Planet Killers    by Sean Brandywine
Price: $5.95 USD. 36930 words. Published by Strict Publishing International  on September 12, 2009. .
Someone tried to destroy the Earth. They nearly succeeded, just missing and shattering our Moon. Huge fragments hit the Earth. Millions died. Four surviving starships were converted from exploration to military use, and sent out on a journey taking them farther into the galaxy than any humans had ever gone before. The goal: find the race that tried to destroy them. The mission: revenge.

War and Space    by Steve Challis
Price: $0.99 USD. 17910 words. Published by Steve Challis  on August 27, 2011. .
After 150 years of peace on Earth the unarmed Interstellar Exploration Ship, the "Highway to Heaven" is attacked without apparent provocation by unknown aliens with much more advanced technology than the Earthmen.