The Shattered Stars
Bantam Books 
Synopsis: Moses Callahan has a debt-laden starship. Desperate for crew and cargo, he accepts a very shady cargo from a businessman and hires Deacon Halloran, a shell-shocked veteran of war to pilot his ship. The businessman turns up very dead but the cargo, a Bethe trigger able of catalysing a wide range of nuclear reactions, arrives anyway. Planning to hand it over to the legal authorities at the far end, Moses accepts it.