Actually, the amount of Oxygen is a finite thing on any current spacecraft, including the ISS, without resupply somehow. Humans consume Oxygen and emit CO2. While the scrubbers do take out the CO2. Once the Oxygen or air, in the tanks is depleted. There is no more fresh air.
Now, remember how plants on Earth give us Oxygen and we still give off CO2. The plants act as a scrubber of CO2 and then gives off the Oxygen for us to breath. No space craft by Russia, the US or China(???) has ever had enough plants on board to give back enough Oxygen, for the astronauts to have an almost infinite supply of Oxygen. Also, those scrubbers can only take in a certain amount of CO2, before they are saturated.
The Oxygen/CO2 problem are one of the two main things which have to be addressed for really long space flights. Think years here, like going to Mars or elsewhere. Even staying on the moon, you would either need continuous resupply of Oxygen and scrubbers from Earth or have lots of the right kind of plants on board. The second main problem is food supplies. These 'air plants' would also be a source of fresh food for those long term astronauts.
Now, there is a loss of air, when in space. The pumps can't suck in all the air, when de-pressurizing the airlock. I am almost certain there is also some air lost, when ejecting human waste from the spacecraft.
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booboo-711-314080
15 years ago
Not just the O2. But the RCS tanks on board would they have even been filled just for a test fire? The APU maybe, to stear the main engines perhaps. There would also not be on board the MMU, a space suit or even an airlock in the cargo bay at that pointjust for a test.
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Musashi_MijaBloto
13 years ago
"The regenerative carbon dioxide removal system (RCRS) on the space shuttle orbiter uses a two-bed system that provides continuous removal of carbon dioxide without expendable products. Regenerable systems allow a shuttle mission a longer stay in space without having to replenish its sorbent canisters. Older lithium hydroxide (LiOH)-based systems, which are non-regenerable, are being replaced by regenerable metal-oxide-based systems. A system based on metal oxide primarily consists of a metal oxide sorbent canister and a regenerator assembly. It works by removing carbon dioxide using a sorbent material and then regenerating the sorbent material. The metal-oxide sorbent is regenerated by pumping air heated to around 400 °F at 7.5 scfm through its canister for 10 hours.[11]"
http://en.wikipedia.org/wiki/Carbon_dioxide_scrubber
Also there are scrubbers that absorb CO2 and release oxygen, the following reaction is used in submarines to recyle CO2 and release O2:
Na2O2 + CO2 -> Na2CO3 + 1/2O2
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