Artists impression of. Sentinel-1 satellite. Image Courtesy of ESA/ATG medialab
Next Tuesday, 3rd December, is the current scheduled launch date for the Sentinel-1C satellite. The launch is planned to take off from Europe’s Spaceport in Kourou, French Guiana, at 10.20 p.m. (CEST) aboard the Vega C rocket launcher, which should put the satellite into a sun-synchronous orbit at an altitude of approximately seven hundred kilometres.
The launch is eagerly anticipated by anyone using the synthetic aperture radar (SAR) data produced by Sentinel-1, since the premature loss of Sentinel-1B due to a technical anomaly that occurred on the 23rd December 2021. We wrote about the issue at the time, and a review by European Space Agency and the European Commission confirmed that the power supply unit for the Sentinel-1B SAR antenna unit had failed preventing the radar from being switched on, ending the data collection.
As Sentinel-1, like most of the Copernicus missions, is a dual satellite mission, the loss of 1B has reduced the frequency, temporal resolution, of SAR data as the data collection is undertaken by one satellite – 1A. Once Sentinel-1C has completed it’s commissioning and validation phase, it will once again mean that SAR data is available every six days compared to the current 12 days, with Sentinel-1A itself due to be replaced by Sentinel-1D in 2025.
Sentinel-1 satellites carry a C-band SAR instrument, and captures data in several modes, the most common being the Interferometric Wide swath mode, meaning it takes three scans and combines them into a single image. Each scan has a width of 250km and a spatial resolution of 5m x 20m. The new Sentinel-1C satellite also carries an Automatic Identification System (AIS), developed by the International Maritime Organisation, which assigns a unique ID to every ship allowing its position and movements to be tracked. By combining the SAR and AIS data, it is hoped that users will be able to quickly detect and identify vessels in a large area of the ocean in real-time. This will be useful both to monitor shipping and also to detect piracy activity.
The data from the Sentinel-1 mission is used for a variety of land and ocean applications including monitoring land subsidence, earthquakes, volcanoes, forestry, water management, disaster response; together with Arctic sea-ice monitoring, iceberg and glacier monitoring. This application spread will be further enhanced with the new AIS instrument. At Pixalytics, we’ve used this SAR data in a variety of mostly water-based applications such as monitoring water extent, water height and flooding.
The launch next week will mark the first mission for an upgraded Vega C rocket, with more powerful first and second stages offering potential for heavier payloads, and it has also got an enhanced Small Spacecraft Mission Service dispenser allowing for the launch of many smaller satellites, even at different orbits, on the same mission.
Conclusion
We want to see a, hopefully, successful launch next week and are looking forward to being able to start using the new data from Sentinel-1C.
