Europe's new Vega launch vehicle flew for the first time on February 13, 2012, achieving a flawless inaugural mission.  The small launcher lifted off at 10:00 UTC from the former ELA 1 pad, rebuilt as the Vega Launch Site (ZLV: Zone de Lancement Vega) at the Guiana Space Centre, in Kourou, French Guiana.  Flying the VV01 mission for the European Space Agency (ESA), Vega orbited two scientific satellites and seven picosatellites.  These included Italy’s 400 kg LARES laser relativity satellite, the 12.5 kg ALMASat-1 technology microsatellite demonstrator from the University of Bologne, and seven 1kg university CubeSats.

Vega is powered by three solid propellant stages and a liquid-propellant fourth stage.  The P80FW first stage, roughly speaking, corresponds to one segment of the standard P230 Ariane 5 booster, but is only loaded with 88.365 tonnes of HTPB propellant.  A P230 uses two 100 tonne segments and one 30 tonne segment.  In addition, P80FW uses a carbon-epoxy filament-wound motor casing rather than the steel casing used by P230.

The Zefiro-Z23 second stage and Zefiro-Z9A third stage were developed in Italy for Vega.  Vega’s liquid fourth stage, the restartable, hypergolic bipropellant Attitude and Vernier Upper Module (AVUM), is powered by a 250 kgf Ukranian RD-869 engine.  AVUM is loaded with 550 kg of UDMH/NTO propellant in four tanks. Vega is topped by a 2.6 meter diameter payload fairing. 

The four-stage rocket is designed to inject 1,500 kg into a 700 km x 90 deg polar orbit.  Vega weighed 136.7 tonnes at liftoff and stood 30.1 meters with a maximum diameter of 3 meters.   

During the VV01 mission, AVUM performed three burns.  The first burn trimmed the vehicle into a transfer orbit.  After a 40 minute coast, the second burn pushed the stage into a 1,450 km x 69.5 deg circular orbit, where it released LARES.  AVUM then fired again to reduce the perigee to 350 km before deploying the other payloads. 
 

The four-stage small/medium payload launcher was jointly developed by the Italian Space Agency and the European Space Agency (ESA). ELV S.p.A., a joint venture of Italy’s AVIO S.p.A. and the Italian Space Agency (ASI), is the Vega prime contractor.  

Background

Although the commercial communication satellites launched by Europe’s Arianespace launchers have grown larger and heavier, scientific and Earth observation satellites have tended to remain relatively light, weighing in at two tonnes or less.  Scientific satellites also tend to use polar or other orbits not used by geosynchronous satellites, minimizing chances for shared flights.  Vega was designed to fly such smaller payloads economically by lifting a reference 1.5 metric tonne payload into a 700 km polar orbit.

Although proposed to become a European project by the Italian Space Agency in 1998, Vega did not win ESA approval until December 2000.  In its final form, the project was reshaped to provide spin-off improvements for the Ariane 5 solid rocket booster.  Improvements include the development of a graphite epoxy filament wound case to replace the existing steel casing, an electromechanical thrust vector control system, and a carbon phenolic nozzle.   A modified composite propellant formula, HTPB 1912, was also selected.  Vega’s Zefiro motors were also to employ graphite epoxy filament wound casings.

Development funding totaled nearly $400 million by some accounts.  Italy provided 65% of the total.  France provided more than 12%.  Belgium, The Netherlands, Switzerland, and Sweden together funded the remainder. 

Vega’s target launch price was about $23.5 million, less than comparable U.S. launchers but substantially more than Russia’s comparable Rokot/Briz.  Like many government funded launch programs, the price will not necessarily correspond to the actual cost of the launcher.  ESA governments agreed to provide nearly $290 million of subsidies to the Vega program during its initial five launches.  By agreement, the launch price will remain fixed for several years.
 

The Design

Vega consists of three solid rocket stages topped by a liquid fourth stage.  The 310 tonne thrust P80 first stage is derived from a single segment of the Ariane 5 strap-on booster.  The second stage is a 122 tonne thrust Zefiro 23.  Stage Three is a 32 tonne thrust Zefiro 9.  All three stages are equipped with flexible nozzles and to control vehicle pitch and yaw during their burns. 

