Andrew Yee[_1_]
June 10th 07, 04:03 PM
ESA News
http://www.esa.int
8 June 2007
ESA's water mission instrument passes test programme
After successfully undergoing a rigorous three-month testing programme, the
innovative SMOS (Soil Moisture and Ocean Salinity) payload is about to make
its journey from ESA's Test Centre in the Netherlands to France, where it
will join the platform to form the satellite in preparation for launch next
year.
After more than 10 years of research and development, the SMOS mission is
adopting a completely new approach in the field of remote sensing by
employing a novel instrument called MIRAS (Microwave Imaging Radiometer
using Aperture Synthesis). By capturing images of microwave radiation
emitted from the surface of the Earth at a specific wavelength, this novel
instrument is capable of observing both the moisture in soil and salt in the
oceans. MIRAS will be the first-ever 2-D interferometric radiometer in space
and will provide much-needed data to learn more about the continual
circulation of water between the oceans, the atmosphere and the land -- the
Earth's water cycle, one of the most important processes occurring on the
planet and a crucial component of the weather and climate.
Making sure the instrument will withstand the rigors of launch and the harsh
environment in orbit is an extremely important part of the mission
development. Therefore, with launch scheduled for next year, MIRAS had to
undergo an extensive testing programme in ESA's Test Centre.
In balance
After delivery from the instrument prime contractor EADS-CASA in Spain, the
testing programme started with determining the instrument's 'mass
properties'. This included precisely measuring its overall weight, locating
the centre of gravity and the inertia around its three principle axes. These
values are crucial for both tuning the launcher trajectory and as input for
the satellite's Attitude and Orbit Control System.
Noise
The instrument module consists of a central structure and three deployable
arms. These arms were folded up for the next testing procedure when the
instrument was placed in the Large European Acoustic Facility. Here the
tremendous noise and vibrations levels that are expected to be experienced
under the launcher's fairing were simulated.
Temperature extremes
Having survived the acoustic tests, the instrument was transferred to the
Large Space Simulator. This is a massive vacuum chamber where the extreme
temperature differences of space are simulated. A solar beam, six metres in
diameter, was repeatedly shone onto the instrument and then the instrument
was subjected to extreme cold similar to that of deep space. Not only does
the payload need to function properly under these extremes, the thermal
environment and temperature distribution across the body of the three arms
is an important factor for MIRAS's overall measurement performance. For the
test to be meaningful, the instrument's three arms had to be fully deployed
-- suspended like a string puppet it just fitted into the 10-metre diameter
chamber. These thermal tests continued around the clock for almost 3 weeks.
Testing images
Finally, the instrument was set up in what is called the Maxwell Facility
for two types of tests -- the electromagnetic compatibility test, which
makes sure that nothing is disturbed when, for example, the data downlink is
activated, and the image validation test, which is where an artificial
source mounted on the ceiling is 'imaged' by the instrument under different
conditions. In addition, tests were performed on the algorithms and software
for the Level 1 processor, which converts digital counts into pictures for
scientists to derive information on soil moisture and ocean salinity.
The engineers and scientists involved in this intensive testing programme
are extremely pleased with the results and the MIRAS instrument is now in
the process of being packed up for delivery to Thales Alenia Space (formerly
Alcatel Alenia Space) in Cannes, where it will be joined with the PROTEUS
platform to form the entire SMOS satellite.
Now confident that the instrument will survive the rigors of launch and its
lifetime in space, ESA looks forward to the launch of the SMOS satellite
from the Plesetsk Cosmodrome in northern Russia next year.
[NOTE: Images supporting this release are available at
http://www.esa.int/esaCP/SEMN5JEVL2F_index_1.html ]
http://www.esa.int
8 June 2007
ESA's water mission instrument passes test programme
After successfully undergoing a rigorous three-month testing programme, the
innovative SMOS (Soil Moisture and Ocean Salinity) payload is about to make
its journey from ESA's Test Centre in the Netherlands to France, where it
will join the platform to form the satellite in preparation for launch next
year.
After more than 10 years of research and development, the SMOS mission is
adopting a completely new approach in the field of remote sensing by
employing a novel instrument called MIRAS (Microwave Imaging Radiometer
using Aperture Synthesis). By capturing images of microwave radiation
emitted from the surface of the Earth at a specific wavelength, this novel
instrument is capable of observing both the moisture in soil and salt in the
oceans. MIRAS will be the first-ever 2-D interferometric radiometer in space
and will provide much-needed data to learn more about the continual
circulation of water between the oceans, the atmosphere and the land -- the
Earth's water cycle, one of the most important processes occurring on the
planet and a crucial component of the weather and climate.
Making sure the instrument will withstand the rigors of launch and the harsh
environment in orbit is an extremely important part of the mission
development. Therefore, with launch scheduled for next year, MIRAS had to
undergo an extensive testing programme in ESA's Test Centre.
In balance
After delivery from the instrument prime contractor EADS-CASA in Spain, the
testing programme started with determining the instrument's 'mass
properties'. This included precisely measuring its overall weight, locating
the centre of gravity and the inertia around its three principle axes. These
values are crucial for both tuning the launcher trajectory and as input for
the satellite's Attitude and Orbit Control System.
Noise
The instrument module consists of a central structure and three deployable
arms. These arms were folded up for the next testing procedure when the
instrument was placed in the Large European Acoustic Facility. Here the
tremendous noise and vibrations levels that are expected to be experienced
under the launcher's fairing were simulated.
Temperature extremes
Having survived the acoustic tests, the instrument was transferred to the
Large Space Simulator. This is a massive vacuum chamber where the extreme
temperature differences of space are simulated. A solar beam, six metres in
diameter, was repeatedly shone onto the instrument and then the instrument
was subjected to extreme cold similar to that of deep space. Not only does
the payload need to function properly under these extremes, the thermal
environment and temperature distribution across the body of the three arms
is an important factor for MIRAS's overall measurement performance. For the
test to be meaningful, the instrument's three arms had to be fully deployed
-- suspended like a string puppet it just fitted into the 10-metre diameter
chamber. These thermal tests continued around the clock for almost 3 weeks.
Testing images
Finally, the instrument was set up in what is called the Maxwell Facility
for two types of tests -- the electromagnetic compatibility test, which
makes sure that nothing is disturbed when, for example, the data downlink is
activated, and the image validation test, which is where an artificial
source mounted on the ceiling is 'imaged' by the instrument under different
conditions. In addition, tests were performed on the algorithms and software
for the Level 1 processor, which converts digital counts into pictures for
scientists to derive information on soil moisture and ocean salinity.
The engineers and scientists involved in this intensive testing programme
are extremely pleased with the results and the MIRAS instrument is now in
the process of being packed up for delivery to Thales Alenia Space (formerly
Alcatel Alenia Space) in Cannes, where it will be joined with the PROTEUS
platform to form the entire SMOS satellite.
Now confident that the instrument will survive the rigors of launch and its
lifetime in space, ESA looks forward to the launch of the SMOS satellite
from the Plesetsk Cosmodrome in northern Russia next year.
[NOTE: Images supporting this release are available at
http://www.esa.int/esaCP/SEMN5JEVL2F_index_1.html ]