Jacques van Oene
December 14th 04, 10:15 AM
EADS SPACE, with its subsidiaries, is strongly involved in flight 165.
December 13th, 2004
HELIOS II
credits : EADS Astrium
EADS Astrium is prime contractor for the HELIOS IIA satellite and its ground
segment.
EADS Astrium is co-prime contractor for the ESSAIM system which is based on
4 micro-satellites and their associated ground segments.
EADS Astrium has worked with the CNES on the development of the Parasol
micro-satellite.
EADS Sodern has supplied key equipments to Hélios II such as earth sensors
and star trackers and detection units for wide area and high resolution
instruments. EADS Sodern has supplied as well the Polder instrument for
Parasol.
EADS Space Transportation is the supplier of the Ariane 5 launcher.
EADS Astrium has supplied the ASAP structure (Ariane Structure for Auxiliary
Passenger) to carry micro-satellites.
The Helios II satellites
EADS Astrium was named prime contractor for the new-generation military
observation satellites Helios IIA and IIB satellites by French space agency
CNES (on behalf of the defense procurement agency DGA). It was already prime
contractor for the first-generation Helios IA and Helios IB satellites,
launched in July 1995 and December 1999, respectively.
The new-generation Helios II satellites will ensure continuity of service,
while offering a number of improved features, including:
enhanced resolution
infrared capability (for nighttime observation)
expanded imaging capacity, simultaneously in a number of modes
shorter image transmission times.
Each Helios II satellite will offer:
two imaging instruments:
a Very High Resolution (VHR) instrument operating in the visible and
infrared bands
a Wide Angle (WA) instrument, similar to that used on the Spot 5 civilian
remote sensing satellite.
a platform derived from that used on Spot 5, with greatly improved
maneuverability.
In addition to the day/night intelligence capability delivered by its
visible and infrared functions, the Helios II system will also be used for
targeting, guidance, mission planning and combat damage verification.
EADS Astrium is overall prime contractor for the satellites, including:
the platforms
the wide angle imaging instruments
The Helios IIA satellite will be launched from Kourou, French Guiana in
December 2004. The Helios IIB satellite will be ready in early 2006 for a
launch expected at the end of 2008.
Hélios II characteristics
LaunchHELIOS IIA: 2004
HELIOS IIB: ready 2006
CommissioningHELIOS IIA: early 2005
Weight4,200 kg
Design life5 years
OrbitSun-synchronous, low, quasi-polar, at 800 kilometers
ResolutionClassified
Imaging instruments- Wide Angle (WA), medium resolution - Spot 5 type
- Very High Resolution (VHR) with IR capability
Off-track viewingby tilting satellite
Data storage2 static recorders
Image telemetryEncrypted X band
Attitude control- 2 gyroscopes
- stellar sensors
Attitude command- hydrazine thrusters
- reaction wheels
- magnetic couplers
Remote control/telemetryEncrypted S band
EADS Astrium : nose-to-tail expertise in space imaging systems
Recent conflicts have shown just how central space systems are to overall
defence, highlighting their role as a "force multiplier" in different
theaters of operation. Image-based intelligence gathering systems built
around observation satellites play a decisive role in fulfilling this
mission.
Observation from space provides a way of addressing every type of crisis,
from prevention to management and reconstruction.
Countries with space-based resources enjoy an unrivalled overview of the
situation, enabling government authorities and the entire chain of command
to make the necessary decisions in light of all the facts and without the
need for external input.
EADS Astrium is the European leader in space observation. Since the first
Spot 1 remote sensing satellite, the company has been responsible for 11
optical observation satellites and three radar satellites.
As prime contractor, EADS Astrium has fostered, developed and consolidated
the skills required for the success of these programmes. It offers partners
and customers integrated solutions spanning all applications:
observation satellites
optical instruments (very high resolution imagers, spectrometers and Lidar
instruments) and radar instruments
low-orbit platforms, as well as the development and manufacture of their
avionics
ground segments
secure optical broadband communication terminals and Earth observation
services.
