Creating an infinite oxygen tank?

[Grimlock]

I don,´t know how long the current oxygen tanks in the space suits last, but i guess they won,´t last indefinitely sooner or later you will run out of oxygen and unless your back in your ship by then well then your screwed.

What i am wondering about is this, would it be possible to create an infinite oxygen tank one that keeps producing oxygen in short a forest inside a small tank. So that basically as long as the astronaut draws breath he or she will never be out of oxygen, so in theory you could be in your space suit from you leave earth to you come back again and never once have to refill the tanks.

I haven,´t heard about it being made so far, but could it be done?

 

[Snufkin]

I'm totally rubbish at chemistry, but I'll try to answer

So photosynthesis requires carbon dioxide, water and light and it produces sugars and oxygen.

Getting light and carbon dioxide wouldn't be a problem.
The carbon dioxide would come from the astronauts breath, and the light would come from the sun (the tank would have to be transparent).

The only problem would be the source of water.


Edit:
Removed.

 

[Master_Ghost_Knight]

The answer is yes. It is not a small or easy or cheap aparatus and it would certainly consume allot of energy, but it is most certainly doable.
Water is not problem, water is recycleable. People also breath out water vapor.

 

[Snufkin]

The answer is yes. It is not a small or easy or cheap aparatus and it would certainly consume allot of energy, but it is most certainly doable.
Water is not problem, water is recycleable. People also breath out water vapor.

This is the equation:

6(CO2) + 6(H2O) (+ light) = C6H12O6 (sugar) + 6(O2)

So there's no resulting water from the reaction (is there?), so there's nothing to recycle unless you can change sugar into water (I have no idea if this is possible).

 

[Master_Ghost_Knight]

The answer is yes. It is not a small or easy or cheap aparatus and it would certainly consume allot of energy, but it is most certainly doable.
Water is not problem, water is recycleable. People also breath out water vapor.

This is the equation:

6(CO2) + 6(H2O) (+ light) = C6H12O6 (sugar) + 6(O2)

So there's no resulting water from the reaction (is there?), so there's nothing to recycle unless you can change sugar into water (I have no idea if this is possible).

You eat the sugar.

 

[ArthurWilborn]

The main question I think would be one of scale. No doubt you could build something to create a constant oxygen supply; but by time you have a sufficient through-put for use and leakages, it would no longer be man-portable.

 

[nasher168]

It doesn't seem that far-fetched to imagine some kind of highly efficient synthetic catalyst that could basically photosynthesise at a fast enough rate to keep a human alive. Especially if you already have, say, an enormously high-charged capacitor or ultra-efficient chemical battery in the apparatus to provide the energy required.

 

[RichardMNixon]

It doesn't seem that far-fetched to imagine some kind of highly efficient synthetic catalyst that could basically photosynthesise at a fast enough rate to keep a human alive. Especially if you already have, say, an enormously high-charged capacitor or ultra-efficient chemical battery in the apparatus to provide the energy required.

Enzymes are generally several orders of magnitude faster than synthetic catalysts (they do have 3.5 billion years of R&D), their main issue is fragility. Catalysts start to become competitive at higher temperatures, but then you'd have to be worried about burning the sugar, plus you'd need energy for the high temperature.

One interesting question though is how microgravity would affect the design specs. The weight wouldn't be an issue, but you might need it low mass just to prevent it from gaining momentum and yanking you with it.

 

[Unwardil]

Not the only concern with space though. There isn't really any need to have an infinite oxygen tank on a space suit because you can't actually survive a space walk for anything like as long as you can reasonably supply oxygen to the suit. You get slow cooked by cosmic rays and other radiation, so you die of exposure if you stay out too long. Same reason you don't have infinite dive tanks for deep sea diving. Lack of oxygen is actually the least of your worries. Cold and pressure are far more pressing issues.

Back to the OP though.

Some manner of Photosynthetic algae would be your ticket, built into a lung like apparatus to get maximum surface area. I guess the only really obnoxious thing about that kind of system though is you'd need the algae to be able to hibernate whenever the astronaut either went to sleep or just decided to take the thing off to go to the bathroom, otherwise you'd need to constantly keep feeding them.

