Mugen no rivaiasu (TV series)

In the future, a solar flare called the Geduld Phenomenon spreads a vast, chaotic plasma field across the solar system, killing many but ironically bolstering humanity's drive to colonize space. Many years later, the Liebe Delta astronaut training center is established to educate teenagers in practices such as piloting, nursing and stewardship. But the center, which conceals a prototype battleship called the Black Ryvius, is sabotaged by an unknown party, and the remaining adult instructors sacrifice themselves to save the station from plunging dangerously into the Geduld field. Meanwhile, the station's 400-plus students discover the hidden battleship and are forced to remain aboard it, protecting themselves and governing the student body as best they can while searching for salvation. - IMDb