Sentinel-2

Sentinel-2

Model of a Sentinel 2 satellite
Manufacturer
Operator European Space Agency
Applications Land and sea monitoring, natural disasters mapping, sea ice observations, ships detection
Specifications
Spacecraft type Satellite
Bus AstroBus-L
Constellation 2
Design life 7 years
Launch mass 1,140 kg (2,513 lb)[2]
Dry mass 1,016 kg (2,240 lb)[2]
Dimensions 3.4 × 1.8 × 2.35 m (11.2 × 5.9 × 7.7 ft)[2]
Power 1,700 W[3]
Production
Status Active
Built 2
On order 2
Launched 1
Operational 1
First launch Sentinel-2A
23 June 2015
Last launch Sentinel-2B
March 2017 (planned)
← Sentinel-1 Sentinel-3 →

Sentinel-2 is an Earth observation mission developed by ESA as part of the Copernicus Programme to perform terrestrial observations in support of services such as forest monitoring, land cover changes detection, and natural disaster management. It consists of two identical satellites, Sentinel-2A and Sentinel-2B.

Overview

The Sentinel-2 mission has the following capabilities:

To achieve frequent revisits and high mission availability, two identical Sentinel-2 satellites (Sentinel-2A and Sentinel-2B) are planned to operate simultaneously. The planned orbit is Sun synchronous at 786 km (488 mi) 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's, allowing the combination of Sentinel-2 data with historical images to build long-term time series.

Launch

The two satellites will work on opposite sides of the orbit. The launch of the first satellite, Sentinel-2A, occurred 23 June 2015 at 01:52 UTC on a Vega launch vehicle.[4] Sentinel-2B will be launched in March 2017, also aboard a Vega rocket.[2]

Instruments

The Sentinel-2 satellites will each carry a single multi-spectral instrument (MSI) with 13 spectral channels in the visible/near infrared (VNIR) and short wave infrared spectral range (SWIR).

This MSI imager uses a push-broom concept and its design has been driven by the large 290 km (180 mi) swath requirements, together with the high geometrical and spectral performance required of the measurements.[5]

Sentinel-2 Bands Central Wavelength (µm) Resolution (m)
Band 1 - Coastal aerosol 0.443 60
Band 2 - Blue 0.490 10
Band 3 - Green 0.560 10
Band 4 - Red 0.665 10
Band 5 - Vegetation Red Edge 0.705 20
Band 6 - Vegetation Red Edge 0.740 20
Band 7 - Vegetation Red Edge 0.783 20
Band 8 - NIR 0.842 10
Band 8A - Vegetation Red Edge 0.865 20
Band 9 - Water vapour 0.945 60
Band 10 - SWIR - Cirrus 1.375 60
Band 11 - SWIR 1.610 20
Band 12 - SWIR 2.190 20

Applications

Sentinel-2 will serve a wide range of applications related to Earth's land surface and coastal zones.

The mission will mainly 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.[6]

Products

Sentinel-2's multi-spectral imager undertakes systematic acquisition in a single observation mode.[7]

Training data sets

In June 2013, the Centre National d'Etudes Spatiales (CNES) released and distributed training data sets acquired by the SPOT 4 satellite with the same repetitivity as planned for Sentinel-2, to help future Sentinel-2 users develop methods and applications based on multitemporal data. This experiment, named SPOT4 (Take5), was held between February and June 2013, and provided time series over 45 sites for a variety of applications. To obtain this data set, the orbital altitude of SPOT4 was decreased by 2 kilometres (1.2 mi) in order to place it in a 5-day revisit cycle.[8]

This experiment was repeated with the SPOT 5 satellite, thanks to a co-funding from ESA and CNES, between April and September 2015. On this second experiment, 150 sites scattered all over the world have been observed.

The data from both experiments are freely available from the Spot (Take5) experiment site.[9]

References

  1. ↑ "Sentinel 2 - Earth Online - ESA". ESA. Retrieved 17 August 2014.
  2. 1 2 3 4 van Oene, Jacques (17 November 2016). "ESA's Sentinel 2B spacecraft steps into the spotlight". Spaceflight Insider. Retrieved 17 November 2016.
  3. ↑ "Sentinel-2 Data Sheet" (PDF). European Space Agency. August 2013. Retrieved 17 November 2016.
  4. ↑ Nowakowski, Tomasz (23 June 2015). "Arianespace successfully launches Europe's Sentinel-2A Earth observation satellite". Spaceflight Insider. Retrieved 17 August 2016.
  5. ↑ "Sentinel-2 MSI: Overview". European Space Agency. Retrieved 17 June 2015.
  6. ↑ "Sentinel Monitoring". Sentinel Hub/Sinergise. Retrieved 26 August 2016.
  7. ↑ "Sentinel-2 MSI: Product Types". European Space Agency. Retrieved 17 June 2015.
  8. ↑ Hagolle, Olivier (28 November 2014). "Slides from the second SPOT (Take 5) Workshop". Séries Temporelles. Paul Sabatier University. Retrieved 23 April 2015.
  9. ↑ Spot-Take5 Home (October 2015).
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