page_title: Ariane flight VA241
section_title: Anomaly
hierarchical_section_title: Ariane flight VA241 / Anomaly
caption_attribution_description: Agami Viewing Site, Guyana Space Centre, Kourou, French Guyana, FRANCE
context_page_description: Ariane flight VA241 was an Ariane 5 space launch that occurred from the Guiana Space Centre on 25 January 2018 at 22:20 UTC.
context_section_description: The telemetry of the launcher was lost from about 9 minutes to 9 minutes and 30 seconds (the uncertainty being due to the fact that the data as displayed in real-time may have been extrapolated for a finite amount of time) into the flight, close to the moment when the main stage (EPC) separation and upper stage (ESC-A) ignition should have occurred.
  Then about 1 hour after liftoff, Arianespace's CEO and chairman Stéphane Israël made a quick speech saying that the launcher suffered an anomaly. His statement in front of the VIP audience in the Jupiter control room was:
  "Ladies and gentlemen, so I come to give you some information because we have had an anomaly on this launch. Indeed, we lost contact with the launcher a few seconds after the ignition of the upper stage. At that time, we can consider that the upper composite and the satellite[s] have been satellised [sic: bad translation of French satellisés, meaning put in orbit]. But as I said, we lost contact. So up to now, our customers do not have contact with the satellite[s]. We need now some time to know if they have been separated [sic], and where they are exactly, to better analyse the consequences of this anomaly. I want to present my deepest excuses to our customers, who have entrusted us one more time. We know that there is no launch with no risk. We know that launch is always difficult, and tonight Ariane 5 has had an anomaly, so let's take time now to better understand the situation of the satellite[s]. Arianespace, in full transparency, will come back to you to provide you with some more information as soon as we have them. I apologise on behalf of Arianespace."
  Later in the night, Arianespace issued a first press release mentioning that the Natal tracking station did not acquire telemetry of the launcher, which lasted until the end of the mission, and that the separation of both payloads was confirmed, together with their successful injection into Earth orbit and the link acquisition by both customers.
  On the same day, Arianespace issued a second press release stating that SES and YahSat confirmed the acquisition and good health of the two satellites despite a deviation of their trajectory. It was also stated that the telemetry was lost by the tracking stations 9 minutes and 26 seconds after reference time T, due to a deviation of the trajectory.
  On 26 January 2018, SES informed on their website that while its satellite is in good health it would require to "set up a new orbit raising plan", and that it would thus "reach the geostationary orbit only four weeks later than originally planned", indicating that the satellites were not delivered to the intended super-synchronous transfer orbit (with an apogee of 45,000 km and inclination of 3°) by the launch vehicle. This was confirmed later that day when the orbital elements of the satellites were released, revealing that the deployment orbit's apogee had a minor deviation of about 2,000 km while the inclination suffered a significant deviation of almost 18° from intended.
  The flight path anomaly became obvious when initial analysis showed that the launch azimuth had gone wrong since the very beginning of the flight, during the first stage firing, with unexpected slow roll maneuvre just after liftoff. In standard Ariane 5 launch, the roll maneuvre should only begin around 17 seconds after reference time T or 10 seconds after liftoff.
  The anomaly might have been due to a human error during the programming of the Guidance, Navigation and Control (GNC) combined with a failed verification procedure according to early developments as the launch team reported not to have double-checked the guidance computer parameters to reduce workload duplication, even though double-checking them played the vital role in the rocket's reliability. But Arianespace and ArianeGroup issued a statement insisting that all the control processes remain unchanged, while they restructured the organization now directly from ArianeGroup, affecting the launch team now with many of ArianeGroup engineers.
  Frédérique Vidal, Minister of Higher Educat
caption: The Ariane 5 ECA on the launch pad prior to launch.
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