Optical and radar observation satellites
Optical observation
EADS Astrium was chosen by French space agency CNES as prime contractor for
the entire family of Spot satellites, from Spot 1 to Spot 5, and is
fulfilling the same role for the two new-generation Pleiades satellites.
EADS Astrium is also prime contractor for the Helios family of military
observation satellites, including the Helios I and Helios II generations.
Helios IIA is scheduled for launch at the end of 2004.
In export markets, EADS Astrium was the prime contractor for the Taiwanese
Rocsat satellite and is currently acting in the same capacity for the Theos
project on behalf of the Thai Space Agency. Projects such as these reflect
the capabilities offered by European industry, and help keep high
value-added jobs within Europe.
Radar observation
EADS Astrium has been prime contractor for all radar satellites developed by
the European Space Agency, namely ERS 1 and 2 and Envisat. The company is
also working on the Terrasar-X program now under development for German
space agency DLR.
EADS Astrium is also working on the Microsar micro-satellite concept.
Proven track record in optical and radar instruments
Optical instruments
All of the instruments used in every Spot satellite, including the HRS
instrument on Spot 5, were developed and produced by EADS Astrium as prime
contractor.
EADS Astrium has invested heavily to develop the expertise needed to harness
the very latest technologies and offer its clients the best possible
products. For instance, our new silicon carbide (SiC) composite technology
delivers:
a three to four-fold decrease in mirror weight for a given diameter;
the ability to use the same material for both mirrors and structure, thus
improving the instrument's overall mechanical and thermal performance;
the ability to simplify instrument design, for better control over the costs
and risks involved in such systems.
The Rocsat instrument was developed using these new technologies, which will
also be incorporated on the Theos instrument.
EADS Astrium was also prime contractor for all main meteorological
instruments used in the first and second-generation Meteosat weather
satellites.
Radar instruments
The radar instruments used in the ERS, Envisat and Terrasar-X satellites
were all developed under EADS Astrium control, reflecting unrivalled
expertise in this discipline, which complements optical instrumentation.
Platforms and avionics
The optical instrument may determine the performance of an observation
satellite in terms of its image resolution, but every other aspect of
performance (and particularly mission performance) relies on the platform
and its avionics.
EADS Astrium has been the prime contractor for all low-orbit platforms built
in Europe. We can offer customers a complete range of platforms for use with
satellites from the 4,000-kg class right down to 120-kg class
micro-satellites.
Today, however, the traditional platform concept is disappearing, as
satellites are built around an instrument that incorporates both the payload
and avionics. EADS Astrium's expertise in these highly integrated designs
means that we can create satellites that are more effective, more compact
and more agile.
Ground segment
Control ground segment
Beginning with the Spot 1 satellite, right through to the current generation
Spot 5 and Helios 2 programmes, EADS Astrium has handled the development and
subsequent upgrades of the real-time function in observation satellite
control centers, working for prime contractor CNES. It is currently prime
contractor for the Theos satellite control ground segment.
User ground segment
The user ground segment is decisive in any military observation system,
because it enables completely confidential individual programming of
satellites shared by different countries and users. It also offers the image
reception, processing and operational features needed to make maximum use of
satellite capability and the images they produce.
As prime contractor for the Helios system ground segments, EADS Astrium has
built up unique expertise in this field. The fact that the Helios system is
shared by a number of countries, each with many distinct users all demanding
confidentiality, has resulted in EADS Astrium offering highly innovative
architecture and IT solutions. The need to develop a single, prioritized,
satellite scheduling plan for multiple countries fostered the need to
develop new IT tools and suitable man-machine interfaces.
All of these solutions can easily be transposed in user ground segments of
dual-use satellite observation systems.
Earth observation services
EADS Astrium is also heavily involved in the development of applications,
from the distribution of raw or ortho-corrected images to the supply of
added-value data for use in agriculture, oil exploration, urban planning,
risk management, security and every type of environmental application under
the European GMES (Global Monitoring for Environment and Security) program.