The fourth stage, named “Attitude and Vernier Module” (AVUM), is equipped with a low-thrust liquid hypergolic propulsion system.  The AVUM stage provides roll control during some of the solid rocket stage burns, attitude control during coast periods, circularization burns when needed, and final velocity trim.   Vega avionics, which are derived from Ariane 5 systems, will be located on the AVUM stage.Vega stands 30 meters tall, has a maximum 3-meter diameter, and weighs about 137 tonnes at liftoff.  The launcher flies from Kourou Space Center’s ZLV (Zone de Lancement Vega) launch site, a rebuilding of Kourou's ELA 1 pad.  ELA 1 once handled Europa 2 and Ariane 1.   Arianespace will conduct Vega launch campaigns.  Vega’s initial qualification flight is expected to be followed by two to four operational launches per year.

Development Progress

Vega endured a stop-start development effort during the 1990s.  Original plans called for use of a standard Ariane 5 booster steel-case segment for the Vega first stage.  The second stage would have been a Zefiro 16 (16 tonnes propellant) second stage.  The third stage would have been loaded with seven tonnes of propellant.  The original Vega would only have been able to boost one-tonne payloads to polar orbit. 

Italy initially pressed Vega development forward, performing a Zefiro 16 static test on June 18, 1998.  The effort stalled after that, however, when France balked at fully participating in the project.  The Vega design was subsequently modified both to carry larger payloads and to serve as an Ariane 5 solid rocket booster improvement program.

When Vega won ESA approval in December 2000, development had to be reset.  Initial plans called for an initial test flight by the end of 2005.   Vega’s preliminary design review occurred in mid-2001, but the Critical Design Review did not occur until March 2004, a delay of nearly nine months from original plans.  By late 2006, the program schedule had slipped by nearly two years from original plans, largely due to funding issues.

Avio S.p.A. completed testing of the Vega solid rocket motor igniters by September 2005.  The first Zefiro 9 qualification test burn took place in Sardinia, Italy on December 20, 2005.  A second, unsuccessful test took place on 28 March 2007. During the 2007 test, motor pressure unexpectedly dropped after 35 seconds.  Zefiro 9A motors with a modified nozzle designs were successfully tested on October 23, 2008 and April 28, 2009.

The Zefiro 23 qualification test occurred at the same site on June 26, 2006.  A second Zefiro 23 test took place on March 27, 2008.

P80 was test fired at Kourou on November 39, 2006 and December 4, 2007.  The tests demonstrated the motors ability to produce 190 tonnes of average thrust for 111 seconds.

Europropulsion cast the first inert P80 Vega casing for Avio S.p.A. at the Guiana Propellant Plant (UPG) at Kourou during April 2004. By mid-2006, Europropulsion had cast propellant for the first P80 static qualification test firing article. Snecma in Bordeaux, France delivered the P80 motor nozzle during September 2006. The first P80 static test firing, of the DM1 demonstration motor, occurred at Kourou's vertical solid booster test stand (BEAP) on November 30, 2006.

In September 2006, the AVUM module completed vibration testing at the European Space Research and Technical Center in The Netherlands.

An additional round of solid motor static tests for all three Vega stages took place during and after 2007.

Launch Site

ZLV, The old ELA 1 launch zone, hosts Vega.  ELA 1 was originally built for Europa 2, which flew only one time in 1971.  The pad was subsequently modified for Ariane 1, which it hosted from 1979 until 1989.   The site’s mobile service tower was dismantled in 1991. 

Vega launch site construction began in late 2004 and continued beyond the end of 2008.  Beginning in October 2010, ZLV hosted the buildup of a pathfinder mockup Vega vehicle that was used for a dry run to test facilities and procedures until April 2011.  A few months later, ZLV began to support the VV001 launch campaign.

The rebuilt launch site includes a fixed launch table atop a “launch bunker” fitted with exhaust ducts and a fixed umbilical tower.  A new mobile gantry, essentially a vertical building on wheels, serves as the assembly building for the launcher and payload.   Four lightning towers straddle the launch site.  Vega launch control is performed from Kourou’s Launch Control Center No. 3 (CDL3) building, which also controls Ariane 5 launches.

 
Vehicle Configurations

Vehicle Components

References

"The Small Launcher for Europe", ESA Vega Overview, November 2005
Vega Qualification Flight VV01 Press Kit, ESA, February 2012

Last Update: February 22, 2012

by:  Ed Kyle