Or they could use special reflecting films to accomplish this. Or they could occasionally have sunlight reflected focused to superheat some asteroid matter to serve as an adequate effective small rocket.
Actually it would be safer here to have the settlement formed in a mildly elliptic mildly tilted monthly orbit. It would then usually be somewhat above or below, before or behind L2. Sounds silly? No. Very sensible. There was ample Lunar hidden space all around L2, more than half Luna's width! So if conservative religious murderous haters of genetically altered moderns might ever read any future speculation about a place for maybe several moderns kept hidden at L2, and thus suspiciously had L2 closely viewed by an orbiting telescope, the dark hidden settlement wouldn't be there to see nor to even briefly blink hidden any remote star. Or if ever foes hateful against moderns sought to blast apart anything speculated at L2, there'd be nothing quite there to hit.
By now with extra free time, (thanks to free serving robotic devices), more moderns had assisted making inventions useful to Earth humans. Some had some saved earned profits they now partly combined to pay well the investors taking care of the orbiting settlements, to have them begin having loads sent from source asteroid(s) to begin forming a secret new L2 Fullball world for moderns completely hidden behind Luna. The investors group deserved good payments to reward them for their excellent idea.
The Earth-Luna L2 point is 61,491km from Luna's center. (Luna, of radius 1,738km, is 384,393km from Earth.) Communications cubes sent to the Earth-Luna L4 & L5 Lagrangian points, 60deg before and after Luna in its orbit, could communicate with anything out behind Luna if up there at 15.5% of Luna's radius, (merely .45% of L2's altitude).
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