Author Topic: L1/2 spacestation with depot  (Read 41351 times)

Offline JohnFornaro

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Re: L1/2 spacestation with depot
« Reply #140 on: 08/05/2010 02:33 PM »
After a few minutes of googoling, I didn't find a straightforward statement: The distance from EML-1 to the Moon's surface is 'x' km.  I did find derivation equations and several other interesting sidetracks.  I choose laziness, and accept the figures given.

What I gathered from the article, after a scan, was the idea of what I would call a heliocentric lunar polar orbit of the constellation of six power sats, whose efforts are coordinated to beam power to the polar ISRU plant.  I realize this morning that wasn't quite what the authors were talking about.

So it's time to fire up the scanner:

First, L1 is not the right place for what I have in mind.  I will be continuing on the lunar mining ice thread, but I point it out here since that's where I am right now.

A fleet of six power/com sats would orbit the Moon in a polar fashion at an appropriate altitude.  The polar axis of the Moon would intersect this orbit, and the orbit plane of the constellation would in turn rotate around the Moon's equator as shown.  The tentative term "heliocentric orbit thing" is posed.  The power sats would always face the sun.  As they rotated above the rectenna in the ice filled lunar crater, they would have to coordinate a choreography of power transmission between themselves and the rectenna. 

The rectenna is designed to accomodate the somewhat greater than 120 degree extremes of the power beams, and the losses from the varying angles of incidence are simply a fact of life.  There is no atmospheric attenuation at least, unlike the schemes which purport to beam power to the Earth.

Additionally, the constellation should provide power to the lunar south pole as well, and should be constructed with this ability from the very beginning, realizing that although one pole will be chosen first, the second pole will happen soon enough.  The first application of course, would be for lunar cracking plants, then for outposts.  I don't know what the eventual settlement pattern of the outposts would be, and that's a field of conjecture in itself, since it would have to accomodate the discovery of gold, for example.  For the moment, assume that they would be polar at first.  Equatorial outposts would not benefit from this scheme, realizing that one power conversion and transmission scheme does not solve all problems.

The constellation would include communication abilities from the beginning, obviously.  In addition, the sats would be designed for expansion, since power needs will always grow.  The expansion capabilities are limited to electrical and structural connections.  These do not have to be designed for all time, but rather only for the next cycle of expansion.  The second group of six expansion sats will connect with these.  Future connection parameters can be designed later on, as well as the future interface required to power equatorial outposts.

One of the interesting articles I did find in this morning's search was this presentation of Lissajous orbits for these constellations:

http://web.mit.edu/egralla/www/research/downloads/AAS_04-248.pdf

Edit:  My isometric-fu is off this morning.  I just noticed I drew only <five> dern satellites.  Fixed the scan...
« Last Edit: 08/05/2010 04:28 PM by JohnFornaro »
Sometimes I just flat out don't get it.

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