Hoshizora Kiseki

Cross space, there is always love. 

Both are short sci-fi romances published by Comix Wave Inc., made mainly by a single person. They only feature 2 characters, and the stories revolve around space/stars. Hoshi no Koe, created by Makoto Shinkai, was pretty successful, and the director went on to work on a lot of movies with the studio later on, including Your Name. Hoshizora Kiseki never got that famous, but the creator, Watanabe Akio, worked as a character designer on a lot of different shows afterwards, like Kaminomi and the Monogatari Series.