Alex Terrell wrote:
From http://news.bbc.co.uk/1/hi/sci/tech/6943451.stm

The mission is scheduled to last for 11 days but can be extended to 14
thanks to a new piece of equipment that allows the shuttle to tap into
the power grid of the ISS.

This is what we call a "plug".

The power bus -- er, sorry: grid -- of the ISS is not the same voltage as the
power bus of the shuttle. Thus, a (space rated) DC-DC converter needed to be
designed, built and qualified with both Station and Shuttle systems.

The qualifying of the device probably costs more than one device.

The plug has to be put somewhere... somewhere that it can be plugged in and
unplugged without requiring a space walk.

I'm amazed this hasn't been done before. Both systems must be using
batteries somewhere in their systems so recharging must be pretty

Shuttle has no batteries. Fuel Cells are a replacement for batteries.

Not all battieries are created equal. Some are 1.5v, some 6v, some 12v, some
48v. Some can be charged fast (e.g. flooded led-acid), some have to be chared
slow (e.g. gel cell), some are even more specialized (e.g. lithium ion). And
those are just the batteries that I own!


Glen Overby
Twin Cities, MN