Complex sentence: It was an independent research Institute of the National Observatory of Athens (NOA) until 2012 when it was merged with the Institute of Astronomy and Astrophysics to a single unit entitled Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing (IAASARS).
Split into simpler sentences: It was an independent research Institutes of the National Observatory of Athens (NOA). In 2012 it was merged with the Institute of Astronomy and Astrophysics to a single unit entitled Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing (IAASARS).