[extropy-chat] Space colony behind the moon?

[Anders Sandberg]

A B wrote:
> Could someone here tell me whether or not it would be physically possible
> to place a space station in "Lunar-Synchronous" orbit, such that the
> station would permanently "hover" over the "invisible" face of the moon
> (ie. so that the moon itself would at all times be located between Earth
> and the space station)?

You are thinking of the second Lagrange point. See
http://en.wikipedia.org/wiki/Lagrangian_point for a map. It is unstable,
so you would need to do a bit of station-keeping to remain there, but it
is a very small amount needed.

>   The moon might also serve to shield and "trap" within it's gravity well,
> a payload of malicious nanoreplicators that might be fired toward the
> space station.

But this assumes they are just fired stupidly, not by somebody who
understands orbital mechanics. It is not harder to hit L2 than L1!

The real place to put the space ark is an unknown orbit. Space is big, and
if it is too much of an hassle to find you it is likely nobody will.

-- 
Anders Sandberg,
Oxford Uehiro Centre for Practical Ethics
Philosophy Faculty of Oxford University