Meteorites.  The scary part of living on the Moon.  Popular fiction likes to portray them as huge rocks bearing down on their target like the end of everything.

Well, not quite.  In reality, they come in all sizes, from particles of dust you'd vacuum out of your rug, to grains of sand that hit the Earth's atmosphere at speeds that make a bullet look slow, creating the spectacular trails across the sky that we call shooting stars, to massive rocks every few hundred million years that can wipe out a good fraction of the life on Earth, such as the one that ended the reign of the Dinosaurs.

In Moonbase Inc, we're not concerned with the really tiny stuff.  That kind of thing is handled by the regular maintenance that has to occur anyway, due to solar radiation and changes in temperature as the Moon rotates relative to the Sun.  Instead, it's the bigger ones that are of concern - the ones the size of a fist, that hit once every few years.

In game, they initially are set to hit randomly, averaging out to around once every 4 minutes.  That's only an average, though. You might go 10-20 minutes without seeing a hit, or you might get 2 or 3 in the space of a single minute.  It's all in how the dice rolls.

At first, while your base is small, they'll usually hit somewhere else out in the playing area.  When they do, or when they hit a road, they tend to leave behind a small pile of rubble, most of the time containing some of the games Resources such as metal, gold, or uranium.

However, sometimes you get unlucky, and they will hit one of your buildings.  When this happens, that building gets knocked offline, and depending on what kind of building it was, the loss of resources it's providing could cause other buildings to shut down as well, in a cascade.  However, if you simply tap it, and tap the ON/OFF button, it'll be fixed and back into operation immediately.

SkyShield Missiles
At first, the extra metal, gold, and uranium comes in handy, but as your base grows larger, it becomes more and more likely that it'll be one of your buildings that gets hit, instead of a road or the open surface.  At that time you probably want to start building SkyShield Missiles and Lunar Security buildings which fires off even bigger missiles.

Each SkyShield Missile you build adds 30 seconds to the average time between meteors.  Build two of them, and the average time between strikes rises to 5 minutes, adding another would then raise it to 5 1/2 minutes average between strikes.  Again - this is only averages, so you might still get a cluster sometimes quickly, but other times, it may stretch out quite a while before you get any more strikes.