How Much Air Pollution Is Produced by Rockets? (2017)

With that said, I would be quite surprised if unspecific metal debris/dust is going to have any major effects, except as it already is as a threat to the functionality of satellites, space stations, and rockets.

The meteorite argument is quite strong, but not unassailable, as meteorites in general has a chemical composition that is quite different from space hardware.

Not that we use a lot of Antimony in rockets, but it works as en example. If I interpreted the numbers correctly, we can put an upper limit on the contribution of atmospheric Antimony from 78000 tons of meteorites at ~16 kg, or roughly 35 lbs.

Thus, it's not entirely impossible that some of the space hardware over it's life, and death, can contribute more of certain unusual elements to the atmosphere than meteorites do in the same period.

Organic molecules however, those are a bit more concerning, as we already know that some species can greatly affect our atmosphere!

Rocket launches presently have a small effect on total stratospheric ozone (much less than 0.1%). Space industry developments indicate that rocket emissions may increase more significantly than reported in the previous Assessment. Their impacts will depend on rocket design (particularly the altitude of emissions), launch vehicle sizes, launch rates, spaceport locations, and fuel types. Important gaps remain in understanding rocket emissions and their combined chemical, radiative, and dynamical impacts on the global stratosphere and in projections of launch rates. These gaps limit the confidence level of predictions of present and future impacts of rocket emissions on stratospheric ozone and suggest periodic assessments are warranted. The lifetime of the most important rocket emissions is limited, and the stratospheric accumulation of rocket-emitted black carbon and alumina particles varies in correspondence with global launch rates and altitude of emissions.

If we do ramp up to that kind of tempo, economics will spur on efficiency advances. Nipping progress in the bud now because it might be a problem some undefined period of time down the line is cowardly and depressing.

This way we can protect our species from getting wiped out with our single habitat, as well as likely solving all our resource and energy issues with the wastly bigger resources of space compared to what we would have available if we never leave the planet.

There's also that point where the sun will become a red giant or something and Earth will physically be unable to support life, but there's at least 600 million years before that one becomes an issue, and I'm sure something would have figured out space travel before then.

It's like running a large website and using multiple servers/cloud hosting/multiple datacentres. Or hosting your site, domain and email at different providers. Makes it far less likely the whole system will collapse at once.

There are local solutions for global warming, it's simply to consume less, people in developed countries could consume roughly 20x less, which is already more than enough (I can relate), and apply a sort of birth-control globally

Space travel sounds like the apogee of consumerism, it's possible to live differently, durably on this planet

But it doesn't have to mean we put a full stop on all space activity. But rather that we research what the effects are, and take measures to reduce those effects to the extent they can be done at reasonable cost. Say, if alumina and chlorine compounds from solid rocket boosters are bad, maybe we should use liquid fueled rockets. If soot from RP-1 is a problem, maybe think about switching to, say, methane.

"I think there is a world market for maybe five computers."

Thomas Watson, president of IBM, 1943

Rockets to Earth orbit are the bootstrap stage, like electro-mechanical relays are to transistors. We will have orders-of-magnitude more efficient methods, and they will bring humanity to space and its treasures to us, without dumping chemicals into the air.