Sentinel-1D

Sentinel-1D is a C-band synthetic aperture radar (SAR) satellite developed and operated by ESA as part of the Copernicus Earth observation programme, on behalf of the European Commission.^[1] Airbus Defence and Space served as prime contractor. Sentinel-1D was launched 2025-11-04 on an Ariane 6 rocket (Arianespace flight VA265) and completed in-orbit commissioning on 2026-05-01.^{[2] [3]} User data access opened on 2026-04-17.^[4]

Sentinel-1D carries a C-SAR instrument operating at 5.405 GHz (C-band) plus an Automatic Identification System (AIS) receiver. Four imaging modes are available:^[5]

Sentinel-1D orbits at 693 km in a Sun-synchronous polar configuration with an 18:00 local time descending node.^[6] It is the fourth satellite in the Sentinel-1 series. The pairing of Sentinel-1C and Sentinel-1D gives a six-day revisit cycle with a one-day ground-track offset between the two satellites. Three-satellite operations with 1A, 1C, and 1D ran from mid-April to approximately mid-June 2026; the final operational pair is 1C and 1D, with Sentinel-1A scheduled for phase-out circa July 2026.^[7] Sentinel-1B ended operations in August 2022.

Sentinel-1D and Sentinel-1C both carry a new separation mechanism to reduce space debris risk, a design change relative to Sentinel-1A and 1B.^[6] Tasking is not supported; Sentinel-1D operates as an open-access, observation-mode instrument.