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Martian methane probe in trouble

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  • Joe (uk-ufo) McGonagle
    http://www.nature.com/news/2005/050905/full/050905-10.html Published online: 7 September 2005; |
    Message 1 of 1 , Sep 11, 2005
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      http://www.nature.com/news/2005/050905/full/050905-10.html
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      Published online: 7 September 2005; | doi:10.1038/news050905-10
      Martian methane probe in trouble
      Device may be unable to settle debate over indications of life
      Mark Peplow

      One of the best chances for solving Mars's methane mystery may
      have been lost. The Planetary Fourier Spectrometer (PFS) on board
      the Mars Express orbiter seems to be broken, perhaps for good.

      The instrument's failure would be a blow for scientists who want
      to find out how the red planet is producing the methane that has
      been detected in recent years.

      Almost all the methane on Earth comes from some sort of
      biological source. As a methane molecule typically survives for
      only a few hundred years in the martian atmosphere, something
      must have been spewing it out recently, scientists reason. And
      this has fuelled hopes for discovering life on Mars.

      But scientists have recorded very different methane levels with
      different techniques. In 2004, the PFS found that methane
      averaged abut 10 parts per billion in Mars's atmosphere,
      suggesting that more than 100 tonnes of the gas is released from
      the surface each year. That same year, Mike Mumma of NASA's
      Goddard Space Flight Centre in Maryland spotted levels of 250
      parts per billion using a telescope in Hawaii. This week he told
      an American Astronomical Society meeting in Cambridge that he had
      spotted levels of 44-63 parts per billion from a different part
      of the planet.

      Source searching

      To pin down the source of the gas, these disagreements need to be
      sorted out. One explanation might be that methane is venting
      intermittently from specific points on the surface. To check,
      researchers hope to take simultaneous readings of exactly the
      same place using both orbiting and earth-based instruments.

      But the chance to do this may now be lost, says Thérèse Encrenaz,
      of the Paris Observatory in France, who is part of the PFS team.
      She says that the spectrometer has been in trouble for two
      months, and various attempts to fix it have proven fruitless.

      "There's still a chance it could be fixed," she told
      news@... at the Cambridge meeting. "But if it cannot be
      fixed then the experiment will be stopped."

      Ludmilla Zasova of the Space Research Institute in Moscow, says
      the instrument stopped working some time in July. "It's a problem
      with the vibration of the spacecraft," says Zasova, who leads the
      Russian contingent of scientists working with the PFS. These
      vibrations have shown up in PFS data for the duration of the
      mission, although scientists have been able to filter out the
      effects to generate clean results. Zasova thinks the vibrations
      are affecting a pendulum inside the instrument that helps to
      control the way it collects light.

      But team members are unclear about the severity of the problem.
      Vittorio Formisano of the Institute of Physics and Interplanetary
      Science in Rome, Italy, would not confirm that it is broken.
      Formisano is in charge of the instrument and says he is being
      kept busy working on it.

      Troubled interpretations

      This isn't the first trouble that Mars Express has had. The
      European Space Agency's craft had difficulty opening some radar
      booms needed for its water detection experiment in May, although
      these are now working well (see 'Mars Express radar on hold' ).

      And there have been controversies surrounding interpretation of
      data from the spectrometer. In February of this year, Formisano
      said that the PFS had found large quantities of formaldehyde
      around Mars (see 'Formaldehyde claim inflames martian debate').
      This implied that millions of tonnes of methane were being
      released by the planet each year: much, much more than thought.
      Encrenaz says most scientists now agree that these claims about
      formaldehyde were incorrect.

      Without nailing the methane numbers, it will be hard for all
      scientists to agree on a source for the gas. For now, many say it
      is probably due to heating of water and carbon dioxide with a
      mineral called olivine, rather than life, says Sushil Atreya, a
      member of the PFS team from the University of Michigan in Ann
      Arbor.

      If the Mars Express methane instrument fails to provide further
      data, the next opportunity will be NASA's Mars Science
      Laboratory, due to blast off in 2009. This will not only measure
      trace levels of methane, but also check its isotopic make-up for
      signs of biological activity.
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