The second Global Positioning System Block IIA satellite on Monday reached 20 years on orbit. It’s still functioning as part of the current 31-satellite GPS constellation. The Air Force and its industry partners launched GPS Block IIA-11 (SVN-24) into space on July 4, 1991; USAF cleared it for use on Aug. 31, 1991. SVN-24 follows SVN-23 (Block IIA-10) in achieving the milestone of 20 years in space. The latter entered the realm on Nov. 26, 1990. Both have functioned on orbit nearly three times longer than the 7.5-year design life of the Rockwell-built (now Boeing) Block IIA spacecraft. The current GPS constellation consists of: 11GPS Block IIAs, 12 Block IIRs, 7 Block IIR-Ms, and the first Block IIF satellite. The second IIF spacecraft is on track to launch from Cape Canaveral AFS, Fla., on July 14. (Los Angeles release)
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