The final piece of a planetary surveillance puzzle has reached orbit
On 4 November 2025, the Ariane 6 rocket carried Sentinel-1D into space, marking the arrival of the final satellite in the first generation of the Copernicus Sentinel-1 mission. This launch completes a vital orbital network designed to monitor Earth's most critical environmental changes.
The launch, designated flight VA2_265, departed from Europe’s Spaceport in French Guiana at 22:03 CET. Within just 34 minutes of liftoff, the satellite reached its intended orbit. The mission team confirmed the success of the deployment at 23:22 CET, when the first signal was received on the ground, an essential milestone known as the acquisition of signal.
Sentinel-1D is not a solitary observer; it is designed to operate in tandem with Sentinel-1C. The two satellites will fly in the same orbit but positioned 180° apart. This configuration optimizes global coverage, ensuring that the mission can provide frequent updates of Earth's surface. Both spacecraft utilize C-band synthetic aperture radar (SAR) technology, which allows for high-resolution imaging regardless of weather conditions or light levels, effectively providing radar vision through clouds and during the night.
Beyond environmental monitoring, the satellite carries Automatic Identification System (AIS) instruments. These tools enhance the tracking of maritime traffic by capturing data on vessel identity, location, and direction of passage. This capability is critical for maritime authorities and disaster response teams who rely on precise, actionable data.
This launch represents a significant transition for the Copernicus programme. Once fully commissioned, Sentinel-1D is expected to replace Sentinel-1A, a satellite that has served for over 11 years, far exceeding its original planned lifespan. According to Simonetta Cheli, Director of ESA’s Earth Observation Programmes, this continuity is vital for addressing global challenges, from monitoring ice sheet movements and forest ecosystems to tracking ground shifts.
The successful deployment is the culmination of years of work by ESA and partners including Thales Alenia Space and Airbus Defence and Space. As mission manager Ramon Torres noted, the arrival of 1D completes a key milestone for a mission dedicated to answering the most pressing scientific questions of our time.
Source: Sentinel-1D is launched on Ariane 6
