The Johns Hopkins University Applied Physics Laboratory (APL) said Nov. 1 that the TIMED science satellite it built for NASA at the beginning of the decade will continue to operate through 2014 under the latest mission extension approved by the U.S. space agency.

TIMED, short for Thermosphere, Ionosphere, Mesophere Energetics and Dynamics, has had its mission extended four times since its original two-year mission began in January 2002. The latest extended mission, which began Oct. 1, will focus on the sun’s effect on temperature changes in the upper atmosphere.

“The greenhouse gas loadings in the upper atmosphere have been increasing during the past few decades,” Sam Yee, the TIMED project scientist at APL in Laurel, Md., said in a statement. “The solar energy inputs and their effect on our atmosphere, however, are changing following the rising and declining activities of the solar cycles. Systematic observations taken longer than a full solar cycle would allow us to delineate potential human-induced changes from the naturally occurring solar-driven changes.”

By the time TIMED’s latest mission phase ends, the four-instrument spacecraft will have collected data during a full 11-year solar cycle. Built for roughly $200 million, the 660-kilogram satellite launched in December 2001 atop a Delta 2 rocket from Vandenberg Air Force Base, Calif.