Return of the Star Raiders

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 lower 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 military SF novel is the story of three generations of a family as they fight to protect their planet and loved ones from the forces of chaos.

Excerpt:
He quickly checked the distance to the mine site and compared that with the missile's own effective range and the X-12's speed. There was a slim chance of getting within firing range before the enemy ships got too high. The throttles were already pushed as far forward as they could go, but there was one more thing Strider could try in order to get more speed. He initiated the afterburners, which poured fuel directly into the hot engine exhaust, causing secondary combustion and additional thrust. The sudden surge in speed felt like someone had just kicked him in the back. The enemy ships were starting to gain altitude faster now. The distance between them and the X-12 was dropping faster too, but there was no way to know for sure if it was dropping fast enough.

With seconds to go until the enemy ships got within missile range, Strider armed the warhead, opened the weapons bay and lowered the missile's launch platform. The fuel exhaustion warning light lit up, and he heard the accompanying warning alarm that he was almost out of fuel. Landing without fuel was going to be a bitch, but he couldn't worry about that now. He had to focus on getting within firing range. Without radar, there was no way to know for sure, but his estimated position relative to the mine site told him that the enemy ships were now within missile range. He activated the Mark 3 warhead's guidance system, which would begin radar scanning as soon as the missile launched and pressed his thumb down on the red firing button.