The solar arrays used on the ISS were launched in 4 different launches. Starting in 2000 for the first array, used on the Z-0 truss, to 2007, 2008, and 2009 for the final three.

Are all 4 of them identical in design? Therefore the question, were they manufactured as a set?

Or did the first array go up, and based on its experience in orbit and new solar cell technology contribute to a modernized design for the next three?

  • $\begingroup$ I will look for a reference, but I think they were all the same. Later the batteries got swapped out, but that was after they were already in orbit. $\endgroup$ Commented Jun 30, 2015 at 16:50
  • $\begingroup$ @OrganicMarble My theory is, spec was written whenever, say in 1995. And then they started building all 4 and kept them in storage till they were used. Much cheaper to build 4 in a row, than 1, make lots of changes, then build 1, then 5 years later build 1, then 1 year later build another, etc. $\endgroup$
    – geoffc
    Commented Jun 30, 2015 at 16:51
  • $\begingroup$ The qualification process for a space hardware design is so torturous that the payback would have to be enormous for them to change anything. I am pretty sure the kind of incremental advances you are talking about would not be worth it. $\endgroup$ Commented Jun 30, 2015 at 17:19

1 Answer 1


Took a bit of digging but I found a press release from 2009 that indicates that they were all identical:

The truss segment, a carbon copy of the Port 6 element already on orbit...

The 2009 launch was the fourth (last) set of solar arrays added to the station, and wikipedia confirms that the port 6 segment was the first set of solar arrays:

The first pair of arrays are attached to the P6 truss segment, which was launched and installed on top of Z1 in late 2000 during STS-97.

While the press release doesn't discuss the manufacture of all the solar panels this quote strongly suggests they were all manufactured one after another:

The truss has had the longest time on the ground of any single ISS element -- it arrived at KSC on Dec. 17, 2002 -- with a Boeing team regularly maintaining it, cleaning it and inspecting it for corrosion.


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