The location I have chosen to place Terra Nova is "L5." (see Figure 3) L5 is one of the five Lagranian libration points found in the Earth/Moon planetary system.
The five Lagranian points were discovered by a French astronomer by the name of LaGrange about 200 years ago. He discovered that there are five points in the region around the Earth and the Moon where gravity has no effect on orbiting bodies. The Moon's gravity is so balanced by the Earth's gravity in these locations that a body can remain fixed at these points. The bad news is that the first three points, L1, L2, and L3 are all very unstable. To keep a body in orbit at these points would require it to be constantly positioned by rockets which would use a lot of fuel. Without this constant positioning the body would be sucked in either by the Earth or the Moon. The good news is that the two other points, L4 and L5, are stable.
L4 and L5 are located at equal distances from the Earth and the Moon - the first 60 ahead of the Moon, and the second 60 behind the Moon. That means that both of these points form an equilateral triangle with the Earth and the Moon, L4 or L5 being the third point.
The good thing about these two points is the fact that they, unlike the three other points, are stable. If an object wanders off course while orbiting around the Earth at either L4 or L5, the object will return to the point naturally. An object orbiting at L4 or L5 does not need to waste fuel constantly repositioning itself, nor does it have to be worried about crashing into the Earth or the Moon. That makes L4 and L5 ideal locations for space colonies.
However, the Lagranian points 4 and 5 are more like a region than specific points. They have an oval or a kidney shape, with orbits of their own, while still orbiting Earth. Because of this, Terra Nova could be placed exactly on L5 while her emergency facilities, mass catcher, and SPS could orbit around her.
Space colonies located at either L4 or L5 would thrive. They are stable points in space that are near, and easily accessible from both the Earth and the Moon. There is little difference between the two points, but nonetheless, I chose L5 as the location of Terra Nova. The reason I did so was for sentimental reasons more than scientific. Gerald O'Neill, the pioneer of space settlement, originally picked L5 as the location of his space colony.
Some people have the uninformed idea that settling the surfaces of other planets is somehow better than settling space. Although I believe colonizing other worlds is a good idea, I feel colonizing space is more important, and must come before we can settle such worlds as Mars.
The space settlement concept maintains that planets are not the best places for human colonization beyond the Earth. For one thing, other planets have different gravities than the one man is used to on Earth. This change in gravity can be hazardous for several reasons. With long term exposure to zero or low gravity, the human body has been known to lose muscle and bone calcium. This may make it impossible for colonists on other worlds to ever come back to Earth. Their bodies would not be able to adjust to the strong gravity which our home world exerts. Changes in fetal development may be irreversible for babies born on other planets or moons. They may never be able to see their home world. Colonists on Terra Nova would have a full gee of gravity at their principle living area, so these problems would not effect any generation of space colonists.
Each planet and moon has a specified orbit, causing the length of day/night to be different than the twenty-four hour clock on Earth. This can have dangerous psychological effects on planetary colonists. Can you imagine not seeing the sun for fourteen days, and then being unable to experience night for another fourteen? Such is the problem of Moon colonists. Humans are not used to this pattern. On Terra Nova, the times for day and night could be adjusted to whatever the colonists wanted, using mirrors and shades. In the beginning, at least, it should probably remain the familiar twenty-four hour cycle.
Some people who want to colonize other worlds also think they should terraform them as well. For example, some people want to change Mars' atmosphere and biosphere to make it suitable for humans to live in without the need for protective coverings. However, terraforming is a very long-term project. It would take 200 years or more, and it would require technology not even invented yet. Also, terraforming is not guaranteed to work. We do not know what the consequences of making other worlds exactly like Earth would be. Terra Nova offers a better solution than terraforming. She could be built in the near future; the required technology is here now, and her builders would live to actually see her made and perhaps even live in her. Space settlement seems a more attainable goal than terraforming.
Although I believe we need and should have colonies on other planets and moons, I think the majority of space colonization should be done in orbital space settlements like Terra Nova. These would have all the benefits of space with all the comforts of home.
