Two twin satellites were tracked second by second as they were destroyed in Earth’s atmosphere.
They were called Samba and Tango and belonged to Cluster, a European Space Agency mission launched in 2000. The mission’s four spacecraft studied Earth’s magnetic environment. After 26 years of activity, their end of life became a scientific experiment in its own right.
Artist’s impression of the Cluster constellation flying in formation around Earth.
Credit: ESA
To understand the operation’s importance, we need to look at what happens to a satellite when it re-enters. At very high speed, the air in front of it heats up considerably and the spacecraft begins to fragment. Some parts disappear, while others can survive longer. Current models predict this process, but direct observations remain rare.
The ESA therefore prepared the orbits of the four Cluster satellites to trigger their reentry above an isolated area of the South Pacific. Maneuvers carried out well before the fall positioned their trajectories so that the reentry would be predictable.
Samba reentered the atmosphere on August 31, 2026, followed by Tango on September 1. An aircraft departing from Tonga positioned itself beneath their trajectories. On board, the ROSIE team had 30 instruments, including cameras capable of observing different parts of the radiation emitted during the destruction.
Researchers tracked the two satellites for about 50 seconds on average. For Tango, the pilot even tilted the aircraft at the right moment to extend the observation.
Glowing fragments of the Samba satellite during its reentry into the atmosphere on August 31, 2026.
Credit: ESA/ROSIE/University of Stuttgart (HEFDiG)
Fragments of the Tango satellite observed during its atmospheric reentry on September 1, 2026.
Credit: ESA/ROSIE/University of Stuttgart (HEFDiG)
This repetition is particularly useful because the four Cluster satellites were identical. Salsa had already reentered in September 2024, followed by Rumba in 2025. Scientists therefore have several destructions of the same type of spacecraft, under different atmospheric conditions and along different trajectories.
These measurements should help improve predictions of when a satellite will break apart, which parts will survive, and where they might fall. They will also help in designing spacecraft that disintegrate more easily at the end of their missions. The next step will be the Draco mission, planned for 2027, with more than 200 sensors and four cameras installed directly on the satellite during its reentry.