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Mars Orbiter Explanation

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  • tkreevesjr
    `Dumb math error blamed for death of Martian probe Published Friday, October 1, 1999, in the San Jose Mercury News
    Message 1 of 3540 , Oct 1, 1999
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      `Dumb' math error blamed for death of Martian
      probe<br><br>Published Friday, October 1, 1999, in the San Jose Mercury
      News
      <br><br><a href=http://www.mercurycenter.com/premium/front/docs/mars01.htm target=new>http://www.mercurycenter.com/premium/front/docs/mars01.htm</a><br><br>BY ROBERT LEE HOTZ<br>Los Angeles Times <br><br>NASA
      lost its $125 million Mars Climate Orbiter because
      spacecraft engineers failed to convert from English to
      metric measurements when exchanging vital data before
      the craft was launched, space agency officials said
      Thursday.<br><br>A navigation team at the Jet Propulsion Laboratory
      in Pasadena used the metric system of millimeters
      and meters in its calculations while Lockheed Martin
      Astronautics in Denver, which designed and built the
      spacecraft, provided crucial acceleration data in the English
      system of inches, feet and pounds.<br><br>As a result,
      engineers at the Jet Propulsion Laboratory mistook
      acceleration readings measured in English units of
      pound-seconds for a metric measure of force called
      newton-seconds.<br><br>In a sense, the spacecraft was lost in
      translation.<br><br>The loss of the Mars probe was the latest in a series
      of major spaceflight failures this year that
      destroyed billions of dollars' worth of research, military
      and communications satellites or left them spinning
      in useless orbits.<br><br>Earlier last month, an
      independent national security review concluded that many of
      those failures stemmed from an overemphasis on
      cost-cutting, mismanagement and poor quality control at
      Lockheed Martin, which manufactured several of the
      malfunctioning rockets.<br><br>Still investigating<br><br>``It
      was launched that way,'' said Noel Hinners, vice
      president for flight systems at Lockheed Martin's
      space-systems group. ``We were transmitting English units, and
      they were expecting metric units. The normal thing is
      to use metric and to specify that.''<br><br>None of
      the Jet Propulsion Laboratory's rigorous
      quality-control procedures caught the error in the nine months it
      took the spacecraft to make its 461 million-mile
      flight to Mars. Over the course of the journey, the
      miscalculations were enough to throw the spacecraft so far off
      track that it flew too deeply into the Martian
      atmosphere and was destroyed when it entered its initial
      orbit around Mars last week.<br><br>``I can't think of
      another example of this kind of large loss due to English
      vs. metric confusion. It is going to be the
      cautionary tale until the end of time.''<br><br>Accepting
      blame<br><br>At the Jet Propulsion Lab, which owes its
      international reputation to the accuracy it has displayed in
      guiding spacecraft across the shoals of space, officials
      did not flinch from acknowledging their role in the
      mistake.<br><br>``We know this error is the cause,'' said Thomas
      Gavin, deputy director of the lab's space and Earth
      science directorate, which is responsible for the JPL
      Mars program. ``And our failure to detect it in the
      mission caused the unfortunate loss of Mars Climate
      Orbiter.<br><br>``When it was introduced and how it was introduced, we
      don't know yet.''<br><br>In any event, scientists are
      anxious that the conversion error does not affect a
      second spacecraft, the Mars Polar Lander, now
      approaching the red planet for a landing Dec. 3. The lost
      orbiter would have served as a radio relay for the lander
      before beginning its own two-year survey of the Martian
      atmosphere and seasonal weather.<br><br>Data exchanges for
      the Global Surveyor, which has been orbiting Mars
      since 1997, have been conducted exclusively in the
      metric system, Hinners said. Mission controllers expect
      to use the Surveyor as a relay station in place of
      the lost orbiter.<br><br>``It is ironic,'' Logsdon
      said, ``that we can cooperate in space with the
      Russians and the Japanese and the French, but we have
      trouble cooperating across parts of the United States.
      Fundamentally, you have partners in this enterprise speaking
      different languages.''
    • jefftibb
      The SEDS site has a short list of Messier Marathon locations where people will congregate to count the Messier Objects. If you would like to join a
      Message 3540 of 3540 , Mar 13, 2002
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        The SEDS site has a short list of Messier
        Marathon locations where people will congregate to count
        the Messier Objects.<br><br>If you would like to join
        a group and do it check out this
        site:<br><br><a href=http://seds.lpl.arizona.edu/messier/xtra/marathon/mm2002.html target=new>http://seds.lpl.arizona.edu/messier/xtra/marathon/mm2002.html</a><br><br>Many will be happening this weekend.
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