Author Topic: ISS Solar Panels upgrade?  (Read 63411 times)

Offline FinalFrontier

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Re: ISS Solar Panels upgrade?
« Reply #40 on: 07/22/2012 01:38 am »
Each Solar Array Wing  (SAW) has been classified as an ORU.  The question is how would we get a new SAW to ISS now.  Can Dragon hold a SAW in its unpressurized section?  It is likely that the P6 SAW's will have to be replaced if the ISS is to be operated through 2028.  So what will be done?
Two options.
Launch on F9 v 1.1, use orbital bus based on dragon to get it to ISS.
Or.
Launch on Delta IV, use centaur common upper stage (which would be operating by then) as the orb bus, as it will be designed with more flexibility toward long duration missions in mind.
Doubt one would fit in the dragon trunk, and if it did it would probably be too heavy. But flying one on an EELV class vehicle on its own with  a simple orbital bus is no problem.
Or unpressurized Cygnus.
Antares have enough boost for that?
A SAW is only like 2400 pounds. Should be good enough, at least the "enhanced" version.
Are you including the truss array as well?
It occurs to me that ultimately the "preferred" method of replacing these might be to simply build new truss segments for each one and replace all the gear in a modular fashion. Just disconnect umbilical and undock the four interlock pins. Might be easier then trying to replace individual components like the arrays themselves on the truss.
That's why I was thinking it would probably be good to include quite a bit of margin weight wise.
If you replace the whole truss:
A) Where will you relocate the ELCs, EPs, and AMS?
B) Center of gravity changes, as I recall when P3/P4 (or was it S3/S4) was being installed the CMGs started overloading as it was being moved from shuttle to install position. That is one reason why all of the Port trusses were not assembled all at once, instead they were assembled Starboard-Port-Starboard-Port et cetera. Spin-stablization is probably not a good option given the size and potential restrictions on power, fuel, CMGs, Arm use, et cetera, but I lack the details on such limits.
C) Without a shuttle around, how will you stabilize the ISS while you swap the trusses out (inner trusses would be a major problem to swap out)?

A) Don't know but possibly hand some off to dexter and leave them hanging.
B) Go one at a time and slowly first of all. Next use VV's for extra stabilization if possible.
C) VV's again.

Would have to be weighed against the difficulty of simply replacing the array wings themselves without messing with the truss segments.

Would be difficult, but perhaps not as bad if you did them one at a time.
« Last Edit: 07/22/2012 01:39 am by FinalFrontier »
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Offline Jim

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Re: ISS Solar Panels upgrade?
« Reply #41 on: 07/22/2012 02:42 am »
There is no reason to replace the trusses

Offline Go4TLI

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Re: ISS Solar Panels upgrade?
« Reply #42 on: 07/22/2012 02:49 am »
I recommend and endorse a nuclear reactor

No way. Too close to earth. If you must use a reactor in space put it high enough that it won't return in a few years without rebost.

Ahh, thank you.  While I was very much joking with my response this kind of statement goes a long way as to why we are at times limited in our capabilities.

Offline pathfinder_01

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Re: ISS Solar Panels upgrade?
« Reply #43 on: 07/22/2012 03:15 am »
I recommend and endorse a nuclear reactor

No way. Too close to earth. If you must use a reactor in space put it high enough that it won't return in a few years without rebost.

Ahh, thank you.  While I was very much joking with my response this kind of statement goes a long way as to why we are at times limited in our capabilities.

nah, I am pro-nuclear although not for nuclear thermal propusion due to cost. However safety first esp. that of Earth. Without reboost something like the ISS would come to earth very quckiy(like less than a decade). You could put it high enough that it won't return for hundreds of years.

Anyway for the panes lots of ways to get them up. Cgynus, HTV, and Dragon all have unpressuired capability. It might require a little redesign to fit into them but that is that.

Offline Prober

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Re: ISS Solar Panels upgrade?
« Reply #44 on: 07/22/2012 03:24 pm »
Augment and increase power supply until complete failure is near.

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Offline FinalFrontier

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Re: ISS Solar Panels upgrade?
« Reply #45 on: 07/22/2012 04:37 pm »
There is no reason to replace the trusses

Would it be easier to replace the Array wings themselves and individual components (like the battery arrays) as opposed to simply flying an entirely new truss and replacing in a modular fashion.


