Author Topic: Main Bus Switching Units (MBSU)  (Read 7935 times)

Offline Olaf

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Main Bus Switching Units (MBSU)
« on: 11/11/2017 07:18 pm »
I have tried to create a timetable of the movements of MBSU´s on the ISS, but there must be at least one mistake.
The main problem is, that on FRAM-4 ESP-2 only one unit can be installed , but another FRAM is or was not empty.
Maybe someone can help to resolve the problems?

That´s my table
11.04.2002   installation of S0 Truss with four MBSU´s
03.08.2005   installation of ESP-2 with one spare MBSU on FRAM-4
30.10.2007   installation of one spare MBSU, delivered on STS-120, on ESP-2 FRAM-6
25.08.2013   installation of one spare MBSU, delivered on HTV-4, on ESP-2 FRAM-4 

30.08.2012    changing the MBSU, delivered on ESP-2 with one MBSU failed on S0
28.01.2013    relocation of the failed MBSU to ELC-2
08.02.2016   deinstallation/reinstallation of the MBSU on ELC-2 for test purposes
04./05.05.2017   changing the MBSU, delivered on HTV-4 with one MBSU failed on S0
08.08.2017   relocation of the failed MBSU from ESP-2 to JEM
20.10.2017   deinstallation of the MLI from one MBSU on ESP-2
04.11.2017   relocation of the repaired MBSU from JEM to ESP-2
« Last Edit: 01/28/2018 07:02 pm by Olaf »

Offline Olaf

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Re: Main Bus Switching Units (MBSU)
« Reply #1 on: 11/29/2017 07:21 pm »
On page 4 of https://www.nasa.gov/sites/default/files/atoms/files/nov_2017_nac_iss_status_and_transition_final.pdf
is shown that it is planned in January 2018 to moved one MBSU inside the ISS and later again outside.
I think that this will be the unserviceable MBSU, which is at the moment installed on ELC-2 FRAM 3.

Offline russianhalo117

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Re: Main Bus Switching Units (MBSU)
« Reply #2 on: 11/29/2017 08:01 pm »
On page 4 of https://www.nasa.gov/sites/default/files/atoms/files/nov_2017_nac_iss_status_and_transition_final.pdf
is shown that it is planned in January 2018 to moved one MBSU inside the ISS and later again outside.
I think that this will be the unserviceable MBSU, which is at the moment installed on ELC-2 FRAM 3.
correct.

Offline Olaf

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Re: Main Bus Switching Units (MBSU)
« Reply #3 on: 01/24/2018 02:20 pm »
https://blogs.nasa.gov/stationreport/2018/01/
Quote
Three-Day Look Ahead:
Thursday, 01/25: ... JOTI/MBSU install

Offline Olaf

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Re: Main Bus Switching Units (MBSU)
« Reply #4 on: 01/26/2018 01:50 pm »
https://blogs.nasa.gov/stationreport/
Quote
In preparation for the upcoming Main Bus Switching Unit (MBSU) maintenance, today the crew extended the A/L slide table into the JEM pressurized module (JPM), removed the passive capture mechanism, and installed JEM ORU Transfer Interface (JOTI) on the slide table.  Next week, robotics ground controllers will remove an MBSU from its location outside the station and place it on the JEM A/L slide table for transfer inside.  Once inside, station crew will perform maintenance on the MBSU to recover its functionality and then pass it through the JEM A/L again for reinstallation outside the station.

Offline Olaf

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Re: Main Bus Switching Units (MBSU)
« Reply #5 on: 01/29/2018 07:26 am »
It  seems, that the transfer inside is planned on February,4.
http://iss.jaxa.jp/kiboexp/plan/180124.html?utm_source=dlvr.it&utm_medium=twitter

Offline Olaf

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Re: Main Bus Switching Units (MBSU)
« Reply #6 on: 01/30/2018 02:25 pm »
It  seems, that the transfer inside is planned on February,4.
http://iss.jaxa.jp/kiboexp/plan/180124.html?utm_source=dlvr.it&utm_medium=twitter
It is possible, that this will be delayed due to the problems with the LEE:

