How do the astronauts obtain oxygen while in (a) the shuttle (b) a
space walk, and (c) space station?
Also,(d) what is the arrangement for peeing? How do they make sure it
doesn't float around the cabin?

Dear renoir-ga 

First as to the oxygen supply in the space shuttle and space station. 
The space shuttle carries the required oxygen in canisters and this is
fed into the shuttle cabin. The space station carries water which has
electricity passed through it to separate it into oxygen and hydrogen.
The oxygen is then fed into the space station cabin. When conducting a
space walk the astronaut carries his own life support system which
includes sufficient oxygen for 7 hours. The hygiene arrangements are
complicated and are described in great detail in the link below.


These are the answers to similar questions which appear on the NASA
Frequently Asked Questions page.

"Answer: A shuttle flight is relatively short compared to the time a
crew will spend on the ISS, so the shuttle simply carries canisters
that are the source of oxygen for its missions. The Russian built
Elektron is the primary source of oxygen for the ISS. The Elektron
uses electrical power to separate water into gaseous oxygen and
hydrogen. The hydrogen is vented overboard and the oxygen replenishes
the crew air supply.?

?Answer:
Basically they are shipped up from Earth. The shuttle uses cryogenic
oxygen in tanks for crew breathing air and also to combine with
cryogenic hydrogen to make electricity and drinking water in the fuel
cells. The ISS uses sunlight to make electricity and uses that
electricity to split water into hydrogen and oxygen. The hydrogen is
vented into space, and the crew breathes the oxygen. Water for the ISS
comes from Progress resupply ships and also from the spare water the
shuttle makes.?


?Answer:
The approach is different for station and shuttle. The shuttle carries
3 to 9 cryogenic oxygen tanks that supply oxygen for the cabin
atmosphere and oxygen for the oxygen/hydrogen chemical reaction to
produce water and electricity. The atmosphere is kept to a ratio of
80% nitrogen and 20% oxygen. The 20% oxygen to 80% nitrogen ratio is
supplied by the shuttle Pressure Control System (PCS).

The space station uses the following methods to provide oxygen: the
oxygen Generator called the Elektron, a Solid Fuel oxygen Generator,
Russian Progress Resupply oxygen Tanks, and after STS-104, two oxygen
tanks installed in the airlock. The oxygen generator decomposes water
(H2O) into oxygen and hydrogen. The [oxygen] is delivered to the
atmosphere while the hydrogen is vented overboard. The Solid Fuel
oxygen Generator uses chemical cartridges to produce oxygen via an
exothermic reaction. On STS-104, currently scheduled for June 2001,
the shuttle will be delivering the station's airlock. The airlock will
have two oxygen tanks available, and on future missions there are
plans for the shuttle to give oxygen to the station's airlock oxygen
tanks.?

To see these questions and answers in full, go to
http://spaceflight.nasa.gov/shuttle/reference/faq/index.html
Type> shuttle oxygen in the search box.


This is from another part of the NASA web site.

Space Walk

?During an EVA, the astronauts wear a pressurized space suit, called
the Extravehicular Mobility Unit (EMU). The EMU consists of three
major assemblies: the upper torso, the lower torso and the portable
life-support system. The upper and lower torso connect around the
waist by a joint ring. Attached to the back of the upper torso is the
portable life-support system, which contains enough oxygen and
electric power for 7 hours of operation. The astronauts wear a cooling
and ventilation garment for temperature regulation inside the suit.?
http://lsda.jsc.nasa.gov/kids/L&W/eva.htm

Additional information appears on this page
http://lsda.jsc.nasa.gov/kids/L&W/emusuit.htm


Personal hygiene facilities and urine and faeces disposal is described
on this page.
http://lsda.jsc.nasa.gov/kids/L&W/hygiene.htm

Detailed information also appears here
http://spaceflight.nasa.gov/shuttle/reference/shutref/orbiter/eclss/wcs.html


I hope this answers your question. If it does not, or the answer is
unclear, then please ask for clarification of this research before
rating the answer. I shall respond to the clarification request as
soon as I receive it.
Thank you
answerfinder

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Request for Answer Clarification by renoir-ga on 27 Jul 2005 15:43 PDT

The links to the NASA sites were very helpful.

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Clarification of Answer by answerfinder-ga on 28 Jul 2005 01:42 PDT

Pleased I could help.
answerfinder