WASHINGTON — NASA has agreed to pay Boeing Satellite Systems some $289 million to build an additional Tracking and Data Relay Satellite (TDRS). The U.S. space agency placed the spacecraft order as the first of two available contract options was about to expire.

Boeing is currently building two satellites, TDRS-K and TDRS–L, under a $700 million fixed-price contract NASA awarded in 2007 to replenish the constellation of geosynchronous satellites the agency uses to communicate with the international space station and other spacecraft in near-Earth orbit. The contract gave NASA until Nov. 30, 2011, to order TDRS-M; the second option, for TDRS-N, expires Nov. 30, 2012.

NASA said exercising the contract option extends Boeing’s period of performance through April 2024 and will allow the El Segundo, Calif.-based company to retain at least 300 jobs.

“With the first-generation TDRS spacecraft retiring by 2015, NASA must continue to replenish the fleet,” Pete Vrostos, network services director for space communications and navigation at NASA headquarters here, said in a statement. “TDRS-M is the agency’s first step in assuring the space network will meet NASA’s and the U.S. government’s relay satellite requirements by 2017.”

The TDRS constellation — which is frequently used by the U.S. Department of Defense, Missile Defense Agency, National Science Foundation and others — comprises eight satellites, including six active satellites and two backups.

The next satellite in the constellation, TDRS-K, is due to launch aboard a United Launch Alliance Atlas 5 rocket in late 2012, followed by TDRS-L in mid-2013.

Dan Leone is a SpaceNews staff writer, covering NASA, NOAA and a growing number of entrepreneurial space companies. He earned a bachelor’s degree in public communications from the American University in Washington.