Why doesn't the Space Shuttle bring back space junk each trip?

Most of it is whizzing by on different orbits (the space station's orbit is fairly clear of debris), so it would use huge amounts of fuel to modify the orbit. Also, any extra manuever always add risk, and the shuttle's are getting quite old.

But there is talk of creating future un-manned satellites to deal with it. Again, though, the goal is not to match orbits and "remove" the debris, but in most cases they want to simply lower its orbit a bit, then within 5 years or so it would burn up on its own. That would take less fuel.

One plan involved using jets of water to knock them down a bit. Within a short amount of time, the water turns to harmless vapor.

It is millions of tiny bits all going in different directions at thousands of miles per hour. There is no way they could catch any of it. Even if there was one defunct satellite in an easy to reach orbit, they would need special hardware to catch it (it is probably tumbling out of control) and hold it in the cargo bay safely and firmly enough for entry and landing. It is easier and MUCH cheaper to have every space craft in the future avoid that one satellite than it is for the shuttle to carry the extra weight of special hardware to grab it and spend time and fuel to alter orbit to pick it up. And any complete satellite or spend booster big enough to bother with and also in a low enough orbit to be reached by the shuttle will come down in a few years anyway, because there are enough air molecules in orbits that low to cause a microscopic drag force amd make the orbit decay in just a few years, and spiral down and reenter. The International Space Station orbit would decay and cause it to reenter if they didn't re-boost it every year or so.

the fact that some of the debris is flying insanely fast, it would be like trying to catch a missile With a baseball glove, and some of the junk is very small. beyond the shuttles ability to grasp , and the orbits would have to match, speed and trajectory. im sure some of the bigger stuff might be grabbed but the risk is very high. what we need is a shuttle based laser that can target debris on its own and vaporize the really unstable bits.

Probably the same reason everyone leaves rubbish behind. Is just too much hassle. There is so much space up there that you would have to be really really unlucky to run into any of it if you were and astronaut. Although if you did hit some in space you would certainly die.

It's not feasible. 1. They have to manouver to a position to safely grab it, 2. They have to safely stow it. 3. They then have to dispose of it once they get it back.

#2 is a real problem, particularly if there are any emergencies.

Do the words 'relative velocity' mean anything to ya?

It would be overloaded for landing.