Sentinel-1B reentry phases

Preparations for Sentinel-1B’s disposal began in September 2022, right after the mission ended.

Building on their shared commitment to reducing space debris, a collaborative effort between experts from ESA, the European Commission, as well as industrial partners led to a well-structured disposal plan that maximised the satellite's remaining potential.

The plan, based on ESA’s previous satellite disposal experiences, involved multiple stages that allowed the ESA team to monitor and adjust as needed, after which the reentry itself will be uncontrolled:

• Orbit clear-up: Sentinel-1B’s orbit was lowered by a few kilometres to free up the orbit for the arrival of Sentinel-1C and Sentinel-1D satellites.
• Manoeuvre testing: New manoeuvres were tested and validated to complement conventional ones, and lower altitude much further.
• Active orbit lowering: The spacecraft was placed it in a final orbit, from which it will naturally decay and eventually burn up in the atmosphere.
• Passivation: The spacecraft was passivated, to remove as much stored energy as possible to avoid accidental breakups, and all powered systems were actively shutdown. 

Disposal operations for Sentinel-1B began in February 2023, as planned. For the first six months, the operations went smoothly but as the orbit lowering progressed the teams had to overcome multiple challenges to stay on track. In April 2024, the final orbital altitude was reached, allowing for re-entry within 25 years. Electrical passivation took place on 12 September 2024, marking the end of the satellite’s operational life.

This careful operation helped gather useful knowledge about the spacecraft's capabilities and limitations, which will facilitate future Sentinel-1 operations for years to come.

Read full story: Sentinel-1B journeys back to Earth