Early in 2002 an Ariane-5 rocket will launch the largest and most advanced
Earth observation satellite ever built in Europe from the European
Spaceport at Kourou in French Guiana. From an altitude of 800 kilometres
Envisat will deliver images and data that will help us better understand
and more effectively protect the Earth.

This gigantic Earth observation satellite, the size of an articulated
lorry, was developed under the supervision of ESA experts from the
European space research and technology centre (ESTEC) in Noordwijk, the
Netherlands, at a cost of 2.3 billion euros. Programme Manager Jacques
Louet called the satellite, which has more measuring instruments on board
than any other to date, “a huge challenge for ESA and Europe”.

In 1988 the “Polar Platform” project, as it was then called, was agreed
upon; at the beginning of the 1990s the satellite, which every hour will
gather as much data as can be stored on a dozen PC hard disks, became
ENVISAT (ENVIronmental SATellite). The spacecraft can monitor and show the
status of the Earth, including the complex life cycle of algae blooms, or
give advance warning of natural catastrophes. Envisat, with its 14 x 4.5 m
solar array which delivers 6.6 kilowatts of electrical power, was ferried
to its launch pad in Kourou by a Russian Antonov and two Boeing 707

The space laboratory will send its gigabytes of data to ESA’s ground
station in Kiruna, Sweden, the Italian ground station in Fucino or the
geostationary Artemis satellite orbiting the Earth at a distance of 36000
km. The ‘super satellite’ will register the tiniest surface movement and
give advance warning of floods, mud and snow avalanches and storms; it
will observe polar ice and the level of the oceans; recognise El Niño
before it builds its treacherous waves in the Pacific ocean; measure the
ozone layer; identify bush and forests fires and pinpoint water sources
in deserts.

Michael Rast, a scientist in ESA’s Directorate of Earth Observation, calls
Envisat “our Cassandra in Space”. The German geologist has always known,
long before the Climate Conference in Rio and the Kyoto Protocol, that
politicians are skating on thin ice when they argue about greenhouse gas
emissions. Envisat delivers facts. Rast quotes a report from the
Intergovernmental Panel for Climate Change (IPCC): “Mankind does not
understand the processes underlying our environment well enough. More
measurements and more research are needed: this can only be achieved on
the basis of quality data and quantitative analysis”.

Envisat is controlled via Kiruna, and when needed, its position is
corrected by radio signals from the operations centre at ESOC, ESA’s
Control Centre, in Darmstadt. Envisat circles the Earth at 100-minute
intervals, 14 times a day, returning in a 35-day cycle to the same orbit,
and in 3 days draws a complete map of the world. Rast states that, “we
want to retain an overview, for example, of ocean water quality, of
greenhouse gases or temperature distribution in the atmosphere, and to be
able to establish the extent to which tropical forests are being cut

The ten instruments on board Envisat, more than on any other satellite,
cover a wide spectrum of phenomena, delivering evidence of the
interactions between the atmosphere, the ocean and the surface of the

The Germans are particularly proud of SCIAMACHY on board Envisat: the
SCanning and Imaging Absorption spectroMeter for Atmospheric CartograpHY
searches the atmosphere for trace gases, ozone and similar substances as
well as clouds and dust particles, confirms the total amount of the gases
and indicates the different altitudes. SCIAMACHY shows the consequences of
forest fires, industrial emissions, arctic haze, dust storms and volcanic
eruptions. SCIAMACHY was provided by the German, Dutch and Belgian
national space entities and built by space companies from those
countries. One of the most sophisticated sensors on board, it will observe
and measure the migration of greenhouse gases through the atmosphere.

Europe’s eyes in space also measures the plankton movements in the world’s
seas in order to establish – as a complement to the knowledge about the
biological productivity of the oceans – a basis for setting fishing
quotas. Michael Rast states “We can prevent overfishing of the seas
because we can guide the fleets”. And furthermore: “There are poisonous
algae, toxic blooms, that have already decimated ecosystems. Once their
presence is identified from space, poisonous algae can be prevented from

Envisat should achieve even more: “If we can establish how much carbon is
absorbed by algae, we will be better able to establish how much
greenhouse gas the environment can actually tolerate, which will assist
the prediction of climate development”.

Envisat can also take stock of the Earth’s resources. For Dr Michael Rast:
“We will be able to trace the smallest changes to the Earth’s surface
better than from the ground”. Early warnings of volcanic eruptions and
earthquakes are slowly becoming reality. Data from Envisat will certainly
be used in vulcanology and seismology. Michael Rast believes “that in the
future we will be able to at least support earthquake damage estimates and
possibly predictions”.

The German scientist considers the satellite ” a pillar of the European
space programme”. He hopes that “with Envisat we will gain enormous
insight into the situation of the environment and climatic processes so
that in future we will be able, with this better understanding of the
relationships, to target specific problem areas with smaller satellites”.
He admits that it is a great risk to pack so much know-how into just one
satellite, “However, if we want to have a comprehensive understanding, we
must follow this path”.

Note to Editors: This Information Note is the first of a series devoted
to the Envisat programme and its applications. Pictures relating to
Envisat are available in low and high resolution on the Web at
http://www.esa.int/ (under Image Gallery), or in the electronic version of
the relevant Information Note.

For further information:

ESA Media Relations

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