Astrium to Supply Radar Instrument for the “Space Sentinel”
Astrium to Supply Radar Instrument for the “Space Sentinel”
Astrium and Thales Alenia Space sign delivery contract... New ESA satellite for environmental monitoring and security... Astrium continues its radar success story with Sentinel-1.
Source : Astrium.
Friedrichshafen, 16 November 2007 (Astrium)
-- Astrium is writing another chapter in its
space radar success story: Following the radar instruments for the ERS1/2,
Envisat and Metop satellites, the company is to develop and build the latest
imaging radar for an ESA satellite. The development and delivery contract is to
be signed in Friedrichshafen today by Massimo Di Laz-zaro, Senior Vice President
and General Manager of Thales Alenia Space BU Observation Systems & Radar, and
Uwe Minne, Director of Earth observation and Science at Astrium Germany. The
European Space Agency (ESA) awarded the main contact for the Sentinel-1
satellite in February to Thales Alenia Space. Astrium is now to supply the
C-band radar for the Sentinel-1 satellite. The contract value of the entire
project is €229 million, with the SAR instrument worth approximately €85
million. Sentinel-1 is one element in the GMES (Global Monitoring for
Environment and Security) programme, an initiative by the European Commission
and ESA to set up a sustainable European network for recording and analysing
environmental data. Sentinel-1 will help to monitor and analyse environmental
events round the globe.
Weighing some 2.2 metric tons, the satellite will orbit the Earth at an
altitude of 700 kilometres from 2011. Its orbital path will take it across the
poles on each orbit, enabling the radar instrument to scan the Earth in “swaths”
as it rotates beneath the satellite. Designed as a successor to the present
satellites ERS and Envisat to assure continuity in radar-based Earth
observation, Sentinel-1 will observe the Earth from orbit for at least seven
years. In contrast to its predecessors ERS and Envisat, however, the radar
instrument carried by Sentinel-1 will include improvements such as enhanced
antenna performance, which in turn will ensure better data quality.
The Astrium-built C-band SAR (Synthetic Aperture Radar) instrument, which
delivers radar images of the Earth’s surface, is the core element of the
mission. By taking advantage of the satellite’s flight motion, SAR is able to
simulate a considerably larger antenna than is in fact present, thus
significantly increasing the image resolution. The radar on Sentinel-1 operates
in the C band frequency range. The C-band radar beam, which has a wavelength of
six centimetres, penetrates forests and scrub to reach the ground, and the C
band radar registers any movements or changes on the Earth’s surface to within a
Sentinel-1 will be equipped with an active antenna made of up 280 individual
antennas, in-cluding electronic front ends (transmit/receive modules) provided
by Thales Alenia Space Italy. The active antenna can be electronically directed
towards a new observation terrain without having to be physically moved. Thanks
to this technology, several adjacent swaths can be scanned on each overflight
and later combined to form a larger overall picture.
The radar instrument can operated in four different observation modes which
differ primarily in the width of the scanned corridor and the resolution of the
radar images. This enables Sentinel-1 to respond to a wide range of varying
requirements. In strip-map mode, strips of terrain 80 kilometres wide are
scanned at a resolution of 5x5 metres. The interferometric wide-swath mode
registers corridors 250 kilometres wide at a pixel size of 5x20 metres. The
extra-wide swath mode provides a more extensive overview of larger expanses of
terrain. In this mode, a corridor 400 kilometres wide is mapped at a resolution
of 100x25 metres. The fourth mode, known as wave mode, scans 20x20 kilometre
spots at a resolution of 20x5 metres.
Sentinel-1 has been specifically designed to cover a wide range of
environmental and security tasks. Observing the melting ice masses in Greenland,
for example, should provide im-portant data to help predict rises in sea levels.
Sentinel-1 will also be used for the observation of environmental events such
as forest fires and for reconnaissance and support in criti-cal situations where
up-to-the-minute data is needed at extremely short notice.
Accurate and up-to-date maps compiled from satellite data also better
co-ordination of humanitarian relief projects and rebuilding activities after
natural disasters. Sentinel-1’s sophisticated radar technology will be
particularly useful during floods to help make reliable predictions of water
levels and potential severity of the flooding in affected areas. To date,
disaster relief organisations often rely on data from optical sensors. This can
mean waiting a long time for the data, particularly when it is night or there is
a lot of cloud. In situations like these, Sentinel-1’s radar technology makes it
vastly superior to optical devices. Radar has numerous advantages over optical
imagery: first, radar generates its own “illumination” which is precisely
defined at all times. This is very different from optical satellite images, in
which the position of the sun at any given time greatly affects the appearance
of a landscape. Secondly, radars operate day and night, and thirdly it is
capable of delivering clearly focused images even in adverse weather conditions.
This makes it possible to plan and co-ordinate protective measures much more
efficiently and comprehensively.
A further application for the data from Sentinel-1 is in supporting
agricultural projects. The satellite delivers information that is vital to
monitoring crop growth with a view to harvesting.
Astrium has been the one of the leading provider of space radars for many
years. As well as bearing the overall industrial responsibility for Envisat,
ERS-1/ERS-2, TerraSAR-X and Tan-DEM-X, EADS Astrium also developed and built the
SAR payloads AMI (ERS), ASAR (Envi-sat), and ASCAT (Metop).
GMES (Global Monitoring for Environment and Security) is a joint initiative
by the EU and ESA for comprehensive Earth observation using ground- and
space-based sensors, to provide political decision-makers and experts with
up-to-the-minute factual information on which to base all manner of decisions
concerning environmental, economic, transport and security policy.
The objective of the programme is to integrate the different Earth
observation and geo-science activities in Europe, on the one hand by using the
existing satellite systems and the data they supply as efficiently as possible,
and on other by setting up sustainable operational systems that are specifically
adapted to this range of tasks. The Sentinel series of satellites is a response
to the Earth observation needs of the GMES programme in Europe.
Astrium, a wholly owned subsidiary of EADS, is dedicated to providing civil
and defence space systems and services. In 2006, Astrium had a turnover of €3.2
billion and 12,000 employees in France, Germany, the United Kingdom, Spain and
the Netherlands. Its three main areas of activity are: Astrium Space
Transportation for launchers and orbital infrastructure, Astrium Satellites for
spacecraft and ground segment, and its wholly owned subsidiary Astrium Services
for the development and delivery of satellite services. EADS is a global leader
in aerospace, defence and related services. In 2006, EADS generated revenues of
€39.4 billion and employed a workforce of more than 116, 000.
European leader in satellite systems and at the forefront of orbital
infrastructures, Thales Alenia Space is a joint venture between Thales (67%) and
Finmeccanica (33%). Together with Telespazio, Thales Alenia Space forms a Space
Alliance between the two groups. The company is a worldwide reference in
telecoms, radar and optical Earth observation, defense and security, navigation
and science. With 7200 employees and 11 industrial sites, Thales Alenia Space is
located in France, Italy, Spain and Belgium.
Thales Alenia Space Press Contact :
Rémi Roland (Astrium FR) - Phone: +33 (0) 1 77 75 80 37
Jeremy Close (Astrium UK) - Phone: +44 (0)1 438 77 3872
Mathias Pikelj (Astrium GER) - Phone: +49 (0) 7545 8 91 23
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