Introduction.
In February 2025, the residents of western Poland could see a bright object streak across the night sky. It was not a meteor, but the uncontrolled re-entry of the upper stage of a SpaceX Falcon 9 rocket, which had failed to perform its planned deorbit burn over the ocean. As it passed through the atmosphere, the stage broke apart, and parts of it reached the ground, landing near a warehouse outside the city of Poznań.
No harm was done, but the event illustrated a challenge that is becoming increasingly common. The space around Earth is more congested than ever before, with modern societies relying more on space technologies for navigation, communications, weather forecasting, financial services, and national security. As the number of objects in orbit continues to grow, so too does the importance of understanding how this environment is monitored, managed, and kept safe.
A Crowded Orbit: The Growing Problem of Space Debris.
According to the publicly available U.S. Space Surveillance Network catalogue, summarised by CelesTrak, around 34,300 objects are currently tracked in Earth orbit. Roughly half of these are active satellites, while the remaining half consists of space debris: defunct satellites, spent rocket stages, and numerous fragments left behind by explosions or collisions. However, these are only the objects large enough to be routinely tracked. The European Space Agency estimates that there may be around 1.2 million debris fragments larger than 1 cm, and around 130 million larger than 1 mm, orbiting the Earth. Travelling through space at approximately 7.5 km/s, even these small fragments can cause significant damage when striking operational spacecraft.
Objects in low Earth orbit, a few hundred kilometres above the surface where traces of the atmosphere are still present, gradually lose altitude and eventually re-enter the atmosphere after months or years in orbit. Smaller objects burn up completely during re-entry, but larger ones, built from heat-resistant materials, can survive the descent and reach the ground. This has happened, for example, with the remains of the Chinese Jielong-3 rocket, which fell in a mining region of Western Australia – an event like the one observed in Poland. Predicting precisely where and when such objects will fall is of high importance for public safety and crisis management. Yet the process remains highly uncertain. In 2022, during the uncontrolled re-entry of a Chinese Long March 5B (CZ-5B) rocket stage, Spain temporarily closed part of its airspace while the object passed overhead shortly before re-entering the atmosphere.
When Space Junk Comes Back to Earth.
Before they return to Earth, however, these objects also pose a threat to the active satellites in orbit – the ones that modern societies increasingly depend on. As orbital congestion grows, especially with the development of mega-constellations like Starlink, the number of close approaches requiring assessment continues to rise. The International Space Station, which operates under particularly stringent safety criteria because it carries astronauts, received nearly 1,500 close-approach alerts in 2022 alone, although only a small fraction required evasive action. Each such manoeuvre consumes fuel, reducing the spacecraft’s operational lifetime.
Protecting the Satellites We Depend On.
The situation is different at higher altitudes, where there is effectively no atmosphere. This is where navigation satellites orbit at around 20,000 km above the Earth, and geostationary communications satellites at approximately 36,000 km. Although these regions contain fewer catalogued objects and offer much more space, debris remains a significant concern, particularly because detecting and actively tracking small objects at such distances is considerably more challenging.
Without atmospheric drag, objects in these higher orbits remain there effectively forever, unless deliberately moved. Bringing large satellites back to Earth would require substantial amounts of fuel and would be highly expensive. The current solution is therefore to relocate retired satellites to so-called graveyard orbits, typically around 300 km above the operational orbital regime. While this reduces the immediate risk to active spacecraft, it is only a temporary solution that postpones rather than eliminates the problem.
Higher Orbits, Permanent Problems.
Orbital debris is not the only challenge. Space has now been recognised by NATO as an operational domain alongside land, sea, air, and cyberspace. The Secure World Foundation regularly assesses the capabilities of different states to conduct hostile activities in space. These include anti-satellite missile attacks, electromagnetic interference such as GPS jamming, and the interception of satellite communications. Much of today’s space technology is dual-use technology: the same satellites that support navigation, communications, and scientific research also provide capabilities of military value. Technologies developed for on-orbit servicing – including rendezvous, inspection, docking, and satellite relocation – have clear civilian applications, such as debris removal and satellite servicing. At the same time, the same capabilities could be used to interfere with or disable another nation’s spacecraft.
Space Security in an Era of Dual-Use Technology.