This expertise draws on its involvement in the Spot program managed by its
Spot Image subsidiary, and the future Terrasar X radar project run by its
Infoterra GmbH subsidiary.
All of these activities are currently grouped within a Europe-wide structure
called Infoterra Global.
Infoterra Global was founded to develop these operational services in Europe
(through subsidiaries in France, Germany and the UK) and export them to meet
growing demand anywhere in the world.
ESSAIM, micro-satellites in formation
ESSAIM
The French defence procurement agency DGA chose EADS Astrium as a joint
prime contractor for the development of the ESSAIM system. This
demonstrator, based on 4 micro-satellites flying in formation through space,
will analyze the electromagnetic environment on the ground in a number of
frequency bands used exclusively for military communications.
The ESSAIM program is a "turnkey" system, comprising the space segment,
ground segment, satellite launch facilities and operations. The other
partner in this program, Thales Airborne Systems, is contributing its
electromagnetic systems expertise.
Space segment
The space segment comprises four satellites, flying in controlled formation
in two out-of-phase orbits. The four 120-kg micro-satellites are based on
the Myriade platform, developed by French space agency CNES in partnership
with EADS Astrium.
This program features the very latest space technologies to meet the payload
weight and size restrictions imposed by micro-satellites. These technologies
include triple junction gallium arsenide solar cells, lithium-ion batteries,
highly-integrated electronic components and fiber-optic gyros.
Ground segment
Co-located X-band terminals at the mission centre at the DGA's weapons
electronics centre (CELAR) in Bruz, near Rennes in western France will
receive the data stored on the satellites, as they become visible.
The dedicated ESSAIM satellite control centre is located at the CNES
facility in Toulouse, near CNES's other Myriade micro-satellite control
centers.
EADS Sodern: advanced optronics for Helios II and Parasol
The Optronic equipment for space requires a wide range of multi-disciplinary
skills in optics, mechanics, electronics and thermal control.
EADS Sodern has been involved in the Spot/Helios Earth observation programs
since the outset, building up expertise unrivaled in Europe in the
conversion of "space photons" into electrons. Its expertise spans both the
detection chain at the heart of the imaging instruments, and the sensors
used for attitude measurement.
EADS Sodern called on its space optronics skills to make a major
contribution to two of the satellites launched on Flight 165.
It supplied several key components to Helios II prime contractors EADS
Astrium and Alcatel Space:
Earth sensors and star trackers to stabilize the satellite;
the detection units which are the core of the Wide Swath and High Resolution
instruments.
It also supplied French space agency CNES with the camera for the instrument
on the Parasol micro-satellite.
HELIOS IIA
Earth sensors
The STD16 low-altitude Earth sensor helps provide three-axis satellite
stabilization. Helios II is equipped with two of these units. Operating in
the infrared band, the sensor uses dual conical scanning to observe the
transition zone between the Earth and space, detecting four angular
positions per second. The roll and pitch angles that determine the satellite
's attitude in relation to the Earth are calculated by combining these
positions.
The STD16 sensor is the successor to the STD12 model, developed for the
first Spot satellites, and also gave rise to the STD15 version for
geostationary satellites.
These components have been supplied to customers worldwide. In December
2003, Sodern delivered the 100th unit in the STD15/16 family.
Star trackers
The SED12D star tracker used on the Helios I and II satellites is a
higher-performance version of the SED12, the first to be developed by EADS
Sodern using charge-coupled device (CCD) technology instead of the previous
dissector tubes. An SED12 performed successfully for 12 years on the Russian
Granat satellite.
Following the initial standby mode, the tracker can operate either in search
mode, or tracking mode. It then determines the direction of one or several
stars designated by the onboard computer in a reference frame related to its
mounting plane. The unit can track stars with a visual magnitude of -4.5 to
+8.
