Flight 207: Ariane 5 ECA/Echostar-17 - Astrium - EADS

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Data relating to Flight 207 This is reference time H1, and occurs at about H0 + 141 s at an altitude of 67 km and a relative velocity of 2,012 m/s. For the remainder of the flight (EPC flight phase), the launcher follows an attitude law controlled in real time by the on-board computer, based on information received from the navigation unit. This law optimises the trajectory by minimising burn time and consequently consumption of propellant. The fairing is jettisoned during the EPC flight phase as soon as aerothermodynamic flux levels are sufficiently low not to impact the payload. For this mission, separation of the payload will occur about 197 s after lift-off at an altitude of 107 km. The EPC powered flight phase is aimed at a predetermined orbit established in relation to safety requirements, and the need to control the operation when the EPC falls back into the Atlantic Ocean. Shutdown of the Vulcain engine occurs when the following target orbit characteristics have been acquired: Apogee altitude 172.3 km Perigee altitude -1,064.3 km Inclination 7.2° Perigee argument -38.3° Ascending node longitude -124.2° This is time reference H2. It happens at H0 + 539.2 s. The main cryogenic stage (EPC) falls back into the Atlantic Ocean after separation (see below), breaking up at an altitude of between 80 and 60 km under the loads generated by atmospheric re-entry. The stage must be depressurised (passivated) to avoid any risk of explosion of the stage due to overheating of residual hydrogen. A hydrogen tank lateral nozzle, actuated by a time delay relay initiated on EPC separation, is used for this purpose. This lateral thrust is also used to spin the EPC, and thus limit breakup-induced debris dispersion on re-entry. The main cryogenic stage angle of re-entry is -2.6°. The longitude of the point of impact is 4.1°W. The subsequent ESC-A powered flight phase lasts about 16 minutes. This phase is terminated by a command signal from the OBC, when the computer estimates, from data calculated by the inertial guidance unit, that the target orbit has been acquired. This is time reference H3. It happens at H0 + 1,497.4 s. 12
Data relating to Flight 207 The purpose of the following ballistic phase is to ensure: • Pointing of the upper composite in the direction required by ECHOSTAR XVII and MSG-3 and then in that required for SYLDA 5, • Composite slow transverse spin-up before separation ECHOSTAR XVII • Triple-axis stabilisation before separation of SYLDA 5, • Composite slow spin-up at 30.7°/s before separation of MSG-3, • Separation of ECHOSTAR XVII, SYLDA 5 and MSG-3, • Final spin-up of the composite at 45°/s, • Passivation of the ESC-A stage pressurised LOX tank and LH2 tank, preceded by a prepassivation phase involving simultaneous opening of the eight SCAR nozzles. These operations contribute to short- and medium-term management of the mutual distancing of objects in orbit. The ballistic phase for the mission comprises 23 elementary phases described hereafter. These include separation of ECHOSTAR XVII (phase 5), SYLDA 5 separation (phase 10), and MSG-3 separation (phase 13). 13
Page 1 and 2: ARIANE 5 Data relating to Flight 20
Page 3 and 4: Data relating to Flight 207 1. Intr
Page 5 and 6: Data relating to Flight 207 Compare
Page 7 and 8: Data relating to Flight 207 ESC-A t
Page 9 and 10: Data relating to Flight 207 SYLDA 5
Page 11: Data relating to Flight 207 Flight
Page 15 and 16: Data relating to Flight 207 Staging
Page 17 and 18: Data relating to Flight 207 The fol
Page 19 and 20: Data relating to Flight 207 The sat
Page 21 and 22: Data relating to Flight 207 MSG-3 T
Page 23 and 24: Data relating to Flight 207 To prod
Page 25 and 26: Data relating to Flight 207 * Dimen
Page 27 and 28: Data relating to Flight 207 Princip
Page 29 and 30: Data relating to Flight 207 6. Laun
Page 31 and 32: Data relating to Flight 207 Synchro
Page 33 and 34: Data relating to Flight 207 H0 - 6s
Page 35 and 36: Data relating to Flight 207 time /H
Page 37 and 38: Data relating to Flight 207 Astrium

Flight 207: Ariane 5 ECA/Echostar-17 - Astrium - EADS

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