From what I am seeing here it sounds like the former is easier.

IMO the "easiest" solution would simply be to tie in a new power module, if needed in the future, to the existing USOS power supply and dock it to one of the CBMs (maybe Harmony Zenith) to augment the power supply, rather then trying to replace aged solar arrays.
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Offline oldAtlas_Eguy

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Re: ISS Solar Panels upgrade?
« Reply #46 on: 07/22/2012 05:12 pm »
The defining item on EOL for the station seems to be a power level of 200kw. With the current arrays that level is not reached until 2028 which is why that date was picked for a maximum possible extension of ISS. To extend beyond that new or additional arrays would be needed. In fact a single array replacement would make the new max operable date to be 2035.

Even though a 15 year EOL is stated for the arrays they do not really have a drop deap point. The first array added to the station in 2000 reaches the 15 year point in 2015. The next in 2021 and the last in 2024.

The major concern about power is the batteries which have a average life of just 6.5 years. There are 4 sets of 38 batteries with each battery weighing 375lb. It would take 2 Dragon flights complete external weight capability to do a single battery set replacement.

Newer batteries with longer life and same form factor is an option. Even a 50% improvement in lifetime to 10 years would be a tremndous cost savings.

Offline Prober

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Re: ISS Solar Panels upgrade?
« Reply #47 on: 07/22/2012 05:36 pm »
Good post OldAtlas_Eguy maybe you can address these questions.

What about mico meteorite damage to the panels?  Is there an on going review of the condition of the panels?



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Offline oldAtlas_Eguy

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Re: ISS Solar Panels upgrade?
« Reply #48 on: 07/22/2012 05:57 pm »
Good post OldAtlas_Eguy maybe you can address these questions.

What about mico meteorite damage to the panels?  Is there an on going review of the condition of the panels?





With one pannel with a baseline of 12 years the power output curve should be fairly accurately predictable which includes micrometorite damage. The remaining items is shorts or open circuits which are more than just a cell degradation. These can be minor or major. If no major events of this type occur then no swapout before 2028 would be needed. But if a major damage/fault occurs then the array would need to be swapped out before then.

For ongoing panel damage studies just google. They seem to be doing regular inspections of the arrays using the camaras on the SRMS.

Offline joek

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Re: ISS Solar Panels upgrade?
« Reply #49 on: 07/22/2012 06:18 pm »
The major concern about power is the batteries which have a average life of just 6.5 years. There are 4 sets of 38 batteries with each battery weighing 375lb. It would take 2 Dragon flights complete external weight capability to do a single battery set replacement.

Isn't it 48 battery ORUs total, with each ORU weighing ~375lb? (24 battery sets, each consisting of 2 battery ORUs.  Each ORU contains 38 individual Ni/H2 cells, each of which is relatively small and light.)

Offline oldAtlas_Eguy

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Re: ISS Solar Panels upgrade?
« Reply #50 on: 07/22/2012 06:49 pm »
The major concern about power is the batteries which have a average life of just 6.5 years. There are 4 sets of 38 batteries with each battery weighing 375lb. It would take 2 Dragon flights complete external weight capability to do a single battery set replacement.

Isn't it 48 battery ORUs total, with each ORU weighing ~375lb? (24 battery sets, each consisting of 2 battery ORUs.  Each ORU contains 38 individual Ni/H2 cells, each of which is relatively small and light.)


I think I found better data:

24 BCDU's each weighing 100kg. The earlier 38 value is for the individual cells in a BCDU.

6 BCDU's per array.

The P6 (2000) array had its batteries replaced in 2010. I am not sure whether this is the first or the second battery replacement for the array? If the first then battery life is demonstrated to be 10 years, if not then its closer to 5.

Offline Nomadd

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Re: ISS Solar Panels upgrade?
« Reply #51 on: 07/22/2012 06:56 pm »
 Average battery life for who? Most all forms of batteries can go for 15 years or more at 90% original capacity if someone with the brains of a lemur controls their operation. it always amazed me, how many so called engineers were making battery decisions, who didn't know the basics of use/cycle/charge time compromises needed to figure lifespan decisions on very expensive systems.
 Point of rant being, increasing battery mass by 20% to lean toward life span vs initial capacity is no doubt taken into consideration by ISS decision makers. 6.5 years seems hard to take in
 oldAtlas_Eguy, you'd have my eternal gratitude (which would buy you 1/4 cup of Starbucks coffee added to $.50) if you'd give me a link to the doc that timeline came from.

