Sentinel-3D is the fourth satellite in the Sentinel-3 constellation, which provides high-accuracy optical, radar and altimetry data for marine and land services. No earlier than December 2028 · To Be Determined Vega-C — Avio S.p.A, to Sun-Synchronous Orbit Ariane Launch Area 1 (ELV), Guiana Space Centre, French Guiana Program: Copernicus Data: Launch Library 2, The Space Devs. Image by ESA/CNES/Arianespace/Optique vidéo du CSG–S. Martin (ESA Standard Licence) via The Space Devs.