Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

ESA’s miniature Earth observer put to many uses

05.05.2004


Think of ESA’s Proba as the little satellite that does a lot. It is only the size of a washing machine but its main instrument - the smallest hyperspectral imager ever flown in space – has an expanding portfolio of uses encompassing agricultural mapping, water quality monitoring, charting forest fire damage and disaster management.


CHRIS image of Italy’s Stromboli volcano. It was acquired by the Proba instrument on 3 December 2003. Stromboli is one of the Aeolian Islands, and stands about 900 metres above the level of the Tyrrhenian Sea.

Credits: ESA


San Francisco seen from PROBA-1’s CHRIS instrument.
Credits: ESA



Launched in October 2001, the Project for Onboard Autonomy (Proba) satellite measures just 60 x 60 x 80 cm. Its main instrument takes up around a third of this pint-sized orbiter and is known as the Compact High Resolution Imaging Spectrometer (CHRIS).
Operating from a distance of 600 km away, CHRIS acquires 14-km square images of the Earth’s surface to a resolution of 18 metres, in a combination of up to 19 out of a total of 62 spectral bands to provide added environmental information. And the same scene can be viewed from a variety of different angles because Proba is manoeuvrable enough to perform controlled rolls.

That remarkable combination of abilities has aroused the interests of researchers worldwide. Last week around 40 of them met up at ESA’s European Space Research Institute (ESRIN) centre at Frascati, Italy. They discussed their current and future uses of the instrument at the three-day Second CHRIS/Proba Workshop from 28 April.



"Proba was launched as a technology demonstrator with all sorts of experimental equipment aboard, including CHRIS," explained Evert Attema, Head of the ESA Scientific Campaign Unit. "But once in orbit we found both Proba and CHRIS performed well above expectations, and so we put out an Announcement of Opportunity for scientists interested in making use of CHRIS data. Some 60 different groups responded, and we are hearing about their projects during this event."

Looking at life on land

CHRIS’s ability to retrieve hyperspectral and multi-angular data makes it especially useful for the study of vegetation cover on land. Francois Kayitakire of the University of Louvain’s Water and Forest Unit in Belgium recounted research being carried out on the 10000-hectare Nismes forest.

CHRIS’s hyperspectral capability helped differentiate tree species – identifying coniferous and deciduous trees as well as spruce and pine groups – while differing canopy shadows seen in multiple angle views yielded data on woodland density, tree height and limb span.

Ray Merton of the School of Biological, Earth and Environmental Sciences of the University of New South Wales in Australia explained how his team used CHRIS imagery as part of an investigation of how the reflectance properties of cotton might be used on an operational basis to estimate the crop’s health, maturity and yield.

Merton’s team are documenting the spectral properties of cotton on a variety of scales, from looking at individual cotton leaves in the lab to making field acquisitions close-up, from using airborne hyperspectral imagers all the way up to Landsat data.

He stated that the CHRIS data acquired served as a useful bridge between the aerial and Landsat imagery. The research had been hampered by a persistent drought affecting their test area, but even so, CHRIS data was shown to be able to differentiate between cotton species, crops with high, normal and low water content and also high and low fertility of the underlying soil.

Working over water

CHRIS was designed for Earth Observation over land surfaces, but a number of research teams are investigating its use to study inland water bodies as well as coastal water sites.

Ramon Pena-Martinez of the Centre for Hydrographic Studies of Spain’s Centro de Estudios y Experimentación de Obras Públicas (CEDEX) explained how he was preparing to use CHRIS data in support of a project employing the Medium Resolution Imaging Spectrometer (MERIS) instrument on ESA’s Envisat spacecraft to detect traces of potentially harmful phytoplankton in his country’s reservoirs.

"Because most rain in Spain falls in the north, the country has hundreds of large reservoirs to redistribute water where it is needed," Pena-Martinez explained. "We are interested in monitoring levels of photosynthetic pigments on the surface of a number of sample reservoirs as an indication of phytoplankton concentrations and overall water quality.

"We are interested in using whatever hyperspectral sensor is available for this task, including airborne instruments, and monthly acquisitions from CHRIS represents a valuable additional resource for us."

Joining forces for fire mapping

CHRIS is also set to join forces with another mini-satellite to survey the longer-term damage done by forest fires. When Proba was launched it shared its rocket with the Bi-Spectral Infrared Detection (BIRD) spacecraft designed by the German Aerospace Centre (DLR) to detect high-energy and fire events across the Earth’s surface.

This being so, the joint research programme outlined to the Workshop by Dieter Oertel of DLR represents a sort of reunion. CHRIS will re-acquire the sites of forest sites charted within the last year by BIRD to map the extent of the burnt area and identify any vegetation regrowth. Areas under target include last year’s fire zones in Spain and Portugal as well Australia and Siberia.

"Fire is the single most active environmental change agent," Oertel said. "Within many ecosystems such as boreal forests low to medium intensity fires are actually beneficial, reducing fuel loads and stabilising the environment. However high intensity fires can be more destructive, leading to destruction of the dominant plant species, soil degradation, increased water run-off, flooding and landslides.

"The data from the two satellites will help develop a system to decide when a fire is either beneficial or destructive."