Far more accurate than an Earth sensor, the stellar measurement unit uses
two of the three onboard trackers in operational mode. It provides
three-axis attitude control independent of the Earth's position, which gives
the satellite a high degree of agility, and excellent pointing precision for
the imaging instrument.
The SED12D tracker, also used on the Envisat platform and the Odin
satellite, has given rise to the new SED16 product line, a totally
autonomous tracker, with more than 70 sold to date. Since May 2002, there
are five satellites in orbit, including Spot 5, with SED16 units.
Image detection
EADS Sodern made the image detection components at the heart of the High
Resolution and Wide Swath observation instruments. The optronic detection
chain is responsible for a large part of the geometric and radiometric
performance needed for missions. The "detection chain" comprises:
charge-coupled devices (CCD), which convert photons into electrons; these
are detectors assembled on high-precision optics to reconstruct the image
line;
associated electronics, to control the CCDs, signal processing and
digitization.
The components in the detection chain are installed along the focal plane of
the imaging instrument to a very high degree of precision - within a micron.
This assembly guarantees the opto-mechanical stability of the structure in
orbit, along with the thermal control needed to support CCD operation.
Because of the demanding specifications, the quality of manufacture is as
important as the quality of design, and requires the concurrent development
of special ground facilities. Each Spot/Helios camera was developed by the
same teams at EADS Sodern that developed the test bench, an approach which
maximized the benefits of feedback.
The camera test bench guarantees the performance of two vital functions:
the geometric quality of the detection chain, by enabling the adjustment of
detector positions;
radiometric quality, by simulating the optical conditions of orbital
operation, to characterize the performance of the subassemblies and
calibrate the video systems.
On Helios II, even more than the previous generation, the performance
depended on an in-depth understanding of the imaging models, which was
achieved via a large number of very fine bench characterization tests.
EADS Sodern offers more than 20 years of experience in the development and
construction of detection chains and focal planes. Today, it is developing
the focal plane for the instrument used in the Pleiades HR program.
PARASOL
The Parasol micro-satellite carries an improved version of the Polder
instrument, two of which were installed on the Japanese satellites Adeos I
and II, launched in 1996 and 2002, respectively.
Operated in conjunction with Japanese space agency NASDA (Polder), then NASA
(Parasol), these instruments mark CNES's involvement in joint international
environmental monitoring programs, and more particularly those concerning
climatology.
Polder and Parasol both measure the directional characteristics and
polarization of the light reflected by terrestrial surfaces and the
atmosphere. Inside the instrument, a motorized filter wheel enables the
successive study of different wavebands of visible light. By adding a band
in the near-infrared, Parasol expands the spectrum being analyzed, and
provides an even richer harvest of scientific data.
EADS Sodern is supplying CNES with the entire imaging function for Parasol,
as it did for Polder. The instrument covers a swath on a field 2,100 x 1,600
kilometers, with a resolution of 5 to 6 kilometers.
Parasol is one of five satellites in the future French-American space
observatory Aqua-Train. EADS Sodern is also playing a major role on another
satellite in this series, Calipso.
With this launch, EADS Sodern fetes the 30th anniversary of its space
endeavors: the French-German satellite Symphonie was launched on December
18, 1974, with four Sodern Earth sensors aboard. This initial success kicked
off a long-standing contribution to space, with some 230 optronic components
and subassemblies already launched.
EADS Sodern, based at Limeil-Brévannes near Paris, is a medium-sized
enterprise with 370 employees. Its space customers come from around the
world, in Europe (CNES, ESA, Alcatel Space, EADS Astrium, EADS ST), Russia
(NPO PM), the United States (Orbital), Israel, India, China and Japan.
Contacts:
Rémi ROLAND
EADS SPACE (FR)Tel: +33 (0) 1 42 24 27 34
Francisco LECHÓN
EADS SPACE (E)Tel: +34 (0) 91 586 37 41
Dr. Christian W Erles
EADS SPACE (FR)Tel: +33 (0) 1 39 06 32 53
--
--------------
Jacques :-)
www.spacepatches.info
December 13th, 2004
HELIOS II
credits : EADS Astrium
EADS Astrium is prime contractor for the HELIOS IIA satellite and its ground
segment.
