The Haunted Stars
ExoSkeleton Powered Armor aka ESPA
ESPAs were invented late in the 21st century for use in World War III. Incredibly effective, powered armor units were able to move in cramped urban environments with ease, while still carrying the ordnance of an infantry unit 3-4 times its size.
After the war, ESPAs were adapted to civilian use in the construction of orbital stations, proving ideal for use in outer space.
Eventually, the technology evolved into the more powerful Mechs, but ESPAs still saw widespread use in the military and civilian industries.