Four satellites developed by Airbus in partnership with the CNES have been placed in orbit from the Guyanese space center. Their mission: to generate a Extremely detailed 3D card of the earth’s surface. Code name: CO3Dpour 3D optical constellation.
This program is based on new generation optical technology, embedded on board four 285 kg satellitespositioned at an altitude of 502 km in HĂ©liosynchrone orbit.
These satellites are intended to deliver a Digital surface model (DSM) in high definition, based on stereoscopic images of 50 cm resolution.
What is a 3D card on the planet for?
A 3D card is not just a nice image. It means a precise altimetric representation From each corner of the globe, taking into account variations in reliefs, slopes, volumes.
- Military and strategic surveillance : during geopolitical tension periods, know where natural obstacles, access routes or favorable positions can be made up.
- Regional planning : Anticipate flood risks, model urban areas, optimize infrastructure.
- Earth sciences : follow the ground movements, study erosion, tectonics, water resources.
The CNES will receive full access to the 3D model of France as well as an area nicknamed “the crisis arc”, a set of territories deemed strategic.
A new way of photographing the earth
CO3D satellites do not use a classic linear scanning. They apply a mode baptized Step and Stare.
- Stare : The satellite remains fixed for a few seconds on an area to capture a very clear image.
- Step : He then performs an orbital micro-repositioning to aim for an adjacent area.
Each image covers approximately 7 km par 5 kmand the rapid succession of sockets makes it possible to constitute observation bands 7, 14, 21 or 28 km wide.
This system optimizes precision Without sacrificing geographic coveragewhile adapting to the priorities of the moment.
A production chain inherited from commercial constellations
CO3D satellites were designed in Airbus workshops in Toulouse. The assembly chain is inspired by that of Oneweb satellites, with a industrialized approachmodular, automated.
- Electronic components from the civil world, Suitable for spatial constraints.
- Standardized architecture that reduces production costs while guaranteeing reliability.
- Digital modeling tools that simulate upstream the behavior of orbit instruments.
This model produces quickly An operational constellation, without compromise on data quality.
A cloud to transform images into useful data
The raw data collected by CO3D satellites are not directly usable. They are treated on the ground, via a Cloud infrastructure managed by Airbus.
- To associate stereoscopic images for reconstruct the relief.
- To correct the effects linked to the atmosphere, to the geometry of the sensors, to light variations.
- Delivered ready -to -use cards for civil, military or scientific applications.
A parallel mission for the climate
The same VEGA-C launcher took another passenger: the satellite MicroCarbfruit of a collaboration between the CNES and the British space agency.
Objective: measure the carbon dioxide (COâ‚‚) in the atmosphere with unprecedented precision.
Microcarb takes on a Spectrometer designed by Airbuscapable of analyzing the solar light reflected by the earth and of extracting the concentrations of greenhouse gases.
An ideal complement to CO3D: while one mapping the reliefs, the other observes the atmosphere.
Summary to remember
- CO3D satellites are designed to produce a precise 3D card of the earth 50 cm resolution.
- They use an innovative imaging mode called Step and Stare to optimize coverage and precision.
- The program is carried by Airbus and the CNES, with an industrial anchoring in Toulouse.
- 3D data will be processed in the cloud to supply military, civil and scientific applications.
- The launch also made it possible to deploy the microcarb satellite dedicated to the measurement of atmospheric COâ‚‚.
- The constellation is distinguished by a manufacture inspired by the industrial model of oneweb commercial satellites.
- The first objective: mapping France and the crisis arc in 18 months after the orbit test phase.
