Can we "just" build a Mars space elevator? It should be free of a lot of the concerns an earth space elevator would have - no terrorists, no populated areas, rather less gravity.
I've heard that this could be done with current materials science. Same for the moon. The problem is that it's a solution without need for now. It's somewhat like building a cross continental railway before San Francisco was founded. One day hopefully we'll need something like the elevator, because that implies lots of other interesting things would be going on.
The problem is Phobos, which orbits closer than areostationary orbit.
Could we just tether Phobos with an elevator?
Since Phobos isnt areostationary, the base of your tether on mars would have to move around for this to work. Additionally, you would have to constantly adjust its length. Therefore, boarding the elevator would be more difficult.
Or set the height above the highest obstacle on the orbit and have some variant of planes or wilder mechanisms get the cargo up to that dangling tip.