A file image shows the twin solid rocket boosters propelling the Ariane 5 off the launch pad. Photo: ESA

A test firing of an Ariane 5 solid rocket motor (MPS) is to take place today on the booster teststand (BEAP) at the Guiana Space Center, Europe's spaceport in Kourou, under the Ariane-5 Research and Technology Accompaniment program.

ARTA-5 is a European Space Agency program, the technical and financial management of which is delegated to CNES. Its objectives are to verify that Ariane 5 launcher qualification, reliability and performance levels are maintained and also to qualify modifications resulting from obsolescence or changes in technology. ARTA activities cover the solid rocket motors built by Europropulsion.

This motor test will also serve to qualify Ariane 5 improvements designed to increase launcher lift-capability and get production costs down.

Overall planning for the test is built around four main objectives:

• Qualify new procurement sources for one constituent of the propellant, involving use of Amonium Perchlorate produced by the US company WECCO.
  
  
• Evaluate the effect of ageing and analyse behaviour on an over 6-year-old rear booster's segment (S3).
  
  
• Further qualify an 'increased-load' forward segment S1 (MPS/EAP) containing an extra 2.2t of solid propellant (10% of its mass). The new definition of this segment, which delivers about 50% of the thrust during the first part of the burn, will raise launcher GTO lift-capability by about 200 kg.
  
  
• Test a new design of the nozzle developed with the objective of reducing the recurrent costs

The prime contractor for the test is Europropulsion, which defines the objectives and supplies the specimen. Responsibility for conducting the test has been assigned to CNES, whose role covers stand deployment, supplying the test facilities and conducting operations with Arianespace's assistance.

The solid rocket motor (275t, including 240t of propellant) built by Europropulsion comprises a nozzle, an igniter and three loaded segments: the 26t S1, 107t S2 and 107t S3.

The solid-propellant booster developed by EADS-LV is the complete stage incorporating the motor with all command systems, (ignition, flight control, destruct and possibly recovery), forward/aft skirts and connections to the launcher's core stage.