Re: SPACE: Why so much EVA on ISS?

From: S.J. Van Sickle (
Date: Sat Mar 17 2001 - 10:51:25 MST

On Sat, 17 Mar 2001 wrote:

> There's no question that the ISS design is right in maintaining the main
> connection between modules as a simple opening for people to pass through
> that can be easily closed and sealed.

There is no reason that interior connections have to pass through open
hatches. Cables and piping can penetrate the hull around the hatch and
pass into the pressurized tunnel connecting the two modules. The
connections are then made in the pressurized tunnel after docking,
retaining the ability to close the hatches on both modules. I believe
that this is how connections were made between the Apollo command module
and the LM.

The advantages are obvious: no EVA required for these connections, fewer
penetrations between pressure volume and vacuum, easier to get at the
connectors if there is a problem, rapid disconnection in an emergency,
more benign environment for the connectors, much easier to add connecting
lines in the future. The only disadvantage that I can see is that you
might need a slightly larger connecting tunnel.

I have asked, and never heard an reasonable explaination why intermodule
connections were not done this way.


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