EADS Astrium is co-prime contractor for the ESSAIM system which is based on
4 micro-satellites and their associated ground segments.
EADS Astrium has worked with the CNES on the development of the Parasol
micro-satellite.
EADS Sodern has supplied key equipments to Hélios II such as earth sensors
and star trackers and detection units for wide area and high resolution
instruments. EADS Sodern has supplied as well the Polder instrument for
Parasol.
EADS Space Transportation is the supplier of the Ariane 5 launcher.
EADS Astrium has supplied the ASAP structure (Ariane Structure for Auxiliary
Passenger) to carry micro-satellites.
The Helios II satellites
EADS Astrium was named prime contractor for the new-generation military
observation satellites Helios IIA and IIB satellites by French space agency
CNES (on behalf of the defense procurement agency DGA). It was already prime
contractor for the first-generation Helios IA and Helios IB satellites,
launched in July 1995 and December 1999, respectively.
The new-generation Helios II satellites will ensure continuity of service,
while offering a number of improved features, including:
enhanced resolution
infrared capability (for nighttime observation)
expanded imaging capacity, simultaneously in a number of modes
shorter image transmission times.
Each Helios II satellite will offer:
two imaging instruments:
a Very High Resolution (VHR) instrument operating in the visible and
infrared bands
a Wide Angle (WA) instrument, similar to that used on the Spot 5 civilian
remote sensing satellite.
a platform derived from that used on Spot 5, with greatly improved
maneuverability.
In addition to the day/night intelligence capability delivered by its
visible and infrared functions, the Helios II system will also be used for
targeting, guidance, mission planning and combat damage verification.
EADS Astrium is overall prime contractor for the satellites, including:
the platforms
the wide angle imaging instruments
The Helios IIA satellite will be launched from Kourou, French Guiana in
December 2004. The Helios IIB satellite will be ready in early 2006 for a
launch expected at the end of 2008.
Hélios II characteristics
LaunchHELIOS IIA: 2004
HELIOS IIB: ready 2006
CommissioningHELIOS IIA: early 2005
Weight4,200 kg
Design life5 years
OrbitSun-synchronous, low, quasi-polar, at 800 kilometers
ResolutionClassified
Imaging instruments- Wide Angle (WA), medium resolution - Spot 5 type
- Very High Resolution (VHR) with IR capability
Off-track viewingby tilting satellite
Data storage2 static recorders
Image telemetryEncrypted X band
Attitude control- 2 gyroscopes
- stellar sensors
Attitude command- hydrazine thrusters
- reaction wheels
- magnetic couplers
Remote control/telemetryEncrypted S band
EADS Astrium : nose-to-tail expertise in space imaging systems
Recent conflicts have shown just how central space systems are to overall
defence, highlighting their role as a "force multiplier" in different
theaters of operation. Image-based intelligence gathering systems built
around observation satellites play a decisive role in fulfilling this
mission.
Observation from space provides a way of addressing every type of crisis,
from prevention to management and reconstruction.
Countries with space-based resources enjoy an unrivalled overview of the
situation, enabling government authorities and the entire chain of command
to make the necessary decisions in light of all the facts and without the
need for external input.
EADS Astrium is the European leader in space observation. Since the first
Spot 1 remote sensing satellite, the company has been responsible for 11
optical observation satellites and three radar satellites.
As prime contractor, EADS Astrium has fostered, developed and consolidated
the skills required for the success of these programmes. It offers partners
and customers integrated solutions spanning all applications:
observation satellites
optical instruments (very high resolution imagers, spectrometers and Lidar
instruments) and radar instruments
low-orbit platforms, as well as the development and manufacture of their
avionics
ground segments
secure optical broadband communication terminals and Earth observation
services.
