The Moon as Starport?

Laer Carroll · Aug 8, 2017

This week there's a conference in Monterey called Starship Congress 2017 whose purpose is to explore creating a launch site for interplanetary and interstellar travel on the Moon.

Speakers include Miguel Alcubierre, David Brin, and Alan Kay, as well as a host of space industry speakers. Alcubierre is known to most of us as the proposer of a faster than light drive and Brin as an SF writer. Kay is a pioneer in computer science and technology. The organizers are Icarus Interstellar - not a name I'd chosen for a spaceflight advocacy group!

For more info on the Congress and its organizers click the following link: http://www.icarusinterstellar.org/

Most SF stories I've read posit creating advanced spaceships in Earth orbit and launching from there. What do you think of the idea of the Moon as a launch pad for advanced space travel?

ManWithTheMetalArm · Aug 8, 2017

It'd be a pretty logical step. Getting off Earth is hard, like really hard. This is from NASA's website: : "At liftoff, an orbiter and External Tank carry 835,958 gallons of the principle liquid propellants: hydrogen, oxygen, hydrazine, monomethylhydrazine, and nitrogen tetroxide. The total weight is 1,607,185 pounds." https://www.nasa.gov/centers/kennedy/about/information/shuttle_faq.html#12 This is mostly due to our atmosphere being so dense, but the moon doesn't have one, so achieving liftoff from it would be far easier. In fact, with stations like these, whether in orbit or on a moon, there would be no need for incredibly large spacecraft to venture planetside, helping to cut down on the cost of space travel in general. Though that still leaves the question of getting the material needed into orbit, and unless we're mining asteroids, getting the material off earth will be just as time consuming, and possibly as expensive, as getting those large spacecraft into orbit in the first place. One problem solved, another takes its place. This is obviously one of those ideas that needs a long time to develop, and one that a future unknown tech will remedy, but, until then, we can only dream.

benbenberi · Aug 9, 2017

The Moon is a logical launchpad for us now, since it's close to earth but it doesn't have the heavy lift requirement to launch from. As ManWithTheMetalArm says, a lot of that advantage disappears if all the materials have to be lifted from earth to the moon in the first place, but it would allow construction of vehicles that don't have to be atmosphere-compatible.

As a starport for FTL vehicles, obviously it mostly depends on the technology & the context. But on an interstellar scale Moon = Earth, & they're both very deep in the solar gravity well.

Laer Carroll · Aug 10, 2017

A number of problems must be solved before a moon village or villages could be created. A paper by George Butiri discussed most of them and suggested solutions. A couple of his suggestions sounds unworkable. Within the village the "economic system [would be] based on a free for all concept" and "no system of control, no money, or rules."

He also didn't mention a couple of other problems surrounding this issue of money. Who would pay for creating and maintaining a Lunar village? What source of money could pay back the investors? To me these sound bigger and harder problems than any technical or scientific problems.

Curlz · Aug 10, 2017

Laer Carroll said:
Who would pay for creating and maintaining a Lunar village? What source of money could pay back the investors? To me these sound bigger and harder problems than any technical or scientific problems.

I don't think that obstacle is as large as it appears. Considering the amount of generosity around in general, and the amount of people interested in space in particular, it seems possible that such a project could be at least partially supported by volunteers and funds collected directly from the public. Joint space programs between different nations, too. :Thumbs:

Laer Carroll · Aug 11, 2017

One idea floated recently to increase public interest in Lunar activities was to allow anyone to tap into the vision stream arriving on Earth of the robots exploring the Moon and building things there. People could watch via VR goggles to give viewers the feeling of actually being there.

The robots could be remotely controlled from Earth, though they'd have to be fairly smart, because there's a minimum of about three seconds round-trip communication delay between the Moon and Earth. So the bots would have to be pretty smart, because if an operator put on the brakes of a transporter, or did anything else, that delay could cause an accident.

Still, telebots have the advantage that they don't need air or food or rest and there's no danger of human injury or death. My guess is that the first Lunar villages will be built solely by them and made safe and ready before any humans go to the Moon to live in a village.

People could also sign up to control some of the telebots. They'd have to screened to be sure they are responsible and able to drive the bots. Preference might be given to engineering interns at college, or tech-savvy high school students - future tax payers who might be willing to fund Lunar exploration and exploitation. Or contribute via crowdfunding.

Kjbartolotta · Aug 11, 2017

Did anyone read Luna: New Moon, BTW? Seems to be a long-running plan of the powers that be in the series. Which you should read.

First you get the He3. Then you get the starport. Then you get the women.

Laer Carroll · Aug 14, 2017

Kjbartolotta said:
First you get ... Then you get ... Then you get the women.

Erh. Women are ALREADY a part of the movement to create Lunar villages, and are some of the creators as well. I'm sure they will also be among the first inhabitants, not some luxury imported to pleasure the boys who would be The Brave Pioneers.

To change the subject, my interest is mainly in the engineering aspects, such as building the habitats. Writing about the process makes it seem likely be: land robots which will dig a big hole at a site, land a prefabbed habitat in the hole, put it together, then cover it with the dirt and rock dug up earlier. The bots would be programmed for the jobs, but controlled remotely from Earth when the bots meet situations their smarts don't cover.

