|My initial reaction was one of "I want more information". This is a good thing, but there is a lot of information that I'm wanting to know, such as:
The identity of the Navigator. He's an nameless, faceless, trait-less individual at the moment. There is a brief history concerning his kind, but the reader does not even know if he is human, although the reader is led to believe that.
Who sent the Navigators?
Why is time blocked? By what means is it measured (eg Earth time-scale)?
Who developed NavCom, and what is its purpose?
On a related note, why would NavCom shut down at the end of its directive? I understand the implication that there are no more stars, and no more life in the universe, but it still seems odd.
Overall, a competently written piece. Good grammar, spelling, etc. I realize it's a short story, but perhaps you would wish to expend it and flesh it out more? It has an interesting premise, I would like to hear more about it. Perhaps historically, as there doesn't seem to be a future. :D