On 3/12/2010 2:32 PM, Frogwatch wrote:
On Mar 12, 2:42 am, Pat wrote:
Life extension concepts are being discussed:http://spaceflightnow.com/news/n1003/11station/
...one problem in doing this is that, like Mir, you would then be using
equipment that was never rated for anywhere this long of orbital
lifetime, so you can expect a lot of failures as things wear out.

Pat

How could you make ISS "upgradable"? After all, it seems a shame to
de-orbit it just when it gets finished and it has yet to accomplish
anything.

On Mir, the original idea was that the modules could be replaced as they
aged, but that idea was quickly dropped due to budget constraints, and
it still left the problem of what to do as the core module they all
docked to itself aged.
ISS isn't really designed with completely replaceable plug-in modules in
mind, as everything attaches to the core group of manned modules that
form its spine, and you can't start tearing the spine back into pieces
once built.
It is supposed to use replaceable equipment racks inside the shells of
the modules (at least on the US built part), but completely cleaning out
a module and replacing everything in it is going to be a very involved
operation, as well as requiring something bigger than a Progress to
carry up the replacement equipment.

Pat