Yesterday Atlas V (431) rocket operated by United Launch Alliance delivered to orbit fifth Echostar satellite in its history. Echostar-19 was deployed on Super-Synchronous Orbit and will start to operate and provide HughesNet service as soon as it reach GTO orbit with altitude of 35880 km.
After 138 launches it should not be surprising – we have another success of Atlas V. United Launch Alliance managed to deliver Echostar-19 communication satellite to Super-Synchronous Orbit, from where it will begun its journey to GTO orbit with altitude of 35880 km. It will operate from 97.1° West orbital slot. Weighing 6300 kg satellite built by SSL on SSL-1300 bus, will provide broadband internet access under HughesNet service offered by subsidiary of Echostar, Hughes Network Systems. Satellite will also provide internet access for passengers of planes flying on high altitude. It will join to two other satellites operating from following orbital slots: 107.1° West (Echostar-17) and 95° West (Spaceway-3). Satellite will start to operate after in -orbit tests on March 2017 and it will cover with range of its Ka-band high efficiency transponders North America.
ULA decided to use for delivering Echostar-19 431 configuration of Atlas V. It was third launch of this rocket – last time rocket with 4 m fairing, three AJ-60A boosters and upper stage with single engine was launched in 2009 and earlier in 2005. Satellite was encapsulated on 5 December and rocket was rolled out on 17 December 2016 from assembly building to the pad at Cape Canaveral’s Complex 41. Launch was planned for Sunday for 18:27 UTC. Countdown begun on 06:07 EST on 18 December and around fifteen minutes later guidance system test was conducted. On 11:53 UTC first weather forecasts were given with 70% of launch probability. At 15:26 UTC planned countdown hold started and pad was cleared off. At 15:54 UTC fueling process begun and three minutes later countdown was resumed. At 17:23 tanks were full and in case of upper stage chilled as well. At 17:52 UTC countdown entered into planned hold phase – last weather forecast was announced five minutes later still giving green light for the mission. Rocket was ready to launch. Last polling for go was conducted at 18:17 UTC, five minutes later pyrotechnical charges were armed and enabled. At 18:24 UTC tanks reached correct pressure before launch. One minute later countdown was hold – rocket became safed and countdown recycled; launch window was extended to 20:27 UTC to give time for evaluating problem. At 18:58 UTC problem was found and six minutes later everything seemed to be fine. Polling was repeated just as part of the procedures – rocket wa switched to internal power and its safety system was armed. Finally at 19:12 UTC rocket started to raise over the launch pad. Three unsymmetrically installed boosters and RD-180 engines powering first stage started to work. At T+46″ rocket reached speed of 1 Ma and 12 seconds later entered into phase, when dynamic pressure reaches peak value. AT T+1’33” boosters were cut off and 32 seconds later they separated. Each long for 17 m with diameter at 1.6 m AJ-60A (made by Aerojet Rocketdyne) burned during 94 seconds 41 t HTPB providing thrust at 1688.4 kN. At T+4’30” RD-180 was cut off after burning 284 t of RP-1/LOX stored in tanks installed inside long for 32.46 m first stage (diameter is 3.81 m). Eight seconds later stage separated and at T+4’45” RL-10C, main propulsion of Centaur upper stage, started to work. It started to provide 101.8 kN of thrust burning 20830 kg of LH2/LOX; ten seconds later payload fairing was jettisoned. First cut off was performed at T+13’52”. After ballistic flight phase Centaur restarted engine at T+23’19”. After six minutes, at T+29’04” engine was cut off. Echostar-19 was deployed at T+32’08” on the correct orbit.