock), checking on PGTs (Pistol Grip Tools) #1001 w/battery 1009 for EV-1, PGT #1006 w/battery 1008 for EV-2, backup PGT #1004 w/battery 1006 in bag), filling DIDBs (Disposable In-suit Drink Bags) from PWD (Potable Water Dispenser), verifying installation of HL (Helmet Light) batteries (1029, 1030, 1031 &1035).]

Afterwards, Tracy, Doug & FE-6 Shannon Walker spent ~3 hours on reviewing latest EVA procedures. [The review included revised detailed procedures, a QD (Quick Disconnect) operations briefing package, and Robo/SSRMS (Space Station Remote Manipulator System) instructions.]

A teleconference by Tracy, Doug & Shannon with EVA specialists at MCC-Houston wrapped up preps.

In an attempt to restore the failed CO2 (carbon dioxide) sensor in Doug's EMU (Extravehicular Mobility Unit) #3005, Doug set up the sensor to flow O2 (oxygen) through it for an hour to remove the suspected moisture, and then check the sensor's functionality. The procedure worked, and as of now Doug's CO2 sensor is OK.

Working with Doug, FE-3 Mikhail Kornienko retrieved three Russian "Pille-MKS" radiation dosimeters, recorded their dosages in the Reader and equipped each of the two EMUs for tomorrow's spacewalk with a sensor unit (A0306 & A0307). [A third sensor, A0311, which had been in the Reader, was read in manual mode.]

Meanwhile, Shannon:
Reviewed uplinked briefing material on NH3 (ammonia) decontamination procedures and verified hardware readiness.
• Configured the Cupola RWS (Robotic Workstation) as backup for her SSRMS ops. on the Lab RWS tomorrow.
• Swapped the DOUG (Dynamic Onboard Ubiquitous Graphics) cable from the A31p laptop used for EVA-15 to the SSC-8 (Station Support Computer-8), a DOUG-equipped T61p model.
• Verified that telemetry is properly being received from the Robotics systems for "driving" the DOUG animation during EVA-16.
• Reviewed the new SSRMS EVA procedures.
• Powered down the amateur/ham radio equipment in the SM to prevent RF (Radio Frequency) interference with the spacewalkers.
• Closed the protective shutters of the windows in the US Lab, JPM, and Cupola.

After completing preparations of A/L EL for tonight's lockout, Doug (EV-1) and Tracy (EV-2) will begin their "campout" (nachalo desaturatsiy = desaturation start) in the A/L with hatch closure and depressurization of the CL (Crew Lock) from 14.7 to 10.2 psi, followed by mask prebreathe with oxygen (~7:55 PM to 9:00 PM GMT) and sleep from 9:30 PM to 6:00 AM GNT. [The CL hatch will then be cracked (i.e., temporarily repressurized to 14.7 psi) for a hygiene break/with mask prebreathe for Tracy & Doug at 6:35 AM to 7:45 AM GMT. Shannon will provide suited support in the A/L around 7:45 AM GMT, the hatch will be closed again for EVA preps in 10.2 psi (7:45 AM to 9:15 AM GMT), followed by EMU purge (~9:15 AM to 9:30 AM GMT) & prebreathe (~9:30 AM to 10:20 AM GMT). Afterwards, Walker will support CL depressurization until egress at ~10:55 AM GMT.]

Steps for EVA-16 will be:
1. Retrieve VTE (Vent Tool Extender) – EV-1.
2. Close M3 QD – EV-1 [If no leak (or "snowflakes"), keep M3 closed & do not do Step 4 (total time saved if M3 is OK = ~2 hours EVA time). If large leak reoccurs, open M3 to 90% (with SPD (Spool Positioning Device)) and proceed with original steps].
3. Install & Route VTE on S1 truss – EV-1.
4. Close M1/F105 (Male 1/Female 105) QD at S1-to-S0 interface – EV-1.
5. Close M1/F55 QD at S1 DDCU (DC to DC Conversion Unit) – EV-2.
6. Start vent of line & PM (~20 minutes) – EV-2.
7. Close M2, close Vent Tool, clean up Vent Tool – EV-1/EV-2.
8. Demate & bag M3 – EV-1.
9. Break torque on all (4) old PM bolts – EV-1.
10. Release old PM electricals and 3 bolts – EV-2.
11. Retrieve AGB (Adjustable Grapple Bar) from ESP-2 (External Stowage Platform-2) – EV-1.
12. Attach AGB to failed PM – EV-1/EV-2.
13. Remove failed PM from S1 Truss and stow on POA (Payload ORU Accommodation) on the MBS (Mobile Base System) at WS-2 (Worksite-2) – EV-1/EV-2.

Possible get-aheads:
1. C/L bag transfer to ESP-2.
2. Vent GN2 (gaseous nitrogen).
3. Break torque on bolts of spare PM.

---------- Post added at 09:00 PM ---------- Previous post was at 08:55 PM ----------

From NASA's Main ISS Webpage:

Expedition 24 Flight Engineers Doug Wheelock and Tracy Caldwell-Dyson spent the day completing preparations for their second spacewalk tomorrow out of the Quest airlock to replace the failed ammonia coolant Pump Module on the S1 Truss of the complex while the International Space Station Mission Management Team gave its final approval to proceed with the spacewalk.

Overnight, ground controllers activated the Gaseous Pressure Regulator Valve (GPRV) for the Loop A Nitrogen Tank Assembly, lowering the overall pressure in the plumbing for the inactive cooling loop in advance of tomorrow’s spacewalk by Wheelock and Caldwell-Dyson. The GPRV's pressure reduction will assist in the closure of quick disconnect valves at the S0/S1 Truss interface tomorrow by Wheelock and Caldwell-Dyson as part of the isolation of the line for the removal of the fourth and final fluid line connector holding the failed Pump Module in place. The lowered pressure will also facilitate the remate of all of the fluid lines once the new pump is installed. That activity is targeted for the third spacewalk no earlier than Sunday.

Once outside on Wednesday, Wheelock and Caldwell-Dyson will isolate the Loop A ammonia cooling line upstream from that final connector by closing quick disconnect valves, then will use a tool to vent residual ammonia from the failed Pump Module before the final cooling line is disconnected. That will lead to the disconnection of five electrical and data cables and four bolts from the old pump so it can be extracted from the truss through the use of a grapple bar and parked on a payload bracket on the station's Mobile Base System. If all goes as planned, the spare pump will be installed during the third spacewalk.

Wheelock and Caldwell-Dyson conducted final timeline reviews today with flight controllers and will move into the Quest airlock just before 4 PM EDT today to begin their overnight "campout" to reduce the nitrogen in their bloodstreams. They will be awakened at 2 AM Wednesday to complete spacewalk preparations and to suit up for their day's work. This will be the fifth spacewalk for Wheelock, who will wear the suit bearing the red stripes, and Caldwell-Dyson's second spacewalk. She will wear the unmarked suit.

NASA Television coverage of the spacewalk begins at 6 AM. The spacewalk is scheduled to begin just before 7 AM.

---------- Post added 11th Aug 2010 at 12:07 AM ---------- Previous post was 10th Aug 2010 at 09:00 PM ----------

From NASA's Main ISS Webpage:

NASA managers decided to begin Wednesday's spacewalk one hour later than originally planned. The additional time will allow teams to fine-tune robotic procedures and get some extra rest. NASA TV coverage now will begin at 7 AM EDT, and the crew is scheduled to switch to battery power [beginning the EVA] at 7:55 AM.