Mars Express PFS spectrometer back at work (Forwarded)

ESA News
http://www.esa.int

2 November 2005

Mars Express PFS spectrometer back at work

The Planetary Fourier Spectrometer (PFS) on board ESA's Mars Express
spacecraft is now back in operation after a malfunction, reported a few
months ago.

The instrument had been successfully investigating the chemical
composition of the Martian atmosphere since the beginning of 2004, when
Mars Express began orbiting the Red Planet.

PFS is a very sensitive instrument, capable of measuring the distribution
of the major gaseous components of the atmosphere, the vertical
distribution of their temperature and pressure, and determining their
variation and global circulation during the different Martian seasons.

PFS is also capable of detecting minor gaseous species and the presence of
dust in the atmosphere and, during favourable observing conditions, even
deducing the mineralogical composition of the soil.

PFS was the first instrument ever to make direct 'in situ' measurements of
methane in the atmosphere of Mars, and provided first indications of
traces of formaldehyde, both candidate ingredients for life.

To identify the nature of chemical compounds of the Martian atmosphere and
their physical status, PFS detects the distinctive infrared radiation
re-emitted by different molecules when they are exposed to the light of
the Sun.

The complex PFS instrument uses the interferometry technique, a
high-precision measurement method in which beams of electromagnetic
radiation are split and subsequently recombined after travelling different
path-lengths. The beams interfere and produce an 'interference pattern'.

This pattern, or 'interferogram', is then used to measure physical
properties such as temperature, pressure and chemical composition.

The PFS instrument was unable to produce scientific data from July to
September 2005. A series of tests and investigations took place between
September and October this year.

The 'pendulum motor', used to drive various elements in the instrument
optics, was shown to be at fault. The recovery was made possible through
using internal instrument redundancy.

After switching to the instrument's back-up motor, more powerful than the
first one -- the instrument has been shown to be able to produce science
data just as before. Following this recovery activity, PFS will start to
take new measurements routinely in early November 2005.

Notes to editors:

PFS is a 'double pendulum' interferometer. The incident radiation is
divided into two beams by a mirror and then filtered before being directed
into two separate interferometers. The interferometers are positioned with
their planes of operation one above the other so that a single motor can
be used to move both pendulums.

PFS measurements have a spatial resolution ranging from 7 to 12 kilometres
when Mars is observed from an altitude of 250 kilometres.

For more information:

Prof. Vittorio Formisano, PFS Principal Investigator
IFSI-CNR, Rome, Italy
E-mail: formisan @ nike.ifsi.rm.cnr.it

Fred Jansen, ESA Mars Express Mission Manager
E-mail: fjansen @ rssd.esa.int

Agustin Chicarro, ESA Mars Express Project Scientist
E-mail: agustin.chicarro @ esa.int

Enrico Flamini, ASI Mars Express Mission Manager
E-mail: enrico.flamini @ asi.it

More about...

* Looking at Mars
http://www.esa.int/SPECIALS/Mars_Express/index.html
* Orbiter instruments
http://www.esa.int/SPECIALS/Mars_Exp...C75V9ED_0.html

Related articles

* Mars Express instrument under investigation
http://www.esa.int/esaCP/SEMSEK7X9DE_index_0.html
* Mars Express confirms methane in the Martian atmosphere
http://www.esa.int/esaCP/SEMZ0B57ESD_index_0.html
* Chances of life are linked to water
http://www.esa.int/esaSC/SEMN3AR1VED_index_0.html
* Geography of Mars
http://www.esa.int/SPECIALS/Mars_Exp...PNXLDMD_0.html

Related links

* Planetary Fourier Spectrometer
http://www.pfs-results.it
* High Resolution Stereo Camera
http://berlinadmin.dlr.de/Missions/e...indexeng.shtml

IMAGE CAPTION:
[http://www.esa.int/esaCP/SEM6N9638FE_index_1.html]
ESA's first mission to the Red Planet, Mars Express, was launched in June
2003. It comprised an orbiter carrying seven scientific instruments to
probe the planet's atmosphere, structure and geology, including a search
for evidence of hidden water. The main spacecraft released the UK's small
Beagle 2 lander to gather and test rock and soil samples on the surface.
As well as its science objectives, Mars Express also provides relay
communication services between Earth and landers deployed on the surface
by other nations, thus forming a centrepiece of the international effort
in Mars exploration.

Mars Express is a pilot project for new methods of funding and managing
ESA space missions, built more quickly and launched at a much lower cost
than any previous mission of a similar nature.

Credits: ESA