A Zefiro 9-A motor completed its first firing test at the Salto di Quirra Inter-force Test Range in Sardinia (Italy), the European Space Agency announced.

This was the penultimate firing test for the engine prior to the Vega launcher’s qualification flight, scheduled to take place by the end of next year.

The Zefiro 9-A (Z9-A) solid-fuel rocket motor, which will power the Vega launch vehicle’s third stage, left the production facility of Avio, in Colleferro, Italy, at the end of September and was installed at the test site over the last three weeks.

After a nominal 120-second burn time, during which a maximum combustion pressure of 75 bar was reached, the roar of the motor stopped as expected.

The first results confirm the expected performance increase for this enhanced version of the motor, as well as the robustness of the modifications introduced in the nozzle design.

This improved version of the Z9, with its new nozzle design and an optimized propellant loading, is fully flight-representative of the Vega third-stage motor — the only exception being the use of a truncated nozzle in order to partially adapt the motor to sea-level conditions

The Zefiro 9-A motor, with an overall height of 3.17 meters (10.4 feet) and a diameter of 1.92 meters (6.3 feet), contains 10.5 tons of propellant and provides a maximum thrust of 320 kN (about 32.6 tons-force), in vacuum. The Z9-A has the highest propellant-mass to inert-mass ratio of any space-transportation solid-propellant rocket motor ever fired, according to the ESA.

Some 400 sensors fitted to the motor allowed monitoring of its behavior during and after the firing test. The data collected will enable engineers from ELV SpA (Italy), the Vega launch vehicle prime contractor, and Avio SpA (Italy), in charge of motor development and qualification, to check its performance, in particular:

• Ballistic performance (pressure and thrust curves)
• Internal thermal-protection efficiency
• Thrust-vector control performance
• Induced thermal and dynamic environment

Following the test firing, the motor will be shipped back to Colleferro, for detailed inspection.

A second qualification test for the Zefiro 9-A is planned for February. This will complete the qualification process of the Vega solid rocket motors. The P80 first-stage motor and the Z23 second-stage motor, both of which also use solid propellant, have already completed successful qualification firing tests.

The Vega launcher qualification flight is scheduled to take place before the end of next year from Europe’s spaceport at Kourou, in French Guiana, South America.

Vega is a single-body launcher composed of three solid-propellant stages and a liquid-propellant upper module.