Sentinel-1D is the newest of the European Space Agency's Sentinel missions. It has been operating along with Sentinel-1A and 1-C since April 17, 2026, and will replace Sentinel-1A to re-establish a two-satellite Sentinel-1 constellation. The expected sequence of events to achieve this will be:
- Sentinel-1C will be maneuvered to establish a six-day nominal revisit frequency with Sentinel-1D. This maneuver will occur between June 9-23, 2026.
- During this period of orbit adjustment, Sentinel-1C operations will be suspended. Sentinel-1A and 1D will remain fully operational.
- Sentinel-1C will resume nominal operations on June 24. Sentinel-1D will assume the same observation scenario as Sentinel-1A.
- Sentinel-1A operations will be terminated on June 29, 2026.
- The new Sentinel-1C and Sentinel-1D constellation orbit configuration will shift the 6-day revisit pattern by 1 day relative to the previous Sentinel-1A and 1B timeline.