In April 1970 the crew of Apollo 13 knew they had a problem when both the service module's oxygen tanks were destroyed, leaving only the meagre supplies in the command module.
You'd think the biggest problem in supplying air is the lack of oxygen, but the greater concern was excess carbon dioxide.
An astronaut (or submariner) inhales air at a concentration of CO2 at 0.04 per cent, then exhales it at 5 per cent. That means they will poison themselves with CO2 before they run out of oxygen.
Oxygen supply obviously comes from pressure vessels. CO2 on the other hand is reduced by a device called a ''scrubber''. While there are a variety of materials used, the principle is similar. Air is passed through a substance such as (as in the case of Apollo) lithium hydroxide which absorbs CO2.
In most techniques the CO2 becomes bonded, but in others it can be released.
As with a spacecraft or a submarine, there is no global problem with low oxygen caused by the prodigious rate of burning caused by humans.
Since we are now experiencing the disastrous affects of climate change, the real issue is CO2. This leads to the question of whether scrubbing can be used to capture then store CO2 pollution.
Indeed there have been attempts to develop scrubbers using materials called ''amines''.
However, producing an industrial-scale system is a very different proposition to one that only operates on a few cubic metres of air. Submarine or spacecraft operators can easily tolerate the cost of a small system, but to a fossil fuel plant or steel mill it could be prohibitive.
There are a couple of major hurdles. One is energy.
Aside from the considerable costs, the system saps energy. For a coal- or gas-fired power station, this energy is subtracted from the plant's output.
Electricity that would otherwise be fed into the grid is diverted for no gain other than to capture CO2 and, as a result, efficiency is reduced.
The second hurdle is what to do with the captured CO2. The main strategy is to inject it into geological reservoirs with the risk that it could leak, thus negating the entire purpose.
While CO2 is being stored this way, the objective is to enhance oil recovery where leakage is unimportant as long as oil is extracted. And, in this case, it increases profits while straight carbon capture and storage is just another cost.
These costs rapidly grow and there has been a series of very expensive failures.
The good news is nature provides free and ecologically sustainable alternatives such as grass, trees, wattles and sea grass. Even humble soil is a stupendous way of storing carbon if it is cared for.
The other strategy, of course, is to stop burning.
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