Sentinel-1D

Sentinel-1 satellite (radar antenna missing)
Mission type	Earth observation
Operator	ESA
COSPAR ID	2025-251A
SATCATno.	66315
Website	Sentinel-1 (ESA)
Mission duration	Planned: 7 years[1] 19 days (in progress)
Spacecraft properties
Spacecraft type	Sentinel-1
Bus	Prima[2]
Manufacturer	Thales Alenia Space Airbus Defence and Space[1]
Launch mass	2,164 kg (4,771 lb)
Start of mission
Launch date	4 November 2025, 21:03 (2025-11-04UTC21:03) UTC
Rocket	Ariane 62 (VA265)[3][4]
Launch site	KourouELA-4[3]
Contractor	Arianespace
Orbital parameters
Reference system	Geocentric
Regime	Low Earth
Altitude	693 km[5]
Sentinel-1 ← Sentinel-1C Sentinel ← Sentinel-5A Sentinel-6B →

Sentinel-1D is a Europeanradar imagingsatellite launched in November 2025.^[6][7] It is the second of two additional satellites, and the fourth satellite overall, in theSentinel-1constellation, part of theEuropean Union'sCopernicus programme forEarth observation. The satellite is equipped with aC-SAR sensor, capable of providing high-resolution imagery regardless of weather conditions.^{[8][9][10][11]} It is designed to replaceSentinel-1A, which had been in orbit for 11 years at the time of Sentinel-1D's launch, long beyond its planned mission duration. Sentinel-1D will work in tandem withSentinel-1C,^[12][13] orbiting 180° apart.^[14]

Like the otherSentinel-1 satellites, Sentinel-1D will use its radar to capture high-resolution images over land, ice, and sea.^[15][16][17] These freely accessible data^[18] are used inland management^[19] anddisaster response, e.g. for real-timeflood detection and monitoring^{[20][21][22][23][24]} orhurricane^[25] andearthquake damage detection.^[26][27][28]

TheSentinel-1 satellites can detectground movement changes in terms of millimetres per year,^[29][30][31] which is used for monitoring agriculture,^[31] construction,^[32] or infrastructure^[33] likerailway networks,^[34][35][36] as well as for predictinglandslides.^[37]

Both Sentinel-1D andSentinel-1C include anAutomated Identification System (AIS) instrument for detecting AIS signals from marine vessels in coastal areas and theArctic. This, combined with ship detection in the satellite's radar images, is used inmaritime surveillance for monitoringshipping traffic,^[38] as well asoil spills,^[39][40]illegal fishing,^[41][42] and other suspicious maritime activities.^[17][43][44]

Development contract was signed withThales Alenia Space of Italy in December 2015.^[45] In November 2022, the satellite's launch was scheduled for the second half of 2024.^[46] In January 2025,ESA signed a contract withArianespace to launch the satellite in the second half of 2025 onAriane 6.^[47]

In September 2025 the satellite was transported from thecleanroom inCannes, France, viaTurin, Italy toFrench Guiana by the UkrainianAntonov Airlines.^[48][49] At the same time, control teams atESOC inDarmstadt, Germany begun simulations of the Sentinel-1D'sLaunch and Early Orbit Phase (LEOP). This was the first time an ESOC-operated satellite was launching onAriane 6.^[50]

In early October 2025, the satellite has undergone functional tests atGuiana Space Centre and had itsAIS antenna assemblies integrated.^[51] The spacecraft Flight Readiness Review took place in mid-October, paving the way for fuelling. By 20 October, the spacecraft was fuelled. On 24 October, it was encapsulated inside itsrocket fairing^[52][53] and later placed on top of theAriane 6 launch vehicle in a launch tower at theGuiana Space Centre^[54] for the launch planned for 4 November 2025.^[12][55]

The Ariane 6 flight VA265 with Sentinel-1D lifted off on 4 November 2025 at 21:03UTC and the satellite was successfully deployed in its planned orbit 34 minutes after launch.^[6][56][14] After releasing Sentinel-1D, the Ariane 6 upper stage fired itsVinci engine once again todeorbit itself and prevent creation ofspace debris. The Ariane 6 flight VA265 officially ended on 5 November 2025 at 01:16 UTC.^[57]

The first acquisition of signal from the satellite occurred as planned^[12] on 4 November 2025 at 22:22 UTC viaTroll Satellite Ground Station inAntarctica.^[58][59] Then, controllers atESOC deployed the satellite's solar arrays and radar antenna in a 10-hours long deployment sequence.^[60][61]

• 2025 in spaceflight
• List of European Space Agency programmes and missions

• Copernicus Programme
• Earth observation satellites of the European Space Agency
• Synthetic aperture radar satellites
• Spacecraft launched in 2025
• 2025 in spaceflight

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