Vega rocket fails to reach orbit, losing two payloads

A Vega rocket lifts off. Credit: Arianespace

NOV. 18, 2020–On Monday night, Vega mission VV17 lifted off from the European Space Agency (ESA)’s launch site in Kourou, French Guiana, on an ill-fated mission. While the first three stages performed nominally, when the fourth stage, known as the Attitude Vernier Upper Module, or AVUM, fired eight minutes into the flight, things began to go astray. ESA Ground Control watched as the trajectory of the mission slowly degraded, followed by a total loss of control of the stage, and finally, confirming the loss of the mission and its two payloads.

This mission was originally set to place the upper stage into a parking orbit in order to complete burns to deploy two satellites into correct orbits. However, as the stage failed, Vega came just short of reaching orbit, re-entering the atmosphere over the arctic. While the cause of failure was not immediately clear, Arianespace later pinpointed the error to the integration of AVUM’s nozzle activation system. According to Arianespace’s CTO, Roland Lagier, the exact culprit was found to be human error, as two cables were crossed and connected incorrectly during the fabrication of the stage. These cables were attached to the thrust vectoring system of the stage, which allows the engine nozzle to move in order to direct thrust to maintain its orientation and steer, and in this case, caused the corrections from the nozzle to be inverted, leading to a loss of control. This is similar to a problem with Roscosmos’ Proton K rocket that happened in 2013, where a series of accelerometers were installed upside down, causing the rocket to flip and crash into the ground.

Vega’s AVUM upper stage. Credit: Arianespace

VV17 was set to deliver two satellites into orbit, SEOSAT-Ingenio, and TARANIS. The former was a Spanish Satellite meant to image the Earth’s surface in order to monitor land use in order to plan for urban development and manage water usage, and the latter, TARANIS, was a satellite from the French space agency CNES, designed to observe luminous, radiative, and electromagnetic phenomenons. Both satellites were inevitably lost in the mission. ESA is now communicating with the Spanish government in order to establish a system to replace SEOSAT-Ingenio.

The Vega rocket, similar to the one flown on this mission. Credit: Space Scout/Lavie Ohana

The Vega rocket is a four-stage commercial rocket designed to launch small and medium payloads by Arianespace, an aerospace corporation based in France. Vega is one of a family of rockets, with other Arianespace rockets including the Ariane 5 as well as the upcoming Ariane 6 and Vega-C rockets. Vega is built to be able to take 1500 kg to a circular polar orbit, as well as rideshares for CubeSats. The rocket has three solid stages, known as the P80, Zefiro-23, and Zefiro-9, with the fourth being the liquid-fueled AVUM stage that failed on this mission. Vega is an international rocket, being worked on by many member states of the European Space Agency. The upcoming Vega-C rocket is an upgraded version of the Vega, with a 50% boost in payload capacity to polar orbits.

The Trajectory of the AVUM upper stage on flight VV17. Credit: Arianespace.

This mission marks the second failure of a Vega rocket in the last 3 launches, as Vega mission VV15 which was carrying the UAE’s Falcon Eye-1 failed in late 2019. The Zefiro-23 solid-fueled second stage suffered a structural problem 14 seconds into the burn, causing a breakup of the rocket and mission failure.

ESA Director-General Jan Wörner commented on the situation, saying “I will personally make sure that we fully understand the root cause, but also that we bring Vega back to the robustness and reliability of service it has shown since its first launch in 2012.” Prior to the last 3 launches, Vega launched 14 consecutive successful missions.

Best of luck to ESA, Arianespace, and CNES in fixing Vega’s problems and implementing better testing regimes.

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