WASHINGTON — The launch of three U.S. Air Force space surveillance satellites July 24 was postponed for the second time in as many days, this time because of weather conditions, according to a United Launch Alliance spokeswoman.

The trio of satellites comprising the Air Force Space Command (AFSC)-4 mission was scheduled to lift off from Cape Canaveral Air Force Station in Florida around 7 p.m. EDT aboard a ULA Delta 4 rocket. But the weather never cleared enough during a 65-minute window.

The postponement followed a delay July 23 caused by “an issue with the ground support equipment environmental control system that supports the launch vehicle,” ULA spokeswoman Jessica Rye said. ULA has rescheduled the launch for July 25 at 6:55 p.m., although weather forecasts only show a 40 percent chance of favorable conditions then, she said.

The primary payload onboard the Delta 4 are two satellites that will serve as the first-generation of the Geosynchronous Space Situational Awareness Program, a previously classified space surveillance system first disclosed in February by Gen. William Shelton, commander of Air Force Space Command.

The rocket will also carry the Automated Navigation and Guidance Experiment for Local Space, or ANGELS, satellite. Managed by the Air Force Research Lab at Kirtland Air Force Base in New Mexico, the satellite is intended to test multiple techniques “for providing a clearer picture of the environment around our vital space elements,” according to an Air Force ANGELS fact sheet.

All three satellites were built by Orbital Sciences Corp. of Dulles, Virginia.

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Mike Gruss is a senior staff writer for SpaceNews. He joined the publication in January 2013 to cover military space. Previously, he worked as a reporter and columnist for The Virginian-Pilot in Norfolk, Va. and The Journal Gazette in Fort Wayne, Ind. He...