>I just wonder if humanity’s adventurous nature is leading us away from a proper focus on the sustainability of our civilization, our specie, and our fragile planetary environment?
But we still need spaceflight at least for planetary defense against asteroids, mining asteroids(so we don't have to mine Earth), etc.
With chemical rockets, not much.
With "a propellant-less propulsion propulsion system such as solar sails or electric sails," bringing water (propellant) to low-earth orbit starts making sense [1], as does mining platinum, but only if "the quantity of platinum from space would substitute an equal quantity of terrestrial platinum," i.e. moving heavy industry off the Earth's surface [1].
Given asteroid-mining profitability is dominated by "the throughput rate, which depends on the mining process," it's possibly to see a path to certain rare-earth minerals becoming profitable to mine in space if environmental controls on Earth are tightened while constant-thrust propulsion technologies advance.
The energy involved in chemical rocketry is actually not that much. Getting a kilogram to LEO is roughly as expensive (in energy) as flying it to the other side of the world in an airliner. Getting stuff back from an earth-crossing asteroid can also be very cheap energetically, with very small delta-V (if one is willing to wait long enough).
Also, the materials we're talking about from asteroid mining, like platinum group elements, probably are shipped by air, just for security.
This whole argument is reminding me of the facile and bogus argument that launch to earth orbit from planet's surface is expensive because of the energy needed.
So far we have... "maybe platinum." Maybe!
Aside from the conspicuous absence of math, "maybe platinum" isn't remotely important enough a factor in earthbound mining to justify asteroid mining on the basis of preserving earth, obviously.
I don't need to argue things are practically mineable in space to rebut the point. I just need to argue if they aren't practically mineable, energy consumption isn't a reason.
I have already given you the counterargument.
> we have maybe platinum
Those making the energy argument need to rebut every possibility. The "it takes to much energy to ship back" is ludicrously wrong for platinum. The argument destroyed, why would we need to say more?
It takes as little as 0.1 km/s delta V to get onto an Earth-intersecting orbit from known NEOs. The energy of a mass moving at 100 m/s is 5x10^3 J/kg, or 1.4e-3 kWh. If a kWh costs $1 in space, this would be a fraction of a cent per kilogram. This delta-V is so small that the energy cost of sending back base metals would be affordable. Hell, the energy cost of shipping gravel from space would be affordable! Other costs, probably not, but that's not the claim we're addressing.
By moving mining off planet to the moon and asteroids we eliminate the carbon emissions and environmental damage that occurs from these processes.
So how do we do it? We don't need to start sending fleets and fleets of crafts into space which is energetically expensive and time consuming, what we need to do is develop self-replicating mining equipment that we can send to turn the things we want to mine into more things that can mine for us. We won't achieve full self-replication immediately but we can definitely send machines that can do partial self-replication at first and work on improving the ratio of material sent to material returned.
What do we send back? titanium, platinum, aluminum, nickel, iron, whatever we find there. If platinum was as cheap and plentiful as aluminum was now we would have all sorts of catalytic uses for it that would significantly clean up our Earth based industrial practices.
How do we send it back? If we're sending it back from the moon that's easy -- a space elevator or rail gun. If we're sending it back from asteroids inefficient but cheap iron ion thrusters. Use iron from the asteroids as fuel.
Bonus points: Send it back covered in ablative material like mined olivine that can react with CO2 in the atmosphere to sequester it, that way the whole process isn't just moving environmentally damaging industrial practices to other solar bodies but we're undoing some of the damage from past human activities.
We'll have to get very very creative with nickle-iron and silicates to build a small automata civilization on big flyby rocks.
Firstly we're now at a point where we have lots of cheap energy available, principally chemical. Depending on many factors it's conceivable that we are in fact at or near peak human energy output (e.g. WW3 or civilization collapse - the next iteration of civilization won't have so much cheap oil to exploit).
Secondly LEO is not yet full of junk, meaning that it's trivial to find launch windows to LEO and beyond. That could easily change very much for the worse in a relatively short time (I infer decades from the books).
Finally it's unrealistic to expect us to colonize the Moon or Mars using only Earth-mined materials. You can launch a spacecraft to Mars easily, but to launch a small city's amount of construction equipment and raw materials is beyond our capabilities.
Conclusion: now is the best time to mine asteroids. We can do all of the processing and much of the construction in LEO (or even better at Earth-Moon or Earth-Sun lagrange points) and then, with relatively low delta-v, we'd actually have a chance of becoming an interplanetary species!
But, the novels warn, the window of opportunity will eventually ("soon") close. Well worth the read.
Maybe someone else more familiar with the arguments, who has also read these novels, can offer a critique?
... but this won't happen unless it's economically advantageous, with all risk, transit, and upfront investment included
We already don't have the political will to force single-digit increases in cost of output to reduce environmental damage. Why would we then?
So far that's the best answer, so thanks for providing it.
You may also find in your scrolling that I did not say "it takes too much energy to ship back." I said "What resources are on asteroids that justify the energy expenditure to get from space and back?"
Obviously getting down is not the expensive part. We've all heard of gravity. Getting the equipment up that is needed to get stuff down is. This is also due to gravity.
I'm afraid you misread my first comment and responded as if I thought it was energy expensive to drop stuff onto earth.
Not too sure! Probably one part is to disabuse people of the notion that we have alternatives available if only we could just dedicate more brainpower to space travel.
The real answer is to eliminate the tradeoffs through scientific innovation. As mentioned elsewhere, the real way to protect earth (and our species) is to produce better plastics, proteins, and pesticides. Each smart person wrapped up in sci-fi fantasies of simply off-planeting heavy industry is another brain dedicated to -- as far as I can tell (thus my questioning here) -- an almost completely useless endeavor.
Which is why I believe the aforementioned disabusal is critically important. There's just no evidence that big explosions and adventures are what we need. We need people in labs nudging molecules over and over with a 0.0001% success rate.
Nuclear fission is more stable, less maintenance, less risky, less upfront and ongoing environmental damage, less vulnerable to all sorts of risks, and produces way way more energy.
> We find the SBSP designs are more expensive than terrestrial alternatives and may have lifecycle costs per unit of electricity that are 12-80 times higher
https://www.nasa.gov/wp-content/uploads/2024/01/otps-sbsp-re...
> This study assessed lifecycle cost and emissions based on the following scenario: SBSP systems are developed on the ground in the 2030s and launched to low-Earth orbit (LEO), and then transferred to and assembled in geostationary orbit (GEO) in the 2040s.
Furthermore, one main benefit of SBSP over nuclear is that the receivers don't need to be connected to the grid; each household or piece of infrastructure can have one. This would help manage situations like the power outage in Spain earlier this year or the situation at the start of KSR's Ministry for the Future where a deadly heatwave in India is made 10x worse by coinciding power outages.
In any case, a nearby planet or its orbit would seem to be the most logical place to start for any supervillain species seeking to colonize its galaxy. :-)
> This would help manage situations like...
Aren't these situations trivially solvable with batteries if there were political will to be prepared for them?