Bad Ariane launch fed by wrong data
February 26, 2018
By Chris Forrester
The January 25th launch by an Ariane rocket of two satellites, owned by SES of Luxembourg (SES-14) and Al Yah (YahSat-3) of Abu Dhabi, suffered a major trajectory deviation because wrong programming data was supplied to the rocket’s computers. Both satellites were subsequently contacted in orbit and given fresh guidance information.
At the time of the launch ordinary members of the public, lined up at a beach-side location to watch the lift-off, were alarmed that the rocket seemed to be flying overhead and not on a normal flight-path. The rocket was heading South-East, and not the more usual East, in its flight direction. Amateur video seemed to show that the rocket flew over French Guiana’s land, and not directly out over the Atlantic Ocean.
The official Board of Inquiry stated: “The azimuth required for the alignment of the inertial units was 70 degrees instead of 90 degrees, as is most often the case for missions to geostationary transfer orbit. This gap led to the 20-degree shift to the south in the launcher trajectory from the initial seconds of flight. The cause of the trajectory deviation, therefore, was due to a bad specification of one of the launcher mission parameters that was not detected during the standard quality checks carried out during the Ariane 5 launches’ preparation chain.”
Arianespace thanked the Board and stated that the cause of the anomaly was now “perfectly understood” which must be a relief for on-going clients for the launch company. Arianespace has been told to beef up their pre-flight verifications and to add extra checks.
The investigators stated there was no danger to the town of Kourou, just a few miles from the launch site.
While talk of an insurance claim from SES has subsided, there might still be a claim from Abu Dhabi because the intended life of its satellite appears to have been curtailed.
In fairness to Arianespace, this was the first malfunction of any major degree in 15 years of activity.