An independent inquiry board is being created to investigate the upper stage
propulsion anomaly on Flight 142’s Ariane 5, and the group has been asked to
submit its first findings in early August.

Arianespace Chairman and CEO Jean-Marie Luton said the board member’s names
will be announced on Monday, and they will begin work immediately in order
to have their initial findings completed in two weeks.

Speaking to reporters at the Spaceport this morning, Luton said the goal is
to return Ariane 5 to service as soon as possible, and the company has
pledged to work with its clients to help satisfy their launch requirements
in the most rapid manner.

“In keeping with Arianespace’s policy of openness, we will communicate
regularly on the progress of the board’s work, coordinating closely with our
customers,” he said.

As the investigation moves ahead, Arianespace is keeping its next Ariane 4
mission on schedule – with the liftoff of Flight 143 targeted for August 24
with the Intelsat 902 satellite. This mission will use the 44L version of
the Ariane 4 launcher family.

Edouard Perez, Arianespace Senior Vice President – Engineering, said the
Flight 142 investigation will focus on the operation of the launcher’s
storable propellant upper stage. The Ariane 5’s core stage and the solid
boosters worked as expected, providing propulsion from liftoff through the
first 9-plus minutes of flight.

The anomaly occurred as the upper stage began its operation, Perez said,
followed by a shortfall in thrust. Both satellite payloads were released in
the proper deployment sequence, but their orbit was degraded: 17,528 km.
apogee, 592 km perigee, and inclination of 2.9 deg. (compared to the
targeted orbit: 35,853 km. apogee, 858 km., and 2 deg. inclination).

Ariane 5’s upper stage uses MMH fuel and N204 oxidizer that are fed from
pressurized tanks to its Aestus engine.