Lunar laser PDC idea, need particulars

[Saibot (OP)]

So because beam weapons are affected by atmosphere, and because Luna has none, and because this playthrough gave it no minerals so I won't be making it my shipyard planet like I usually do, I want to use it for a beam PDC. 2 questions; first what's the distance between Earth and Luna? I want my first PDC to be able to shoot "across" Earth to where the moon would be, and later models to expand on that with better tech. Secondly, is there a button or quick function for determining distance between 2 points?

[Steve Walmsley]

So because beam weapons are affected by atmosphere, and because Luna has none, and because this playthrough gave it no minerals so I won't be making it my shipyard planet like I usually do, I want to use it for a beam PDC. 2 questions; first what's the distance between Earth and Luna? I want my first PDC to be able to shoot "across" Earth to where the moon would be, and later models to expand on that with better tech. Secondly, is there a button or quick function for determining distance between 2 points?

To determine distance, hold shift and mouse-drag a line.

Distance from Earth to Moon is 384,000 km on average, although it varies from that in real life (363,104 km at perigee and 405,696 km at apogee).

[Saibot (OP)]

Thanks. Hm looking at the ranges possible with current tech I think my fire across Earth will be more of a late model PDC.

[Starmantle]

You could always go for a particle beam.

I've always put some missile bases on Luna, but I do like the idea of a beam platform too.

Though I think timing and logistics might make it really challenging to have something like that act as reliable point defense.

Instead, I like Earth-based hangars filled with 500 ton fighters with small, slow engines and little gauss turrets.  Instant missile point defense when you need it.

[TheDeadlyShoe]

I find this sort of thing works way better for literally every planet in the game except Earth.  384k distance starts to stretch even AMM defense capabilities for most reasonable tech levels. 

Phobos orbits Mars at less than 10k, Portia orbits Uranus at 55k, etc.  These are close enough to make viable defense points for a colony or fuel harvesting op (respectively).  Many exosolar planets are in similar situations.

OTOH, 384k is enough distance to make an armed camp on luna and an armed camp on earth able to defend against the others missiles to a limited degree...

[Bgreman]

The distance could also have been checked by

1) Finding Luna's entry in the F9 window and checking the orbital distance.
2) Clicking on Luna in the System Map, and then viewing the Body Info tab.  "Orb Distance" will give the orbital distance.

[Saibot (OP)]

Phobos and Mars looks promising. Short distance and gives the AI a choice between attacking defenses or population. As far as defending my fuel harvesters, Cordelia is the closest orbiter, any particular reason you pointed out Portia instead? Still want to fortify Luna since I'm planning to move my research centers there, but the mutual defense value will be more limited than I thought.

[nafaho7]

There is another reason to stash beam weapon installations on Luna.  Think of how juicy a target a size 50, resolution 1, sensor mounted in a PDC would look to any opposing force, NPR or player.  Put it on the moon, and just keep adding to the local point defence net as the march of progress continues.