 I'm still waiting for realistic trunk cargo numbers from Elon Co. when M1D/F9 1.1 numbers are set.
« Last Edit: 07/22/2012 06:58 pm by Nomadd »
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Offline joek

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Re: ISS Solar Panels upgrade?
« Reply #52 on: 07/22/2012 06:59 pm »
24 BCDU's each weighing 100kg. The earlier 38 value is for the individual cells in a BCDU.

BCDU = Battery Charge Dischange Unit; not the same as a battery ORU (a BCDU is not a battery and contains no cells).  There is 1 BCDU per battery set; 2 battery ORUs per battery set (48 battery ORUs); each battery ORU ~375lb.  Reference here.


p.s. In some of the literature a "battery" is defined as 2 battery ORUs; in other places it is referred to as a "battery set".
« Last Edit: 07/22/2012 09:16 pm by joek »

Offline Prober

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Re: ISS Solar Panels upgrade?
« Reply #53 on: 07/22/2012 07:02 pm »
Looking futher into this....
 
first solar space cells search came up with: 
 
http://www.emcore.com/solar_photovoltaics/space_solar_cells
 
29.5% Minimum Average Efficiency
Triple Junction


so rollinging up the worst condition solar array, and then replacing it with a new one doubles the power output.
 
now to check the ORU's Just found this very good info.
http://www.nasa.gov/mission_pages/hubble/servicing/SM4/main/Battery_FS_HTML.html
« Last Edit: 07/22/2012 09:17 pm by Prober »
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Offline joek

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Re: ISS Solar Panels upgrade?
« Reply #54 on: 07/22/2012 07:10 pm »
Average battery life for who? Most all forms of batteries can go for 15 years or more at 90% original capacity if someone with the brains of a lemur controls their operation.

A bit harsh there.  There have been advances, but these systems are relatively old and there are in-space considerations; e.g., see (among others):
Nickel Hydrogen Batteries -- An Overview, NASA-TM-106795, Jan 1995
International Space Station Nickel-Hydrogen Battery On-Orbit Performance, NASA/TM-2002-211721, Jul 2002

Offline Prober

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Re: ISS Solar Panels upgrade?
« Reply #55 on: 07/22/2012 07:26 pm »
Getting back to the idea of trade of services with ESA
 
this is a quick pop up.
 
http://www.saftbatteries.com/SAFT/UploadedFiles/PressOffice/2011/CP_30-11_en.pdf
 
sure there are more.
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Offline Jim

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Re: ISS Solar Panels upgrade?
« Reply #56 on: 07/22/2012 07:27 pm »
Why fixate on trading services?

Offline Prober

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Re: ISS Solar Panels upgrade?
« Reply #57 on: 07/22/2012 07:51 pm »
Why fixate on trading services?

 The ATV SM for Orion should have been killed a year ago. http://forum.nasaspaceflight.com/index.php?topic=27029.390
 
 
« Last Edit: 07/22/2012 09:19 pm by Prober »
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Offline Jim

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Re: ISS Solar Panels upgrade?
« Reply #58 on: 07/22/2012 08:05 pm »
Why fixate on trading services?

surprised, you should be smart enough for this.    The ATV SM for Orion should have been killed a year ago. http://forum.nasaspaceflight.com/index.php?topic=27029.390
 

Not related. 


Offline Prober

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Re: ISS Solar Panels upgrade?
« Reply #59 on: 07/22/2012 08:19 pm »
see if this is right.....???


 1) The battery ORUs can be changed out robotically using a special purpose manipulator on the end of the station’s robotic arm. Each battery measures 41 inches (104.1 cm) by 37 inches (94 cm) by 19 inches (48.3 cm) and weighs 372 pounds (168.7 kilograms).
 
2) The batteries have a design life of about seven years
 
3) Two battery ORUs makes a battery set. There will be 24 battery sets on ISS at assembly complete.
 
So to upgrade 1/2 of the battery ORU's; replacement of 24 ORU's x weight of 372 pounds (168.7 kilograms).
 
Full station ORU replacement would be 48 ORU's x 372 pounds.
 
 
« Last Edit: 07/22/2012 08:20 pm by Prober »
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