 Model of a Sentinel-1 (radar antenna missing) | |||
| Manufacturer |
| ||
|---|---|---|---|
| Country of origin |  European Union | ||
| Operator | European Space Agency | ||
| Applications | Land and sea monitoring, natural disasters mapping, sea ice observations, ships detection | ||
| Specifications | |||
| Spacecraft type | Satellite | ||
| Constellation | Active: 2 | ||
| Launch mass | 2,300 kg (5,100 lb) | ||
| Dry mass | 2,170 kg (4,780 lb) | ||
| Dimensions | 3.9 m × 2.6 m × 2.5 m (13 ft × 8.5 ft × 8.2 ft) | ||
| Power | 5.9 kilowatts (5,900 W)[2] | ||
| Batteries | 324Ah | ||
| Design life | 7 years (12 years of consumables) | ||
| Production | |||
| Status | Active | ||
| On order | 4 | ||
| Built | 4 | ||
| Launched | 4 | ||
| Operational | 3 | ||
| Retired | 1 | ||
| Maiden launch | Sentinel-1A(3 April 2014)[3] | ||
| Last launch | Sentinel-1D(4 November 2025) | ||
| Related spacecraft | |||
| Subsatellite of | Copernicus Programme | ||
| |||
Sentinel-1 is the first of theCopernicus Programme satellite constellations forEarth observation operated by theEuropean Space Agency (ESA). Data collected via the satellites are usede.g. for marine and land monitoring, emergency response to environmental disasters, and economic applications.[4]
The mission was originally composed of a constellation of two satellites,Sentinel-1A andSentinel-1B, which shared the same orbital plane. Sentinel-1B was retired following a power supply issue on 23 December 2021, which left Sentinel-1A the only satellite of the constellation to be operating,[5] untilSentinel-1C was successfully launched on 5 December 2024.[6][7]Sentinel-1D launched in November 2025.[8][9][10]
The first satellite, Sentinel-1A, launched on 3 April 2014, and Sentinel-1B was launched on 25 April 2016. Both satellites lifted off from theGuiana Space Centre inKourou,French Guiana on aSoyuz rocket.[11] Sentinel-1D is in development.[12] An equipment failure on Sentinel-1B in December 2021 accelerated work on Sentinel-1C,[13] which has been successfully launched in December 2024.[14]
The satellites have aSun-synchronous, near-polar (98.18° inclination) orbit.[15] Their orbits have a 12-day repeat cycle and complete 175 orbits per cycle (having a 98.6 minute orbital period). The satellites operate at 693 km (431 mi) altitude, with 3-axis altitude stabilization.
TheEuropean Space Agency and European Commission's policies makes Sentinel-1's data easily accessible. Various users can acquire the data and use it for public, scientific, or commercial purposes for free.
Sentinel-1A was launched on 3 April 2014.[3]
Sentinel-1B was launched on 25 April 2016.[3] Unavailable due to a power issue since 23 December 2021. Mission end declared on 3 August 2022.[16]
Development contract signed withThales Alenia Space of Italy in December 2015.[17] It was launched on 5 December 2024.[18]
Development contract signed withThales Alenia Space of Italy in December 2015.[17] It was launched on 4 November 2025.[8][19][20]
The prime contractor of the mission isThales Alenia Space Italy, with whole system integration and also with production of platform Spacecraft Management Unit (SMU) and payload Data Storage and Handling Assembly (DSHA). Other technologies such as the T/R modules, the C-band synthetic-aperture radar antenna, the advanced data management and transmission subsystems, and the on-board computer, were developed in L'Aquila and Milan.[21] The C-SAR instrument is the responsibility ofAstrium Gmbh. Sentinel-1A was constructed in Rome, Italy. The ground segment prime contractor is Astrium with subcontractorsTelespazio, WERUM, Advanced Computer Systems, and Aresys. Final test verification of the satellite was completed at Thales Alenia Space's clean rooms in Rome and Cannes.[21]
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Sentinel-1 spacecraft are designed to carry aC-bandsynthetic-aperture radar (C-SAR) instrument which provides a collection of data in all-weather, day or night, as well as anSDRAM-based Data Storage and Handling Assembly (DSHA).[22]
The single C-SAR instrument with its electronics provides 1 dB radiometric accuracy with a central frequency at 5.405 GHz.[15] This instrument has a spatial resolution down to 5 m (16 ft) and a swath of up to 410 km (250 mi).[23] The data collected in C-SAR was made to be continuous after the termination of a previous mission (Envisat mission).[24]
The DSHA has an active data storage capacity of about 1,443 Gbit (168GiB), receiving data streams from SAR-SES over two independent links gathering SAR_H and SAR_V polarization, with a variable data rate up to 640 Mbit/s on each link, and providing 520 Mbit/sX-band fixed-user data-downlink capability over two independent channels towards ground.
Sentinel-1 has four operational modes and four types of data products available. All data levels are publicly available for free online within 24 hours of observation.[25] The four operational modes offered by Sentinel-1 are:[15][26][27]
The four types of data products offered by Sentinel-1 are:[26]
A major goal of the mission was to provide C-Band SAR data.[24] Sentinel-1 provides continuity of data from theERS andEnvisat missions, with further enhancements in terms of revisit, coverage, timeliness and reliability of service. Recently, Sentinel-1 has worked in conjunction withSMAP to help achieve a more accurate measure of soil moisture estimates.[28] Observations from both instruments show them to be complementary of each other as they combine data of soil moisture contents.
A summary of the main applications of Sentinel-1 include:[29]
The C-SAR instrument is capable of measuring land subsidence through the creation ofinterferometric synthetic-aperture radar (InSAR) images. The analysis of phase changes between two or more synthetic aperture radar images taken at different times is able to create maps of the digital elevation and measure the land surface deformation of an area. High spatial (20m) and temporal (6 days) resolutions allow Sentinel-1 to improve on current InSAR techniques and provide systematic continuity to the data.[30]
Shortly after the August2014 South Napa earthquake, data collected by Sentinel-1A was used to develop aninterferometric synthetic-aperture radar, or InSAR, image of the affected region. The Sentinel-1 satellites are expected to make analysis of earthquakes using InSAR techniques quicker and simpler.[31]
Examples of images produced from Sentinel-1 data.
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