 Nozzle of the Zefiro 23,Paris Air Show 2015 | |
| Manufacturer | Avio |
|---|---|
| Country of origin | Italy |
| Used on | |
| Launch history | |
| Status | Active |
| Total launches | 23 |
| Successes (stage only) | 21 |
| Failed | 2 |
| First flight | 13 February 2012 |
| Last flight | 11 July 2019 |
| Second stage (Vega) – Zefiro 23[1] | |
| Height | 8.39 m (27 ft 6 in) |
| Diameter | 1.9 m (6 ft 3 in) |
| Empty mass | 2,486 kg (5,481 lb) |
| Gross mass | 26,300 kg (58,000 lb) |
| Propellant mass | 23,814 kg (52,501 lb) |
| Maximum thrust | 1,120 kN (250,000 lbf) |
| Specific impulse | 287.5 s (2.819 km/s) |
| Burn time | 77.1 seconds |
| Propellant | AP /Al–HTPB (1912APCP) |
| Second stage (Vega C / Vega E) – Zefiro 40[2] | |
| Height | 8.07 m (26 ft 6 in) |
| Diameter | 2.4 m (7 ft 10 in) |
| Gross mass | 40,477 kg (89,237 lb) |
| Propellant mass | 36,239 kg (79,893 lb) |
| Maximum thrust | 1,304 kN (293,000 lbf) |
| Specific impulse | 293.5 s (2.878 km/s) |
| Burn time | 92.9 seconds |
| Propellant | AP /Al–HTPB |
| Third stage (Vega / Vega C) – Zefiro 9[3] | |
| Height | 4.12 m (13.5 ft) |
| Diameter | 1.9 m (6 ft 3 in) |
| Empty mass | 1,315 kg (2,899 lb) |
| Gross mass | 12,000 kg (26,000 lb) |
| Propellant mass | 10,567 kg (23,296 lb) |
| Maximum thrust | 317 kN (71,000 lbf) |
| Specific impulse | 295.9 s (2.902 km/s) |
| Burn time | 119.6 seconds |
| Propellant | AP /Al–HTPB (HTPB 1912APCP) |
Zefiro is a family ofsolid-fuelrocket motors developed byAvio and used on theEuropean Space AgencyVega rocket. The name Zefiro derives from the acronymZEroFIrst stageROcket,[4] conceived when this motor was intended to be used as first and second stages ofSan Marco program of theItalian Space Agency (ASI). The name also references theGreek god of the west wind,Zephyrus.
As of 2024[update], two modelsZefiro 40 andZefiro 9 are in use on theVega C rocket. TheZefiro 23, which powered the originalVega is no longer in production.
The first engine completed was Zefiro 9, the third stage engine. The first test firing was carried out on 20 December 2005, at theSalto di Quirra Inter-force Test Range, on theMediterranean coast in southeastSardinia. The test was a complete success.[5] After a critical design review based on the completed first test firings,[6] the second test-firing of theZefiro 9 took place at Salto di Quirra on 28 March 2007. After 35 seconds, there was a sudden drop in the motor's internal pressure, leading to an increased combustion time.[7] On 23 October 2008, an enhanced version of theZefiro 9 with a modified nozzle design and increased propellant load, theZefiro 9A, was successfully tested.[8] On 28 April 2009, the final qualification test firing ofZefiro 9A took place at the Salto di Quirra Interforce Test Range in Sardinia, Italy.[9]
TheZefiro 23 was test fired twice on 26 June 2006 and 27 March 2008 at Salto di Quirra. Both tests were successful and the motor qualified for use on Vega.[10][11]
Zefiro 40 first test occurred on 8 March 2018 also at Salto di Quirra with a successful 92 seconds burn.[12]
A failure of theZefiro 23 occurred shortly after the planned ignition during the FalconEye 1 mission on 11 July 2019 which resulted in the loss of the satellite and a mission failure. TheZefiro 23 was supposed to fire for 77 seconds. Telemetry data showed theVega rocket achieved a top speed of approximately 2.17 km/s, 233 seconds into flight. The rocket then deviated below its planned ascent trajectory before falling into theAtlantic Ocean north of theCentre Spatial Guyanais.[13]
A failure of a Zefiro-40 second stage occurred on 20 December 2022, reported as under-pressure issues at launch.[14]
The propellant of allZefiro models is HTPB 1912 with a nominal composition of 19% ofaluminium powder, 69% ofammonium perchlorate with 12% ofhydroxyl-terminated polybutadiene binder.[15]
Zefiro 23 andZefiro 9A, where the number represent the intended propellant weight at design phase, are used respectively as second and third stage of Vega rockets. Both motors have a 1.9 m diametercarbon epoxyfilament wound case, a low densityEPDM insulation, a flexiblerocket nozzle joint and an electromechanicalthrust vector control system.
Zefiro 23 is 7.5 meters tall and weighs 26 tonnes, of which 24 tonnes consist of solid propellant. It has a nominal burn time of 103 seconds with combustion chamber pressure of 95bars.[1][16]
Zefiro 9A, designed and built exclusively with Avio technologies, is 3.5 metres tall, weighs 11.5 tonnes and burns 9 tonnes of solid propellant. It has a nominal burn time of 77 seconds with combustion chamber pressure of 95bars, consumed in slightly more than 110 seconds.[3][16]
Zefiro 40 is used as second stage of Vega-C and is intended to be used with the Vega-E. In comparison to its predecessorZefiro 23, the motor has an increased exercise pression, better structural load margins for both the casing and the propellant grains and an improved flexible rocket nozzle joint.[2]
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