發信人: perceval.bbs@bbs.ntu.edu.tw (念書), 看板: astronomy
標  題: Re: [新聞]俄Soyuz-U火箭 發射29秒爆炸
發信站: 台大計中椰林風情站 (Fri Oct 18 04:20:37 2002)
轉信站: Lion!news.ntu!Palmarama

==> journeyman.bbs@bbs.ee.ncu.edu.tw (㊣加強三向電壓！旋風無敵劍！) 提到:
> > 嗯~~~~!!在這之前我記的也有好像類似ㄉ情形發生
> >         這我想應該 是有關火箭引擎發射時與推進器
> >         內之間的特殊演算法有出入 才會這樣吧(如有錯誤請更正)
> 特殊演算法！？恕我沒聽過這個講法
try this:
http://www.ima.umn.edu/~arnold/disasters/ariane.html

The Explosion of the Ariane 5

On June 4, 1996 an unmanned Ariane 5 rocket launched by the European Space Agency exploded just forty
seconds after its lift-off from Kourou, French Guiana. The rocket was on its first voyage, after a decade of
development costing $7 billion. The destroyed rocket and its cargo were
valued at $500 million. A board of inquiry investigated the causes of
the explosion and in two weeks issued a report. It turned out that the
cause of the failure was a software error in the inertial reference
system. Specifically a 64 bit floating point number relating to the
horizontal velocity of the rocket with respect to the platform was
converted to a 16 bit signed integer. The number was larger than
32,767, the largest integer storeable in a 16 bit signed integer, and thus the conversion failed.

The following paragraphs are extracted from the report of the Inquiry Board. An interesting article on the
accident and its implications by James Gleick appeared in The New York Times Magazine of 1 December 1996.
The CNN article reporting the explosion, from which the above graphics were taken, is also available.

On 4 June 1996, the maiden flight of the Ariane 5 launcher ended in a failure. Only about 40 seconds after initiation
of the flight sequence, at an altitude of about 3700 m, the launcher veered off its flight path, broke up and exploded.

The failure of the Ariane 501 was caused by the complete loss of guidance and attitude information 37 seconds after
start of the main engine ignition sequence (30 seconds after lift-off). This loss of information was due to specification
and design errors in the software of the inertial reference system.

The internal SRI* software exception was caused during execution of a data conversion from 64-bit floating point to
16-bit signed integer value. The floating point number which was converted had a value greater than what could be
represented by a 16-bit signed integer.

--
==============================================================================
  What we are really living for is the experience of life, both the pain
  and the pleasure.
                                                        Joseph Campbell
==============================================================================
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