Comments on: Today’s Ariane 5 launch NOT a failure https://behindtheblack.com/behind-the-black/points-of-information/todays-ariane-5-launch-not-a-failure/ Sat, 27 Jan 2018 21:44:55 +0000 hourly 1 https://wordpress.org/?v=6.9.4 By: Kirk https://behindtheblack.com/behind-the-black/points-of-information/todays-ariane-5-launch-not-a-failure/#comment-1039090 Sat, 27 Jan 2018 21:44:55 +0000 http://behindtheblack.com/?p=49949#comment-1039090 Discussions on NSF suggest that since SES-14 was originally built to launch from Florida, it would have significant propellant reserves. SpaceX’s Florida launches are from 28° North, and the lowest inclination GTO insertion they’ve provided to date is 20.55° with SES-8, quite similar to what was actually achieved by the wayward Ariane. There is the complication that SES-14’s apogee is not as the orbit crosses the equator, which is supposed to make the plane change more expensive, but it will probably arrive in its intended location without much less propellant than it would have had launching from the Cape.

]]> By: Kirk https://behindtheblack.com/behind-the-black/points-of-information/todays-ariane-5-launch-not-a-failure/#comment-1039079 Sat, 27 Jan 2018 18:23:32 +0000 http://behindtheblack.com/?p=49949#comment-1039079 SES-14 is already on its way, having raised perigee by 100 km since launch, though it appears that Al Yah 3 is still working out its flight plan.

2018-012A 43174 AL YAH 3 780.32min 20.65° 43164km 232km
2018-012B 43175 SES 14 783.17min 20.56° 43200km 334km
2018-012C 43176 ARIANE 5 R/B 771.77min 21.01° 42787km 198km
2018-012D 43177 ARIANE 5 DEB(SYLDA) 780.63min 20.67° 43177km 235km

SES-14 was planned to go into service in July, but this is now expected to be pushed back at least until August.

]]> By: Kirk https://behindtheblack.com/behind-the-black/points-of-information/todays-ariane-5-launch-not-a-failure/#comment-1039067 Sat, 27 Jan 2018 16:30:17 +0000 http://behindtheblack.com/?p=49949#comment-1039067 Last summer SES swapped SES-12 (originally scheduled to fly on the Ariane) and SES-14 (originally scheduled to fly on a SpaceX Falcon 9) in order to get SES-12 into service sooner given the transponder failures on NSS-806. The SES-12 launch is still penciled in for 2018-Q1 but doesn’t have a solid date yet and I expect it to slip into April or possibly May.

]]> By: Kirk https://behindtheblack.com/behind-the-black/points-of-information/todays-ariane-5-launch-not-a-failure/#comment-1039065 Sat, 27 Jan 2018 16:19:31 +0000 http://behindtheblack.com/?p=49949#comment-1039065 Here SES reiterates that SES-14 will reach its operational orbit only four weeks late, and that they still expect it to meet its designed life time. It was presumably provisioned with a reserve to maintain station keeping well past that designed life time of 15 years and the extra maneuvering will eat into that. SES-14 is replacing NSS-806 which was launched in early 1998 and is still functioning almost 8 years past its designed life time, though it did lose the use of 12 of its 31 transponders last year.

I still haven’t heard anything definitive on Al Yah 3.

]]> By: Edward https://behindtheblack.com/behind-the-black/points-of-information/todays-ariane-5-launch-not-a-failure/#comment-1039009 Sat, 27 Jan 2018 01:03:12 +0000 http://behindtheblack.com/?p=49949#comment-1039009 Ouch!

20 degrees is way off target. One of the advantages of launching from Arianespace’s Kourou, French Guiana is that the geostationary transfer orbit — or in this case the supersynchronous transfer orbit — is only a couple of degrees of inclination. This requires less fuel onboard the satellite for getting into geostationary orbit than launching from KSC (28 degrees) or Russia (60-ish degrees).

The loss of 1/3 of one satellite’s lifespan and the possible loss of the other satellite’s entire mission has got to hurt Arianespace. They had worked hard, these past couple of decades, to gain an excellent reputation, and now they have to overcome this stain on it.

This was a big error.

]]> By: Kirk https://behindtheblack.com/behind-the-black/points-of-information/todays-ariane-5-launch-not-a-failure/#comment-1038995 Fri, 26 Jan 2018 21:56:50 +0000 http://behindtheblack.com/?p=49949#comment-1038995 I’ve been following the discussion on NSF, and it appears as if the first stage had the wrong azimuth from the start. It flew nearly over Natal instead of well north of it, and with the Natal tracking station looking where it expected the vehicle to be, neither it nor any of the subsequent tracking stations acquired signal.

The resulting orbit was about 230 x 43160 km x 20 deg. They were targeting 250 x 45000 km x 3 deg. That is a huge inclination error and with the orbit’s perigee at 15 deg S, corrections will take more delta-V than from a typical GTO orbit. SES says that their satellite will take an extra four weeks to correct its orbit and one calculation on NSF suggests that it will use additional propellant equivalent to about 4.5 years worth of station keeping.

Orbital-ATK isn’t as specific, only saying that they “are working to place the satellite into its intended orbit”.

]]> By: Edward https://behindtheblack.com/behind-the-black/points-of-information/todays-ariane-5-launch-not-a-failure/#comment-1038904 Fri, 26 Jan 2018 04:53:26 +0000 http://behindtheblack.com/?p=49949#comment-1038904 Whew!

]]> By: mkent https://behindtheblack.com/behind-the-black/points-of-information/todays-ariane-5-launch-not-a-failure/#comment-1038886 Fri, 26 Jan 2018 01:03:14 +0000 http://behindtheblack.com/?p=49949#comment-1038886 Now they’re saying the payloads made orbit. Stay tuned.

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