Optical and radar observation satellites
Optical observation
EADS Astrium was chosen by French space agency CNES as prime contractor for
the entire family of Spot satellites, from Spot 1 to Spot 5, and is
fulfilling the same role for the two new-generation Pleiades satellites.
EADS Astrium is also prime contractor for the Helios family of military
observation satellites, including the Helios I and Helios II generations.
Helios IIA is scheduled for launch at the end of 2004.
In export markets, EADS Astrium was the prime contractor for the Taiwanese
Rocsat satellite and is currently acting in the same capacity for the Theos
project on behalf of the Thai Space Agency. Projects such as these reflect
the capabilities offered by European industry, and help keep high
value-added jobs within Europe.
Radar observation
EADS Astrium has been prime contractor for all radar satellites developed by
the European Space Agency, namely ERS 1 and 2 and Envisat. The company is
also working on the Terrasar-X program now under development for German
space agency DLR.
EADS Astrium is also working on the Microsar micro-satellite concept.
Proven track record in optical and radar instruments
Optical instruments
All of the instruments used in every Spot satellite, including the HRS
instrument on Spot 5, were developed and produced by EADS Astrium as prime
contractor.
EADS Astrium has invested heavily to develop the expertise needed to harness
the very latest technologies and offer its clients the best possible
products. For instance, our new silicon carbide (SiC) composite technology
delivers:
a three to four-fold decrease in mirror weight for a given diameter;
the ability to use the same material for both mirrors and structure, thus
improving the instrument's overall mechanical and thermal performance;
the ability to simplify instrument design, for better control over the costs
and risks involved in such systems.
The Rocsat instrument was developed using these new technologies, which will
also be incorporated on the Theos instrument.
EADS Astrium was also prime contractor for all main meteorological
instruments used in the first and second-generation Meteosat weather
satellites.
Radar instruments
The radar instruments used in the ERS, Envisat and Terrasar-X satellites
were all developed under EADS Astrium control, reflecting unrivalled
expertise in this discipline, which complements optical instrumentation.
Platforms and avionics
The optical instrument may determine the performance of an observation
satellite in terms of its image resolution, but every other aspect of
performance (and particularly mission performance) relies on the platform
and its avionics.
EADS Astrium has been the prime contractor for all low-orbit platforms built
in Europe. We can offer customers a complete range of platforms for use with
satellites from the 4,000-kg class right down to 120-kg class
micro-satellites.
Today, however, the traditional platform concept is disappearing, as
satellites are built around an instrument that incorporates both the payload
and avionics. EADS Astrium's expertise in these highly integrated designs
means that we can create satellites that are more effective, more compact
and more agile.
Ground segment
Control ground segment
Beginning with the Spot 1 satellite, right through to the current generation
Spot 5 and Helios 2 programmes, EADS Astrium has handled the development and
subsequent upgrades of the real-time function in observation satellite
control centers, working for prime contractor CNES. It is currently prime
contractor for the Theos satellite control ground segment.
User ground segment
The user ground segment is decisive in any military observation system,
because it enables completely confidential individual programming of
satellites shared by different countries and users. It also offers the image
reception, processing and operational features needed to make maximum use of
satellite capability and the images they produce.
As prime contractor for the Helios system ground segments, EADS Astrium has
built up unique expertise in this field. The fact that the Helios system is
shared by a number of countries, each with many distinct users all demanding
confidentiality, has resulted in EADS Astrium offering highly innovative
architecture and IT solutions. The need to develop a single, prioritized,
satellite scheduling plan for multiple countries fostered the need to
develop new IT tools and suitable man-machine interfaces.
All of these solutions can easily be transposed in user ground segments of
dual-use satellite observation systems.
Earth observation services
EADS Astrium is also heavily involved in the development of applications,
from the distribution of raw or ortho-corrected images to the supply of
added-value data for use in agriculture, oil exploration, urban planning,
risk management, security and every type of environmental application under
the European GMES (Global Monitoring for Environment and Security) program.
