In 2023, the National Aeronautics and Space Administration (NASA) released the 16th edition of its comprehensive report titled “History of On-orbit Satellite Fragmentations.” This extensive document, compiled by the Orbital Debris Program Office, provides a detailed account of all known satellite breakups and anomalous events that have occurred in Earth’s orbit since the dawn of the space age.
Overview of Satellite Fragmentations
As of May 1, 2022, the report identifies a total of 268 fragmentation events and 87 anomalous events that have contributed to the growing population of orbital debris. These incidents have resulted in a 21% increase in the number of cataloged space objects since the previous edition of the report, which had a cut-off date of July 4, 2018. The number of on-orbit objects has seen a staggering 34% increase during this period.
The report highlights several significant events that have had a profound impact on the orbital debris environment. These include the intentional destruction of the Fengyun-1C spacecraft by China in 2007, the accidental collision between the Iridium 33 and Cosmos 2251 satellites in 2009, and the recent anti-satellite (ASAT) tests conducted by India in 2019 and Russia in 2021.
Causes and Consequences of Fragmentations
Satellite fragmentations can occur due to various reasons, such as propulsion system malfunctions, deliberate actions, and collisions. These events can instantly increase the Earth’s satellite population and pose significant risks to operational spacecraft. The debris generated from these fragmentations can remain in orbit for years, if not decades, depending on the altitude of the event.
The report emphasizes the need for responsible space operations and the implementation of debris mitigation measures. It acknowledges the efforts made by space-faring organizations to mitigate known causes of breakups, such as the Delta second stage failures and the Cosmos 862-type events.
Specific Fragmentation Events
The report provides detailed information on each identified satellite fragmentation event. Some notable examples include:
- Transit 4A Rocket Body (1961-015C): This was the first known satellite fragmentation, occurring on June 29, 1961. The Ablestar stage broke up approximately 77 minutes after successfully deploying three payloads. The event was likely caused by the explosion of residual hypergolic propellants on board. The fragmentation produced 317 cataloged debris, of which 193 remain in orbit.
- Fengyun-1C (1999-025A): On January 11, 2007, China intentionally destroyed its Fengyun-1C weather satellite in an ASAT test. The event occurred at an altitude of 865 km and created over 3,000 pieces of trackable debris, making it the worst fragmentation event in history in terms of debris generation. As of May 2022, 2,786 debris from this event remain in orbit, posing long-term risks to spacecraft operating in low Earth orbit.
- Iridium 33 and Cosmos 2251 Collision (1997-051C and 1993-036A): On February 10, 2009, the operational Iridium 33 satellite collided with the defunct Russian Cosmos 2251 satellite at an altitude of 789 km. This was the first accidental hypervelocity collision between two intact spacecraft. The collision generated over 2,000 pieces of trackable debris, of which 1,668 remain in orbit as of May 2022.
- Microsat-R (2019-006A): India conducted an ASAT test on March 27, 2019, intentionally destroying its Microsat-R satellite at an altitude of 300 km. The test generated approximately 400 pieces of debris, most of which have since reentered the atmosphere due to the relatively low altitude of the event. However, the test raised concerns about the long-term sustainability of the space environment and the potential for debris generation from such tests.
- Cosmos 1408 (1982-092A): On November 15, 2021, Russia conducted an ASAT test against its defunct Cosmos 1408 satellite, which was orbiting at an altitude of approximately 480 km. The test generated a large debris cloud, with over 1,500 trackable fragments cataloged to date. The debris poses a significant threat to spacecraft operating in low Earth orbit, including the International Space Station, which had to maneuver to avoid potential collisions.
Cataloging Challenges and Limitations
The report also discusses the challenges associated with detecting, identifying, and cataloging debris from fragmentation events. The sensitivity of the Space Surveillance Network (SSN) varies depending on the altitude and inclination of the satellites, leading to inconsistencies in the historical record. Additionally, the cataloging of debris from highly elliptical orbits and deep space events may be limited due to the SSN’s coverage and capabilities.
Environmental Impact and Future Outlook
The orbital debris environment continues to evolve, with new sources of fragmentations emerging as older ones are mitigated. The report underscores the importance of international collaboration and the development of guidelines and best practices to ensure the long-term sustainability of space activities.
As the space industry continues to grow, with the deployment of large constellations and increased human presence in space, it is crucial to address the challenges posed by orbital debris. The “History of On-orbit Satellite Fragmentations” report serves as a valuable resource for policymakers, researchers, and space operators in understanding the current state of the orbital debris environment and informing future mitigation strategies.
The report also highlights the need for continued research and development of technologies to improve space situational awareness, debris tracking, and active debris removal. As the number of satellites in orbit continues to grow exponentially, it is essential to develop and implement effective measures to minimize the generation of new debris and mitigate the risks posed by existing debris.
Furthermore, the report emphasizes the importance of international cooperation and the establishment of global standards and guidelines for responsible space operations. The United Nations Committee on the Peaceful Uses of Outer Space (COPUOS) has been working on developing guidelines for the long-term sustainability of outer space activities, which include measures to mitigate the creation of orbital debris and promote responsible space behavior.
Conclusion
The “History of On-orbit Satellite Fragmentations” report provides a comprehensive overview of the challenges posed by orbital debris and the efforts being made to address them. As we continue to explore and utilize space, it is crucial that we do so in a sustainable and responsible manner, ensuring that the benefits of space activities can be enjoyed by future generations.