The United Earth Stellar Navy, UESN for short, was formed in the early 22nd century as a planetary defence military that incorporated the former space organisations of the old nation states after the formation of the United Earth Government.

 

Unlike UESPA, the UESN is a military organisation, tasked with the duty to defend Earth and her colonies from Alien aggression.

 

After the Xindi Conflict, it became standard policy for UESPA vessels to have a tactical and security force made up of UESN Officers and MACO ground troops. The effectiveness of the UESN foces on UESPA vessels was made apparent that without their involvement the Xindi conflict would have had a vastly different outcome.

 

UESPA and UESN would cooperate in deep space exploration missions together, with a UESN officers assigned to UESPA vessels as tactical and security officers however UESPA has full jurisdiction over the mission and vessel.