Complex sentence: In July 1999, she transferred to the Marshall Space Flight Center as Director of the Flight Projects Directorate, which was responsible for the International Space Station (ISS) Payload Operations Center, ISS hardware and the Chandra X-Ray Observatory Program.
Split into simpler sentences: In July 1999, she transferred to the Marshall Space Flight Center as Director of the Flight Projects Directorate. Her Directorate is responsible for the International Space Station (ISS) Payload Operations Center, ISS hardware and the Chandra X-Ray Observatory Program.