The Eventual Challenge, of Designing a Closed, Life-Support System

In Science Fiction, a concept which occurs often, is ‘A Closed Life-Support System’. But just like eventual ‘travel at half the speed of light’, a real, closed life-support system has largely remained elusive.

Back in WW2, German Submariners knew a trick to extending the life of the air in their submarines during adverse moments, of sprinkling lime powder – i.e., CaO. But the only real effect this had, was to absorb carbon dioxide out of the air mixture in the submarine, and to hold it in some form of CaCO3 . The lime powder itself did not generate any oxygen, O2, in return for scrubbing the CO2 out of the air mixture. This actually served WW2 submariners well, because until that time, the dangers of CO2 toxicity were usually greater, than the real-life dangers of hypoxia. The era only came later really, that the USA launched various high-altitude platforms, and that hypoxia started to become a common problem, to be dealt with.

CaO reacts vigorously with H2O to form Ca(OH)2 , and nothing else.

This simple fact should not be taken to mean, that WW2 submarines had no way of generating oxygen. It only means, that lime powder as such, or other strong bases, do not generate oxygen by themselves. ( :1 )

What the current International Space Station does, is to collect various forms of moisture from the habitat, and to use ample electricity from its solar collectors, to electrolyze that water into O2 and H2. At the same time, the ISS collects CO2 from the interior air, using ethanolamine, which is a liquid, weak base. And after CO2 has been absorbed by a weak base, this gives the advantage, that the salt which results only needs to be heated to modest temperatures, to re-release the CO2. But a weakness which the ISS exhibits is then to release two waste-gasses back into space: H2 and CO2. If I’m not mistaken in this statement, the ISS falls short of achieving a real, closed life-support system. The CO2 may be released into space, but doing so ‘is made up for’ with fresh carbon introduced into the cycle, in the form of food, which is transported to the ISS.

Well when I was young, I read books, according to which certain technical problems inherent in space travel would soon be solved, which were never solved. One of them was, to devise a catalyst, or some other type of reactor, to combine H2 with CO2, in a way that produces more H2O, which could then be available for electrolysis again, and which would reduce the amount of waste to some unspecified carbonaceous solid. This carbonaceous solid, could then be made up for, in food that Astronauts ate.

But the unfortunate reality which remains is, that reactions that reduce CO2 using H2 remain unharnessed today. The closest to that which we have, is the famous water-gas reactions from the 19th century, that involve some mixture of carbon monoxide ( CO ) and H2. Well unfortunately, CO has not been reduced all the way to Cs .

(Updated 10/27/2018, 15h30 … )

Continue reading The Eventual Challenge, of Designing a Closed, Life-Support System

Proxima Centauri

One of the facts which I had observed over the decades, was that in my youth, the concept of manned space travel and exploration was followed at first with keen interest, but that interest had waned at some point in time, and that the idea had become unfashionable.

Unmanned space exploration, on the other hand, remains fashionable, partly because it generates more-obvious benefits in the short term, but also because it tends to be more affordable.

But I honestly think that what is happening right now, given that an Earth-Sized Exoplanet has been found orbiting Proxima Centauri – the closest star to our own solar system – is that some, slow revival of the idea of manned space exploration is in the works. I think that even though somebody has just spent decades, effectively shutting down this concept, it is going to be reawakened. Beyond Mars, eventually People are going to want to travel to The Outer Solar System, and eventually to other stars.

It is one of the ways in which Human Nature is predictable, however disappointing it has been in the past.

Proxima Centauri has a known planet.

Dirk

Note: However far-flung the idea might seem according to Engineering Realities, it is actually plausible, that mankind might be able to reach Proxima one day. It will be more difficult than Mars, but still possible, especially since doing so does not actually require that anything travel faster than the speed of light.

But if this is to be taken seriously, it also provides fuel for the recent efforts, to develop something akin to ‘a tractor beam’. Travel at say, 1/2 the speed of light, risks becoming ‘a nuclear sandblasting exercise’, due to cosmic dust, unless something is done to sweep dust particles out of the path of a hypothetical spacecraft. And as it stands, we could design a spacecraft simply to possess a powerful laser pointing forward along its path. But what this would due to dust particles, at most, is to accelerate them down the path our craft would already be taking. So, an impact with a cosmic dust-particle might be delayed by one microsecond, before it emits gamma-rays, etc. Such an impact would have nuclear-range kinetic energies.

If any possibilities exist, to make that particle accelerate along a vector 90° away from the path of the spacecraft, it would be highly useful…

Further, the actual amount of time-dilation which would follow from traveling at 1/2 the speed of light, is 15.470054% (rounded up).