In which quantity are trace gases, such as nitrogen dioxide, ozone, formaldehyde, sulphur dioxide, methane and carbon monoxide, present in our atmosphere? How high are the global and regional concentrations of aerosol particles? Which processes induce changes in our environment, and how do they affect our climate, air quality, and therefore our health?
The most recent satellite to join Europe's Copernicus Earth observation programme is designed to provide answers to precisely these questions: on board a Rockot launch vehicle, Sentinel-5P took off from the Plesetsk spaceport in northern Russia at 11:27 CEST on 13 October 2017. The satellite separated from the launcher on schedule at 12:46 CEST, before deploying its solar panels and sending its first successful signal.
Sentinel-5P – the P stands for 'Precursor' – is part of the Sentinel satellite fleet, which has been gradually formed since 2014. By 2030, the environmental monitoring programme will include 20 Earth observation satellites, providing a hitherto unparalleled level of quality and quantity.
"In terms of measuring trace gases, Sentinel-5P fills the gap as it were between the European environmental satellite DLR Space Agency - Envisat and Sentinel-5, which will be fitted as a sensor to the second-generation MetOp weather satellites from 2021 onwards. Moreover, Sentinel-5P is the first atmospheric sensor in the Copernicus programme to come into operation," explains Albrecht von Bargen from the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) Space Administration in Bonn.
Germany contributes 256 million euro – just over 22 percent – to the European Space Agency (ESA) Earth observation programme and is joint programme leader with the United Kingdom. Copernicus (see Info Box 1) is an Earth observation programme by the European Commission in which ESA and its member states contribute the space components – the Sentinel satellites and the scientific measurement instruments fitted on board. The DLR Space Administration is in charge of coordinating the German contributions on behalf of the Federal Ministry of Economic Affairs and Energy (BMWi) and is also responsible for implementing the national Copernicus services on behalf of the Federal Ministry of Transport and Digital Infrastructure (BMVI). The Federal Cabinet adopted a Copernicus strategy for Germany on 13 September 2017.
Weighing in at around 820 kilograms, the Sentinel-5P satellite will observe trace gases in Earth’s atmosphere from an altitude of 824 kilometres. The TROPOMI (Tropospheric Monitoring Instrument) spectrometer will deliver important information on air pollution, the condition of the atmosphere and climatic changes on a daily basis. With a swath width of 2600 kilometres, almost 1000 high-resolution spectral channels and high spatial resolution, Sentinel-5P will define new technical standards in the continuous mapping of our entire planet: TROPOMI measures in the ultraviolet, visible, near and short infrared wavelength ranges and is able to monitor a wide variety of air pollutants like nitrogen dioxide, ozone, formaldehyde, sulphur oxides, methane and carbon monoxide. The trace gas data will be used in the Copernicus Atmosphere Monitoring Service to provide information on regional air pollution as well. Albrecht von Bargen, Senior Expert for Earth Observation at DLR states: "More and more public sector institutions are using this data to alert citizens of pollutant levels in densely populated areas. This includes measures to mitigate the negative impact on humans as a practical example of the sustainable contribution that the aerospace sector makes to creating a healthier environment."
The mission is also intended to provide other information, for instance by monitoring volcanic ash as part of flight safety or by issuing warnings of excessive UV radiation. Another significant feature of the Sentinel-5P mission is that it will continue the time series initiated by the GOME, SCIAMACHY, GOME-2 and MIPAS measuring instruments, updating the existing long-term climate datasets for incorporation into the Copernicus Atmosphere Monitoring Service.
The The German Remote Sensing Data Center (DFD) developed and integrated the entire payload ground segment, including data reception, processing, archiving and distribution. Operation of the payload ground segment as part of the ESA ground segment also belongs to the remit of the German Remote Sensing Data Center. The data processors that convert the measurement data into geophysical data products were developed by the DLR Remote Sensing Technology Institute, the University of Bremen and the Max Planck Institute for Chemistry in Mainz as part of a European consortium.
Copernicus – The European Earth observation programme
The Sentinel satellites belong to the European Union's Copernicus programme. Its purpose is to collect and analyse remote sensing data of Earth. The information is used by government agencies, companies, the scientific community and interested citizens.
Copernicus consists of six satellite families, known as the Sentinels, which map the Earth and its atmosphere and therefore provide important data for climate protection, sustainable development, humanitarian aid and civilian security, as well as on the condition of the oceans, landmass and vegetation. Measuring devices on the ground, in the air and in bodies of water add to the satellite data.
The European Space Agency (ESA) and the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) operate the 20 environmental satellites.
The German Federal Ministry for Transport and Digital Infrastructure (BMVI) is in charge of the German contribution to Copernicus. The German Aerospace Center (DLR) looks after the programme in Germany.
German partners in industry and research
Sentinel-5P is a cooperation between the Netherlands and ESA, which carries 40 percent of the costs. In addition, companies domiciled in Germany, among them Airbus Defence & Space in Friedrichshafen, have contributed key components of the satellite (mass storage and radiant cooler) and of the monitoring instrument TROPOMI. Important parts of the instrument and platform were built by various German companies – for instance STI GmbH (solar cells) and ZARM Technik AG. The DLR Earth Observation Center in Oberpfaffenhofen, which built the payload ground segment that it operates on behalf of the ESA, is also involved in the Sentinel missions and therefore contributes to the Copernicus programme. A consortium comprising DLR, the University of Bremen and the Max Planck Institute for Chemistry in Mainz built the scientific data processing systems.