Europe’s next radar Sentinel unfolds

In two years’ time, the next Copernicus Sentinel-1 satellite will be launched to join its two siblings in orbit around Earth. With engineers busy building Sentinel-1C, they have recently tested the mechanism that opens its 12 m-long radar antenna.

Copernicus Sentinel-1C radar from the side. Image credit: ESA

Copernicus Sentinel-1C is the third Sentinel-1 satellite, following Sentinel-1A and Sentinel-1B, which were launched in April 2014 and April 2016, respectively. The three satellites are identical, each carrying an advanced radar instrument to provide an all-weather, day-and-night supply of imagery of Earth’s surface. The mission has been used to monitor the movement of icebergs, ice sheets and glaciers, ground deformation because of subsidence and earthquakes, floods after severe storms, and much more.

Sentinel-1C is set to ensure the continuity of critical radar images that so many Copernicus environmental services and scientists now rely on. The mission’s technical success is thanks to its radar instrument – which when open spans a whopping 12 meters. Because the radar is folded to fit into the rocket fairing for liftoff, the deployment mechanism must be thoroughly tested to ensure that all will be well once it is in space.\

This important milestone test has recently been passed at Airbus’ facilities in Germany.

To simulate this operation in as near realistic environment as is possible on Earth, engineers hang the radar from a structure that helps to mimic weightlessness. The deployment test not only enables the hardware needed for the deployment to be tested, but also allows for the antenna planarity and flatness to be measured when fully deployed.

Following these deployment test and planarity checks, the instrument will now undergo radio frequency measurements to measure its radiation patterns and radiometric performance. A second and last deployment test will be carried out in France, once the radar instrument has been connected to the satellite platform.

“While, a lot of attention is, quite rightly, devoted to the further expansion of the measurement capabilities of the Copernicus system, we are also focused on ensuring the long-term availability of data produced by the current suite Sentinels to which Europe is fully committed,” says Guido Levrini, ESA’s Copernicus Space Segment Programme Manager.

“This impressive milestone involving the deployment of the huge Sentinel-1C radar antenna - a technological jewel – has, remarkably, been achieved amid the COVID pandemic.” Copernicus is the biggest provider of Earth observation data in the world – and while the EU is at the helm of this environmental monitoring programme, ESA develops, builds and launches the dedicated satellites. It also operates some of the missions and ensures the availability of data from third party missions.

Source: ESA