Sentinel-2

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Sentinel-2A / 2B
Sentinel-2A / 2B
Type: Earth observation satellites
Operator: European space agencyESA ESA
COSPAR-ID : 2015-028A
Mission dates
Dimensions: 1200 kg
Size: 3.4 m × 1.8 m × 2.35 m
Begin: 2A: June 23, 2015, 01:52 UTC
2B: March 7, 2017, 01:49
Starting place: 2A: CSG , ELV
2B: CSG
Launcher: 2A: Vega
2B: Vega
Flight duration: 7.25 + 4.75 yearsTemplate: future / in 5 years
Status: 2A: launched and in orbit
2B: launched and in orbit
Orbit data
Rotation time : 100.6 min / 100.4 min
Orbit inclination : 98.6 ° / 98.6 °
Apogee height :  797/786 km
Perigee height :  795/784 km

The Sentinel-2 space mission , consisting of Sentinel-2A and Sentinel-2B, is a pair of optical Earth observation satellites in sun-synchronous Earth orbit . Like the satellite pairs Sentinel-1 and Sentinel-3, they belong to the Copernicus program of the European Union for Global Monitoring for Environment and Security and are part of the Sentinel series of satellites. Sentinel-2 is intended to provide data for climate protection , land surveillance and disaster and crisis management on earth .

Mission history

Sentinel-2A launched on June 23, 2015 from the Kourou Space Center with a Vega rocket. The launch of Sentinel-2B followed on March 7, 2017, also on board a Vega missile from Kourou.

Mission objectives

As a continuation of Landsat and SPOT, Sentinel-2 is to carry out the systematic global acquisition of multispectral earth observation data.

This data includes the observation of terrain and ocean divisions, inland waters and rivers, and coasts. Changes in land areas and land use in general are monitored. Land reclamation and disaster relief measures are also supported. In addition, Sentinel-2 provides satellite-based climate monitoring.

Because the two satellites 2A and 2B, offset by 180 °, orbit the earth in the same orbit, and due to the large swath width of 290 km, a high temporal coverage of the earth's surface is achieved. So it is possible that the entire planet, with the exception of Antarctica, can be flown over and measured / examined every 5 days.

construction

Sentinel-2A in a vacuum chamber

The two Sentinel-2 satellites are identical. They have a modular structure according to the ECSS standard.

Sentinel-2 has a multispectral recording device (MSI). It uses the principle of a digital line scan camera which is also used in the SPOT program. When Sentinel-2 was launched, it was the most advanced device in its class.

The light reflected from the earth and the atmosphere is collected in the MSI by a three-mirror telescope with an equivalent total diameter of 150 mm. The MSI has two focal planes and has twelve CMOS detectors for VNIR (visible and near infrared spectrum ) and twelve MCT detectors for SWIR (short wave infrared spectrum). The detectors are staggered in order to cover the entire width of the swath. A dichroic radiation diffuser divides into 13 spectral channels.

Sentinel-2 navigates with a dual GPS receiver and three star cameras ( English star tracker ). A front diffuser for the radiometric calibration is intended to ensure the radiometric performance. In addition, Sentinel-2 has a locking mechanism to protect the instruments from direct sunlight (and from contamination during rocket launch). In order to reduce the mass, this is also used for calibration in conjunction with a spectral diffuser.

Sentinel-2 uses a laser system to transmit the data via optical communication , which is operated by DLR . The data is sent to the geostationary satellites of the European Data Relay System . This allows the rapid transfer of enormous volumes of data.

The Sentinel-2 satellites can carry out their tasks autonomously for up to two weeks without a connection to the ground station.

Sentinel-2 spectral channels

The images are recorded in spatial resolutions of 10 or 20 m per pixel in ten spectral channels in the wavelength range from 490 to 2200 nm. There are also three spectral channels with a spatial resolution of 60 m for measuring the atmospheric properties.

tape Sentinel-2A Sentinel-2B Spatial resolution (m) use
Mean wavelength (nm) Bandwidth (nm) Mean wavelength (nm) Bandwidth (nm)
1 442.7 21st 442.2 21st 60 Aerosols
2 492.4 66 492.1 66 10 Aerosols , land use, vegetation
3 559.8 36 559, 0 36 10 Land use, vegetation
4th 664.6 31 664.9 31 10
5 704.1 15th 703.8 16 20th
6th 740.5 15th 739.1 15th 20th
7th 782.8 20th 779.7 20th 20th
8th 832.8 106 832.9 106 10 Water vapor , land use, vegetation
8a 864.7 21st 864, 0 22nd 20th
9 945.1 20th 943.2 21st 60 Steam
10 1373.5 31 1376.9 30th 60 Cirrus clouds
11 1613.7 91 1610.4 94 20th Land use, vegetation
12 2202.4 175 2185.7 185 20th Aerosols , land use, vegetation

Application and right of use

The data and evaluation of Sentinel are freely available for everyone in the Copernicus program .

In addition, in March 2016 ESA signed an agreement on data usage with NASA , NOAA and USGS . Since then, these agencies have been allowed to transfer the data and add it to their existing database systems.

Web links

Commons : Sentinel-2  - collection of images, videos and audio files

Individual evidence

  1. ↑ a b c Cai Tore Philippsen: The second guard is at his post. FAZ, June 23, 2015, accessed on June 23, 2015 .
  2. ↑ a b Zulfikar Abbany: The mad scanner: Earth observation satellite Sentinel-2B launched. DW, March 7, 2017, accessed March 7, 2017 .
  3. ↑ Orbit data from Sentinel-2A to Sentinel 2A. N2YO, March 8, 2017, accessed March 8, 2017 .
  4. ^ Orbit data from Sentinel-2B to Sentinel 2B. N2YO, March 8, 2017, accessed March 8, 2017 .
  5. ↑ Overview. Accessed June 13, 2018 .
  6. ^ Mission Objectives. ESA, June 23, 2015, accessed March 27, 2016 .
  7. ↑ Mission Detail Sentinel-2. ESA, June 23, 2015, accessed March 27, 2016 .
  8. ↑ ESA's Sentinel satellites - Sentinel-2. (PDF; 298 kB) ESA, accessed on April 12, 2012 (English).
  9. ↑ a b c d e f g Copernicus: Sentinel-2. ESA, March 25, 2016, accessed March 27, 2016 .
  10. ↑ a b c MultiSpectral Instrument (MSI) Overview. ESA, June 23, 2015, accessed October 21, 2018 .
  11. ↑ Sentinel-2. ESA's Optical High-Resolution Mission for GMES Operational Services. (PDF of 7.8 MB) ESA, pp. 9–14 , accessed on December 18, 2013 (English).