Question What would industrialised cis-lunar space actually look like?

Linguofreak

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Ok, somehow we went from hypothetical orbital industry to hypothetical future warfare strategies in one smooth motion... :ROFLMAO: I enjoy it, but a bit more back to topic would be nice. Main takeaway: If lasers as effective weapons enter the picture, the shape of the orbital infrastructure will probably be the thing least affected by it...

Well, what future warfare looks like determines if wars between the big powers are possible, and that bears on whether laser sats make sense.
 

Urwumpe

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Well, what future warfare looks like determines if wars between the big powers are possible, and that bears on whether laser sats make sense.

Usually, it is then a matter of "its better to have it, than to let our enemy have all the good toys alone."

(Even if it is some madness like SDI)
 

jedidia

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Well, what future warfare looks like determines if wars between the big powers are possible, and that bears on whether laser sats make sense.
I get that, and I wasn't criticising your response. But I think for the topic at hand, answering the question about orbital lasers with "maybe, but there's a lot of other things to consider, so maybe better not" is good enough, rather than risking ten pages of hypothetics about future warfare to answer that one question more definitively. ;)
 

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jedidia

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There's another question that's bugging me when thinking about this. It concerns launches from earth.

Obviously, equatorial launches from earth are the most efficient. But most of the launch targets would be somewhere within the confines of lunar inclination. So we have two possibilities: Launching into an equatorial orbit around earth and then change planes, or launching inclined. Just an equatorial launch requires less DV than an inclined launch, but an inclined launch requires less DV than launching equatorial and then aligning planes. But: In the later case, the DV required for the plane change could be supplied from orbital sources, which is cheaper than slogging it up from earth. The question becomes, though, just how much cheaper? Enough to give equatorial launches a competitive advantage?

This seems difficult to answer without an unreasonable amount of math, and my experience is way too limited to even make an educated guess (honestly, I haven't done many launches from earth surface...)
Plus, here's some additional considerations:
  • All the propellant being produced mostly on the moon and at the lagrange points would have to be brought into earth equatorial inclination, so it would effectively have to be paid twice.
  • A lot of the orbital infrastructure would probably be located in lower MEO between the two radiation belts (2000 to 13000 km) to stay well clear of any atmospheric friction. To make the best out of the inclined launch, payloads would have to be boosted to that altitude directly. If that eats into the payload mass too much, there would have to be a transfer station in LEO from where the cargo can be boosted on to higher altitudes. If such a thing would be required anyways, I figure it might as well be in an equatorial inclination.
  • Geography and politics would play a certain role. Everybody will want access to space, but different launch sites in different countries are better or worse for launches to different inclinations. So it would be well imaginable thatthere would be a mainstream approach and a couple nations who do things differently to maintain independance from internationally centralised launch infrastructure.

Personally, I like the concept of a busy transfer station in LEO as a gateway to the wider area of space, but that preference is purely aesthetical, not practical. Anybody experienced enough to make a more educated guess?
 

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Personally, I like the concept of a busy transfer station in LEO as a gateway to the wider area of space, but that preference is purely aesthetical, not practical. Anybody experienced enough to make a more educated guess?

Well, what do you mean with guess there? It should be possible to calculate how economic such a station is, this is pretty much a function of the freight to various destinations.

Maybe I can produce some utility function there for you to play with, but not this week.
 

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Sure possible, but it's a lot of math with a lot of unknown/arbitrary variables, so it doesn't quite seem worth it...

Well, as said, its mostly an utility function as common in economics. It must not even be precise or look closely into the unknown variables. All that really matters is: In which situations is such a station useful - and how useful is it?

The variables could then be explored based on this utility. For example, you could use the utility function to determine, how often a spacecraft has to be reused, for a certain destination to be better than launching an expendable vessel straight from Earth.

Or take the idea of a lunar mass driver - the utility function of the station would not change by it, but the lunar mass driver could be way more useful.
 
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