Zombie Bloodbath 3: Zombie Armageddon

Also known as Zombie Bloodbath 3: Undead Armageddon

A bunch of zombies that are used by the government to fight in a major war in the near future get launched into space. The space shuttle gets caught in a time warp and returns to Earth in the present day. Naturally, the zombies get loose and terrorize a motley assortment of folks who are trapped inside a high school.