Explorer 47Rocket launchby USALaunch time23 Sep 197213:20 UTCsuccessOrbit: HEOSerial number: Delta 90First successful flight of Delta-1000 series.MissionRocketPayloadsRocket Delta1604launched from Cape Canaveral, SLC-17BUSAPayloadsNamePurposeMassCommentExplorer 47 (IMP-I)Magnetospheric research satellite--