The voices of a distant star = Hoshi no koe
Author: Shinkai, Makoto.
"...Mikako joins a research team to explore the recent contact between humans and alien races. She ventures out into space, leaving behind Noboru, the one young man she loves. As she travels deeper into this new frontier, her only connection with her boyfriend is through cell-phone text messages. But the years pass, and Mikako barely ages in the timelessness of space--while Noboru grows older and considers moving on with his life--"--P. of cover.