Submitted by gbbloom t3_zwovmn in Futurology
gbbloom OP t1_j1w1an5 wrote
Reply to comment by csbingel in Why don't we plan for more "staging" at orbital platforms? by gbbloom
It's ridiculously expensive to get off of Earth, no doubt. My thought on b) is that, the more we can send up at one time vs wasting space, don't we go for it? Obviously, the eventual hope would be to find the ability to mine and manufacture outside of Earth... but that's likely decades away (assuming it's even realistic) right? No sci-fi situations any time soon, sadly. :(
csbingel t1_j1w5w53 wrote
Again, not an expert, but volume isn’t the issue, mass is. Every gram costs fuel and infrastructure to launch. That was the benefit of SpaceX’s Falcon platform, and it’s reusable launch stages. But even with that, still beyond most non-government scale budgets to consider.
mortuus_est_iterum t1_j1w6xzk wrote
This is the answer.
But tbh I would also like to see a much larger ISS in a higher orbit.
Morty
gbbloom OP t1_j1wc8f0 wrote
Morty can we dig into why the higher orbit? That one intrigues me... is it to make it even easier to escape Earth's pull if you push off from there? Is there any reasonable way to a) expand the ISS and b) move it further out than it's current orbit?
ADSWNJ t1_j1won62 wrote
There's a couple of different issues with the ISS. one - it's at an altitude that needs regular boosting or else it would reenter. Not a big deal, but annoying that you need to add thrust to keep it at a low orbit, versus putting it out to say 1500km or 2000km alt and it could stay for centuries with no boosting. Second... the inclination of the ISS is not ideal to launch to the moon or the planets due to the plane change needed. It would be much better if the orbital apogee (highest point) were on a nodal point with the planets, and as high as possible, to minimize the Delta-V to exit the base on the right plane and trajectory.
Ruadhan2300 t1_j1wok7a wrote
The ISS is absolutely intended to be expandable, and moving it to a higher orbit is done routinely.
Basically the reason to put a bigger station in a higher orbit is to reduce the effects of atmospheric drag.
The ISS loses kilometers of altitude over a matter of months and has to be boosted regularly to compensate. A bigger station would have an even worse time of that. So putting it in a higher orbit would be worthwhile for that reason.
The ease of escaping earth's hill-sphere is a perk, but the reality is that half the work is achieving orbit. Once you're in LEO, you're halfway to anywhere. Higher or low orbit isn't a big difference compared to getting up there.
mortuus_est_iterum t1_j1ziuel wrote
The ISS orbit is low enough to be affected by atmospheric drag (which slows it down so the orbit gets lower still, increasing the drag, etc.) and it needs fairly regular boosts to keep it orbiting. There is also a truly amazing amount of junk in LEO which poses a constant threat of collision damage to the ISS. If they detect a possible collision, the ISS can be maneuvered a bit to avoid it. And yet after all the effort to keep everything safe, the current Soyuz escape capsule was damaged by a meteor collision to the cooling system.
My desire for a much higher orbit is an attempt to minimize all of those factors because I still hope the ISS can become the research center it was touted to be.
Morty
Michamus t1_j1wdd1d wrote
The rocketry equation includes cargo mass as well. If you increase the cargo of an LEO spacecraft by 100kgs, you're going to need more fuel to lift it.
The best method is to get a factory onto the Moon and then start manufacturing stuff there. All we'd need from that point is to ferry people and supplies for the journey back and forth. As you suspect, leaving the lunar surface requires a small fraction of the energy for leaving Earth. There's sufficient material, including water and oxygen, for lunar colonies to be self-sustainable and generate new craft for industrializing the solar system.
There's an old joke that basically goes: "Once you're in LEO, you're halfway to the rest of the solar system."
UniversalMomentum t1_j1x2po4 wrote
Honestly, there isn’t a big need to mine space because humans only live on a tiny fraction of the planet, called the crust, and that crossed only makes up for about one percent of the mass of the planet.
Humans haven’t even touched 99% of the resources here on earth so you know really space mining is like a fun exercise for imagination but not really useful unless you find amazingly rare minerals, that we somehow really need for something and can’t synthesize on earth, which, I doubt, because, more or less, whatever we find in space, will be able to synthesize on earth for less money than the cost of mine.
When a planet forms, you know the bulk of those interesting heavy materials are in the center of the planet so that’s still where most of earths minerals are and the crust we’ve been mining is just a tiny tiny sample of the real content.
Go look at a picture of the planet and book Halfin the crust really is compared to the mantle in the core and you’ll get an idea about much untapped resources. There are on earth and will remain here on earth for a long time and probably be more accessible than any type of space mining.
At the end of the day, though many people may not like it it’s still kind of hard to find good reasons to establish significant industry or colonies in space when humans are so highly evolved for earth, like conditions and earth has so much more accessible resources than anywhere else in the solar system for humans.
It’s kind of like earth is the jam of the solar system, and there isn’t much more high value targets out there around here. It would’ve been wonderful if Mars was a more earth like an habitable planet, and all we really had to do was get to it and humans could thrive, but it’s a lot more like a giant death trap than an opportunity.
The biggest real opportunities for going to the moon and mars is basically just to look at the rocks and expand our scientific understanding of solar system formation because the mars and the moon don’t have tectonic plates so much weather so the geology there has been preserved for billions of years unlike here on earth, and those are like the best records of the solar system formation, and that’s really the bulk of the value not colonizing super hostile locations and I know that’s not what everybody wants to hear but it’s kind of the same problem that we had in the 60s.
divepilot t1_j1x9jx1 wrote
I think we do need a physical frontier to push, though. We always had one and we could send the crazies there to mellow out.
StupidOrangeDragon t1_j1xat09 wrote
There is an interview with one of the project leaders on the James Webb Space Telescope which touches on this topic. He mentions that he hopes that the next space telescope is manufactured/assembled at least in part in space, the reason he gives are
- The difficulty and complexity of testing the equipment on earth so that we can ensure it works in space.
- The limitations on volume of the launch vehicle can impact the size of the final telescope, and in the case of JWST the complex heat shield unfolding and the systems to support that
Now as to why we don't already do this ?
- It will take us quite some time to build this capability, there is a lot of equipment and infra we would need to get into space to do something like this, and getting things into space is ridiculously costly.
- It will take us quite some time to learn how to do it efficiently and safely in a low gravity environment. Space just makes every step of assembly and manufacturing extremely complicated. Especially if the assembly is done outside in space walk. There is a Joe Rogan podcast with a former astronaut Garrett Reisman where they talk about how complicated space walks are. (link)
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