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ZL2VAL > SPACE 10.01.02 15:59l 58 Lines 2185 Bytes #999 (0) @ WW
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Subj: Water Blamed in Ariane 5 Failure
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From: ZL2VAL@ZL2AB.#46.NZL.OC
To : SPACE@WW
Wed. Jan 9, 2002
Water Blamed in July Ariane 5 Failure
By Peter B. de Selding
Space News
Staff Writer
posted: 02:00 pm ET
08 January 2002
PARIS -- The presence of water in the upper-stage engine has been
identified as the probable cause of an Ariane 5 heavy-lift rocket failure
in July, investigators have concluded.
The failure caused the loss of one satellite, degraded the operational
life of a second and forced a shutdown of Ariane 5 operations.
The exact cause of the failure had engineers stumped for months. But
recent tests of the engine in Lampoldshausen, Germany, showed that it
exhibits the same defects when small amounts of water are added as it did
in the July failure, said Jean-Yves Le Gall, chief operating officer of
Arianespace, the European consortium that operates the vehicle.
"The characteristics of the engine ignition when water is introduced are
very, very similar to what we saw during the July launch," Le Gall said
Jan. 8.
He said the apparent discovery of such a simple cause for the failure has
bolstered Arianespace's confidence that it can return the rocket to
flight in late February.
The Ariane 5's upper-stage engine is routinely filled with water during
hydraulic tests before it is delivered for final integration into the
vehicle.
Le Gall said the engine used in the July launch apparently was not dried
out thoroughly.
"What we have found in the past few weeks is that this engine is
extremely sensitive to the presence of water," Le Gall said.
"So in addition to smoothing out the ignition sequence as part of the
modifications we are adopting, we will ensure that the engines are fully
dried after the hydraulic tests."
=====================================
73 de Alan
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