>Doing anything ambitious in space would require a lot of material, which has limited our ambitions since the 1970s.

We go to the moon because materials are cheap because... we want to build what?

Factories in Orbit, pretty much. There might not be many products today which will benefit from this ability, but a free fall environment brings many benefits to things such as crystallization of materials.

For example, the last resupply mission of Space X to the ISS included an experiment to product optical fibers onboard the space station, the goal is that these fibers will have a much lower number of defects in their crystalline structure then their earth produced counterparts, this means less refraction, which results in less signal loss over a longer distance which reduces the number of repeaters which reduces increases the overall signal speed.

Now, of course if you wanted to deploy these things on a world wide scale you'll need to set up a bigger shop then the ISS - which most likely will go out of service within the next decade anyway...

And while the moon does not provide a free fall environment such as LEO, the gravitational influence is still much lower than on earth itself and scaling up on a surface will most likely prove easier in the long term than doing so in orbit around the earth.

Getting to Moon orbit from the Moon is also much easier that getting in LEO.

An industry in space.

To send larger probes around the Sol system. To build larger orbital laboratories, LEO or otherwise. To build all supporting infrastructure for that. To manufacture things that benefit from microgravity conditions (like optical fibers, see [0]) to be used both on Earth and elsewhere. To enable large-scale Mars missions, including eventual habitation. To eventually access more raw resources than we've ever imagined.

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[0] - http://madeinspace.us/mis-fiber/

If the benefit of manufacturing optical fibre cables in a low gravity environment was so great, would it be more economically viable to build a 'low gravity' factory on earth?

How would one produce low gravity on earth?

Two methods: the vomit comet [1], and shot towers [2].

1. https://en.wikipedia.org/wiki/Reduced-gravity_aircraft

2. https://en.wikipedia.org/wiki/Shot_tower

You want to put a delicate-cable factory on an airplane and figure out how to shape all materials from start to finish in 30-second bursts while also compensating for turbulence, additional Gs on ascend, flight adjustments, and proper stowing for takeoff and landing? ...

Oddly, that's the more practical of those suggestions, because forming a few kilometers of perfect glass by letting it cool while dropping would seem to require a tower impressive in its own right... More relevant, there are QA demands with fiber-optics that don't seem to jive with a "let it hit the ground and throw out the lumpy ones" approach, much less the handling while in full gravity (which is where the issues are).

Go to its center?

Much, much harder than going to the moon.

That's like going back to the 17th century and decrying the exploration of the New World because you're not certain just how much gold there may be and you can't predict what the New World economy might look like.

Barring drastic efficiency increases in launch technology (to a Star Wars style level of ease) a lunar base is essential to enabling a space economy not suffocated by heavy shipping and transaction costs incurred by the cost of fuel and launches. When the cost of shipping materials around in space isn't drastically more expensive than Amazon sending you a package, then you'll find out exactly what we want to build.

Except that back then they couldn't see what was in the new world. Now we can (on the moon), and know that there isn't much.

Also, it would take a lot more than just sending people there for them to be mostly be self sufficient like in the 17th century, because: - there is no oxygen, - there is no food, - there is no water, - there is no magnetosphere.

We can make [oxygen from moon rocks](https://phys.org/news/2009-08-scientists-oxygen-moon.html).

There is [water on the moon](https://www.nasa.gov/mission_pages/Mini-RF/multimedia/featur...).

With oxygen, water, and power, we can make food.

Appropriate radiation shielding is a matter of construction, which could occur on the moon itself using local materials ideally, or building underground enough to be shielded.

Moon habitation is something that makes little sense for its own benefit, but immense sense in an orbital supply chain for... I dunno... harvesting a few trillion dollars worth of minerals.

Space exploration will not be easy. Navigating accurately across thousands of miles of ocean on [a homemade raft](https://en.wikipedia.org/wiki/Polynesian_navigation) with only a coconut named Wilson and your hands isn't easy either :)

> With oxygen, water, and power, we can make food.

And carbon, nitrogen, phosphorous, potassium...

The lunar surface seems to have these elements in short supply, though C-type asteroids can provide many of them.

We are going to need a POC for that. Here's a rock, there's ice in Alaska; go survive. Oh, and you have to do it with mittens on.

Good luck!

Show me the infinity He-3 and Mega-Billions in platinum I can make in an exclusive environment mankind is obligated to conquer on the timeline of a few short hundred years and I will show you some Multi-Billionaires willing to invest heavily as soon as the intersection of orbital access and autonomous robotics is potent enough to mine the crap our of that, and any other, 'Alaska'... Some imagine it will be many decades [never done those before!], until it's cost viable and some imagine 2020 or 2025 [0].

