Table of Contents
On September 8, the European Space Agency (ESA) will witness a rare event as the first of four Cluster satellites, dubbed “Salsa,” reenters Earth’s atmosphere. Launched as part of ESA’s Cluster mission, the satellite will burn up in an uncontrolled but targeted reentry over a remote part of the South Pacific Ocean. The event will provide scientists with a unique opportunity to observe satellite reentry and collect critical data, contributing to safer and more sustainable practices in future space missions.
Understanding Satellite Returns
According to a report By ESA, in almost 70 years of space exploration, around 10,000 intact satellites and rocket bodies have re-entered Earth’s atmosphere. Despite this, scientists still have a limited understanding of the exact dynamics that occur during atmospheric re-entry. To fill this knowledge gap, ESA, in collaboration with Astros Solutions, will perform an in-flight observation experiment during Salsa’s re-entry.
A team of scientists aboard a small aircraft will attempt to collect data on the satellite’s disintegration. This data is invaluable for designing and operating future satellites, so that they can be safely and efficiently destroyed after their mission.
The Importance of the Return of Salsa
According to Holger Krag, Head of Space Safety at ESA, understanding the dynamics of atmospheric re-entry is crucial for maintaining clean and safe orbits around Earth. He explains that the rapid removal of failed satellites is vital to prevent the accumulation of space debris. The re-entry of the Cluster satellites, starting with Salsa, provides a repeatable experiment due to the nearly identical conditions under which each satellite reenters the atmosphere. This scenario allows scientists to observe and compare the outcomes of different reentry angles and conditions, providing insights that will inform the design of future missions.
Focused on the South Pacific Ocean
In January, Salsa’s orbit was modified to ensure that reentry would take place over one of the most remote regions on Earth, the South Pacific Ocean. Bruno Sousa, Cluster Operations Manager, notes that Salsa’s orbit brings it close to Earth every 12 years. This year’s approach allowed for a targeted reentry, with the spacecraft’s orbit modified to ensure that any remaining fragments landed in open waters, minimizing the risk to populated areas.
Preparing for the aerial observation
The airborne observation mission, known as ROSIE-Salsa, is a joint effort between academic institutions such as the University of Stuttgart and the University of Southern Queensland, along with industrial partners such as Hypersonic Technology Göttingen and Astros Solutions. Led by Jiří Silha, CEO of Astros Solutions, the mission aims to capture real-time data during Salsa’s reentry.
The aircraft will be equipped with more than 20 scientific instruments, including cameras and spectrographs, to observe the satellite’s disintegration and capture detailed information. Despite the challenges posed by the unpredictable nature of the reentry and the remote location, the team is prepared to collect crucial data that could improve future predictions of the satellite’s reentry.
Looking ahead
Salsa’s return marks the beginning of a series of controlled re-entry attempts for the remaining Cluster satellites, with the last one scheduled for 2026. ESA’s commitment to reducing space debris is also demonstrated by its Zero Debris approach, which aims to eliminate the production of space debris by 2030.
In addition to the Cluster mission, ESA is also planning the DRACO mission, which involves an actively controlled reentry of a satellite equipped with a “black box” to provide telemetry data from inside. If successful, this mission could set a new standard for satellite reentry observations and contribute significantly to the safe and sustainable use of space.
