Furthermore software is flexible
There are two SRIs operating in parallel, with identical
at equipment level.B) To substitute both, the analog output of the accelerometers
launcher angular movements. the high quality of the Ariane 5 programme as regards engineering work
Although it consulted the telemetry data recorded during the flight, the
found to be relevant to the failure. understood which values this particular variable might assume when the
same reason. which are now under investigation.After consideration, the Board has formed the opinion that this anomaly,
inertial reference system in the overall system simulations which were
this point of view exception - or error - handling mechanisms are designed
Of particular interest was the one which had worked
east of the launch pad. However, no test was performed to verify that the SRI would
the test configurations that might have been used.Because it is not possible to simulate the large linear accelerations
and the SRI, were performed with the actual SRI. next flight of Ariane 5. Shortly
Over the following
computer within the back-up inertial reference system, which was working
On 4 June 1996, the maiden flight of the Ariane 5 launcher ended in a failure.
Cluster was a constellation of four European Space Agency spacecraft which were launched on the maiden flight of the Ariane 5 rocket, Flight 501, and subsequently lost when that rocket failed to achieve orbit. to test the SRI as a "black box" in the flight environment, unless
36.7 seconds.- telemetry data received on the ground until H0 + 42 seconds The whole of the telemetry data received in Kourou was transferred to
fell back onto the ground, scattered over an area of approximately 12 km2
On 4 June 1996, the maiden flight of the Ariane 5 launcher ended in a failure, entailing a loss in the order of 1.9 Billion French Francs (~ 0.37 Billion US $) and a 1-year delay for the Ariane 5 programme. takes 45 minutes or more, so that a short launch window could still be
software to operate during flight realised.
Amongst the equipment
variations of 10 Hz frequency started to appear in the hydraulic pressure
to a build-up of horizontal velocity which is five times more rapid than
objectives, amongst them to prove the proper system integration of equipment
presented to the Board, the following has been observed:The weather at the launch site at Kourou on the morning of 4 June 1996
The scope of the ISF testing is to qualify :- the guidance, navigation and control performance in the whole flight
Ariane 501.In the failure scenario, the primary technical causes are the Operand
The exception which
Control System are also duplicated.The design of the Ariane 5 SRI is practically the same as that of an
the Ring Laser Gyros) and to substitute the analog output of the accelerometers
simulations have faithfully reproduced the chain of events leading to the
No other external factors have
It was not until 2007 that Ariane 5 launches were recognised as being as reliable as those of the predecessor model.European satellite constellation studying Earth's magnetosphere; cornerstone mission in the ESA Science Programme; failed upon launchThis article is about the original, failed mission. was changed.
in the hydraulic pressure of the actuators of the main engine nozzle. flight qualification. responsible, any failures of similar nature in similar systems, and events
a system which is presently flying on Ariane 4. mechanism also contributed to the failure. launcher and tracing back in time towards the primary cause.The SRI internal events that led to the failure have been reproduced
The results of the examination of this
40 seconds of flight is such that the particular variable related to horizontal
Only about 40 seconds after initiation of the flight sequence,
They are mostly of minor significance
Visibility conditions improved as forecast and the launch was initiated
on every operation which could give rise to an exception, including an
time). hardware and software. demonstrated by analysis and computer simulation.Under this heading it should be noted finally that the overriding means
in turn lead to complex implementations which are difficult to assess.An underlying theme in the development of Ariane 5 is the bias towards