State of Space-Based Solar Radiation Management [pdf]
static1.squarespace.com
static1.squarespace.com
If we get lunar mining up and running that opens up a world of space based resources at far cheaper than anything we could launch from earth. With a mass driver and solar power we could avoid the need for propellants for launch.
Once you have an economic reason to be up there getting there will become much cheaper. That will enable a new wave of scientific exploration.
A similar technology could shield Mars from solar radiation and reduce exposure at the surface (at least from the Sun). If we could make it into a lensing system, we could focus protons or Alpha particles from the Sun into a small region of the planetary disc and slowly re-add hydrogen back into the planet’s atmosphere.
We're on an engineering (among other things) forum, and it's surprising that technological solutions to the global climate problem aren't discussed enough. This statement illustrates another problem - "space" technologists assume that carbon cleaning would take "over a century", while some "carbon-cleaning" technologists assume space-related solutions will take too long. And in this thread there's also an opinion that, since we don't know much about global cooling, we should redouble our efforts elsewhere.
On the other hands, we seem to need all of that. We try political solutions, and they work - too bad so far, even though they do show some progress. We start talking about technological approaches - like, take a billionaire and a tech program, make an analysis (it's a sticky part) and then actually try to do something (aerosols? ocean seeding? pulverized minerals which react with CO2? space shadow? direct carbon capture from atmosphere?). We shouldn't tie our hands to the point of inaction, because inaction is also costly. And yes, we need more traditional approaches too - pressure on politicians, economical means of stick and carrot to get the intended results, green energy approaches - but in addition, not instead, since so far we're badly lagging.
Furthermore, direct air capture doesn’t appear to require anything else that isn’t abundant - and the absorption materials and catalysts can be recycled indefinitely.
I’m not sure I’ll live to see it but my belief is that in the latter half of the 21st century we’ll see direct air capture deployed on a truly astonishing scale.
A close approach seems to be taken by Terraform Industries - in a sense of scale. Just like Elon Musk repeats that SpaceX doesn't build rockets as much as it buildы a proper rocket industry, Casey Handmer at https://caseyhandmer.wordpress.com/2023/04/11/climate-tech-c... demonstrates good attention to scale. A BOTE calculations showed that if we have a billion m^3/s of air cleaned from CO2, we'd reduce CO2 in atmosphere twice as fast as we're adding CO2 there. A unit which handles 1 m3/s - given rather simple goal - doesn't look too expensive, and Earth already has a billion personal automobiles, so technically speaking we should be able to have some progress.
We need to pay enough attention to the urgency of the situation, the solutions should really scale.
We should, but we don't do enough of that. So let's put efforts where they bring results - even if they'd theoretically bring more results elsewhere, in practice they don't.
In reality we do try to prevent atmosphere pollution from happening, we just don't do enough of it. Some others of us, who're not involved in this process may have better chances with other, less efficient for now but still useful approaches.
However, we’re going to need to draw down CO2 over the course of this century regardless, and we can probably use stratospheric aerosol injection at a tiny fraction of the cost and for a decade or two if necessary during the process of drawdown.
As such, it doesn’t seem like this kind of space-based shelter is justifiable as a response to the warming we are currently dealing with.
Their plan is to make a lot of small devices rather than one large device. Just talking to the structure(s) is complex as there will be a huge noisy EM source right behind it.
My reasoning:
* people talk about going carbon neutral: great! But this isn't one problem, this is a thousand distinct problems. Our civilization is built on fossil fuels, and every manufacturing process, agricultural process, transportation process, etc, has to be re-invented to not be built on fossil fuels. Progress will never be as fast as we'd like on this front. We can and should push to get there (there is no good path but forward), but every new bit of news we hear out of Antarctica or Greenland should tell you that we need a longer runway.
* people talk about carbon sequestration: scaling up carbon sequestration is hard -- IMO, even with uncertainty, it feels a lot harder than blocking 1% of sunlight. There is a (semi)plausible technological path to the latter, at least. We will obviously have to keep exploring carbon sequestration in the hopes that a silver bullet emerges. But we can't count on nonexistent tech bailing us out. That's magical thinking, and one step above "thoughts and prayers". There has to be a plan in the mean time, and that plan needs to scale. We're probably going to need it.
* geoengineering with aerosols isn't just geo-engineering, it's essentially terraforming. That's a wing and a prayer, and at the scale we'd need to do it to have an impact we'd surely create some nasty unintentional consequences.
* Note: the above is an important risk calculation, because if you're ok with dumping a crapton of aerosols in the atmosphere -- as some people seem to be -- aren't we basically fine on climate already? Just do that indefinitely! Seems fine, right?
* if aerosol spam is not fine, your backup plan can only be something in space: you are here, at this pdf, at the solar sunshade. The sunshade has side effects, but they're much more palatable in my estimation -- the 1% of sunlight blocked will have the effect of making every day seem imperceptibly hazier (this was something I noticed during the 2017 solar eclipse at 50% of the sun being blocked -- seemed like a hazy day at that level of diminished sunlight. That was 50%. With the sunshade we're talking a 1% reduction to reduce the global temp by 2C.)
Anyway, just my 2c...