“Spartans never die. They’re just missing in action.” – Halo series

Spartans in the Halo series were treated as greater beings. Sure they were subject to horrible experiments but the Master Chief wasn’t just an enhanced soldier – he was a one man army, capable of turning the tide of war. As such, the death of Spartans following the SPARTAN-II program going public were thought to cause a loss of morale. So they were never considered to be dead – just missing from action.