Dry mass Diameter Length kg m to end of nozzles Transtage (-1973) 1960? 3.05 4.51 Improved Transtage (1973-) 1828 3.05 4.51 Agena 556 1.52 6.32 IABS 270 2.90 0.70 IUS SRM-2 985 2.5? 3.1? (with EEC) IUS SRM-2 (STS) 1010 2.5? 3.1? Mage 1 30 0.76 1.30 Star 27 (in GOES adapter) 30? 0.68 1.3?