Return of the Star Raiders — Dietmar Arthur Wehr

After the collapse of the interstellar Federation, human civilization descended into a new Dark Age as planets, cut off from Earth and each other, reverted to a pre-industrial tech level. After centuries of struggling to pull themselves back up by their bootstraps, they face a new and terrible threat. Raiders with faster-than-light ships and contra-gravity tanks steal anything they want and kill anyone that gets in their way. This space opera novel tells the story of three generations of the Strider family as they fight to protect their planet and loved ones from the forces of chaos.