Habitable planets are hard to come by. The beauty inherent in such planets should be preserved for all to enjoy. These planets should be kept in their natural state (not including housing and other facilities, though these facilities should be kept small enough that the planet can naturally sustain them.) Asteroids mining can provide nearly all our needs for ore and minerals, and has proven quite safe.
Space debris is a big problem. Not only does it not look pretty, but some of those bits and pieces of junk, particularly the junk in orbit, travel at quite a significant speed. Collisions with space debris can cause major damage to spacecraft. One step that can help combat this ever-growing problem is if new satellite deployment techniques are developed. Ones that do not release further junk into space. Removal of decommissioned satellites is also a must.
The advent of teleportation is a wondrous thing, yet it is still in its infancy. Unless safety can be guaranteed, this technology should not be used on living organisms. In fact, there is increasing evidence that organisms sent though these systems suffer from nerve damage or worse. There are already guidelines that state that electronic devices should not be teleported due to the possibility of it damaging some of the more delicate circuitry. Are circuits more valuable than life?