Living Planet: ESA’s Earth observation programme
The European Space Agency ESA is running an Earth observation programme entitled "Living Planet", to study global environmental change. The programme’s key component is a fleet of dedicated satellites called "Earth Explorers" which will be used by ESA to explore specific aspects of the environment, climate and general status of the planet.
Each mission is the result of a multi-tier selection process. Regular calls invite scientists to deliver their input in the design of the programme. The individual missions of the programme are the successors to the extremely powerful "general-purpose" environmental satellites ERS-1, ERS-2 and ENVISAT, whose successful research has since 2014 been continued by ESA’s and the European Union’s joint programme, Copernicus, under which a family of satellites for global environmental and security monitoring is being set up.
The eight new Earth Explorer satellites at a glance
GOCE (launched on March 17, 2009; re-entry on November 11, 2013)
GOCE (Gravity field and steady-state-Ocean Circulation Explorer) surveyed our planet’s gravitational field at a hitherto unequalled degree of accuracy. Its results are of particular importance in oceanography, geophysics and the exploration of sea levels. One German company that played a major part in the construction of the satellite is Airbus Defence and Space of Friedrichshafen, the prime contractor of the satellite platform.
The Bremen-based company Zarm Technik contributed the mission’s magnetic field based attitude control elements (magnetic torquers) and RWE Space Solar Power of Heilbronn made the solar cells for the mission. Most of the data processing was done by Munich University’s Institute of Astronomic and Physical Geodesy.
Following an operational phase of four years the orbit of the GOCE mission was lowered in several stages until it entered the atmosphere on November 11, 2013. A major part of the satellite burnt up in the atmosphere and a few fragments fell into the South Atlantic Ocean in the vicinity of the Falkland Islands. Its re-entry was recorded by on-board instruments until immediately before the satellite burned up, providing valuable information on the satellite’s final phase as well as data for future de-orbiting management procedures.
SMOS (launched on November 2, 2009)
The SMOS mission (Soil Moisture and Ocean Salinity) was the first one to chart soil humidity and ocean salinity on a global scale. Both of these deliver important data for a better understanding of the Earth’s climate system and water cycle. German research teams are participating in various ways, one of them being to verify mission data by conducting ground measurements and model comparisons, as well as extracting additional information on sea ice. The mission has completed its scheduled operation period but given the excellent results it has delivered and its good technical condition its life was extended until 2017.
CryoSat-2 (launched on April 8, 2010)
The CryoSat mission gathers data on the thickness of the polar ice cover and sea ice. The extent to which global warming affects these parameters is one of the hotly debated issues in the polar climate research discourse. The satellite is a replica of CryoSat-1 which was lost in a launch failure in October 2005. The mission’s prime contractor was Airbus Defence and Space of Friedrichshafen. The excellent results obtained so far, particularly with regard to changes in the thickness of the polar ice caps, and the good condition of the satellite led to the decision to extend the duration of the mission until 2017.
Swarm (launched on November 22, 2013)
Swarm is a constellation of three satellites. It has been delivering the most accurate information on the Earth’s magnetic field and its variation over time so far, which will provide a deeper insight into the structure and processes both of the planet’s interior and the upper atmosphere. On top of that, many other areas of application stand to benefit as well, such as space weather forecasting, navigation, and the prospection for mineral deposits. Airbus Defence and Space in Friedrichshafen acted as chief contractor in the manufacturing of the Swarm satellites. The first global static model of the Earth’s magnetic field generated from Swarm data has meanwhile become the established reference model in geoscience.
Aeolus (to be launched early 2018)
The purpose of the Aelous mission is to produce three-dimensional observation data of the global wind field. These observations will fill a major gap in the existing meteorological observation network and may contribute materially towards the enhancement of numerical weather forecasting - especially with regard to medium-term forecasts. The cutting-edge mission will be use a novel measuring technology based on powerful laser pulses.
EarthCARE (to be launched early 2019)
EarthCARE (Earth Clouds, Aerosols and Radiation Explorer) is a joint Japanese and European mission. Its aim is to investigate the interactions between and impact of clouds and aerosol particles on the Earth’s radiation budget. In present climate evolution models, clouds, aerosols and their interaction with each other constitute a major uncertainty factor. Exact data relating to cloud processes will also improve the quality of numerical weather forecasting. This satellite, too, is being built by Airbus Defence and Space in Friedrichshafen. One of the instruments is a contribution from Japan’s space agency JAXA.
BIOMASS (launch date not before 2021)
BIOMASS is a radar mission to determine the total biomass contained in the Earth’s forest areas. To date, scientists have had to rely on estimates with a very high uncertainty factor. Since biomass nearly exclusively consists of carbon, it is equivalent to the major proportion of organically bonded carbon in the terrestrial carbon cycle. This makes it one of the essential climate model parameters. To have a more accurate idea of the planet’s total biomass would therefore permit better global warming forecasts.
FLEX (Launch date: not before 2022)
FLEX was selected in October 2015 to become the eighth Earth Explorer mission. Its task will be to measure the amount of light emitted by plants, using an imaging spectrometer. Based on these fluorescence measurements, scientists will be able to determine the quantities involved in the photosynthetic activity of entire ecosystems. That knowledge will provide clues as to the efficiency of photosynthesis, plant growth rates, and the stress factors affecting the vegetation. FLEX is essentially built on preliminary research done in Germany, notably at the Jülich research centre, which is engaged in fundamental research concerning photosynthesis by remote sensing. An airborne system was developed at the Jülich research centre by which the general feasibility of this type of research has been demonstrated.
Another element on the Living Planet programme is the Earth Watch line in which future satellite systems are prepared for their operational missions under the aspect of sustainability. Its focus is to guarantee a data services that is long-term. One basic requirement is to ensure that routine operation should be funded from sources outside ESA, like, for example, the development and construction of the weather satellites of the Meteosat series which are implemented as a cooperation with the European EUMETSAT organisation.
Next to meteorology, where the technology is well-established, a number of other applications with major strategic and business potential are being studied. These include agriculture, forestry, geology, environmental monitoring, ocean and coastline management, cartography, public utilities and security. These activities have now been amalgamated into a separate programme, GMES. To develop a regime of data utilisation for GMES under an initiative called GSE (GMES Service Element) is equally a component of the Earth Watch programme.
Climate Change Initiative
In 2009, ESA launched its Climate Change Initiative (CCI) as part of the Earth Watch programme. In 13 projects, satellite data are being used by scientists to build a consistent time series for each single essential climate variable. Scientists are hoping that the satellite data will give a substantial boost to GCOS (the Global Climate.Observing System). Computed and provided within a uniform infrastructure, these data will be available to researchers as well as service providers. Next to climate research, typical applications include a wide variety of aspects influenced by climate changes.