Complex sentence: The pad was demolished, and subsequently rebuilt as the first launch complex for Ariane rockets, ELA-l'Ensemble de Lancement Ariane, later redesignated ELA 1, which was used for Ariane 1,2 and 3 launches until it was retired in 1989.
Split into simpler sentences: The pad was demolished, and subsequently rebuilt as the first launch complex for Ariane rockets. Renamed "ELA" (later redesignated "ELA 1"), it was used for Ariane 1 and Ariane 2 and 3 launches until being retired in 1989.