With its "Living Planet" earth observation program the European Space Agency keeps track of global environmental change. Basis of the program is a series of special type of satellites called Earth Explorers used by ESA to monitor the environment, climate and overall status of the system Earth.
Each mission is defined on the basis of a multi-stage selection process. Regular calls for mission proposals ensure continued scientific input into the program. Today’s dedicated missions are built on the heritage of what used to be more generic missions, like the extremely powerful environmental satellites, ERS-1, ERS-2 and ENVISAT. Their successful series of measurement missions has now to a large extent been taken over by the GMES program (Global Monitoring for Environment and Security), a joint EU and ESA initiative to build an independent system for global environmental and security monitoring.
Six new Earth Explorer satellites are currently being built. Three further ones are currently undergoing feasibility studies as possible candidates in a tendering process for a seventh mission.
GOCE orbits the Earth
GOCE (launched on 17 March 2009):
The environmental satellite GOCE will be measuring the Earth’s field of gravity with unprecedented accuracy. The expected datasets are expected to be extremely helpful in oceanography, geophysics, and in monitoring sea levels. The major part of the satellite was built by German firms: EADS Astrium in Friedrichshafen is the principal contractor for the satellite platform. The magnetic torquers were manufactured by the Bremen-based company Zarm Technik, and the mission’s solar array came from RWE Space Solar Power GmbH in Heilbronn. Most of the data processing is conducted by the Institute for Astronomical and Physical Geodesy at Munich Technical University.
SMOS (Launch date: 2 November 2009)
The SMOS-Mission (Soil Moisture and Ocean Salinity) will deliver the first global maps of soil moisture and ocean salinity. Both of these will provide essential information for a better understanding of the Earth’s climate and its water circulation systems. German research teams are involved in the verification of mission data based on ground measurements and model validation, as well as in collating further knowledge on sea ice.
CryoSat-2 (launched on 8 April 2010)
The CryoSat-Mission is to collect data on the thickness of polar ice caps and sea ice. The extent to which global warming affects these developements is one of the most hotly debated questions in polar climate research. The satellite used is a replica of CryoSat-1 whose launch was aborted in October 2005 as a result of a launcher rocket failure. The prime contractor for the mission is EADS Astrium in Friedrichshafen.
Swarm (Launch date: not before early 2013)
Swarm is a three-satellite constellation. It is to deliver the most accurate sensing data ever of the Earth’s magnetic field and its variation over time, providing new insights into the structure and processes in Earth’s interior as well as in the upper atmosphere. Many other applications will benefit from the mission, too, such as space-borne weather forecasting, navigation und mineral prospection. EADS Astrium in Friedrichshafen is the prime contractor building the Swarm satellites.
ADM-Aeolus - Measurement of the wind field
ADM-Aeolus (Launch date: not before mid 2015)
The purpose of the ADM-Aeolus mission is to deliver global observation data of the three-dimensional wind field. These data will close a major gap in the existing meteorological observation network and will go a long way to improving the quality of numerical weather prediction, especially in the medium term range. This ambitious mission uses a new sensing technology based on powerful laser pulses.
EarthCARE (Launch date: not before end of 2015)
EarthCARE (Earth Clouds, Aerosols and Radiation Explorer) is a joint Japanese-European mission. It will study the effect that cloud and aerosol particles have on the the Earth’s radiation balance. Clouds, aerosols and their interaction constitute a major uncertainty factor in existing models of the climate system. An enhanced method of recording cloud processes is also critical for improving numerical weather forecasting. This satellite, too, is built by EADS Astrium in Friedrichshafen. One instrument is provided by the Japanese Space Agency, JAXA.
Choosing a mission for Earth Explorer 7 (Launch date: not before 2017)
The most recent call for mission proposals was issued in mid-March 2005. 24 submissions were received, which is more than the response to any earlier explorer mission calls. With three proposals entered by German-led research teams and a further twelve German researchers in other teams, the Federal Republic was well represented. ESA’s scientific committee for earth observation missions shortlisted six missions for initial assessment in May 2006. Based on the results of these studies and on presentations made at a conference in Lisbon in January 2009, candidate missions were assessed in depth, and the committee decided that three missions were to enter phase A feasibility studies.
The three remaining candidates:
- BIOMASS: A Radar mission to determine the biomass of Earth’s forests.
- CoReH2O: Recording snow volumes to enhance modeling of the Earth’s water balance by means of a dual-frequency radar system.
- PREMIER: Observations for a better understanding of the dynamic interaction between the chemistry and the radiation balance of the upper troposphere and the stratosphere (layers above about five kilometers).
The final selection of the mission will be at the beginning of 2013.
Choosing a mission for Earth Explorer 8 (Launch date: not before 2019)
In order to continue the successful Earth Explorer series, a call for an Earth Explorer 8 mission had been announced by ESA in October 2009. Finally, 28 mission proposals had been submitted whereby four proposals were under lead of a German Principle Investigator. Additionally there were also further 18 proposals with German contributions. Finally, ESA’s scientific committee for Earth Observation selected in November 2010 two mission proposals:
- CarbonSat: A Green House Gas Imaging Spectrometer will allow the quantification of the magnitude and the spatial and temporal distributions of CO2 and CH4 sources and sinks from regional to suburban scales.
- FLEX: The recording of vegetation fluorescence by imaging spectrometry will provide the photosynthetic efficiency rate of the terrestrial ecosystem.
CarbonSat is a German mission proposal under the lead of the University of Bremen. Some further objectives are also the identification of the CO2 uptake mechanism of the terrestrial biosphere and oceans and the response of CO2 and CH4 sources and sinks to a changing climate, as well.
It is planned that a feasibility study (Phase A) and a system requirements study (Phase B1) will be performed for both mission proposals. In order to find the optimal solution for the feasibility and the system requirements, a trade-off approach was followed by carrying out two parallel studies for each of both mission proposals.The study results will be basis for the final Earth Explorer 8 mission decision after Phase B1.
A further component of the Living Planet program is Earth Watch, which prepares future satellite systems for continuing operation. The idea of Earth Watch is to enable ongoing data services on a regular basis. A condition is that the funding for operational routine services be provided by non-ESA sources. A case in point is the Meteosat series of meteorological satellites developed and built in cooperation with the EUMETSAT organization. Besides their traditional meteorological use, numerous other applications of a high strategic value and economic potential are now being envisaged, including agriculture and forestry, geology, environmental observation, ocean and coastal zone management, cartography, the utilities, and security. All these additional activities have been moved to the GMES program. GSE (GMES Service Element) prepares data sets for exploitation by GMES and is also a part of the Earth Watch program.