Boeing and its customer NASA have announced that the Tracking and Data Relay Satellite (TDRS) K-L program successfully completed its system-level Critical Design Review (CDR) and Production Readiness Review (PRR) in El Segundo on Feb. 19.

When TDRS satellites K and L join the operational TDRS constellation on orbit, they will provide voice, data and communications relay services to Earth-orbiting spacecraft, such as the International Space Station, several launch vehicles and the Hubble Space Telescope.

The CDR and PRR bridge the design and manufacturing stages of the TDRS program. The reviews validate that the TDRS K-L system design will meet NASA's requirements, is backed with solid analysis and documentation, and will operate effectively when the satellites launch in 2012 and 2013. Based upon this successful review, Boeing will begin assembly of the K and L satellites.

"The K-L series of spacecraft are critical for ensuring the continued availability of high-bandwidth communications necessary for the success of many NASA missions," said TDRS Project Manager Jeff Gramling at NASA's Goddard Space Flight Center in Greenbelt, Md.

"This is a major step toward developing a new generation of tracking and data relay satellites that will deliver high-resolution images, video, voice and data from Earth-orbiting spacecraft to the ground for vital Earth- and space-science missions," said Craig Cooning, vice president and general manager of Boeing Space and Intelligence Systems. "The extraordinary effort by the NASA and Boeing members of the TDRS team to conduct these successful reviews is a testament to the enduring partnership between Boeing and NASA."

The CDR and PRR, held from Feb. 16 to 19, were attended by NASA project, program and headquarters officials. Both reviews were presented to an independent board that evaluated the design aspects of TDRS K and L, including spacecraft assembly and systems integration, testing and safety requirements.

TDRS K and L are the 11th and 12th satellites to be built for the TDRS system. Together with the Boeing-built TDRS 8, 9 and 10, which launched in 2000 and 2002, TDRS K and L will help to replenish the aging TDRS constellation, which was established in 1983 to replace NASA's worldwide network of ground tracking stations.