The European Space Agency published the results of the investigation carried out after the Vega VV17 ruling by an independent commission. The report confirms that the failure was caused by an error in the procedures associated with the AVUM fourth stage integration.
On Tuesday, November 17, Arianespace announced the loss of the Vega VV17 mission, which was carrying two payloads, SEOSAT-Ingenio , an Earth observation satellite developed in Spain, and TARANIS for the French National Center for Space Studies (CNES) . The rocket’s first three stages ran nominally until the AVUM upper stage ignited, eight minutes after lift-off. At that time a degraded trajectory was detected, followed by a loss of vehicle control and subsequent loss of mission.
Investigations initial , performed immediately after the release with the available data, identified a problem related to the integration of control system vector thrust (TVC) of AVUM, the fourth stage, the most likely cause of the loss of control of the pitcher.
Arianespace, the launch service provider, and the European Space Agency (ESA), the launch system development authority, immediately established an Independent Investigation Commission (IEC). The Commission provided the detailed report and conclusions confirming the initially identified root causes of the failure, fully explaining what went wrong in the integration process and why the error was not detected before the flight. According to its findings, the Commission accordingly drew up a roadmap for a robust return to Vega’s flight, the agency said in its statement.
More precisely, the Commission concludes that the cause of failure of the VV17 is not attributable to a failure in the design qualification, but to the incorrect routing and connection of the control lines of the electromechanical actuators of the AVUM upper stage thrust vector control, reversing steering commands and causing path degradation that led to the loss of the vehicle. The detailed series of causes is described as (i) an erroneous integration procedure that causes (ii) an inversion of electrical connections, not detected through (iii) the different control steps and tests carried out between the integration of the upper stage AVUM and final pitcher acceptance due to some inconsistencies between specific requirements and prescribed controls.
The Commission presented a comprehensive set of immediate and permanent recommendations to ensure a safe and rapid return to flight, as well as to ensure the long-term reliability of launch vehicles. The first set of recommendations includes additional inspections and tests on the next two Vega launchers, whose hardware is already fully or partially produced, and on labor. Permanent recommendations have been proposed to further mitigate the identified root causes, with respect to the manufacturing, integration and acceptance processes in Vega’s assembly lines in Italy and their final acceptance in French Guiana.
Starting this week, a working group led by ESA and Arianespace has begun to implement the roadmap proposed by the Commission and will closely monitor its implementation. A set of actions will be implemented by Vega’s prime contractor, Avio, under the supervision of Arianespace, as the launch service provider, and ESA, as the launch system development authority, in order to make the next launch possible. de Vega, VV18, still scheduled for the first quarter of 2021.
“Thanks to their hard work in less than a month, the Commission members have confirmed the cause initially identified after the loss of control of the VV17 mission,” said Stéphane Israël, CEO of Arianespace. “The clarity of the conclusions presented by the independent commission opens the way for the immediate implementation by Avio, Vega’s main contractor, of the recommendations on its integration line, with the support of Arianespace and ESA. This may allow a return to flight by the end of the first quarter of 2021, with full confidence in the quality and competitiveness of Vega in the market.
Daniel Neuenschwander, ESA Director of Space Transport, said: “In recent weeks, the members of the Independent Inquiry Commission have done an exceptional job, with the support of the main contractor Avio. The Commission has drawn up a series of recommendations that, once implemented, should allow a robust, reliable and even rapid return to the Vega flight, helping to ensure autonomy of access to the European Space ”.
Source: ESA
