Why colonising the Sun-Earth Lagrange points?

This post was originally published on blogspot.com on June 6, 2012

In this post I will provide more clarity about our position that man should colonize the Lagrange points of the Earth-Sun system (in this post I simply use the term Lagrange point in order to refer to these).

In two earlier posts I discussed the arguments the colonization of the moon and Mars. Contrary to what most people tend to believe, many space colonization advocates do not support the colonization of these two particular objects. Why? First concern is gravity, in order to stay healthy people need gravity. And since we know that the Moon’s gravity is far too low, and that of Mars is also likely too low, it would be a better idea to use man-made structures, known as space habitats, which provide artificial gravity through rotation.

But gravity is not the only objection for the colonization of objects, one of the most important issues is natural resources. The Moon lacks many resources essential for life, especially hydrogen, carbon and nitrogen. The Near Earth Asteroids (NEAs), however, are expected to posses nearly all elements we need to maintain a high-tech civilization and also easier to reach in terms of energy consumption (for a more detailed discussion see here).

Energy consumption and energy efficiency are very important issues. Since the Lagrange points require less energy to reach than the Moon, it also mean that it would require less fuel to launch a space craft. Less fuel, means less costs. This also implies that returning valuable resources to Earth, will out compete lunar mining activities. Therefore an asteroidal colony has a greater economic viability than a lunar colony in the long run.

Another concern is less technical, but probably more important, is politics. Since the Moon is generally considered to belong to all humans, setting up a lunar colony and mining operations is very likely to become subject of much controversy. Although it’s technically true that this whole common heritage of mankind bullshit, also applies to asteroids, but I expect that most people will not get any strong feelings about a bunch of mere rocks.

Although most NEAs are not located at the Lagrange points, they can easily be reached from there. Further some planetary scientists that so-called Earth trojans might exist, until now the existence of only one such object has been confirmed, see here for more. Some space advocates propose bring NEAs into earth orbit. I don’t believe this will be a good idea, due to the increased risks an asteroid impact, but it could be a nice idea to bring some valuable asteroids to the Lagrange points, if there are no usable Earth trojans.

Although the Lagrange points are easier to reach in terms of energy consumption, the distance between them and the earth is still huge and as a result travel time is in the order of months instead of days in case of the Moon. This both an advantage as a disadvantage, the latter no need an explanation, but the former does. In case of a conflict with one of the major terrestrial powers, a sovereign moon colony will be an easy prey for a military intervention, while Lagrange point colonies are able to detect such mission months in advance and thus they will be able to act accordingly. Particle beam weapons will made it possible to destroy a hostile space craft within hours after detection, without the need of launching an interception missile. So we can conclude that colonies based at the Lagrange points can more easily obtain and maintain their political independence than any lunar colony.

5 thoughts on “Why colonising the Sun-Earth Lagrange points?”

  1. I was wondering how one would travel to and from between the Earth and the settlement? I presume the settlements are located at Sun Earth Lagrange points 4 or 5. What type of trajectory or flight path would be used (that is reasonable)? If one settlement was located at SEL4 and the other at SEL5, how could they travel to each other?

    1. >>What type of trajectory or flight path would be used (that is reasonable)?

      I am looking to find out what trajectory will be used. But there have been several missions to SEL 1 and 2, this suggests that trajectories to SEL 4 or 5 could be reasonable pursued. Of course this really a matter of how much energy one is willing to spend.

      >>If one settlement was located at SEL4 and the other at SEL5, how could they travel to each other?

      My suggestion would be to establish settlements at either SEL 4 or 5 rather than at both, and hence to avoid travel between L4 and L5. But this actually because the distance and the associated travel time, which would make cooperation among space settlers difficult. Which one should colonized first should depend on the accessibility of resources, such as trojan asteroids.

      1. Hello. I also investigated further and similarly encountered orbital phasing. Check out later part of http://ccar.colorado.edu/asen5050/projects/projects_2004/olds/
        It mentions placing satellites at SEL3,4,5 with phase times of 1.499, 0.83, and 1.116 years respectively and (enter + exit) delta V’s of 6.68, 3.98 and 2.84 km/s, exluding delta V’s to reach a low Earth orbit.

        There was also an interesting technique for the STEREO mission that had two probes flyby SEL4 and 5. see http://stereo.gsfc.nasa.gov/orbit.shtml

        Interesting to consider that L4 and L5 would be relatively remote from each other, but I don’t see how it could be different pending extremely advanced propulsion technology.


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