keepthepace

Unburned fuel is also an order of magnitude less in terms of volume than burned fuel. It is also something that’s solvable by better combustion and optimized engines.

Humans are ‘poisoned’ by these things in cities where they live close to thousands of vehicles that pass a few meters away. Inside sometimes a city where this gas accumulates.

And they are not poisoned per se. They lose years of life expectancy and they get preventable diseases. An animal population regulated by predation probably does not notice these differences in life expectancy.

Don’t get me wrong, that’s still a problem, but that’s not an ecological and climatic problem and something that can be addressed after we’ve finished our transition out of the fossil fuel.

I know these are bad for human health, but are they bad for the environment in these quantities and at this altitude?

Which pollution are you thinking of?

Synthetic fuels from direct air capture of CO2 are about 3X as efficient in terms of energy in -> energy in fuel

I have a very hard time believing it to be true, but I am always opened to an unexpected good news. Do you have a specific tech/source in mind for that claim?

By fuel, I was meaning electricity. Electricity is much cheaper than oil and I think will remain so.

That’s a whole different debate. I tend to agree that they are less ideal, that their proponents say, but they are actually renewable. They don’t add durably CO2 in the atmosphere from fossil sources. It is a very different thing. The CO2 they emit is part of a cycle. Ideally, that’s also a type of emission that we cut, but it is possible to include them in a sustainable society.

Biofuel is a possibility too.

There are many ways in which planes can be different.

Smaller plane going shorter distance at a slower speed can also mean that there are more lines and lines avoiding big hubs. If a plane goes slower but closer to your destination, you may not mind!

The cost equation changes a lot if fuel is much cheaper.

Every percent gain in battery weight compounds insanely for commercial flight.

It is the same problem as with rocket fuel. You have to store the energy to carry the capacity to store the energy. And that’s even worse for batteries because at least the rocket gets lighter as it uses its fuel. Whereas a loaded battery is basically the same weight as a loaded one.

What do you mean by “shaded”?

And I think the idea is to have several satellites taking turns at illuminating a given target. Your diesel generator (actually nuclear power plants where I live) will have to turn on anyway without these additional sources, but they lower the need.

Until they reach the endgame of being able to produce continuous illumination all night long.

That sounds like the logical next step for the space industry. Intermittence is a big problem for PV installations, this partially solves it.