Example impression of Sentinel-2. Image courtesy of ESA. Copyright ESA/ATG medialab.
Update: Copernicus Sentinel-2C launched successfully in the early hours of Thursday morning. Launch was delayed 24 hours due to electrical issues.
The launch of the Sentinel-2C satellite is scheduled for the early hours of Wednesday 4th September 2024 Central European Time, from the European Spaceport based at Kourou in French Guiana, South America. This will be a fantastic step forward for the Copernicus Programme as it will be the first satellite launched to provide dataset continuity.
As its designation suggests, this will be third Sentinel-2 satellite launched. It follows Sentinel-2A which was launched on 23rd June 2015 and Sentinel-2B that went into space two years later, on the 7th March 2017. Once in orbit, Sentinel-2C will replace Sentinel-2A, while Sentinel-2D is expected to be launched in the coming years to replace Sentinel-2B.
These satellites are part of the European Union’s Copernicus Programme which, to-date, has launched a suite of eight satellites. Apart from the Sentinel-2 satellites, this includes:
- Sentinel-1A and 1B, which are C-Band synthetic aperture radar (SAR) satellites.
- Sentinel-3A and 3B, which mainly focus on ocean measurements.
- Sentinel 5P monitors the atmosphere and maps trace gases, aerosols, and pollutants.
- Sentinel 6 is an oceanography satellite carrying both a pulse altimeter and radiometer.
Sentinel-2C
Unlike the Landsat missions, which are single satellites, Sentinel-2 satellites are built to operate as a pair. They are in the same orbit at an altitude of 786 kilometres, but they fly 180° apart to maximise coverage and revisit time that, at its best, is 5 days.
The Sentinel-2’s are all optical satellites and carry identical 290-kilometre-wide swath high-resolution Multispectral Imagers (MSI) with 13 spectral bands:
- Four visible and near infrared bands with a spatial resolution of 10 metres.
- Six shortwave infrared spectral bands with a spatial resolution of 20 meters
- Three atmospheric correction bands with a spatial resolution of 60 meters.
The satellite will be taken into orbit on a Vega rocket, and last week was sealed within the Vega rocket fairing. We wrote about the satellite’s arrival in Kourou earlier this year, and since then it has passed a series of checks to ensure it is ready to launch.
The data from Sentinel-2 is used for a range applications including agriculture, , water quality monitoring, natural disaster management and methane emission detection. At Pixalytics, Sentinel-2 imagery and data is something we use almost daily and we have used in projects as varied as the detection waste plastic, assessing coastal water quality, understanding crops growing and the concentration of methane, a greenhouse gas, in the atmosphere.
It is also not just us that use Sentinel-2, in 2022 the European Space Agency commissioned a study to see the impact of the Sentinel missions. Up until 2021 there were nearly 12,000 publications, with that number growing exponentially, and Senintel-2 had the largest contribution of publications, followed closely by Sentinel-1.
Conclusion
One of key strengths of Landsat has been the continuity of its dataset, now over fifty years in length, achieved by NASA continually launched another Landsat mission when one was coming towards end of life. When the Copernicus programme began it also set out an aim to achieve dataset continuity, and the launch of Sentinel-2C is the first time this commitment will be demonstrated.
This is an exciting development for all researchers, scientists, and small businesses, like Pixalytics, who can have confidence in developing products and services based on Sentinel-2. We are looking forward to seeing the first datasets from this new satellite.
