So, I've been working on a few ideas for next year's novels, and I've come up with something that I don't think I've ever seen before. Giving Earth dozens of new moons. Sounds crazy, but thinking about it, this is a development that is likely to take place at some point over the course of this century, and craziest of all, we're going to do it ourselves. I'll start by positing that we're going to be mining asteroids. Because we almost certainly will; there are too many resource shortages coming up.
That probably doesn't mean going out to the Asteroid Belt and setting up prospecting camps, though. My guess is cubesats, launched from orbit to investigate potential targets, and those that pay out are followed up with a second trip to alter the asteroid's trajectory, and bring it close enough to go into a very high Earth orbit. (Very high. I really don't see anyone being allowed to go close, and certainly there will be size restrictions, and for once this will be very easy to police – anyone with a telescope will be able to work out if something's going wrong.)
It'll take years to move the asteroid, even if it's already in a reasonably close orbit, but we've got a good handle on the techniques required. It just makes a lot more sense to bring the asteroid to us, rather than going all the way out to the Belt. Especially because human presence is going to be required, even if only for tele-operation, and having a time-lag in the minutes is problematic. Driving a rover around Mars is a major feat; operating large amounts of heavy equipment will be far more difficult. My guess is man-tended installations, operated from Earth, maintained from LEO. (Or the Moon, thinking about it – because parking these rocks in lunar orbit means that if something goes wrong, nothing happens to Earth. That might be a good reason for Moonbase, ultimately...)
For me, this is interesting in itself, and suggests a host of story possibilities – because the data being transmitted from some of those interplanetary cubesates will be worth billions of dollars, and that alone provides the motivation of all sorts of chicanery. Not to mention that these will be years in transit, and anything can happen in that time – either out in space, or down on Earth. Even so, I'm reaching forward a few decades, after this has become mature.
Because Earth – or the Moon – now has a lot more satellites orbiting it, and most of them will be perfect hiding places for all sorts of fun. No asteroid will ever be completely refined; which means tumbling rocks, or better still, shells in cislunar space. Probably with abandoned equipment, because stuff always breaks, or newer models turn up. More asteroids arriving all the time, others still being excavated decades later, maybe for less valuable materials – because if you've mined out all of the platinum, there's no point just leaving the aluminium out there, not when Scrooge McSpaceman is wanting structural components for his private space station – which again means something fun.
I don't really have anything specific here, not yet, but I'm definitely playing with this idea as something for the future...