The same bots might then be re-programmed to create air and air refreshers, lay out conduits for air, water, power, and communication, fill reservoirs with air and water, and plant grass and trees to help with enviro maintenance. All still with robots and material supplied from Earth.

Eventual expansion of the villages would depend heavily on 3D printers which'd use local materials. All before a single human sets foot inside a habitat.

Kjbartolotta · Aug 14, 2017

Sorry Lael, couldn't resist a Scarface joke.

I suppose once you're ready to upgrade to lunar cities, the first spots you'd pick out are the lava tubes peppering the surface. Pretty much what you've described, but on a larger scale, attempting to cap over the whole tube and giving you some pretty significant sealed environment. Before that, when you're at village status, I'd imagine the first stop would be Shackleton crater, where you have access to lunar ice and unlimited solar energy from the sun endlessly shining along the crater rim.

JimmyB27 · Aug 15, 2017

ManWithTheMetalArm said:
Though that still leaves the question of getting the material needed into orbit, and unless we're mining asteroids, getting the material off earth will be just as time consuming, and possibly as expensive, as getting those large spacecraft into orbit in the first place.

Space elevator.

Or, once we've sussed the Heisenberg compensators, transporters. :greenie

benbenberi · Aug 15, 2017

Space elevator would definitely be the way to move loads into orbit. Not as far as the moon, though. You'll need a transfer terminal & infrastructure of some sort at the top of the elevator.

JimmyB27 · Aug 15, 2017

benbenberi said:
Space elevator would definitely be the way to move loads into orbit. Not as far as the moon, though. You'll need a transfer terminal & infrastructure of some sort at the top of the elevator.

Sure. But that's still a heck of a lot cheaper and easier than getting a ship into orbit from the ground.

Laer Carroll · Aug 16, 2017

benbenberi said:
Space elevator would definitely be the way to move loads into orbit.

Good point. From the context I'm guessing you mean a Lunar space elevator.

A Lunar space elevator is a lot more doable than one on Earth. Material stresses on it are a lot less on it, so it's more technically feasible with current tech. It would be smaller, so easier to build. Fear of it falling would be much less because it would fall on uninhabited terrain (lunarain?!).

A prime location for the "top" of the elevator would be the Lagrange 1 spot. It would only take a little bit of energy to maintain a space station there to act as your transfer point for cargo going to and from the Moon. A solar sail might work as a maintainer, or ion rockets.

L1 people would need protection from radiation. A shell holding water (maybe mined from the moon) would do that. L1 people would also suffer from zero-g dystrophy, but maybe they could spend time on the Moon. Or, once the L1 station got big enough, it could have a rotating ring or the like to provide artygrav.

benbenberi · Aug 17, 2017

Laer Carroll said:
Good point. From the context I'm guessing you mean a Lunar space elevator.

No, I don't. (Though in a world where space elevators are built and a lunar base exists it's a logical thing to have.)

But you get a lot more bang for your space elevator buck building one from Earth to high orbit, because it's so much more expensive to lift loads out of Earth's gravity the old-fashioned way. Of course it's technically complicated, risky in failure, and requires materials and technology that are not currently available. We're not building any of this with current tech, though, so that's not a bar. I know there are people working on the problems now. I expect the economic and political problems around it will be more significant obstacles when the time comes.

blacbird · Aug 17, 2017

The moon may not have the gravity of the Earth (it's about 1/6 as I recall), BUT, to get a launch point there, you still need to get all the relevant stuff there from Earth.

caw

Thomas Vail · Aug 17, 2017

The reason that starports and bases and such are used is that once you've gotten stuff out of Earth's gravity well, it doesn't make a whole lot of sense to immediately throw it down another one. There's also the fact that in terms of getting stuff from Sol point A to elsewhere, that not being ground bound lets you put things in places where various orbital gravity interactions make it easier to get outbound. You don't need the same sheer energy boost to 'break orbit.'

ManWithTheMetalArm · Aug 17, 2017

Actually, I remember something from Gundam 00 that is actually a really cool concept of the whole space elevators thing. In total, there were three space elevators all connected to each other via a ring of humongous solar panels. Hell, half the show was based around the world's three nations fighting for control of these elevators. Still, it would require tech we don't have yet, especially in the case of space debris and potential collapse, but it was a really cool idea to help get stuff into space faster. Hell, ordinary citizens could just buy a ticket and ride a train into orbit! How cool is that!

Laer Carroll · Aug 21, 2017

A Moon-space elevator seems feasible now, but an Earth-space elevator pretty far away. One among many problems is the effect of atmosphere upon it. A hurricane or tornado would almost certainly destroy it. For that matter, a long hard rain or a series of thunderstorms might also do it in.

