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Europe’s new MetOp weather satellite reaches polar orbit
For 28 years, Europe has been operating its famous Meteosat weather
satellites in geostationary orbit. Today, they were joined by the first of
a brand new generation of meteorological satellites. MetOp is designed to
provide a closer view of the atmosphere from low earth orbit, delivering
data that will improve global weather prediction and enhance our
understanding of climate change.



(PressZoom) - The first of three satellites developed under a joint
programme being carried out by the European Space Agency and the European
Meteorological Satellite Organisation ( EUMETSAT ), MetOp-A was
successfully launched from Baikonur, Kazakhstan by a Russian Soyuz
2/Fregat rocket operated by the Euro-Russian company Starsem.

The Soyuz 2 launcher, on its first operational mission, lifted off at
18:28 CEST ( 16:28 UT ) with the 4093kg spacecraft encapsulated in a new
4.1m diameter payload fairing, similar in shape and size to that of Ariane
4. The newest member of the nearly 50-year old Semyorka family of
boosters, Soyuz 2 is due to be launched from French Guiana from 2008
onwards.

Some 69 minutes after launch, the Fregat upper stage released the first
MetOp satellite into a circular orbit at an altitude of 837km over the
Kerguelen archipelago in the South Indian Ocean. With a slightly
retrograde 98.7° inclination, this orbit will enable MetOp-A to circle
theglobe from pole to pole while always crossing the equator at the same
local time, i.e. 9:30 am. Known as ‘sun-synchronous’, this type of orbit
allows revisits to almost each point of the Earth’s surface under similar
solar illumination conditions on an approximately daily basis.

The satellite is now under the control of ESA’s European Space Operations
Centre ( ESOC ) in Darmstadt, Germany, and has deployed its solar array.
Over the coming days, it will undergo the first technical check-outs of
its systems and will deploy its antennas. Handover to EUMETSAT is expected
on 22 October for full satellite commissioning and routine operations.

MetOp-A will form the space segment of the EUMETSAT Polar System ( EPS ),
designed to collect atmospheric and environmental data to complement the
hemispheric survey conducted from geostationary orbit by the Meteosat
system. EPS will be operated in coordination with the US Polar Operational
Environmental Satellite ( POES ) system managed by the National Oceanic
and Atmospheric Administration. While NOAA satellites are deployed in an
‘afternoon’ orbit ( i.e. crossing the equator in the afternoon, local time
), Europe’s MetOp will take up service in a ‘morning’ orbit.

The most complete atmospheric probe ever

To fulfil its ambitious mission, MetOp-A incorporates a comprehensive
remote-sensing payload consisting of a set of new-generation European
instruments, plus a set of ‘heritage’ instruments provided by the United
States similar to those flown on current NOAA satellites.

Supplied by the French space agency CNES, the Infrared Atmospheric
Sounding Interferometer ( IASI ) will take measurements in more than 8000
channels to provide temperature and water vapour profiles with
unprecedented accuracy to feed numerical weather-prediction models. Its
soundings will be complemented by measurements from the US heritage
instruments and the Microwave Humidity Sounder ( MHS ), a five-channel
radiometer developed for EUMETSAT but also planned to fly on future NOAA
satellites.

Jointly developed by ESA and EUMETSAT, the second-generation Global Ozone
Monitoring Experiment ( GOME-2 ) is an improved version of a scanning
spectrometer already flown on ERS-2 which is designed to probe the
atmosphere for profiles of ozone concentrations as well as other trace
gases.

Another ESA/EUMETSAT instrument with a strong ERS programme legacy is the
Advanced Scatterometer ( ASCAT ). This enhanced C-band radar will measure
the speed and direction of winds over the surface of the oceans, also to
feed numerical weather prediction models, but in addition providing useful
information on ice, snow and soil moisture.

One new instrument developed by ESA and EUMETSAT is the GNSS Receiver for
Atmospheric Sounding ( GRAS ), which will use occultation of satellite
navigation signals through the atmospheric limb to derive atmospheric
temperature and humidity profiles.

NOAA-supplied instruments include: the third-generation Advanced Very High
Resolution Radiometer ( AVHRR-3 ) to acquire global imagery of cloud cover
as well as of ocean and land surfaces; two 15-channel Advanced Microwave
Sounding Units ( AMSU/A ) to scan atmospheric temperature profiles; and
the fourth-generation High Resolution Infrared Radiation Sounder ( HIRS ),
a 20-channel equivalent of the IASI interferometer which will support
validation of data collected by the European instrument and serve as a
back-up afterwards.

In addition, MetOp-A carries an advanced Argos data collection system
supplied by CNES to locate and communicate with automated stations,
whether fixed or mobile; two search & rescue payloads respectively
provided by the Canadian Space Agency and CNES to support the
international Cospas-Sarsat network by picking up and retransmitting
distress signals; and a US-supplied Space Environment Monitor ( SEM-2 ), a
spectrometer to survey the charged particle flux in space.

A major boost to weather forecasting

Approved back in 1992, MetOp is a meteorological operational satellite
programme like Meteosat. ESA’s contribution to its inception is being
managed through the Earth Watch component of its Living Planet programme.
ESA is in charge of the satellite’s development and procurement. In that
capacity, it funded most of the first flight model manufacturing. EUMETSAT
is in charge of the operational system and is funding the development of
the ground segment and follow-on satellites, the launchers and operations.

Three flight models have been ordered from an industrial team led by EADS
Astrium. The spacecraft, integrated in Toulouse, France, are based on a
bus derived from ESA's Envisat and France's Spot 5 satellites and
incorporate advanced equipment to ensure flexible operations, with more
than 36 hours’ autonomy and a 24 Gbit data storage capability.

MetOp satellites will circle the planet some 14 times a day, gathering
data that they will download to the EPS Command & Data Acquisition ( CDA )
ground station located in the Svalbard archipelago, North of Norway. Due
to its high latitude ( 78°N ), the CDA station will be visible to MetOp on
each of its orbits, as the satellite flies over the Arctic. Once
collected, MetOp data will be transmitted to EUMETSAT’s facilities in
Darmstadt for processing and distribution. In addition, some real-time
Polar System data will be broadcast directly to regional meteorological
organisations whenever the satellite comes into visibility in terms of
their receiving stations.

Thanks to its advanced payload and broadcast capacity, MetOp will be able
to detect and report the early development of localised severe weather
conditions, such as violent thunderstorms, which cannot be observed from
geostationary orbit. The satellite will thus make it possible to issue
weather alerts at much earlier notice than at present.

“I congratulate our friends and partners from EUMETSAT, NOAA, CNES,
Starsem, the European space industry and the international meteorological
community on this successful launch”, said ESA Director General
Jean-Jacques Dordain.” Like the two generations of Meteosat, this
programme is more than a success story for international cooperation; it
is the perfect illustration of what priceless benefits space can bring to
all citizens. The harvest of data expected from MetOp-A and its follow-on
satellites will provide a new dimension to our knowledge of the Earth’s
atmosphere and climate. Not only will these data lead to tremendous
improvements in the accuracy of weather forecasting in Europe and
worldwide; they will also enable the science community to develop more
complex models of our planet’s climate in order to better understand
ongoing global change and steer international environmental policies
accordingly.”