Why the Moon is Better Than Mars

When the world gets you down, it's nice to be able to look up at the Moon hanging serenely above you... and think about how the dozens of people who live there have made you feel wonder again. They've made you feel differently about what is possible in life. They have reawakened in you the feeling that dreams matter. And they are right there, you almost feel like you can see them. In fact, in another day or two the Moonstar will be aligned again and you will be able to see them, at least see the beacon they built as a symbol of hope. It makes you feel that even though the Great Barrier Reef is dead, crop failure has shot upwards, and last year Shanghai was hammered by the biggest cyclone ever seen, that people just have to pull together and anything is possible. It makes you believe humanity can find the will to reverse climate change before true catastrophe strikes, and you resolve again to do what you can.

That's why we have to colonize the Moon. Only the more exuberant, fidgety engineers think Mars is a better place to put humanity's first space colonists. I say that with affection, but it's true. Their calculations zoom in on a handful of convenient features that make the technical challenges of establishing a human outpost on Mars much easier - once you are there, and assuming everything goes smoothly. What they don't consider is the only thing that matters about our very first off-world colony: how inspiring it is to the people of Earth. It's value will be determined by that alone. And not just its ineffable value as a source of wonder and new attitudes, its cash value. People will pay for inspiration.

Some of you will be brushing this off because you think settling the Moon is too hard - it has no water, it has no carbon, nitrogen, or phosphorus. Shipping that stuff would be so expensive it scuttles the whole thing, right? Well, hang on now. First, recent mapping of the Moon shows that there is water ice in certain craters near the poles. There may be hundreds of millions of metric tons of it, in fact. And if there is, there are also similar quantities of nitrogen and carbon chemicals in the same shadowy depths that never see sunlight. That would be a mighty precious reserve, the frosty seeds of an entire ecosystem. But it is also possible that the tantalizing glimpses that hint at that are too rosy, and there are only smidges in those depths. Time will tell. Anyways, that stuff is only needed once people are there. Send robots first and get them to build most of the infrastructure needed. Robots on the Moon can be operated from Earth, they don't have to be smart.

While your robots slave away, one of several technologies may mature that vastly reduce the cost of shipping supplies to the Moon. Planetary Resources may succeed in learning how to capture and redirect small asteroids, in which case they could take one made mostly of water ice and carbon, put it into orbit around the Moon, and start spitting chunks of it down to the lunar surface. SpaceX is working away on its reusable rocket, and major new sources of business are needed so they can really make use of it. Shipping bulk chemicals to the Moon is perfect, it isn't like mission failure would result in the loss of anything valuable (besides the rocket). That wouldn't deliver as much material as a hijacked asteroid, but it could be an order of magnitude more than can be shipped with current technology for the same price. The Skylon space plane might complete development successfully and be another reusable vehicle that could be used to get cargo to orbit. Once you are in orbit, as far as the fuel you need you are already more than half way to the moon. And that's just scratching the surface. The thing is, the larger the space industry gets, the more space there is for far-out ideas to take off (as it were). If there is enough money on the table, someone will build a space cannon, or a laser-assisted launch system. Then the cost of getting to space crashes, the magic moment every space nerd has been waiting for. But you have to give people a place they really want to go - lots of people, to do lots of things, for lots of time.

We'll get into all that once we've established why the Moon kicks butt as a starter kit for a space-faring civilization. The difference between it and Mars is roughly equivalent to the difference between looking up like the person above at the Moon, or at Mars. Can you even find Mars in the night sky? If you want your kid's eyes to light up when you mention space, you want a Moon colony. Mars can come later.



Mount Sharp on Mars, taken by the Curiosity rover
Hey, okay photo. Where was it taken, southern Libya?
Earthrise, 1967, Apollo 8
Wow. That never gets old.

See that thing in the sky there, in the Moon photo? That thing makes a huge difference. There's the communication time, the transport time, and all that they imply, which we will discuss in the sections that follow. First, let us consider the sheer sight of it. Isn't it beautiful? Couldn't you gaze at it for hours, slowly spinning, constantly changing? Good. Because on the Moon you sure are going to have plenty of chance to do that, and after a while you will be extremely thankful you can.

We won't sugar coat this. The Moon and Mars are dead planets. You won't be able to step outside on either one without a clumsy, bulky spacesuit on. While outside you won't be able to scratch your nose but you will be able to thoroughly test the conjecture that people can't smell their own farts. Inside quarters will be cramped, the air stale, the food so-so. There will be nowhere to go, except outside for brief periods. The haunting beauty of the barren landscape will soon be overwhelmed in your mind by the urge to run barefoot through flowering fields, possibly giggling like a maniac.

But on the Moon, at least you will always be able to gaze lovingly at your home planet, 15 times the size of the Moon as seen from Earth and 50 times as bright. Because the Moon is in a tidally locked orbit around the Earth, on the Moon's near side the Earth is always in the sky. Cool, huh? It would always be there for you. At any time you can look at it, to remind yourself that you are there ultimately for the sake of the people on that blue orb. And that after work you can call your bro and have a long talk. And that in a year you get to have a nice long visit. And that if it was necessary, at any time you could leave and be back there in just three days.