And I think my vision, and Elon Musks, has something more like autonomous driven lunar vehicles powered by machine learning and mesh networks for robust exploration. Like... 15 Teslas talking over wifi but with no traffic, no time limits, no pedestrians, no speed limits or laws against having jump rockets...

I totally agree we have to build PoCs, and test new equipment, and do science, and do engineering. But most of the "hard parts" WRT to survival have been done on earth [for a poor ROI on earth!], and the really hard parts WRT time differentials and manufacturing look very much like self driving cars and robots made for the moon or mars. Teslas and Foxconn, friend. Europa is just... what we do every day in Subsea exploration + what we do every day with our _amazing_ rover program.

I'm not saying we're there tomorrow. I'm saying that if our robots are there next week making oxygen generators and water pumps and harvesting and collecting, with steady resupplies of better robots and smarter factories, we could Kerbal ourselves f-ing far. H2O is rocket fuel - pure delta-v. Independent mining robots could extract the raw ore for our Expanse/BSG-ish space fleets over the next hundred years, and your grandkids could figure out how to spend an asteroids belt worth of mineral fortune :)

There are many Billions being spent on this pursuit today, in 2018. Cynicism aside, sometimes the VCs know a thing or two...

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[0] - https://www.inverse.com/article/33556-asteroid-mining-multi-...

Yes, yes, we can do all that stuff. But why would we? What justifies the expense?

>That's like going back to the 17th century and decrying the exploration of the New World because you're not certain just how much gold there may be and you can't predict what the New World economy might look like.

No it isn't. Exploration of the new world offered obvious substantive benefits - the trees alone were priceless to a countries that had to manage forests very carefully, not to mention new and useful crops coupled with an abundance of land. In short, it was a no-brainer.

And it was extremely cheap compared to building space infrastructure, since food could be grown or purchased from the natives, there was air, sunburn was the only radiation problem.

In space we'll have none of that. There are unsettled regions on earth far more hospitable to human life than anything we'll find outside our gravity well. The idea we ought to sink trillions of dollars into and infrastructure to produce things that are already good enough is hard to justify.

A giant radio telescope on the 'dark side' of the moon to let us peer into the depths of time without interference from the noisy monkeys in unit 3a ;)

Ships, structures, and anything heavy that we could avoid pulling out of earths gravity well would be big cost savers if we're putting around the solar system or putting up shop anywhere.

There are also some high-energy applications that could get dicey on earth but wouldn't be too bad to setup on a neighboring geographic area with no atmosphere or food chain to worry about.

Oxygen generators, habitats, water refiners, nuclear reactors... Ideally from autonomous building robots, these would be the foundation of long term habitation.

I'm not sure what the delta-V is like to get materials from an asteroid vs the Moon, but I'd expect there is much more variety of resources on asteroids. I think an orbital station is also more attractive than the Moon from a delta-V standpoint.

> but I'd expect there is much more variety of resources on asteroids

As far as I understand, in terms of easy access, yes - in particular resources that on planemos tended to sink to the core as the object formed and cooled down.

> I think an orbital station is also more attractive than the Moon from a delta-V standpoint.

LEO? Not necessarily. You still need to burn your way up the pretty steep gravity well.

Both the Moon and the asteroids are vital components of expansion into the Solar System; they're interesting in different ways.

Interesting, I didn't realize Earth's gravity was still so strong at 500km up. Getting payloads to the station from space would still be cheaper because we could rely on aerobraking, but accelerating mass to Earth escape velocity from LEO would require an extra 1km/s of delta-V compared to the Moon. I think the Moon might make sense if we can mine significant materials from it, but I haven't read much about what's there.

Source: https://en.wikipedia.org/wiki/Delta-v_budget#/media/File:Del...

Yup, our well is steep :).

See also this subway-style ∆v map of our system (inspired by a similar map for Kerbal Space Program): http://i.imgur.com/AAGJvD1.png. I feel it would work great as a poster on a wall.

The map really brings home the point that "Low Earth Orbit is halfway to anywhere in the Solar System".

Neat pic (after I figured out I had to zoom in to see the destinations). It's just missing the route from the Moon to Earth Intercept(/Escape). I'd also love to see these maps include routes to the asteroid belt from the Earth/Moon/Mars.