What determines when the shuttle has to return to earth?

"Brian Gaff" wrote in message
.uk...
Well, I've seen the 0G urine device, seems to be a kind of semi
rectangular pipe end with a sort of seal that you hold against the body
area required, an a suction device makes sure that all goes in the right
direction.

I imagine the solid waste device works in much the same way, though
obviously in suits, nappies and tablets seem to be the norm!

But the details are interesting. The Skylab method was pretty successful,
but when the shuttle toilet was designed it just *had* to be different and
it sucked. Well, actually the problem came after you shut the valve that
produced the airflow...

Eventually the shuttle design got better, but I'd have stuck with the Skylab
design, unless there was some reason to avoid that design that I don't know
about.

I imagine its pretty basic in the Soyuz though....

Does Soyuz even have a toilet? I don't know the details of the Russian
space toilets. ;-)

Jeff
--
"They that can give up essential liberty to obtain a
little temporary safety deserve neither liberty nor
safety"
- B. Franklin, Bartlett's Familiar Quotations (1919)