Another transportation solution which need burn little or no fuel is the magnetic catapult/catcher. The "catcher" part is just as important as the catapult. Basically just a reverse catapult, it might have a large opening used mostly to sense an incoming spaceship and use its fields further down to pull the vehicle into the center of the catcher tube and slow it down. The spacecraft might not even need rockets to make the final landing, though I'd guess most craft would have them for emergencies.

benbenberi · Aug 21, 2017

Building a lunar space elevator would be silly unless there is already an efficient means to lift heavy loads off Earth. Whatever technology does that, will also serve for the moon.

But I will repeat what I mentioned upthread -- the moon may have its uses for near-Earth activities, but I question its value as a starport. Too close to the sun, too close to the Earth, and it's got too much gravity of its own to be really useful as a transfer point unless the interstellar vessels for some reason need to park on the ground.

Laer Carroll · Aug 23, 2017

Agree with you, benbenberi, that we need "an efficient means to lift heavy loads off Earth." As someone once wrote (approximately) "In orbit you're already halfway to everywhere."

It's more poetic than factual, but to get even to the lowest orbits takes maybe 20,000 MPH of delta-v, and only another maybe 5,000 MPH to get to the Moon's L1 where gravity's pull of Earth and Moon are equal. (Vague recollection of actual figures.)

Now that Earth's satellites generate enough money to make them profitable a lot of resources are being spent to make their launch cheaper. So Space-X is making their launch vehicles reusable. Other companies are working on one-stage to orbit vehicles. Here's an example, described in a YouTube presentation and by Boeing, which has been granted money by DARPA to pursue studies of it.

https://www.youtube.com/watch?v=tEZDWoJdC7w
http://www.boeing.com/space/phantom-express/index.page

So it's not a stretch to think that someone might someday take an Earth-orbit space elevator seriously. Or a magnetic accelerator built atop Mt. Kilmanjaro or some such. (Maybe Africa will be the home of the first Earth starport!)

benbenberi · Aug 24, 2017

It's so not a stretch to think that someone might someday take an Earth-orbit space elevator seriously, that THEY ALREADY DO!

It won't be easy. Carbon nano-tubes were supposed to be the magic beans, but it seems they may not be after all.

Some of the other proposals and obstacles are summarized here.

The International Space Elevator Consortium is a first-line resource for all things space elevator-y

There is also some work being done by the Liftport Group toward a proposed lunar space elevator, as a less challenging proof-of-concept before anything Earth-based is tried.

Maybe Africa will be the home of the first Earth starport!

That would certainly make sense. A space elevator would have to be on the equator, & it's probably the optimal position for any alternative launch method too. Africa has a strong advantage there, if you're looking to site the spaceport on land.

Laer Carroll · Aug 24, 2017

benbenberi said:
A space elevator would have to be on the equator, & it's probably the optimal position for any alternative launch method too.

I Googled "mountains equator" and found lots of mountains are on or near the equator. I suspect China would prefer Indonesia, Europe mid-Africa, and the US South America. In fact, the highest mountain is in Ecuador, according to Science Alert.

https://www.sciencealert.com/mount-everest-isn-t-really-the-tallest-mountain

My personal preference for a launch method is a magnetic catapult, for no reason at all. Except maybe for the image in When Worlds Collide of a spaceship launch.

frimble3 · Aug 24, 2017

Laer Carroll said:
A number of problems must be solved before a moon village or villages could be created. A paper by George Butiri discussed most of them and suggested solutions. A couple of his suggestions sounds unworkable. Within the village the "economic system [would be] based on a free for all concept" and "no system of control, no money, or rules."

He also didn't mention a couple of other problems surrounding this issue of money. Who would pay for creating and maintaining a Lunar village? What source of money could pay back the investors? To me these sound bigger and harder problems than any technical or scientific problems.

The sections on 'Economy' and 'Society' sound optimistic to the point of wondering if he knows many actual people. Assuming that a group of scientists and engineers are made up of individuals who are going to just see a job and leap to do it, day after day, seems somewhat naïve.
As is the 'want an apple, take and apple', 'want a chair, build a chair' notion. There are reasons there are specialists in various skills, it's more efficient, and makes for a better product. And, in the here-and-now, there are problems when one person takes the last 'whatever' and doesn't replace it or notify anyone - how much worse when there isn't an easy-to-get replacement.

GeoWriter · Aug 26, 2017

I think that it's difficult for us to know the best technologies for launching, or the best location to launch from, until we have a better understanding of what a permanent presence in space entails. I think that the Moon is the perfect place to gain that understanding. On the Moon we can learn what psychological and social challenges to permanent space presence need to be overcome, and we can learn to run mining and manufacturing operations that make transporting materials (except people) from Earth unnecessary. The Moon contains the entire periodic table of elements, and so has all the raw materials needed to produce anything that is needed (both fuel and materials). Due to it's low water, ore-forming processes were probably quite different from Earth, and therefore ore deposits of a different character, but they will still exist. Learning to find them, extract them, and use them in manufacturing, is the right 'next step' in space exploration--and a necessary step before we can really know what methods might be best for reaching the stars, or even best methods for regular travel to other bodies in our own solar system.

The Moon as Starport?

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practical experience, FTW

Aerospace engineer turned writer

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