Activity at the Spaceport’s SLV launch site during recent days included completion of fueling for Vega’s AVUM bipropellant upper stage, which will inject the flight’s Proba-V, VNREDSat-1 and ESTCube-1 payloads into their respective orbits.

This mission’s launch on Friday is set for a precise moment: 11:06:31 p.m., local time at the Spaceport, for a flight lasting 2 hours, 48 seconds from liftoff to separation of the final spacecraft in its payload “stack.”

The flight profile calls for Proba-V – the upper payload – to be released from its position atop Vega’s VESPA (Vega Secondary Payload Adapter) dispenser system at 55 minutes and 27 seconds after liftoff.  It will be followed by VNREDSat-1 and ESTCube-1, both of which are riding inside the VESPA dispenser.

During the mission, the initial powered phase will be performed by the Vega’s three solid propellant stages (designated the P80, Zefiro-23 and Zefiro-9), lasting 6 minutes and 19 seconds.  The AVUM upper stage will be ignited for four separate burns for the payload deployment sequence, followed by a final burn that deorbits the upper stage to ensure that it does not remain as a debris threat.

Vega will release its satellites into Sun-synchronous orbits.  Proba-V is to be injected at an altitude of 820 km., while VNREDSat-1 and ESTCube-1 are intended for separations at 665 km. orbital altitudes.

Proba-V (which is named from the acronym: Project for On-Board Autonomy and Vegetation) is part of the Proba spacecraft series developed by the European Space Agency (ESA) in supporting the development of new space technologies.  Its primary objective is to continue the mission performed by the Vegetation instruments carried on Spot 4 and 5 satellites – which also were launched by Arianespace.

Built by QinetiQ Space Belgium, the Proba-V platform weighs 140 kg. and will be placed into the same orbit as the Spot remote-sensing satellites.

The VNREDSat-1 optical satellite is part of Vietnam’s initiative to create an infrastructure enabling better studies of climate change effects, improving predictions for natural disasters and optimizing the country’s natural resource management.  This 120-kg. spacecraft was built by Astrium on behalf of the Vietnam Academy of Science and Technology (VAST).

ESTCube-1 is Estonia’s first satellite, designed and built by a team of students at the country’s National University of Tartu, under supervision of the Estonian Space Office.  The project involved a collaboration of students from the Estonian Aviation Academy, Tallinn University of Technology and the University of Life Sciences – and was developed in conjunction with the Finnish Meteorological Institute and the German Space Center (DLR). In addition to extending a small conductive tether for testing of electric solar wind sail technologies, the 1.33-kg. cubesat will help establish an Estonian infrastructure for future space projects.

Vega is tailored for launching 1,500-kg.-class payloads to a reference altitude of 700 km., providing Arianespace with a light-lift vehicle capable of accommodating scientific and governmental satellites, as well as commercial payloads.  It was developed in an ESA program financed by Italy, France, Germany, Spain, Belgium, the Netherlands, Switzerland and Sweden.

The Vega launcher’s design authority and prime contractor is Italy’s ELV company – a joint venture of Avio and the Italian Space Agency.  Arianespace handles launch operations, with Vega completing its launcher family, joining the medium-lift Soyuz and heavyweight Ariane 5 in side-by-side operations at the Spaceport.

Vega’s launch on May 3 is designated VV02 in Arianespace’s mission numbering system, and represents the debut of ESA’s VERTA (Vega Research and Technology Accompaniment) program, which will demonstrate the light-lift vehicle’s flexibility and versatility.   The first Vega flight was performed from the Spaceport in February 2012, and served as the vehicle’s qualification mission.