This expertise draws on its involvement in the Spot program managed by its
Spot Image subsidiary, and the future Terrasar X radar project run by its
Infoterra GmbH subsidiary.
All of these activities are currently grouped within a Europe-wide structure
called Infoterra Global.
Infoterra Global was founded to develop these operational services in Europe
(through subsidiaries in France, Germany and the UK) and export them to meet
growing demand anywhere in the world.
ESSAIM, micro-satellites in formation
ESSAIM
The French defence procurement agency DGA chose EADS Astrium as a joint
prime contractor for the development of the ESSAIM system. This
demonstrator, based on 4 micro-satellites flying in formation through space,
will analyze the electromagnetic environment on the ground in a number of
frequency bands used exclusively for military communications.
The ESSAIM program is a "turnkey" system, comprising the space segment,
ground segment, satellite launch facilities and operations. The other
partner in this program, Thales Airborne Systems, is contributing its
electromagnetic systems expertise.
Space segment
The space segment comprises four satellites, flying in controlled formation
in two out-of-phase orbits. The four 120-kg micro-satellites are based on
the Myriade platform, developed by French space agency CNES in partnership
with EADS Astrium.
This program features the very latest space technologies to meet the payload
weight and size restrictions imposed by micro-satellites. These technologies
include triple junction gallium arsenide solar cells, lithium-ion batteries,
highly-integrated electronic components and fiber-optic gyros.
Ground segment
Co-located X-band terminals at the mission centre at the DGA's weapons
electronics centre (CELAR) in Bruz, near Rennes in western France will
receive the data stored on the satellites, as they become visible.
The dedicated ESSAIM satellite control centre is located at the CNES
facility in Toulouse, near CNES's other Myriade micro-satellite control
centers.
EADS Sodern: advanced optronics for Helios II and Parasol
The Optronic equipment for space requires a wide range of multi-disciplinary
skills in optics, mechanics, electronics and thermal control.
EADS Sodern has been involved in the Spot/Helios Earth observation programs
since the outset, building up expertise unrivaled in Europe in the
conversion of "space photons" into electrons. Its expertise spans both the
detection chain at the heart of the imaging instruments, and the sensors
used for attitude measurement.
EADS Sodern called on its space optronics skills to make a major
contribution to two of the satellites launched on Flight 165.
It supplied several key components to Helios II prime contractors EADS
Astrium and Alcatel Space:
Earth sensors and star trackers to stabilize the satellite;
the detection units which are the core of the Wide Swath and High Resolution
instruments.
It also supplied French space agency CNES with the camera for the instrument
on the Parasol micro-satellite.
HELIOS IIA
Earth sensors
The STD16 low-altitude Earth sensor helps provide three-axis satellite
stabilization. Helios II is equipped with two of these units. Operating in
the infrared band, the sensor uses dual conical scanning to observe the
transition zone between the Earth and space, detecting four angular
positions per second. The roll and pitch angles that determine the satellite
's attitude in relation to the Earth are calculated by combining these
positions.
The STD16 sensor is the successor to the STD12 model, developed for the
first Spot satellites, and also gave rise to the STD15 version for
geostationary satellites.
These components have been supplied to customers worldwide. In December
2003, Sodern delivered the 100th unit in the STD15/16 family.
Star trackers
The SED12D star tracker used on the Helios I and II satellites is a
higher-performance version of the SED12, the first to be developed by EADS
Sodern using charge-coupled device (CCD) technology instead of the previous
dissector tubes. An SED12 performed successfully for 12 years on the Russian
Granat satellite.
Following the initial standby mode, the tracker can operate either in search
mode, or tracking mode. It then determines the direction of one or several
stars designated by the onboard computer in a reference frame related to its
mounting plane. The unit can track stars with a visual magnitude of -4.5 to
+8.
