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The Chandra X-ray Center
Smithsonian Astrophysical Observatory Smithsonian Astrophysical Observatory

The Chandra program exemplifies NASA's initiative to make its space programs more efficient by encouraging expert teams located outside NASA centers to assume expanded responsibilities. The flight operations, mission planning, data processing and user support for the Chandra mission are carried out by the Chandra X-ray Center (CXC), at the Smithsonian Astrophysical Observatory (SAO) in Cambridge, Massachusetts. The staff of the CXC includes scientists, engineers and technicians from SAO, MIT and Chandra prime contractor NGST, who have been directly involved with the design, construction and testing of the telescope and its scientific instruments.

The Operations Control Center
Operations Control Center
Operations Control Center

In June 1997, NASA awarded the SAO a $63 million contract extension to establish the Operations Control Center (OCC) as part of the CXC under the direction of NASA's Marshall Space Flight Center. As the name suggests, the Operations Control Center controls the operation of the Chandra spacecraft while it is in orbit. Scientists and engineers design an observation plan for efficient scheduling of the observatory. The time spent moving from one target to another is minimized while avoiding potentially harmful direct X-rays from the Sun. Commands for executing the observation plan are transmitted from the OCC to one of three stations comprising NASA's Deep Space Network in Spain, Australia and Owens Valley, California, then they are relayed to the orbiting spacecraft.

Scientific data and monitoring information on the state of the observatory such as power consumption and temperature are sent from the spacecraft to the OCC via the Deep Space Network approximately every eight hours. The monitoring data are analyzed to assess the condition of Chandra, and the observation plan can be modified if necessary for the health and safety of the observatory.

Operations Control Center
Operations Control Center

The electronic data stream received by the OCC from the observatory are processed at the CXC to produce X-ray images of cosmic sources. The data are then given to the scientists who proposed the observations. Selected images are made public immediately, and after one year all processed data are placed in a public archive.

The OCC, located near Kendall Square in Cambridge, has a viewing gallery, a glass walled enclave, where press and visitors can watch Chandra mission specialists as they communicate with the observatory and carry out the space flight operations.