His journey has begun: the German environmental satellite EnMAP, who on behalf of German space agency at DLRDeveloped and built in Germany with funds from the Federal Ministry for Economic Affairs and Climate Protection (BMWi) and tested for its use in space is ready for its launch. “As a German environmental mission, EnMAP has its sights set on climate change and its effects on all ecosystems – on land as well as on water. Germany is not spared from these changes either. The forests in this country are particularly badly affected, because they are stressed by negative environmental influences ‘has increased for our forest. Most of the damage has so far been recorded visually by the forest officials on site – a mammoth task, because 90 billion trees are spread over an area of 11.4 million hectares, “explains Dr. Walther Pelzer, DLR Board Member and Head of the German Space Agency at DLR.
A third of Germany’s surface area is covered with forest: “EnMAP can help here. Its hyperspectral instrument will also ‘scan’ the forest areas with 242 channels and thus determine the health of trees and plants from a height of 640 kilometers,” explains Pelzer. With the EnMAP mission, Germany wants to make an important contribution to the global monitoring of environmental changes in agriculture and forestry, soil science, geology and also in research into coastal areas and inland waters. The satellite itself was from theOHB System AG developed and built and by the IABG mbHtested for its use in space. The scientific management of the mission lies with the German Research Center for GeosciencesGFZ, as well as the DLR a Helmholtz center. The ground segment is being developed by the DLR in Oberpfaffenhofen. With its precise view from space, EnMAP is intended to help find solutions to the challenges of climate change.
In the future, for example, the plant metabolism could be examined over a large area and it would be possible to identify which areas are lacking certain nutrients or which air pollutants affect the plants. “Thanks to the information from space – despite changing climatic and environmental conditions – forests and fields can be managed in an economically better and more ecologically sustainable way in the future. That is why not only foresters but also farmers will benefit greatly from the EnMAP data,” explains Dr. Sebastian Fischer, EnMAP project manager at the German Space Agency.
From the OHB System AG site in Bremen, the satellite is to be brought to NASA’s Cape Canaveral space airport in Florida in an Ilyushin Il-76 transport aircraft at the end of February 2022. From there, EnMAP is to set off to its target orbit in April 2022 on board a Falcon 9 rocket from the US space company SpaceX. EnMAP is to collect environmental data for at least five years.
Environmental tests as the basis for a successful mission
“In order to survive its flight and its stay in space undamaged, EnMAP had to be put through its paces beforehand. Because the ‘ride’ on the rocket, extreme temperature fluctuations and the harsh radiation in space demand a lot from the extremely sensitive instruments on the satellite “, says project manager Sebastian Fischer. The satellite was therefore subjected to a test campaign lasting several months in the IABG space test center in Ottobrunn near Munich. “EnMAP passed the tests with flying colors. The instruments and the entire technology worked extremely well under extreme conditions.”
Tracking environmental changes with 242 channels
But what is special about EnMAP, how does this satellite work? All materials on the earth’s surface reflect sunlight in a characteristic way called a spectral signature. EnMAP can “read” this signature with the help of its measuring instrument. However, in order to avoid confusion with other elements, these signatures must be recognized very precisely. This is done with the help of multi-channel images, so-called hyperspectral images. This method allows the direct identification of the recorded materials and their quantification. An example: you can not only see which type of fruit is grown in a field, but also how well it is supplied with nutrients. Minerals in soils can also be identified and quantified.
Extensive and highly detailed
EnMAP does not only have the land area in its sights. The hyperspectral instrument with its two imaging spectrometers will also take a close look at the coastal areas and inland waters in a wavelength range from 420 to 2,450 nanometers. With a spectral resolution of 6.5 nanometers in the visible and near-infrared range and ten nanometers in the short-wave infrared range, EnMAP sees details that are hidden from the human eye. His hyperspectral instrument makes pollutants in lakes and coastal waters visible, for example, and allows them to be precisely quantified.
Where water samples used to be taken at great expense, in the future a view from space will be sufficient to determine the water quality over a large area. The same applies to mineral samples, for example to determine the degree of soil pollution. This can be useful after accidents in chemical plants, for example. “Instead of exposing people to the risk of collecting samples on site, a risk-free view from space will in future be sufficient Meters under the microscope. This way, comparatively rapid changes in space and time, such as erosion processes or plant growth, can be documented very well, “explains Sebastian Fischer.