Space junk it becoming a bit of a problem. With half a million bits of trash currently being tracked, and far more to come in the near future, low Earth orbit could potentially become a dangerous place to be. There have been lots of plans proposed to deal with space junk, from lasers used to ablate the leading faces of small bits to cause them to deccellerate and deorbit, to satellites that would grab other, dead satellites and drag them down to their firey dooooom. But with hundreds of thousands of bits being tracked, and millions of bits too small to track, something a bit broader might need to be tried.
As with a lot of environmental cleanup plans, a big issue here is that cleaning up LEO will cost money but not necessarily generate income. But what if it could?
Assume that the SpaceX Starship and Super Heavy come to pass. The Starship is supposed to be able to take a jetliners worth of passengers to Mars… but only a small percent of that number could sit at sizable windows at any one time. So… modify a Starship specifically for short-duration space tourism, with the number of passengers dictated not by mass but by how many could sit at the window all at once. And instead of going to orbit, the Starship simply goes *up.* So, what about the wasted payload potential? Water. Lots and lots of water. As the Starship coasts through space, it sprays out a fine mist of water, creating a cloud of water vapor at the *altitude*of low Earth orbit, but not the *velocity*of low Earth orbit. The cloud would of course follow the ship both up and down, spending a matter of minutes in space. Any small bits hitting the cloud will be substantially slowed, perhaps enough to fall out of orbit almost immediately; larger satellites would of course also be affected, so timing would be important.
This suborbital hop could be straight up, leaving a cylinder of vapor perhaps many hundreds of miles high. The Starship could also launch from, say, California to land in Florida; the maximum altitude reached would be lower, but the duration in space would be longer. And the return trip from Florida to California would result in much higher impact velocities between space junk and the cloud. North-South flights would put a long “net” across equatorially orbiting bits.
SpaceX has said that they think they can fly the Starship to orbit for something like $10 million. A suborbital hop filled not with rocket fuel but water should be substantially cheaper. If this sort of suborbital hop could fly for $5 million and carry 20 passengers, that means that each passenger could pay $250,000 for both the short bit of suborbital tourism… and get the satisfaction of cleaning up a bit of space.
Further benefits could be had if the water wasn’t purely water, but had some sort of “reflectant” in it. As the cloud came back down, it would hit the upper atmosphere and smear out across it, leaving, for a time, a high altitude cloud that would reflect sunlight back out into space, aiding with that “global warming” thing.