Ariane 6 Launches the New Sentinel-1D Earth Observation Satellite

On November 4, 2025, at 21:02 UTC, an Ariane 62 rocket lifted off the ELA-4 launch complex at Europe’s Spaceport in Kourou, French Guiana. The launcher ascended towards Sun-Synchronous Orbit and deployed its payload, the Sentinel-1D satellite. The spacecraft is equipped with a Synthetic Aperture Radar, capable of observing the surface of the Earth day and night, regardless of weather conditions.

Relive the moment!

Watch the replay of #Ariane6 lifting off on mission #VA265, carrying #Sentinel1D from Europe’s Spaceport .

Part of the EU’s #Copernicus programme, Sentinel-1D will deliver all-weather, day & night radar imagery of Earth.

Replay below pic.twitter.com/jjkimIowyB

— Arianespace (@Arianespace) November 4, 2025

As the countdown reached T-0, the Vulcain 2.1 engine and the two P120C solid rocket motors ignited, lifting the 530-ton rocket off the pad. The two boosters burned out and detached at T+2:14, while the central core kept burning through its liquid hydrogen and liquid oxygen propellants until T+7:43.

The second stage then separated and its Vinci engine ignited, carrying Sentinel-1D to its target orbit. Payload deployment took place at T+33:51. An hour and a half later, the Vinci engine fired again to deorbit the spent second stage and avoid creating dangerous space debris.

Sentinel-1D

Sentinel-1D is an Earth observation satellite that is part of the Copernicus Programme, managed by the European Union in collaboration with the European Space Agency. The program provides a wide range of data, from optical imagery to atmospheric composition, from altimetry to radar imaging. The information, made available free of charge, can be used to coordinate emergency responses, to monitor icebergs, to track climate change, for regional planning, and for commercial activities.

Sentinel-1D is equipped with a high-resolution Synthetic Aperture Radar, capable of acquiring images regardless of surface illumination or cloud cover. It can detect land movements with an accuracy of millimeters per year, providing valuable data for agriculture, infrastructure monitoring, and disaster prevention. For example, it will allow tracking of the movement of landslides. The satellite also has an Automatic Identification System to receive signals from ships, helping to monitor maritime traffic and detect illegal activities at sea.

The spacecraft was built by Thales Alenia Space and weighed 2.3 tons at liftoff. It is designed to last at least 7.5 years in orbit. It will replace the older Sentinel-1A satellite, ensuring continuity in data collection. The satellite is fitted with Galileo receivers to allow more accurate in-orbit positioning.

Ariane 6 gearing up

The mission marks the fourth flight of Ariane 6, and the third in 2025. Europe’s new heavy lift launch vehicle debuted in 2024 by successfully placing into orbit eight cubesats from various dispensers. However, the upper stage failed to perform the deorbit burn, preventing the deployment of two reentry capsules. Since then, all other missions have been full successes.

The rocket is manufactured by a consortium of more than 600 companies, led by prime contractor ArianeGroup. Launches are operated by the subsidiary ArianeSpace. It is available in two versions, Ariane 62 and Ariane 64, sporting two and four P120C solid rocket motors, respectively.

Ariane 6 is scheduled to fly one more time by the end of the year, launching a satellite for the Galileo positioning constellation. Afterwards, the heavier 64 configuration will debut by launching its first batch of Kuiper satellites. Amazon’s subsidiary represents a large customer for the rocket, with a total of 18 flights on order.

^{*Cover image credits: ArianeSpace via YouTube}