Copernicus Sentinel-1C Launch: What’s new?

For the last decade, Copernicus Sentinel-1 has been delivering a wealth of radar data for a wide range of applications to users around the world. Building on the legacy of pioneering European satellite missions such as ERS and ENVISAT, Sentinel-1 has provided invaluable data serving a wide range of sectors and many types of users in a variety of activities. Despite the early retirement of Sentinel-1B due to an anomaly related to the instrument electronics power supply, the mission continues with Sentinel-1A still operational and Sentinel-1C soon to be launched.

Full, free, and open radar data for numerous sectors worldwide 

Copernicus Sentinel-1 is unique. It’s the only radar satellite mission whose data is available to users on a full, free, and open basis. Since its operations began in 2014, the mission has generated over 30 PB of data, with more than 14 million products made available to users to date. For context, that as much data as you would consume by streaming all 8 seasons of Game of Thrones in UHD (4K) every single day for nearly 36 years. Each month, more than 150,000 products based on Sentinel-1 data are published and made available to users. Given its scope and accessibility, it’s no surprise that data from this mission supports numerous sectors worldwide and one critical area where Sentinel-1's impact is especially significant lies just beneath our feet. 

 Safety on the high seas with Sentinel-1 radar and AIS

On the open seas, traditional methods of observing and tracking ships methods have significant limitations. Ground-based radar systems, for example, have a limited range, typically restricted to coastal areas, making them ineffective for monitoring vessels in remote ocean areas. To address this, two primary systems are used to track marine vessels: cooperative and non-cooperative tracking.  

In cooperative tracking, ships actively share their identities and locations through specific tracking methods. One of the most widely used systems is the Automatic Identification System (AIS), which operates worldwide, enabling extended tracking capabilities. AIS relies on vessels to report their positions voluntarily by means of a transponder; therefore, if a ship chooses not to broadcast its location, it will not appear in the cooperative tracking system. 

Sentinel-1A, on the other hand, uses radar to detect ships regardless of whether they are equipped with AIS or any other tracking system. In the following image, created by combining Copernicus Sentinel-1 radar data from January 2022 to December 2023, thousands of white dots, representing ships, are visible just off the Greek coast. 

Thousands of white dots representing ships near the port of Athens at the time of acquisition, as well as their routes forming distinct shipping lanes in the Aegean Sea. Credit: European Union, Copernicus Sentinel-1 data 

The Sentinel-1A approach is useful for identifying smaller fishing boats and vessels operating illegally, which may deliberately avoid cooperative tracking. However, to improve these tracking capabilities, Sentinel-1C will be equipped with an AIS signal antenna. This will complement the satellite’s ability to detect non-cooperative ships by adding the capability to track and identify cooperative vessels. AIS improves Sentinel-1’s ability to monitor the movement of ships, indicating their direction and speed, supporting efforts to detect illegal activities, and helping ships avoid collisions.

Read more on this week’s EU Space Observer 

Looking ahead to Sentinel-1C

The Sentinel-1 satellite mission continues to advance, bringing new features and capabilities to its wide range of applications. On Wednesday 5 December at 22:20 CET, Copernicus Sentinel-1C is scheduled to launch from Europe's spaceport in Kourou, French Guiana with the Vega C Return-to-Flight launch.

Besides having an AIS signal antenna, Sentinel-1C's GNSS (Global Navigation Satellite System) receivers will also be compatible with Galileo. The European Commission, in collaboration with the European Space Agency (ESA), will conduct a demonstration of the Galileo High Accuracy Service (HAS). This test will showcase the use of precise point positioning (PPP) enabled by Galileo’s E6 band, achieving onboard real-time accuracy of up to 0.2 metres. The demonstration will use Sentinel-1C’s advanced GNSS receivers and complete multiple orbits during the 6–7-hour test period.

Once operational, Sentinel-1C will ensure that Sentinel-1 returns to its nominal two-satellite constellation configuration. Sentinel-1D construction is also under finalization and will be ready for launch in the coming year, further securing the mission’s long-term future.