Earth Shadows (Earthrise): Daniel Arenson, Jeffrey Kafer.

They came from deep space. They came to destroy us. Fifty years ago bloodthirsty aliens devastated the Earth. Most of humanity perished. We fell into darkness. But now we rise from the ashes. Now we fight back. Marco Emery was born into the war. After his mother is killed, he joins the Human Defense Force, Earth's ragtag army. Emery must survive basic training, become a soldier, and finally face the aliens in battle. Against the alien onslaught, Earth stands alone. But we will fight. We will rise. We will win.

Author clearly did not research any technical subjects and editor must not have actually read the book. Purchase was a real regret.

Earth burns. We call them the scum. They came from deep space. Creatures of claws and endless malice, they ravage the world. As the war flares, as cities crumble, Private Marco Emery and his platoon blast into space. They won one battle on Earth. Their next battle must be fought in the darkness. The scum will not rest until the last human is dead. Marco and his friends must defeat them. They must win. Or Earth will fall.

It's all-out war. Our cities fall. Millions die. The scum, these cruel aliens from deep space, are determined to kill us all. So we must kill them. Humanity musters its greatest fleet. Thousands of starships rally. Millions of soldiers deploy. For Earth to stand a chance, we must invade the aliens' home world. We must destroy their planet. Before they destroy ours. Earth's fleet flies through space. We fly toward millions of enemy ships. We fly to almost certain death.

Five years ago, we won our first galactic war. We defeated the scum, a race of alien centipedes. But the marauders are stronger, smarter, and crueler by far. And they will show us no mercy. Marco Emery, hero of the last war, struggles today as a civilian. Shell shock cripples him. Nightmares haunt him. Yet now he must become a soldier again. Now his old platoon must reunite. Together, they must defeat the greatest threat Earth has ever known. Or humanity will fall.

The marauders, terrors from deep space, hit us hard. Our starships shattered. Our armies collapsed. Our cities crumbled. As Earth smolders, the marauders imprison us in camps. They farm us like cattle. They torture us for sport. Earth weeps. But there is hope. The Ghost Fleet, an ancient alien armada, might still exist in deep space. In a single starship, Sergeant Marco Emery and his friends seek this mythical fleet. They must find it. They must return with its might. Or the marauders will kill us all.