Far more accurate than an Earth sensor, the stellar measurement unit uses
two of the three onboard trackers in operational mode. It provides
three-axis attitude control independent of the Earth's position, which gives
the satellite a high degree of agility, and excellent pointing precision for
the imaging instrument.
The SED12D tracker, also used on the Envisat platform and the Odin
satellite, has given rise to the new SED16 product line, a totally
autonomous tracker, with more than 70 sold to date. Since May 2002, there
are five satellites in orbit, including Spot 5, with SED16 units.
Image detection
EADS Sodern made the image detection components at the heart of the High
Resolution and Wide Swath observation instruments. The optronic detection
chain is responsible for a large part of the geometric and radiometric
performance needed for missions. The "detection chain" comprises:
charge-coupled devices (CCD), which convert photons into electrons; these
are detectors assembled on high-precision optics to reconstruct the image
line;
associated electronics, to control the CCDs, signal processing and
digitization.
The components in the detection chain are installed along the focal plane of
the imaging instrument to a very high degree of precision - within a micron.
This assembly guarantees the opto-mechanical stability of the structure in
orbit, along with the thermal control needed to support CCD operation.
Because of the demanding specifications, the quality of manufacture is as
important as the quality of design, and requires the concurrent development
of special ground facilities. Each Spot/Helios camera was developed by the
same teams at EADS Sodern that developed the test bench, an approach which
maximized the benefits of feedback.
The camera test bench guarantees the performance of two vital functions:
the geometric quality of the detection chain, by enabling the adjustment of
detector positions;
radiometric quality, by simulating the optical conditions of orbital
operation, to characterize the performance of the subassemblies and
calibrate the video systems.
On Helios II, even more than the previous generation, the performance
depended on an in-depth understanding of the imaging models, which was
achieved via a large number of very fine bench characterization tests.
EADS Sodern offers more than 20 years of experience in the development and
construction of detection chains and focal planes. Today, it is developing
the focal plane for the instrument used in the Pleiades HR program.
PARASOL
The Parasol micro-satellite carries an improved version of the Polder
instrument, two of which were installed on the Japanese satellites Adeos I
and II, launched in 1996 and 2002, respectively.
Operated in conjunction with Japanese space agency NASDA (Polder), then NASA
(Parasol), these instruments mark CNES's involvement in joint international
environmental monitoring programs, and more particularly those concerning
climatology.
Polder and Parasol both measure the directional characteristics and
polarization of the light reflected by terrestrial surfaces and the
atmosphere. Inside the instrument, a motorized filter wheel enables the
successive study of different wavebands of visible light. By adding a band
in the near-infrared, Parasol expands the spectrum being analyzed, and
provides an even richer harvest of scientific data.
EADS Sodern is supplying CNES with the entire imaging function for Parasol,
as it did for Polder. The instrument covers a swath on a field 2,100 x 1,600
kilometers, with a resolution of 5 to 6 kilometers.
Parasol is one of five satellites in the future French-American space
observatory Aqua-Train. EADS Sodern is also playing a major role on another
satellite in this series, Calipso.
With this launch, EADS Sodern fetes the 30th anniversary of its space
endeavors: the French-German satellite Symphonie was launched on December
18, 1974, with four Sodern Earth sensors aboard. This initial success kicked
off a long-standing contribution to space, with some 230 optronic components
and subassemblies already launched.
EADS Sodern, based at Limeil-Brévannes near Paris, is a medium-sized
enterprise with 370 employees. Its space customers come from around the
world, in Europe (CNES, ESA, Alcatel Space, EADS Astrium, EADS ST), Russia
(NPO PM), the United States (Orbital), Israel, India, China and Japan.
Contacts:
Rémi ROLAND
EADS SPACE (FR)Tel: +33 (0) 1 42 24 27 34
Francisco LECHÓN
EADS SPACE (E)Tel: +34 (0) 91 586 37 41
Dr. Christian W Erles
EADS SPACE (FR)Tel: +33 (0) 1 39 06 32 53
--
--------------
Jacques :-)
www.spacepatches.info