which provides radar vision for the Copernicus Earth observation programme - has a new addition to its family of satellites, with the arrival in orbit of Sentinel-1D, the last of the groundbreaking first generation. The launch took place at 22:02 CET (18:02 local time), on Tuesday, 4 November, on board an Ariane 6 launcher from Europe's Spaceport in French Guiana.
The satellite was placed in its orbit 34 minutes after launch, and a signal was received from the satellite at 23:22 CET - this 'acquisition of signal' is a key moment in any launch when the team operating the mission on the ground can confirm that the satellite is in orbit and is able to communicate.
The Sentinel-1 mission delivers high-resolution synthetic aperture radar (SAR) images of Earth's surface whenever needed, in all weathers, day-and-night. This service is used by disaster response teams, environmental agencies, maritime authorities, climate scientists, and the wider Earth observation user community worldwide, who depend on frequent updates of critical data.
Simonetta Cheli, Director of ESA's Earth Observation Programmes, said, "This launch on board Ariane 6 is an important one for ESA, as it completes the Copernicus Sentinel-1 mission - soon Sentinel-1D will be commissioned and fully operational, together with Sentinel-1C. The continuity of service this provides for the EU Space Programme is vital for addressing the global challenges we face. Citizens will benefit from the contribution this mission makes to scientific understanding of our environment - by providing accurate, reliable and actionable radar data on movements in our ice sheets, on our forest ecosystems, ground movements and much more."
"I thank all the teams involved: from the mission team at ESA to our many partners in European industry, including Thales Alenia Space, Airbus Defence and Space, and of course our partner for the Copernicus Programme, the European Commission," added Simonetta.
ESA's Sentinel-1 Project Manager, Ramon Torres, noted, "My team is delighted to complete this key milestone for this groundbreaking mission - it's the culmination of many years of excellent work to ensure that Sentinel-1 will continue generating high-quality radar images and data responding to the key scientific questions and challenges we face today.
"As I reach the close of my professional journey, I am deeply moved by the dedication of my remarkable team, by the exceptional flight operation colleagues at ESA's operations centre in Germany and the incredibly committed mission operation teams based in Italy. Together we managed the successful launch of four satellites aboard three of Europe's finest launchers, which has been nothing short of extraordinary. As long as we have SARs we've got a chance."
Cutting-edge technology for enhanced data
Sentinel-1D will join its twin, Sentinel-1C. When fully commissioned, it will replace Sentinel-1A, which has been in service for more than 11 years, well beyond its planned lifetime.
The Sentinel-1D and Sentinel-1C satellites will work in tandem, orbiting on opposite sides of the globe, 180° apart, to optimise global coverage and data delivery. Both satellites carry a C-band SAR instrument on board, together with an Automatic Identification System (AIS) instrument - so while capturing high-resolution imagery of Earth's surface, the mission also improves detection and tracking of ships over maritime zones. When Sentinel-1D is fully operational, it will enhance AIS observations, including more data on vessel identity, location and direction of travel, and precise tracking. Sentinel-1D and Sentinel-1C are both compatible with the Galileo navigation system, as well as other Global Navigation Satellite Systems. Additionally, both satellites will be ready to support the Earth Explorer Harmony mission .
How does Sentinel-1 make a difference?
The Sentinel-1 mission, with its first satellite launched in 2014, has brought a paradigmatic change to the way we observe the planet, with a systematic approach to data acquisition and the building of time series of high-quality radar data spanning the past 11 years. This has helped to reshape our view of planet Earth by contributing data to public services and scientific studies on changes in our environment and climate. For example, Sentinel-1's ability to penetrate thick cloud cover allows the mission to track disturbances and subtle changes in tropical forests. The mission's synthetic aperture radar also provides insights into subsidence and land shifts across Europe, feeding data to the European Ground Motion Service. Sentinel-1 data are also complementary to other Sentinel mission data - for example to drive a shift in our ability to observe and understand the water cycle on a global scale.
Some examples of the impact of Sentinel-1 data include:
About the Copernicus Sentinel-1 mission
The Sentinel-1 mission is the result of close collaboration between ESA, the European Commission, industry, service providers and data users. Designed and built by a consortium of more than 70 companies led by Thales Alenia Space and Airbus Defence and Space, it is an outstanding example of Europe's technological excellence.
The mission is part of the Copernicus family of Sentinel satellites, developed by the European Space Agency (ESA) for the European Commission's Copernicus - the Earth observation component of the European Union's Space Programme. It supports the EU in contributing to solutions to address common global challenges.
The data provided by the Sentinel missions form the basis of the operational Copernicus information services, helping to manage the environment, monitor and react to climate change and safeguard lives. Sentinel-1 data are freely available via the Copernicus Data Space Ecosystem , providing instant access to a wide range of data from both the Copernicus Sentinel missions and the Copernicus Contributing Missions.
Sentinel-1A was the first satellite in the series, launched in April 2014, followed by the launch of Sentinel-1B in 2016. The Sentinel-1B mission came to an end in August 2022 after experiencing a technical anomaly that rendered it unable to acquire data. The satellite has been successfully de-orbited and will re-enter Earth's atmosphere within 25 years.
About Ariane 6
Sentinel-1D was launched on an Ariane 6 rocket, flight VA265, equipped with two boosters for this liftoff. Ariane 6 is Europe's heavy launcher and a key element of ESA's efforts to ensure autonomous access to space for Europe's citizens. Its modular and versatile design allows it to launch missions into low-Earth orbit as well as those destined to go much further into deep space. Standing more than 60 metres tall, Ariane 6 can weigh almost 900 tonnes when launched with a full payload.
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