Aftermath of disaster

The Workshop also heard how the international Charter on Space and Major Disasters was considering an increase in its use of CHRIS imagery for high-resolution damage assessment as a response tool during disaster situations. Back in December 2003 a CHRIS image of flooding in the town of Ville d’Arles in France was acquired following a Charter activation.

The nature of Proba’s origin as a technology demonstrator mission means that CHRIS has previously lacked archive data to enable before and after comparisons (although an archive is now being integrated within the ESRIN Multi-Mission ground segment) but the possibility of employing SPOT or Landsat data for comparison purposes was discussed at the Workshop.

Qingxi Tong of the Institute of Remote Sensing Applications of the Chinese Academy of Sciences in Beijing stated that China had a widespread interest in hyperspectral imaging for a variety of uses from mineral prospecting to disaster relief. As part of the flood research element of the joint ESA-China Dragon Programme, CHRIS acquisitions of flood-prone areas near Beijing are being scheduled for the summer.

About Proba

Proba (Project for On Board Autonomy) is an ESA micro-satellite built by an industrial consortium led by the Belgian company Verhaert, launched in October 2001 and operated from ESA’s Redu Ground Station (Belgium).

Orbiting 600 km above the Earth’s surface, Proba was designed to be a one-year technology demonstration mission of the Agency but has since had its lifetime extended as an Earth Observation mission. It now routinely provides scientists with detailed environmental images thanks to CHRIS - developed by UK-based Sira Electro-Optics Ltd - one of the main payloads on the 100 kg spacecraft.

Proba boasts an ’intelligent’ payload, has the ability to observe the same spot on Earth in a large combination of different visible and infra-red spectra as well as from a number of different angles. A follow-on mission, Proba-2, is due to be deployed by ESA around 2005.

Proba’s unique capabilities also makes it a useful resource in the development of the proposed hyper-spectral and multi-angular Surface Processes and Ecosystem Changes Through Response Analysis (SPECTRA) mission, an Earth Explorer spacecraft intended to study terrestrial vegetation across the world’s major biological communities or biomes. If selected for development, SPECTRA would launch around 2012.

Frédéric Le Gall | ESA
Further information:
http://www.esa.int/esaSA/SEMHHH77ESD_earth_0.html

More articles from Earth Sciences:

nachricht A Volcanic Binge And Its Frosty Hangover
21.02.2019 | Universität Heidelberg

nachricht Researchers get to the bottom of fairy circles
21.02.2019 | Georg-August-Universität Göttingen

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: (Re)solving the jet/cocoon riddle of a gravitational wave event

An international research team including astronomers from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has combined radio telescopes from five continents to prove the existence of a narrow stream of material, a so-called jet, emerging from the only gravitational wave event involving two neutron stars observed so far. With its high sensitivity and excellent performance, the 100-m radio telescope in Effelsberg played an important role in the observations.

In August 2017, two neutron stars were observed colliding, producing gravitational waves that were detected by the American LIGO and European Virgo detectors....

Im Focus: Light from a roll – hybrid OLED creates innovative and functional luminous surfaces

Up to now, OLEDs have been used exclusively as a novel lighting technology for use in luminaires and lamps. However, flexible organic technology can offer much more: as an active lighting surface, it can be combined with a wide variety of materials, not just to modify but to revolutionize the functionality and design of countless existing products. To exemplify this, the Fraunhofer FEP together with the company EMDE development of light GmbH will be presenting hybrid flexible OLEDs integrated into textile designs within the EU-funded project PI-SCALE for the first time at LOPEC (March 19-21, 2019 in Munich, Germany) as examples of some of the many possible applications.

The Fraunhofer FEP, a provider of research and development services in the field of organic electronics, has long been involved in the development of...

Im Focus: Regensburg physicists watch electron transfer in a single molecule

For the first time, an international team of scientists based in Regensburg, Germany, has recorded the orbitals of single molecules in different charge states in a novel type of microscopy. The research findings are published under the title “Mapping orbital changes upon electron transfer with tunneling microscopy on insulators” in the prestigious journal “Nature”.

The building blocks of matter surrounding us are atoms and molecules. The properties of that matter, however, are often not set by these building blocks...

Im Focus: University of Konstanz gains new insights into the recent development of the human immune system

Scientists at the University of Konstanz identify fierce competition between the human immune system and bacterial pathogens

Cell biologists from the University of Konstanz shed light on a recent evolutionary process in the human immune system and publish their findings in the...

Im Focus: Transformation through Light

Laser physicists have taken snapshots of carbon molecules C₆₀ showing how they transform in intense infrared light

When carbon molecules C₆₀ are exposed to an intense infrared light, they change their ball-like structure to a more elongated version. This has now been...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Global Legal Hackathon at HAW Hamburg

11.02.2019 | Event News

The world of quantum chemistry meets in Heidelberg

30.01.2019 | Event News

Our digital society in 2040

16.01.2019 | Event News

 
Latest News

JILA researchers make coldest quantum gas of molecules

22.02.2019 | Physics and Astronomy

Understanding high efficiency of deep ultraviolet LEDs

22.02.2019 | Materials Sciences

Russian scientists show changes in the erythrocyte nanostructure under stress

22.02.2019 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>