Vega C: Successful First Test of the Upgraded Zefiro 40 Engine

Today, in a press release, the Italian space company Avio announced a successful firing test of the Zefiro 40 second stage of the Vega C rocket. The test featured the new improved engine nozzle, completely redesigned after a series of failures that grounded Vega C for more than a year. This was the first of two static-fire tests planned for 2024.

*Static-fire test of the Zefiro 40 engine on May 28. Credits: Avio*

Zefiro 40 is a key component of the Vega C rocket, a larger evolution of the Vega launch vehicle, which is equipped with a Zefiro 23 second stage. Z40 provides 200 kN more thrust compared to its predecessor Z23. This, together with the P120C first stage, allows the launch of up to 2300 kg of payload into a polar orbit with a wider mix of different cargoes in terms of shape and weight. Avio is the prime contractor for the production of Vega C, while Arianespace is responsible for the commercial exploitation of the launch vehicle.

A first step towards the return to flight

The 7.6-meter tall solid rocket stage, produced at Colleferro near Rome, was tested on its horizontal test bench at Avio’s Salto di Quirra test facility in Sardinia, Italy. The engine was ignited for a total duration of 94 seconds, thus simulating a nominal in-flight performance. As stated by the company, “initial post review indicates that the new nozzle assembly performed as expected”.

*The Vega C Z40 second stage on the test bench in Sardinia, Italy. Credits: Arianespace*

Now, an additional test is scheduled again in Sardinia for October. This will be crucial for qualifying the second stage in anticipation of the Vega C’s return to launch by the end of the year. The mission will carry the ESA’s Sentinel 1C Earth observation satellite.

These tests are of great importance for Avio, Arianespace, and ESA, especially in light of the retirement of the Vega after its last flight this summer, and the dense launch schedule for 2025 and the years to come.

A troubled rocket

The development of Vega C began in 2014 to enhance the capabilities of the Vega rocket family. The first flight, VV-21, was successfully carried out in July 2022. In December of the same year, during the VV-22 mission, the failure of the Z40 second stage caused the loss of two Airbus Pléiades Neo imaging satellites. An independent ESA investigation revealed that the incident was caused by a ‘thermo-mechanical over-erosion’ of an engine component.

Vega C rocket lifting off from Europe's Spaceport during its maiden launch in July 2022 for VV21 mission. Credits: ESA/S.Corvaja — *Vega C rocket lifting off from Europe’s Spaceport during its maiden launch in July 2022 for VV21 mission. Credits: ESA/S.Corvaja*

A failure of the solid-fuel stage during a static-fire test in June 2023 indefinitely postponed the rocket’s return to flight. Following another investigation, ESA determined that the motor nozzle needed to be completely redesigned and tested.

Now, this latest successful test gives good hope for the return to service of the Vega C, which is a key asset for European indipendent access to space. Over these years, due to delays with Ariane 6 and the absence of Vega C, various institutional and scientific missions have been shifted to SpaceX’s Falcon 9.

Vega-C VV21 with LARES-2 ready for launch on 13 July 2022 at Europe's Spaceport in Kourou, French Guiana. Credits: ESA — *Vega-C VV21 ready for launch on July 13, 2022 at Europe’s Spaceport in Kourou, French Guiana. Credits: ESA*

Not least, it is interesting to note that despite ESA’s approval of Avio for autonomous commercialization of the launcher last November, this transition has not yet been completed. In fact, both in this latest announcement and for the previous commissioning of the SMILE mission launch, Arianespace is still indicated as the launch service provider for Vega C.