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Scientific disaster
1.
2. PRESENTATION OVERVIEW
Scientific Disaster Due To Errors in Calculation
Introduction
Launcher Failure
Problem
Software Failure
Some Other Disasters due to the simple errors
References
3. o A European rocket designed to
launch commercial payloads into
Earth orbit.
o Ariane 5 can carry a heavier
payload.
o Standard launch vehicle for the
European Space Agency
INTRODUCTION
4. LAUNCHER FAILURE
o First test launch of Ariane 5
in June 1996
o Approximately 37 seconds
after a successful lift-off, the
Ariane 5 launcher lost
control
5. o Incorrect control signals were
sent to the engines and these
swivelled so that unsustainable
stresses were imposed on the
rocket
o The vehicle started to break up
because of the stresses imposed
and self-destructed
o The system failure was a direct
result of a software failure.
IRS 1 IRS 2
Instructions to engine control system
6. SOFTWARE FAILURE
Software failure occurred
when an attempt to convert
a 64-bit floating point number
representing the horizontal
velocity to a signed 16-bit
integer caused the number to
overflow (become too big).
0111111111111111
Sign
16-bit integer
Max value (32768)
9. Mars Polar Lander, 1998
Software error that mistakenly
identified
the vibration caused by the
deployment
of the lander's legs as being caused
by the
vehicle touching down on the Martian
surface.
10. Loss of Mariner 1, 1962
Period instead of comma in
FORTRAN DO-Loop.
11. Breakdown of AT&T’s long-
distance telephone network,
1990
A single line of buggy code in a
complex software upgrade
implemented to speed up calling
caused a ripple effect that shut
down the network.
14. Shutdown of 5 nuclear
reactor, 1985
“ Use of arithmetic sum of variables instead
of the square root of the sum of the
squares of the variables. „
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