Offline Olaf

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Re: Main Bus Switching Units (MBSU)
« Reply #7 on: 03/16/2018 02:32 pm »
It looks like the MBSU maintenance is delayed again.
https://blogs.nasa.gov/stationreport/2018/03/
Quote
JEM Airlock (JEMAL): Today the crew reconfigured the JEM ORU Transfer Interface (JOTI) in support of upcoming Materials ISS Experiment – Flight Facility (MISSE-FF) payload operations.  MISSE-FF will be a permanent external platform on the ISS that is modular and robotically serviceable. Remotely controllable sample carriers will provide sample protection and on-demand picture data previously unavailable on prior experiments.  Sample plates containing a variety of surface materials will be exposed to the space environment outside the ISS for varying durations to inform satellite designers on how different materials degrade over time.  MISSE-FF is currently manifested on SpaceX-14.

Quote
Today’s Planned Activities
Structures and Mechanisms JEM ORU Xfer I/F (JOTI) Reconfiguration from MBSU to MTT

Offline eeergo

Re: Main Bus Switching Units (MBSU)
« Reply #8 on: 04/30/2019 12:58 pm »
Bumping for the current MBSU issues.

Do we have an update on what came to be with the MBSU that was supposed to be repaired inside the Station?
-DaviD-

Offline PM3

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Re: Main Bus Switching Units (MBSU)
« Reply #9 on: 04/30/2019 05:25 pm »
NSF article on the MBSU issues
"Never, never be afraid of the truth." -- Jim Bridenstine

Offline Olaf

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Offline eeergo

Re: Main Bus Switching Units (MBSU)
« Reply #11 on: 05/02/2019 05:18 pm »
Bumping for the current MBSU issues.

Do we have an update on what came to be with the MBSU that was supposed to be repaired inside the Station?

Cross posting from the Exp 59 thread, confirming the 2017 MBSU was indeed repaired and substituted the 2019-failed one.

https://twitter.com/AstroKomrade/status/1123974084033941511
-DaviD-

Offline Olaf

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Re: Main Bus Switching Units (MBSU)
« Reply #12 on: 08/29/2019 12:55 pm »
On page 4 of https://www.nasa.gov/sites/default/files/atoms/files/nov_2017_nac_iss_status_and_transition_final.pdf
is shown that it is planned in January 2018 to moved one MBSU inside the ISS and later again outside.
I think that this will be the unserviceable MBSU, which is at the moment installed on ELC-2 FRAM 3.
It looks like after a delay of around 18 months they got it now.
https://blogs.nasa.gov/stationreport/2019/08/28/iss-daily-summary-report-8282019/
Quote
SSRMS Operations in support of upcoming MBSU IFM  (In Work)
Minor correction to the quote: it was FRAM 1 not 3



Offline Olaf

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Re: Main Bus Switching Units (MBSU)
« Reply #13 on: 08/30/2019 12:43 pm »
https://blogs.nasa.gov/stationreport/2019/08/29/iss-daily-summary-report-8292019/
Quote
Main Bus Switching Unit (MBSU) 3 Robotic Operations: Yesterday and last night, the Space Station Remote Manipulator System (SSRMS) used the Special Purpose Dexterous Manipulator (SPDM) to retrieve the failed MBSU 3 from Express Logistics Carrier 2 (ELC2)’s Flight Releasable Attachment Mechanism (FRAM). The FRAM was temporarily stowed on its Enhanced ORU Temporary Platform (EOTP) Side 2, then the empty FRAM was stowed back on ELC2. Today the failed MBSU3 will be placed in the JEMAL for future In-flight Maintenance (IFM).

