Author Topic: LIVE: ISS US spacewalk (EVA-19) - September 5, 2012 (Read 107714 times)

Chris Bergin · « **on:** 09/02/2012 04:30 pm »

Contingency EVA due to the MBSU-1 Installation Failure from EVA-18.

EVA-18:

Main Article - By Pete Harding:
http://www.nasaspaceflight.com/2012/08/astronaut-perform-first-post-shuttle-spacewalk-iss/

LIVE Update Coverage of EVA-18:
http://forum.nasaspaceflight.com/index.php?topic=29721.0

Main Post-EVA Article including full MBSU overview - by Pete Harding:
http://www.nasaspaceflight.com/2012/09/iss-program-recovery-plans-mbsu-1-installation-failure/

EVA-19 Article - by Pete Harding:
http://www.nasaspaceflight.com/2012/09/iss-astronauts-second-eva-install-mbsu-1/

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L2 Resources:

L2 ISS Section:
http://forum.nasaspaceflight.com/index.php?board=33.0

L2 ISS Internal Updates (Daily, extensive):
http://forum.nasaspaceflight.com/index.php?topic=29554.0

L2 MBSU Issue Updates and Presentations:
http://forum.nasaspaceflight.com/index.php?topic=29819.0

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THIS IS A LIVE UPDATE THREAD, So posts only relating to this new EVA should be made here. Continue to use the EVA-18 thread for follow up updates and discussion related to that EVA and the MBSU.

anik · « **Reply #1 on:** 09/02/2012 07:36 pm »

It will be the 100th spacewalk from Quest airlock.

Fuji · « **Reply #2 on:** 09/02/2012 09:05 pm »

NASA official statement.
http://www.nasa.gov/mission_pages/station/living/index.html

Spacewalk Set For 7:15 a.m. EDT Wednesday

Following a thorough review of preparations, the International Space Station Mission Management Team, including all international partners, agreed to press ahead for the follow-up spacewalk. A final readiness review by station program officials will be conducted on Tuesday, Sept. 4.

The most probable cause is likely a combination of a slight misalignment in the positioning of the spare unit for its installation prior to bolting and possible damage to the threads of the receptacle posts on the S-zero truss to which the MBSU must be bolted in place.

dsmillman · « **Reply #3 on:** 09/03/2012 12:26 am »

From today's ISS status report at:

http://www.nasa.gov/directorates/heo/reports/iss_reports/

The following will be done to get the MBSU installed:

" Temporarily remove & stow the MBSU1 (Main Bus Switching Unit 1) near the worksite,

·Go through different inspection & cleaning techniques for the MBSU stanchion and coldplate, i.e. –

o Inspect with suit-mounted WVS (Wireless Video System) cameras,

o Inspect/clean with a magnet,

o Check H1 tolerance by hand,

o Perform cleaning as required,

o Lubricate, and

o Check thread quality of H2 bolt using a scavenged bolt (see below),

·Install the MBSU (it may also have to brought inside the station),
"

The last item implies that the MBSU can be brought into the station through the airlock. Is this correct?

There are more details in the report including a description of tools fabricated to use on the EVA.

psloss · « **Reply #4 on:** 09/03/2012 12:37 am »

Quote from: dsmillman on 09/03/2012 12:26 am

From today's ISS status report at:
http://www.nasa.gov/directorates/heo/reports/iss_reports/

The following will be done to get the MBSU installed:

Permalink:
http://www.nasa.gov/directorates/heo/reports/iss_reports/2012/09022012.html

I liked this little bit of detail:

Quote

[In order to inspect & clean the threads of the bolt/posts on the S0 Truss, Joe scavenged a bolt from a spare PVCU MDM (Photovoltaic Controller Unit Multiplexer/Demultiplexer) bracket that is identical to the H2 bolt on the MBSU. The scavenged bolt will help to tell if the threads on the truss are damaged, and it will “chase” the threads to help remove any FOD (Foreign Object Debris). To turn the bolt and to perform cleaning, Joe, Sunita & Aki built a number of new hand-tools, such as a bolt interface tool, as well as cleaning & lubricating tools using a toothbrush and a wire brush for hand- or PGT use. For in-hole cleaning, Aki build a “chimney-sweep” tool.]

And:

Quote

Then, at ~2:30pm, FE-5 & FE-6 talked with EVA-19 specialists on the ground in a 30-min teleconference via S- and Ku-band. [Uplink to Suni & Aki: “We don't have a smoking gun for why the box didn't install… We are going outside to try our best guesses and hope we get lucky… If not, we have developed a flow to get the MBSU inside and potentially take the bolt out for install during EVA 20…”]

psloss · « **Reply #5 on:** 09/03/2012 01:53 am »

A NASA Media advisory went out this evening (M12-171) noting that live coverage on NASA TV would begin at 6 am Eastern on Wednesday, assuming the EVA stays where it is on the schedule.

catdlr · « **Reply #6 on:** 09/04/2012 06:10 pm »

[ISS] Contingency Spacewalk For Wednesday 5th

Published on Sep 4, 2012 by SpaceVidsNet

Spacewalkers Sunita Williams and Akihiko Hoshide will take part in the second spacewalk in 6 days to try get a Main Bus Switching Unit (MBSU) installed outside the truss of the Station tomorrow, starting at 11:15 UTC.

They failed in their attempt to do so last week on Thursday 30th August during a 8 hour 17 minute spacewalk. If they are unable to get the MBSU installed tomorrow they will bring it inside and repair it, where it will be installed in a future Spacewalk.