image via: Comic Website

I really love this cartoon. You can find it all over the internet, it was made by xkcd.com, a very good website for comics. It’s a very cartoonish way of depicting the solar system’s gravity wells, but it’s much more true than other things we usually see. When we hear about the solar system, usually we see this map with rings. Yeah it displays position, but in space position doesn’t really matter as much as other things. It’s not like you can walk or drive anywhere. Everything is different, and it’s very difficult to communicate many of the effects. Another example of a difficult to explain concept would be orbital stability. Orbital mechanics is a really boring subject, and the meaning of a lot of it is hard to communicate.

Gravity wells are a good way of estimating the energy required to get from one spot to another. Keep in mind that that there are tons of ways to bend the rules. For example, a space elevator could get one from earth to GEO, or from the moon to lunar orbit with relatively little energy. Another example would be orbital gravity assists that can expend more time to reduce the energy required to get from earth to mars. However, orbital assists cannot be used for launching from the ground… and again they add a lot of time to the travel. Truth be told, there is no way yet to break the rules yet, but there’s lots of corners!

Let’s start with our own neighborhood. First off notice that when on a planet you’re essentially at the bottom of a huge well. Something that’s not well communicated in the cartoon is that to get from earth to LEO takes a rocket composed of about 90% fuel and structure to hold said fuel. Simply to get out is a monumental task. This is also true of mars, but since it’s smaller than earth it takes a little less fuel, but still a lot. The whole reason space costs so much is the need to build these gigantic rockets just to get to LEO… and even bigger ones to get here Geostationary orbit.

Another thing to take note of is that the geostationary orbit is easier to get to from the moon than from the ground on earth. This is why people want to go back to the moon and set up permanent camp. It’s just being practical. Well, what if people were living on the moon. What would they do?

For the answer to that we’ve got to look at what the moon has, and doesn’t have.

HAS (MOON TRADES)
MASSIVE ENERGY RESERVES
MASSIVE MINERAL RESOURCES
CHEAP ACCESS TO SPACE
List not comprehensive

DOESN’T HAVE (EARTH TRADES)
AIR
WATER
FERTILIZER
LIFE (NITROGEN, CARBON, HYDROGEN)

So if men were living on, rotating to/from, or had some kind of presence on the moon, they would have to trade what they have for what they need. It’s pretty obvious that minerals, energy, and access to space are in high demand on earth. So the trade would be simple. The details are a little more interesting, I went over it a little in a video of mine. The benefits are monumentally huge, and in exchange a prospective Lunan would want things that are rather abundant on earth. Trade is what I’m talking about here!

The answer to the question, “Why don’t we have a moon base?” is rather simple. The 1967 Space Treaty forbids governments (but not individuals, and companies) from setting up shop in space, or claiming territory. Since space has been a realm exclusively of governments until fairly recently, it’s not hard to understand the press, and good will that efforts like the Google Lunar X-prize, Virgin Galactic, Bigelow Aerospace, and Elon Musk have received. It’s fairly clear that the first man/company on the moon will be a trillionaire trading valuables for dirt, air, and water.

Well that’s the moon. What about all those people who talk about the mars or asteroids?
Ah! Glad you asked.

Mars , and asteroids tend to hang out mainly in this area a little up the hill from earth, but they’re all over the place. There’s earth-crossers, trojans, the belt, and more… comets too! Here’s a sweet video that went viral recently on asteroids. They’re all over the place.

The best thing in the solar system is asteroids. I know that sounds strange, but they’re space candy. A great many of them contain enough minerals to shut down terrestrial mining for a long time. Trillions of dollars worth in all sorts of minerals, and it’s a basic fact… it’s not even challenged as basic knowledge. It makes some men drool. Imagine mountains of gold, silver, platinum, iridium, cadmium, iron, chrome, aluminum, and the list goes on. However, I’m not so sure landing millions of tons of ores from space is particularly a good idea. Maybe thousands of tons of precious metals, but even that’s a bit strange.

So NASA’s current scheme is to land a man on an asteroid. Probably an earth crossing asteroid. Truth be told it’s for political reasons. China is hell bent on a moon landing, as soon as they can. They see the value in the moon, they’re convinced. They don’t just want to go for the sake of planting a flag. They want to land there for the resources.

Anyways, back to asteroids. Why would men want to go there? What would men do with asteroids? For the answer to that we’ve got to look at what the asteroids have, and don’t have.

HAVE (ASTEROID TRADES)
EXTREMELY MASSIVE MINERAL RESOURCES
SOME VOLATILES [code for water, air, and fertilizer]

DOESN'T HAVE
GRAVITY WELL

I love asteroids, people would love to go mine them because they're chalked full of valuables. However, where are we going to send that asteroid mining ship from? Earth? The moon is much more capable of constructing and launching an asteroid mining ship than earth is... except there's nobody on the moon currently. So there's only the specter of some theoretical ghost... that could compete, oh wait am I playing the xenophobia card against China? Remember they want to go to the moon. They would be in specific violation of the 1967 space treaty if they set up camp, but I doubt they'd care about it.

For a long time we heard about a mission to mars. It's all you would hear NASA officials talking about in the press. Still today we hear of the plan 20 years from now to put a man on mars. Somehow average people just don't believe it, they've heard about the plan for 50+ years, and seen no efforts bear fruits. So they just tune it out and consider any laid plan to be a lie.

So let's talk about a mission to mars. Before I start I've got to say I want them to go to mars, but there's some subtlety to the rules of practicality that are in the way. First, we've got to launch from earth to LEO. This will consume at least 90% of the mass of any rocket. So it's got to be huge! Then we've got to get from Low Earth Orbit to Mars Orbit. This will consume a large quantity of fuel, unless aerobraking is used. Then we land on mars, plant a flag, collect some rocks, and launch. This mars launch will consume another massive quantity of fuel, and then return to earth orbit will consume fuel. By this time we're talking about the craft being composed of entirely of fuel. It's just not possible.

Logistics is the word, the real plan is a little more intense. A robotic mission is launched to mars to assemble and fuel the mars launch craft. It would be much easier to launch said robotic mission from the moon. Let's also say that an orbital transfer ship is built on the moon. Men and possibly fuel are launched from earth (they may get some fuel from the moon). They board the ship built on the moon, and all those pesky rules of the practical universe seem to stop blocking the mission. This was the said purpose of the constellation project, but politics got in the way as usual.

So let's set it straight. The moon is very important in space. Yeah we're a big group of dreamers, so what. If we want to return a value to earth we've got to go to the moon. Also, if we want to get to the things just out of grasp, we've got to use some stepping stones. Banging our head against the wall for 40 years is not having any effect. Let it be known very clearly that a moon advocate does not disagree with a plan to go to mars, or asteroids, we just want it to happen so badly we're willing to compromise a bit with reality.