Al Yah 3

 2018-012B

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Yahsat satellite with Ka-band payload. Orbital Geostar-3.

Flight VA241 took off on time, but headed on entirely the wrong launch azimuth, and the rocket delivered the payloads to a 20 degree inclination orbit instead of the planned 3 degree one. Because of the incorrect trajectory, ground controllers lost telemetry around the time of ESC-A ignition, leading to fears the mission was entirely lost - but the satellites were later found in orbits with the correct apogee and perigee, and the wrong inclination.

The investigation report confirms that a single wrong number was responsible for the incorrect orbit achieved by Ariane V241/L5101. The inertial reference system was aligned at the usual 90 degrees azimuth, but for this mission - targeted at a slightly different transfer orbit than usual - 70 degrees should have been specified.

SES-14
Date	Time	Event	Orbit
2018 Jan 25	2220	Launch by Ariane 5ECA L5101	CSG ELA3
		T+0:07 Liftoff
		T+2:19 EAP sep
		T+3:18 Fairing sep
		T+8:51 EPC MECO
		T+8:58 EPC sep
	2229	T+9:01 ESC-A burn
	2244	T+24:46 ESC-A MECO
	2247	T+27:05 SES-14 sep
	2253	T+33:22 SYLDA sep
	2255	T+35:07 Al Yah 3 sep
2018 Jan 26			780.28 231 x 43164 x 20.7
2018 Feb 1	1540	LAM-1, at apogee 48 m/s ?	789.42 677 x 43155 x 20.0
2018 Feb 7	0807	LAM-2 at 34000 km 528 m/s?	1009.90 6141 x 47790 x 21.5
2018 Feb 10	1245	LAM 3 at 44170 km 631 m/s?	1202.1 14973 x 47192 x 9.3
2018 Feb 13	0051	LAM4 at 44000 km 266 m/s?	1350.92 20923 x 47281 x 6.2
2018 Feb 15			1348.08 20828 x 47263 x 6.2
2018 Feb 15			1415.75 23343 x 47524 x 5.6
2018 Feb 22			1415.75 23344 x 47430 x 5.5 GEO 150.9W + 5.2E/d
2018 Feb 27			1440.46 24245 x 47499 x 5.2
2018 Mar 5			1447,44 255225 x 46792 x
2018 Mar 16			1452.53 27504 x 44710 x 3.8 GEO 158.5W-4.1W/d
2018 Apr 13			1454.68 33757 x 38541 x 1.1
2018 Apr 24			1439.92 35855 x 35867 x 0.1 GEO 14.4W+1.0W/d
2018 Apr 30			1438.78 35812 x 35866 x 0.1 GEO 19.3W+0.7W/d
2018 May 2		On station	1436.10 35780 x 35792 x 0.1 GEO 20.1W
2018 May 9			1436.11 35783 x 35791 x 0.0 GEO 20.1W
2018 Jun 7			1436.05 35777 x 35794 x 0.0 GEO 20.1W