In view of all these challenges, how can the security and sustainability of space infrastructure be maintained? The first requirement is effective monitoring. Whether an object is an operational satellite or a piece of debris, accurate information about its orbit, size, and physical characteristics is essential for protecting space assets. The publicly available U.S. Space Surveillance Network catalogue provided through Space-Track.org enables satellite operators and space agencies worldwide to assess collision risks and determine whether avoidance manoeuvres are necessary. Europe is developing complementary capabilities through the EU SST Partnership, which combines observations from participating states into a common catalogue of orbital objects. At the same time, an increasing number of commercial companies – such as LeoLabs, Slingshot Aerospace, and ExoAnalytic Solutions – provide tracking data and related services on the global market.
Can We Clean Up Earth’s Orbit?
Efforts to actively remove debris from orbit also provide reasons for cautious optimism. ESA’s ClearSpace-1 mission aims to capture a large piece of debris in low Earth orbit and guide it into a controlled re-entry. Meanwhile, JAXA’s ADRAS-J2 mission, following the earlier ADRAS-J mission, is designed to inspect a spent rocket stage, assess its condition and attitude, capture it with a robotic arm, and ultimately enable its safe disposal.
Considerable progress has been made in recent years. Our ability to detect and track objects in orbit continues to improve, predictions of uncontrolled re-entries are becoming more accurate, and active debris-removal missions such as ESA’s ClearSpace-1 and JAXA’s ADRAS-J2 represent important first steps towards reducing the existing population of large debris. International guidelines are also becoming more stringent, with satellites now expected to leave protected orbital regions within five years of the end of their missions rather than twenty-five.
Nevertheless, the overall trend remains concerning. The number of new satellites placed into orbit, together with fragments produced by collisions, explosions, and satellite break-ups, still exceeds the rate at which debris can be removed. As humanity’s dependence on space-based infrastructure continues to grow, preserving the orbital environment becomes increasingly important. Near-Earth space is not an unlimited resource but a shared environment whose long-term sustainability will depend on continued investment in monitoring, responsible operations, and effective debris mitigation.
References:
- European Space Agency (ESA). (2026). ESA’s Annual Space Environment Report 2026. ESA Space Debris Office. [Online] Available at: https://www.sdo.esoc.esa.int/environment_report/Space_Environment_Report_latest.pdf
- Secure World Foundation. (2026). Global Counterspace Capabilities Report. [Online] Available at: https://swfound.org/counterspace/
- Current Catalogue Statistics (Boxscore). https://celestrak.org/satcat/boxscore.php (accessed 30 June 2026).
- Dossett, J. (2025, February 20). SpaceX Falcon 9 rocket debris creates dramatic fireball over Europe, crashes in Poland (video).com. https://www.space.com/space-exploration/launches-spacecraft/spacex-falcon-9-rocket-debris-creates-dramatic-fireball-over-europe-crashes-in-poland (accessed 30 June 2026).
- Jones, S. (2022, November 4). Spanish airspace partially closed as Chinese rocket debris falls to Earth. The Guardian. https://www.theguardian.com/world/2022/nov/04/spanish-airspace-partially-closed-as-chinese-rocket-debris-falls-to-earth (accessed 30 June 2026).
- ABC News. (2025, October 20). Space junk from Chinese Jielong rocket found near Newman mine in Western Australia. ABC News. https://www.abc.net.au/news/2025-10-20/space-junk-chinese-rocket-jielong-newman-bhp-iron-ore/105912162 (accessed 30 June 2026).
- Federal Communications Commission (FCC). (2022, September 29). FCC adopts new 5-year rule for deorbiting satellites. https://www.fcc.gov/document/fcc-adopts-new-5-year-rule-deorbiting-satellites-0 (accessed 30 June 2026).
Bio:
Dorota Mieczkowska is a PhD candidate at The University of Western Australia in the School of Physics, Mathematics and Computing. Before moving to Australia, she worked at the Polish Space Agency, where she helped monitor satellites and analyse objects falling back to Earth from space.
Her research now focuses on space debris – the growing amount of “space junk” orbiting our planet. As part of a collaboration between UWA and the Polish Space Agency, she studies debris and satellites using telescopes at Zadko Observatory in Western Australia, helping us better understand and protect the space environment.
You may contact Dorota at: https://www.linkedin.com/in/dorota-mieczkowska-869687117