Nothing in that last paragraph is possible on Mars. Yeah, the Martian day is the length of ours, big deal. Some people feel that Mars will have a comforting familiarity because of that, and its atmosphere. Really? It has a wan yellow light that makes the sky sort of tan, like permanent smog. The atmosphere is one percent the density of Earth's and is composed almost entirely of carbon dioxide. There is a certain amount of weather on Mars because of it, but nothing very homey. In some seasons there will be delicate, wispy clouds high up, but no kind of precipitation. There will always be plenty of wind because of the extreme temperature changes between day and night, but the air is so thin it never feels strong. You can enjoy the sight of slow, tenuous dust devils and how sands gently shift over the months. You may be less enthusiastic about the dust storms. Sometimes they cover the entire planet. Sometimes they last for a month. They aren't very dramatic, though. The dust just kind of toodles around and takes forever to settle. Mars will feel thoroughly alien always and during dust storms will be just grim.

Earth and the Moon as seen from Mars, photo by Curiosity rover, Jan. 31, 2014

Aren't those tiny dots beautiful?

On the Moon the sky is always black and full of stars. The glare of the sun on the lunar regolith (which is the soil) is stark and very bright. For two weeks the sun beats down as the shadows inch around from sunrise to sunset, then for two weeks the landscape is bathed only in Earthshine. There is no weather, everything has a very eternal feel. Okay, perhaps more alien-feeling than Mars, but is that really going to matter? In either place, the important thing is going to be to construct gigantic greenhouses people can relax in, and thus move as quickly as possible towards creating a tiny biosphere reassuringly full of life. Once that is done the feel in those spots will be roughly equally Earth-like on either planet. While that gets done, i'd rather gaze at the Earth always floating above than watch dust-devils twirl by.



Radio waves take a bit over a second to go from Earth to the Moon. Talking with someone there from here would thus be a lot like a trans-Atlantic phone call used to be back in the day of copper cables and giant switchboards, except with video. It's awkward but manageable. If you do it regularly it can be quite helpful to agree to indicate when you are finished speaking, like by saying 'over to you' the way ham radio operators do when sending over long distances. As a matter of fact, radio enthusiasts regularly bounce signals off the Moon to reach people on the other side of the world. A Moon base equipped only with the kind of antenna that used to be on every house with a tv before cable came along could communicate with any ham radio set on Earth.

But of course their actual communications setup will pack power way beyond that. One sensible thing would be to have a bunch of live streams going all the time. In the early days that would mostly be so operators on Earth can properly direct semi-automated construction machinery. Later it would be so people on Earth can have all kinds of interaction with the Moon base. They could watch construction progress, watch the first greenhouses turn green. Later still an entire entertainment and education industry would take hold. Even early on a well-designed reality tv show and conference events for paying audiences are simple options. Once the Moon base is really growing, all kinds of shows are possible. Sports events on the Moon. Mountain climbing and spelunking on the Moon. Giant destroyer robot competitions on the Moon, with a level of gratuitous explosions and firepower an Earth-based battle robot event can't dream of. Moon ballet. I'd pay to see a broadcast of any one of those things. And all of them would as a by-product convince me that space exploration is awesome.

Note that these things can be broadcast live. There would be a delay of about 1.3 seconds due to the the distance the signal has to cover. Did you pay to attend a panel discussion with members of the Moon team? You can ask them a question live. Are you a paying member of the Moon Garden Club? You can remotely tend your very own plants in the club's designated greenhouse from your home on Earth - prune the avocado sapling, take cuttings from the bamboo, harvest the strawberries. Is the UFC broadcasting a live event from their Dodecahedron on the Moon? Go watch it at the stadium hosting the simulcast and know the fighters can hear you cheer or boo as the fight goes on (with a 3 second delay).

Needless to say, none of this is possible with a Mars colony. At best, one-way transmission time between Earth and Mars is 3 minutes, when the planets are closest together, once every 2 years. When they are farthest apart, it is 20 minutes. There are even times when the sun is between Mars and Earth, and then communication is impossible for days and very difficult for weeks. Dedicated transmission satellites in highly eccentric orbits around Mars will be needed to solve that problem. Then there is the issue of signal strength and bandwidth. At its farthest, Mars is a thousand times farther from Earth than the Moon is. Signal strength declines with the square of the distance, so to send a signal from Mars always as strong as an equivalent signal from the Moon, you need a million times more power. This is really the limiting factor for bandwidth, so a million times more power needed means similar technology can send only a millionth of the data from Mars that it can send from the Moon. No ham radio operators are going to talk to Mars.

So if you plan to move to Mars, pack a big media library because media sent from Earth is going to be highly limited, plan to be out of contact with loved ones for weeks at a time, and know that when you can call someone back home, it is going to be more like sending recorded messages back and forth than talking. Or move to the Moon, and be almost as connected as you are on Earth, just 3 seconds slower - so i'd advise against trying a Call of Duty game with opponents back home.