Complex sentence: The former assets of Aérospatiale are now part of Airbus Group, except the satellite manufacturing, which merged with Alcatel and became Alcatel Space, in 1999, now Thales Alenia Space.
Split into simpler sentences: The former assets of Aérospatiale are now part of Airbus Group, except for the satellite manufacturing division. It merged with Alcatel and became Alcatel Space in 1999, now Thales Alenia Space.