A test firing of a full-sized Ariane 5 solid rocket booster was performed Tuesday, marking an important step in Europe's plans to increase the rocket's payload capacity and to lower production expenses.

The exhaust cloud billows into the sky as the solid rocket motor is test fired. Photo: Arianespace

The firing was part of the Ariane 5 Research and Technology Accompaniment, or ARTA, program. ARTA is designed to confirm that the Ariane 5 remains reliable, to qualify performance improvements, and to oversee and validate changes in the system resulting from obsolescence.

The firing occurred on a fixed test stand at the Guiana Space Center in Kourou, French Guiana, the launching base of the Ariane rockets. It lasted for 125 seconds, which is the burn time of the solid rocket boosters on an Ariane 5 flight.

Test objectives for the static firing included the qualification of a newly redesigned nozzle in the booster. Its purpose is to reduce the manufacturing costs of Ariane 5 boosters, partly by simplifying the nozzle and the hydraulic systems that help to gimbal it during flight. The number of components in the nozzle has been decreased from the 20 in the current design to just 13.

Having been successfully tested and with final qualification, the new nozzle will appear in all operational flights of the Ariane 5 beginning in 2004.

Another goal of the test firing was to help validate the use of an added propellant load in the booster's upper section, which embodies an extra 2.2 metric tons of solid fuel -- equivalent to approximately 10 percent of its current mass. The additional propellant will increase the Ariane 5's payload capability to geostationary transfer orbit by around 200 kilograms (about 440 pounds).

The increased amount of propellant will be incorporated into the second production batch of Ariane 5 rockets, which will be flown beginning in July 2002.

Other aims of the test were the evaluation of a six-year-old booster segment when firing, the testing of simplified electrical ducts, and the assessment of the possibility of reducing the number of high-pressure capacities needed for a booster's thrust vector control.

Europropulsion provided the booster and outlined the test objectives. The French space agency CNES, assisted by Arianespace, held responsibility for the test.