 

[Grimlock]

It could be used on space stations.
I can,´t remember the exact series i think it was called Escape From Jupiter, where the crew to escape one of Jupiter's moons used an old space station to try and get back to earth.

To supply them with oxygen they used algae in a giant tank of water placed in a garden it would resupply them with oxygen while at the same time reducing CO2 so that it never rose to lethal levels.

In Disneys The Black Hole they used a giant garden with Tree,´s and everything to supply the Cygnus with air and food.

So a little bonus question how big a garden would you need in order to supply a space station or a giant ship, lets say at the size of our biggest ships that sail the ocean.

 

[Thomas Doubting]

It could be used on space stations.
I can,´t remember the exact series i think it was called Escape From Jupiter, where the crew to escape one of Jupiter's moons used an old space station to try and get back to earth.

To supply them with oxygen they used algae in a giant tank of water placed in a garden it would resupply them with oxygen while at the same time reducing CO2 so that it never rose to lethal levels.

In Disneys The Black Hole they used a giant garden with Tree,´s and everything to supply the Cygnus with air and food.

So a little bonus question how big a garden would you need in order to supply a space station or a giant ship, lets say at the size of our biggest ships that sail the ocean.

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One would have to find out what trees are best for mere oxygen production..
in your example i'd say you have to combine oxygen prouction with food and resources.. it might be easy to calculate how big a garden you need for some amount of people to be able to breathe, but then you burn various things (cooking, machines etc) you might have some animals. you might need plants to make fibres (clothes etc), food like veggies, fruits, roots, spice, medication and so many other things.. and i wonder how many factors i left out to estimate how big that garden would have to be and what plants you need to use... but in short, i'd say you need a hell of a harden :lol:

 

[DepricatedZero]

Does our planet count?

 

[nasher168]

By a remarkable coincidence, a person is going to try living off the oxygen from plants next week. Sorry for the shit source, but it's the best I could find:
http://www.dailymail.co.uk/sciencet...spend-48-hours-airtight-box-plants-alive.html

A scientist is setting out to prove that we're taking vegetation for granted in the most dramatic fashion - by locking himself in an airtight box for two days using the oxygen generated by plants to keep him breathing.
Courageous Professor Iain Stewart will conduct the experiment next week at the Eden Project, a 'plant zoo' near St Austell, Cornwall, to underline the importance of photosynthesis.
The box he will call home for 48 hours measures 2m by 6m by 2.5m (6ft 6in by 20ft by 8ft) and will contain plants known to produce large quantities of oxygen, such as miscanthus grass, zea mays maize and banana trees.

 

[Grimlock]

By a remarkable coincidence, a person is going to try living off the oxygen from plants next week. Sorry for the shit source, but it's the best I could find:
http://www.dailymail.co.uk/sciencet...spend-48-hours-airtight-box-plants-alive.html

A scientist is setting out to prove that we're taking vegetation for granted in the most dramatic fashion - by locking himself in an airtight box for two days using the oxygen generated by plants to keep him breathing.
Courageous Professor Iain Stewart will conduct the experiment next week at the Eden Project, a 'plant zoo' near St Austell, Cornwall, to underline the importance of photosynthesis.
The box he will call home for 48 hours measures 2m by 6m by 2.5m (6ft 6in by 20ft by 8ft) and will contain plants known to produce large quantities of oxygen, such as miscanthus grass, zea mays maize and banana trees.

I think a saw a similar experiment conducted by NASA (on national geographic channel) and this was for a week or so the guy that was locked inside made all the similar daily exercises that astronauts in space makes.

He wasn,´t allowed to use any deodorants at all as the chemicals in it could be harmful to the plants.

He reported that he had no trouble breathing though the smell and the air in the room did become a little acrid towards the end.

 

[nasher168]

This one I think is for a BBC documentary about plants. He's going to live on the absolute minimum number of plants that should be able to keep him alive.