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Comment by imglorp | Hacker News Reader

On the other hand, solving these challenges presents many rewards in space. It seems like a chemistry gift from the universe, if you can transmute between one of the highest energy density fuels to water, electricity, air, and radiation shielding. And water is laying on the ground on many bodies in the solar system.

One final gift is you can quit burning hydrocarbons to get to space, if you can figure out how to do this sustainably.

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It's all about trade-offs. It may be worth the trouble for space craft, and that may open up aircraft applications, or we may have hydro-something in airplanes instead of hydro-carbons - Ammonia (hydrogen+nitrogen), Magnesium Hydride, etc.

> or we may have hydro-something in airplanes instead of hydro-carbons - Ammonia (hydrogen+nitrogen)

Nitrogen in many forms (including ammonia) is bad news for natural ecosystems.

https://news.mongabay.com/2021/09/nitrogen-the-environmental...

So is gasoline, but our main problem with gasoline is the carbon dioxide that is created when you burn it.

The products of ammonia hydrolysis (or any other chemical reaction that releases energy) are N2 (same as atmospheric nitrogen) and water.

Yes, if we leak ammonia, that is very very bad. Ammonia is also an immediate, serious, and acute irritant. Any significant ammonia leak is dangerous to human health.

Using ammonia as fuel doesn't "just" release n2, it also release a lot of nitrogen oxides, which are significantly more powerful greenhouse gases than CO2, contribute to the formation of smog and acid rain, and destroy tropospheric ozone.

https://en.wikipedia.org/wiki/Diesel_exhaust_fluid

There are problems with every idea. I was not suggesting that we should just burn ammonia. Even if I was, there is no way I was outlining a whole solution in a short internet comment.

Why would you want to quit burning hydrocarbons? The combustion product of hydrogen is water vapor, which is a much more potent greenhouse gas than carbon dioxide.

This is confused: water vapor is indeed a fairly potent greenhouse gas, but it remains in the atmosphere for only a short time. Adding water vapor to the atmosphere, even in large quantities, does not result in any non-rounding-error impact on climate.

See https://climateer.substack.com/i/60052576/you-thought-the-ma... for a slightly longer explanation.

can you elaborate on this? wouldn't the albedo effect eventually block more energy from entering than from leaving?

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