 within 0.1° of their nominal orbital longitude, if an Operation Gyrostat 2nd Stage Erect configuration antenna and extend panel Launch Despin payload Perigree stage and Orbit Stable spacecraft spun touch-up spinner and separated from configuration 2nd stage drift (about 200km altitude) Perigree Drift stage fired orbit Apogee Spacecraft motor Orientation reoriented fired and tracked Figure 51.3 Launch sequence of a Hughes spin stabilised geostationary communications satellite using a Delta 3910 expendable launcher 51/8 Communication satellites and systems Table 51.5 Characteristics of the major communication satellite launchers Space Atlas 2 Delta II Proton 4 Ariane 4 Titan IV shuttle March 3 Country Japan Europe China Developer NASA/ NASDA/ General McDonnell Glancosmos ESA/CVES Martin Rockwell Mitsubishi Dynamics Douglas Ministry of Marietta International Machines Length x 56.1 x 23.79 35.35x2.44 475. 3.05 38.4 x 2.44 44.3x7.4 57.1 3.8 43.83 x 3.35 60 x 3.05 diameter (m) Mass (kg) 2040815 135000 187560 228100 700000 243000 202000 800000 Capability Due East 350kg 6780kg to 539kg to Using 4th 1900kg to 1400kg to 1770 to launch from geostationary low earth 28.7° stage block geostationary 31° 200- 28.6° low orbit orbit; 185km; DM 2120ks transfer 35500km earth orbit. Canaveral. 2740kg to 3819kg to orbit; 4600 geostationary Use Centaur Maximum geostationary 90° 185km. geostationary to low earth transfer orbit or ISU for payload into transfer orbit Uses upper transfer orbit orbit geostationary low earth stages for transfer orbit higher orbits orbit or 29478kg geostationary orbit entering service east-west perturbation would cause unacceptable interference to usually obtained from infra red Earth sensors, supplemented by Sun another system (ITU, 1990m). The constraint is eased to 0.5° for sensors. Antenna pointing accuracy of + 0.2° or better is obtained experimental satellites and satellites which do not use fixed satellite with such systems. The thrusters which are used for east-west orbit frequency bands (ITU, 1990n)