Vega-C Zefiro40 Test: Independent Enquiry Commission
announces conclusions
Following the failure of the
Vega-C launch (VV22) in December 2022, an
Independent Enquiry Commission drew several
conclusions and made recommendations to ensure a
reliable return to flight and a robust exploitation.
One of the recommendations was to implement a
(delta-)qualification of the nozzle with a new
Carbon-Carbon throat insert material different from
that previously used on the Zefiro40, the solid
rocket booster of the Vega-C second stage. On 28
June 2023, a static firing test of the modified
Zefiro40 engine took place at the test bench in
Salto di Quirra in Italy. During the test the engine
nozzle suffered significant damages.
ESA Director General Josef
Aschbacher has set up an Independent Enquiry
Commission chaired by the ESA Inspector General,
Giovanni Colangelo, and composed of experts from
CNES, ASI, ESA, Arianespace and academia to
understand the cause of the test anomaly and propose
recommendations.
The Independent Enquiry
Commission concluded that in the current design of
the nozzle, the combination of the geometry of the
Carbon-Carbon throat insert and the different
thermo-mechanical properties of the new material
caused progressive damage of other adjacent nozzle
parts and a progressive degradation eventually
leading to the nozzle’s failure. This phenomenon is
not linked to those observed on VV22 with the
previous Carbon-Carbon material.
The Independent Enquiry
Commission has formulated a series of
recommendations including the need to improve the
nozzle design of the Zefiro40 motor, calibrate
numerical models to predict the behaviour and
conduct two more firing tests to verify performance
with the aim to ensure a reliable return to flight
and a robust commercial exploitation of Vega-C.
A task force steered by ESA and
Avio has been set up and will immediately start to
implement the recommendations proposed by the IEC.
Vega-C, undergoing design changes of the Zefiro40
nozzle and technical reviews as well as the two
firing tests, is expected to return to flight in the
fourth quarter of 2024. In the meantime, another
Vega flight will take place in the second quarter of
2024. A media briefing will be held by ESA, Avio and
Arianespace on 2 October at 12:30 CEST to detail
findings and answer questions.
ESA considers the return to
flight of Vega-C a strategic priority to secure
Europe’s independent access to space and will
support the necessary efforts drawing from already
available resources.
Avio in its role as Design
Authority is committed to fully implement the
recommendations of the Independent Enquiry
Commission and is responsible for the return to
flight of Vega-C.
ESA, as launch system
qualification authority, Avio, as design authority
and prime contractor of the Vega launcher and
Arianespace, as launch service provider, will
continue their joint efforts to achieve the common
objective of a robust exploitation of the Vega
launch system, for the benefit of their
institutional and commercial customers.