Sentinel-2


Sentinel-2 is an Earth observation mission from the Copernicus Programme that systematically acquires optical imagery at high spatial resolution over land and coastal waters. The mission is a constellation with two twin satellites, Sentinel-2A and Sentinel-2B.
The mission supports a broad range of services and applications such as agricultural monitoring, emergencies management, land cover classification or water quality.
Sentinel-2 has been developed and is being operated by ESA, and the satellites were manufactured by a consortium led by Airbus DS.

Overview

The Sentinel-2 mission has the following key characteristics:
To achieve frequent revisits and high mission availability, two identical Sentinel-2 satellites operate together. The satellites are phased 180 degrees from each other on the same orbit. This allows for what would be a 10-day revisit cycle to be completed in 5 days. The 290km swath is created by the VNIR and SWIR, which are each made of 12 detectors that are lined in two offset rows.
The orbit is Sun synchronous at altitude, 14.3 revolutions per day, with a 10:30 a.m. descending node. This local time was selected as a compromise between minimizing cloud cover and ensuring suitable Sun illumination. It is close to the Landsat local time and matches SPOT, allowing the combination of Sentinel-2 data with historical images to build long-term time series.

Copyright

The Sentinel-2 synthetic data and images generated therefrom are subject to an agreement between the ESA and the User, are laid out in a document entitled TERMS AND CONDITIONS FOR THE USE AND DISTRIBUTION OF SENTINEL DATA, which is a type of open access licence.

Launches

The launch of the first satellite, Sentinel-2A, occurred 23 June 2015 at 01:52 UTC on a Vega launch vehicle.
Sentinel-2B was launched on 7 March 2017 at 01:49 UTC, also aboard a Vega rocket.

Instruments

The Sentinel-2 satellites will each carry a single multi-spectral instrument with 13 spectral channels in the visible/near infrared and short wave infrared spectral range. Within the 13 bands, the 10 meter spatial resolution allows for continued collaboration with the SPOT-5 and Landsat-8 missions, with the core focus being land classification.
Designed and built by Airbus Defense and Space in France; this MSI imager uses a push-broom concept and its design has been driven by the large swath requirements, together with the high geometrical and spectral performance required of the measurements. It has a aperture and a three-mirror anastigmat design with a focal length of about ; the instantaneous field of view is about 21° by 3.5°. The mirrors are rectangular and made of silicon carbide, a similar technology to those on the Gaia mission. The system also employs a shutter mechanism preventing direct illumination of the instrument by the sun. This mechanism is also used in the calibration of the instrument. Out of all the different civic optical earth observation missions, Sentinel-2 is the first to have the ability to show three bands in the red edge. The radiometric resolution is 12 bit with brightness intensity ranging from 0-4095.
Due to the layout of the focal plane, spectral bands within the MSI instrument observe the surface at different times and vary between band pairs.
Inter-band PairsTemporal Offset Between Bands
B08 / B020.264
B03 / B080.264
B03 / B020.527
B10 / B030.324
B10 / B020.851
B04 / B100.154
B04 / B021.005
B05 / B040.264
B05 / B021.269
B11 / B050.199
B11 / B021.468
B06 / B110.057
B06 / B021.525
B07 / B060.265
B07 / B021.790
B8a / B070.265
B8a / B022.055
B12 / B8a0.030
B12 / B022.085
B01 / B120.229
B01 / B022.314
B09 / B010.271
B09 / B022.586

These temporal offsets can be used to our benefit, for example to track propagating natural and man-made features such as clouds, airplanes or ocean waves.

Applications

Sentinel-2 will serve a wide range of applications related to Earth's land and coastal water.
The mission will provide information for agricultural and forestry practices and for helping manage food security. Satellite images will be used to determine various plant indices such as leaf area chlorophyll and water content indexes. This is particularly important for effective yield prediction and applications related to Earth's vegetation.
As well as monitoring plant growth, Sentinel-2 can be used to map changes in land cover and to monitor the world's forests. It will also provide information on pollution in lakes and coastal waters. Images of floods, volcanic eruptions and landslides contribute to disaster mapping and help humanitarian relief efforts.
Examples for applications include:
The Sentinel Monitoring web application offers an easy way to observe and analyse land changes based on archived Sentinel-2 data.

Products

The following two main products are generated by the mission:
Additionally, the following product for expert users is also available:
Examples of images taken.