Offline Olaf

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Re: Main Bus Switching Units (MBSU)
« Reply #14 on: 09/03/2019 03:07 pm »
https://blogs.nasa.gov/stationreport/2019/08/30/iss-daily-summary-report-8302019/
Quote
Robotic Operations Main Bus Switching Unit (MBSU): The Mobile Servicing System (MSS) was powered-up and maneuvered the Space Station Remote Manipulator System (SSRMS) and the Special Purpose Dexterous Manipulator (SPDM) Arm2 in position to install the In Flight Maintenance (IFM) MBSU in the Japanese Experiment Module (JEM) ORU Transfer Interface (JOTI) on the JEM Airlock Slide Table. Next, the MSS was maneuvered into position in preparation for MT translation to Worksite (WS3) for MBSU3 AFRAM transfer.

Offline Olaf

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Re: Main Bus Switching Units (MBSU)
« Reply #15 on: 09/04/2019 03:22 pm »
https://blogs.nasa.gov/stationreport/2019/09/03/iss-daily-summary-report-9032019/
Quote
Main Bus Switching Unit (MBSU) Intermediate (I)-Level Maintenance: Last week the on orbit repairable MBSU was placed on the Japanese Experiment Module Airlock (JEMAL) Slide Table using the Space Station Remote Manipulator System (SSRMS) and the Special Purpose Dexterous Manipulator (SPDM). Today the crew opened the MBSU chassis to access a failed circuit card for replacement. A test was then completed to verify functionality of the unit prior to staging it for egress via the JEMAL. The SPDM will be used again this evening in order to swap the repaired MBSU with a failed MBSU. After the swap is complete, the failed MBSU will be brought inside ISS and prepared for return to the ground via SpaceX-19.
The mentioned "failed MBSU", must be that one, which failed in spring this year. It was then stowed on ESP-2 FRAM 4.
« Last Edit: 09/04/2019 03:24 pm by Olaf »

Offline Olaf

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Re: Main Bus Switching Units (MBSU)
« Reply #16 on: 09/05/2019 12:32 pm »
https://blogs.nasa.gov/stationreport/2019/09/04/iss-daily-summary-report-9042019/
Quote
Overnight, Robotics ground controllers powered up the Mobile Servicing System (MSS) and maneuvered the SSRMS with the Special Purpose Dexterous Manipulator (SPDM) to the Japanese Experiment Module (JEM) Airlock. The JEM Airlock slide table was then extended with the repaired Main Bus Switching Unit (MBSU). Once the slide table was extended, the MBSU was removed with SPDM Arm 1. After maneuvering SSRMS and SPDM away from the JEM Airlock, SPDM Arm 2 removed the failed MBSU from the Active Flight Releasable Attachment Mechanism (AFRAM) located on the SPDM Enhanced ORU and Tool Platform (EOTP) side 2. The SPDM Arm 1 was used to install the repaired MBSU on the empty AFRAM. The failed Main Bus Switching Unit (MBSU) was then installed on the JEM Airlock slide table and the slide table was retracted in the JEM Airlock. Finally, the Mobile Transporter (MT) was then translated to Worksite 3.
This should be the penultimate step in this MBSU work.

Offline Olaf

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Re: Main Bus Switching Units (MBSU)
« Reply #17 on: 09/06/2019 02:30 pm »
https://blogs.nasa.gov/stationreport/2019/09/05/iss-daily-summary-report-9052019/
Quote
To finalize this week’s MBSU operations, today the failed MBSU was removed from the Japanese Experiment Module Airlock (JEMAL) slide table and placed in a Cargo Transfer Bag (CTB). The MBSU-3 was declared hard failed on April 29, 2019. The MBSU will return to ground on SpaceX-19.
Quote
Completed Task List Activities:
Repaired MBSU AFRAM robotically stowed at ESP-2 Site 4

Offline Anthropic

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Re: Main Bus Switching Units (MBSU)
« Reply #18 on: 09/10/2019 01:49 am »
The NASA Johnson Flickr posted a photo of the MBSU repair on 9/3.
« Last Edit: 09/10/2019 01:49 am by Anthropic »

Offline jcm

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Re: Main Bus Switching Units (MBSU)
« Reply #19 on: 09/21/2019 08:42 pm »
I'm still confused about one thing here: when did the 'failed MBSU' C250636 get removed from ESP2 Site 4 and placed on the EOTP Side 2?  It's on EOTP by Sep 3 but there's no mention before then
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