WASHINGTON — NASA has awarded General Dynamics C4 Systems of Scottsdale, Ariz., a cost-plus-award fee contract potentially worth $642.2 million over seven years for the Space Network Ground Segment Sustainment project, according to a June 15 agency news release.

Included in the contract, which is slated to begin this month and continue through mid-2017, is an indefinite-delivery, indefinite-quantity portion covering special studies and sustaining engineering NASA might ask General Dynamics to perform. NASA spokesman Michael Curie said the maximum value of that portion of the contract is $27 million.

Part of NASA’s Space Network, the ground segment works with the agency’s Tracking and Data Relay Satellite System (TDRSS) to provide global space-to-ground telecommunications and tracking coverage for near-Earth robotic and human spaceflight missions. The network’s ground segment comprises facilities and systems at the White Sands Complex in Las Cruces, N.M., the Guam Remote Ground Terminal in Guam, and the Space Network Expansion East in Blossom Point, Md.

Under the terms of the contract, General Dynamics will modernize the ground segment, including replacing obsolete systems and creating a more flexible and expandable architecture, the news release states. The work also will improve communications between the Space Network’s user-control centers and ground segment facilities for data and service planning and control.

General Dynamics was part of the team led by Chicago-based Boeing selected in 2007 to build a new generation of TDRSS satellites, with responsibility for upgrading the TDRSS ground segment at White Sands.