The Commonwealth of Alterra joined the CPSC as an observer in 1964 and as a full member nation in 1981, to coincide with the launch of the Alterran Aerospace Command (AAC), a branch of the Alterran Air Force, and the Alterran National Civilian Aerospace Organization (ANCAO). 

Alterra operates a significant space program, having launched several suborbital flights and is currently operating the Southern Solar Observatory, dedicated to observing the sun and its effects on Pacifica and the National Advanced Aerospace Research Facility (NADAR), which is started developing an Alterran orbital launch vehicle in 2006. Being a technologically advanced nation, Alterra is expected to become on of the few nations with an independent orbital launch capability by October 2021 at the earliest.

Alterra expresses great enthusiasm and support in its interactions with the CPSC, stressing the need for nations to work together to explore space.