Time-travel into the future is indeed possible. In fact, I’m doing it at this very moment; I am travelling into the future at a rate of 1 second / second.
In addition to his thoughts on quantum superpositions, Schrödinger’s cat could have allowed him to come up with the Uncertainty Principal that Heisenberg formulated. It would go something like this:
There is a cat, and it is in some state; alert, sleeping, purring, etc. However the mere act of observing it alters the state of the cat because it will react to your presence and become alert or purr, or otherwise stop what it was doing and do something else.