In AD 2225, Kouji Aiba and Aoi Housen are serving as astronauts in-training in Liebe Delta astronaut training center which is located on the edge of a very rough and dangerous area in space called the Geduld Sea. When saboteurs with unknown intentions suddenly ambush the acting crew during a routine dive procedure, the space station plummets into the Geduld Sea, a plasma field that links all planets like a nervous system and crushes any ship that advances too far into it. With all the adults aboard the Liebe Delta killed, the young astronauts must survive the long journey home while dealing with the growing tension amongst each other and various fights for leadership roles.
Infinite Ryvius is one of my favorite space anime shows, second only to Planetes. Even though they are both in the space category of anime, they are quite different: Planetes is more realistic both in animation/art styles and its adherence to actual science. There is plenty of spaceship action and there are quite a few cast members to keep track of, with their various teen social circles.
It is a good one to like -- there are 26 episodes.
(Infinite Ryvius might even be considered "hard space", which basically indicates a high level of realism in the presentation of outer space, or adherence to actual science. I am not sure; I do know that Planetes is considered to be a hard space title.)