Stowaway (Redleg in Space #1)

Lt Zade, on his last days of his last deployment to Afghanistan, still couldn’t find the excitement he so desperately needed. A chance encounter, on his last mission, sends him hurtling through space on the Unity exploration ship XES01. Surrounded by aliens, Zade must quickly learn to interact with the non-soldiers on the crew.
As he tries to earn his place amongst the ship, Zade’s combat prowess quickly earns him a spot as the security officer of the ship. A seat left vacant because of a fatal exchange between the former security officer and the wildlife of a far planet. As Zade begins living the adrenaline filled life of a space explorer, he has to ask himself some very important questions.
How does he get back to earth? Does he even want to?

Disclaimer: The main character is a combat veteran, so there is some rough language throughout the book.