Today’s Ariane 5 launch NOT a failure


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Arianespace’s first launch attempt in 2018 appears to have gotten the satellites into orbit, even though contact was lost during launch.

From the reports, it appears that contact was lost when the second stage began firing.

Before this, the Ariane 5 had completed 83 straight successful launches, a track record that Arianespace repeatedly touted as justification for its higher rates.

Update: Arianespace is now saying that though they had entirely lost contact with the rocket after the second stage fired, the satellite’s themselves reached orbit.

A few seconds after ignition of the upper stage, the second tracking station located in Natal, Brazil, did not acquire the launcher telemetry. This lack of telemetry lasted throughout the rest of powered flight.

Subsequently, both satellites were confirmed separated, acquired and they are on orbit. SES-14 and Al Yah 3 are communicating with their respective control centers. Both missions are continuing.

It appears that the SES-14 satellite can reach its planned orbit using its own engines. Al Yah 3’s status is less certain.

If these results hold up, I will then declare, for the purpose of my 2018 launch standings, that this launch is a success for Arianespace. Arianespace however will certainly not consider it so, and will need to figure out why it lost contact with its rocket and why the upper stage did not function as planned.

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8 comments

  • mkent

    Now they’re saying the payloads made orbit. Stay tuned.

  • Kirk

    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”.

  • Edward

    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.

  • Kirk

    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.

  • Kirk

    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.

  • Kirk

    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.

  • Kirk

    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.

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