If in the field of manned flightsmanned flights and exploration roboticsrobotics l’European Space AgencyEuropean Space Agency (ESA) is much less dreamy than NASA, in the field of climatologyclimatology and Earth observation, Europe stands out and clearly appears at the forefront.
With the selection of the “Harmony” project, the tenth mission Earth Explorer integrated into the ESA FutureEO program, the agency affirms its pioneering role in the field ofEarth observationEarth observation. This mission aims to collect data on the oceans, ice, earthquakesearthquakes and the volcanoesvolcanoesthereby contributing to climate research and risk monitoring. Harmony will also be used to measure small variations in the shape of the earth’s surface, including those associated with earthquakes and volcanic activity, thereby strengthening risk management efforts. The two satellites will be launched together aboard a Vega-C launcher in 2029.
“Harmony will be used to measure small variations in the shape of the Earth’s surface, including those associated with earthquakes and volcanic activity”
As Simonetta Cheli, director of ESA’s Earth observation programs, recalls, the “Earth Explorers are essential for our FutureEO program, which aims to develop innovative satellite missions and concepts as well as test cutting-edge technologies ».
Observe changes in the shape of the Earth
Harmony consists of two identical satellites orbiting the Earth, equipped with a synthetic aperture radar, to capture the transmitted and backscattered signals from Sentinel-1, and a multi-view thermal infrared imager. These technologies, although requiring rapid development within five years, are designed to enable efficient tandem flight with Sentinel-1. Concerning the radars, produced by Thales Alenia Space, these instruments represent a generational advance in the architecture of synthetic aperture radars (SAR), because they meet observation requirements by taking full advantage of the digitizationdigitization electronic. They perform a samplingsampling direct echo signal on the carrier frequency used by Sentinel-1 (C band).
Regarding the main functions of these instruments of receptionreceptionthe concept of non-cooperative bistatic radar fuels the development of innovative techniques for time and phase synchronization. Furthermore, to achieve the required observation performance, while being part of a class of platform compatible with the simultaneous launch of two satellites by the launcherlauncher VEGAVEGA-C, it is imperative to design optimized solutions in volumevolume et massemasse.
Unprecedented mission
The two Harmony satellites will work in synergysynergy with the Copernicus Sentinel-1C satellite to provide high-speed observations resolutionresolution of the movementsmovements on the surface of the Earth. This mission is “ unique both in its measurement technique and in the diversity of information it will provide », declared Florence Hélière, head of the Harmony project.
The main objectives include the study of “ interactions between the ocean and the atmosphere, the dynamics of glaciersglaciersas well as surface changes related to earthquakes and volcanic activity, in addition to risk management “. The mission will provide valuable data on various Earth processes, such as deformations caused by earthquakes and volcanic activity, as well as glacier movements.
These “changes of form” in fact include movements and deformations “ observed at the interface atmosphereatmosphere-ocean (ventsvents, waveswavescurrents), on the earth’s surface (tectonic tensions, changes in the height of volcanoes) and in the cryospherecryosphere (variations in flow and thickness of glaciers) “. Florence Hélière explains that observing these phenomena from space makes it possible to “ measure on a large scale (several hundred kilometers), repeatedly and across the entire planet “. The Harmony mission will thus contribute to a “ in-depth understanding of these phenomena, allowing scientists to integrate satellite data into their climate modelsclimate models to analyze the effects on the evolution of our Planet ».
Operationally, the mission will begin with a one-year XTI phase, during which the two satellites will fly in close formation to perform interferometric observations. This configuration will generate time series of surface height, facilitating the analysis of changes. Subsequently, the mission will be reconfigured for a three-year Stereo phase, where one Harmony satellite will position itself in front of Sentinel-1 and the other behind it, at a distance of approximately 350 to 400 kilometers to optimize the angular diversity of their observations. .
At the end of this phase, a new one-year XTI period will be implemented to observe slow changes in the topography compared to the first data collected. The space segment of the mission will thus be designed for durationduration total life of five years.
