Sentinel-1

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Sentinel 1A / 1B / 1C / 1D
Sentinel 1A / 1B / 1C / 1D
Type: Earth observation satellites
Operator: European space agencyESA ESA
COSPAR-ID : 1A: 2014-016A
1B: 2016-025A
Mission dates
Dimensions: 2300 kg
Begin: 1A: April 3, 2014, 21:02 UTC
1B: April 25, 2016, 21:26 UTC
1C:
1D:
Starting place: CSG ELS
Launcher: Soyuz -2.1b
Status: 1A and 1B: in operation
Orbit data
Rotation time : 98.7 min
Orbit inclination : 98.2 °
Apogee height :  704 km
Perigee height :  702 km

Sentinel-1 , consisting of Sentinel-1A , Sentinel-1B , Sentinel-1C and Sentinel-1D , are radar satellites and part of the Sentinel satellite series. These are earth observation satellites of the Copernicus program (formerly GMES, Global Monitoring for Environment and Security) of ESA .

Tasks and instruments

Sentinel-1 has the task of making radar-based observations of the earth from its approximately 700 km high orbit. It flies in an orbit near the pole and scans the earth in strips. The width of the observed strips varies between 80 and 400 km depending on the observation mode. Sentinel-1 scans the earth's surface with a C-band SAR ( Synthetic Aperture Radar ) with a wavelength of 6 centimeters. The active antenna of the satellites consists of 560 individual antennas coupled to one another.

The radar can work in four different observation modes (resolutions range × azimuth ):

  1. Strip map mode: 80 km wide strips with a resolution of 5 × 5 meters
  2. Interferometric Wide Swath Mode: 250 km wide strips with a resolution of 5 × 20 meters
  3. Extrawide swath mode: 400 km wide strips with a resolution of 20 × 40 meters
  4. Wave mode: individual areas of 20 × 20 km with a resolution of 5 × 5 meters

Satellites

  • Sentinel-1A - launched April 3, 2014
  • Sentinel-1B - launched April 25, 2016
  • Sentinel-1C - Commission signed in December 2015
  • Sentinel-1D - Commission signed December 2015

Access to the data

ESA grants open and free access to the data collected by the Sentinel satellites. No distinction is made between public, commercial and scientific use, nor between European and non-European users. At the end of May 2016, the "Sentinel National Mirror Austria", the first of several Europe-wide data centers, went into operation. Around three terabytes of data arrive from the satellites every day. These currently only come from the first two satellites (Sentinel 1-A & 2-A), but the data from other satellites will follow successively.

Mission objectives

The data are to be used for the areas of the environment , climate impact research , transport, economy and security. Become of them then promptly ( " near-real time " in about an hour) images and maps for warning of extreme weather events created for navigation as well as for long-term research, especially for Europe, Canada and the two polar regions. Building on previous missions (called the Envisat , which failed in 2012 ), applications that require a series of long-term data as well as researching the long-term effects of climate change - such as the extent of the Arctic sea ice, the mass balancing of the continental ice sheets and glaciers - are being added . The radar can also differentiate between the thinner, annual sea ice and the more dangerous, much thicker perennial ice, in order to make year-round navigation in the ice-covered zones of the Arctic and sub-Arctic safer for shipping. Environmental data can be used to identify oil spills and other environmental pollution.

Mission history

Sentinel-1A was launched on April 3, 2014 at 21:02 UTC , the satellite was disconnected from the upper stage of the Soyuz rocket 23 minutes and 24 seconds after liftoff. Before the satellite could be fully commissioned, it had to perform an orbit maneuver to avoid a collision with NASA's ACRIMSat satellite . Sentinel-1A reached its final orbit on August 7, 2014 and was operational on September 23. The mission is designed for at least seven years.

On August 23, 2016 at 17:07 GMT, a sudden drop in the power of the solar cells and a slight change in the orientation of the satellite were observed. The control station ESOC decided to activate the on-board cameras, which had not been in operation since the solar cell boom had been unfolded. These showed slight damage to the solar cells in an area of ​​40 cm in diameter. Apparently the satellite was hit by a part several millimeters in size. It can no longer be determined whether it was space debris or a small meteoroid . The performance drop of the solar cells is relatively small and does not cause any restrictions in the operation of Sentinel-1A.

The identical twin satellite Sentinel-1B was launched after multiple shifts on April 25, 2016 with a Soyuz rocket.

Web links

Commons : Sentinel-1  - collection of images, videos and audio files

Individual evidence

  1. ↑ FACTS AND FIGURES. ESA, accessed on March 20, 2014 (English): "Launch: April 3, 2014"
  2. ↑ a b Sentinel-1B: The second eye of the earth guardians in space. German Aerospace Center, April 25, 2016, accessed April 26, 2016 .
  3. ↑ ESA: Sentinel-1 satellites combine radar vision. June 22, 2016, accessed June 23, 2016 .
  4. ↑ Orbit data according to SENTINEL 1A. N2YO, June 23, 2016, accessed June 23, 2016 . and SENTINEL 1B. N2YO, June 23, 2016, accessed June 23, 2016 .
  5. ↑ a b c AIRPRESS: Decolla la space economy italiana
  6. ↑ Astrium supplies radar instruments for Sentinel-1A. (No longer available online.) Astrium, October 28, 2013, formerly the original ; Retrieved January 5, 2014 .  ( Page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.@1@ 2Template: Dead Link / www.astrium.eads.net  
  7. ↑ Copernicus: Sentinel-1 - The SAR Imaging Constellation for Land and Ocean Services. ESA, accessed March 20, 2014 .
  8. ^ Sentinel Data Policy. (PDF, 96 pages, 10 MB) In: Sentinel-1. ESA's Radar Observatory Mission for GMES Operational Services. ESA, March 2012, p. 67 , accessed on December 18, 2013 .
  9. ↑ Data from the Sentinel earth observation satellites in Austria can be called up free of charge - ZAMG. In: www.zamg.ac.at. Retrieved May 31, 2016 .
  10. ↑ Sentinel data now freely accessible - science.ORF.at. In: science.orf.at. Retrieved May 31, 2016 .
  11. ↑ Sentinel-1: Europe lofts first Copernicus environmental satellite , ESA, April 3, 2014 (English), accessed on April 4, 2014.
  12. ↑ Elizabeth Howell: European Satellite Dodged Space Debris Hours After Reaching Orbit. Universe Today, April 10, 2014, accessed April 11, 2014 .
  13. ^ ESA: First Copernicus satellite now operational. October 6, 2014, accessed October 6, 2014 .
  14. ↑ Sentinel-1 operations. In: esa.int. Retrieved January 22, 2017 .
  15. ↑ ESA: Copernicus Sentinel-1A satellite hit by space particle. August 31, 2016, accessed September 7, 2016 .