The objective is to monitor the millions of pieces of debris orbiting Earth that could damage satellites, rockets, and the safety of the planet
Alexandre Affonso / Pesquisa FAPESP
Brazil has begun assembling a national information network on space debris. The initiative’s main objectives are to establish a debris monitoring system and to manage the risk of collisions with Brazilian satellites. This will enhance the safety of launches from the Alcântara Space Center in Maranhão and reducing the risk of accidents caused by reentering debris on a collision course with national territory. The network will also cooperate with international space debris monitoring networks. It is estimated that there are more than 130 million objects—most of them millimeters in size—orbiting the Earth.
The first phase will commence once the Aeronautical and Aerospace Engineering Division of the Technological Institute of Aeronautics (ITA) in São José dos Campos has acquired a risk management system and three telescopes. The investment, totaling R$12 million, will come from the Brazilian Funding Authority for Studies and Projects (FINEP).
The ITA is in the process of purchasing the three telescopes, whose lenses measure 40 centimeters (cm) in diameter. The purchase should be made in 2024 if the funds are disbursed on time. According to mechanical engineer Willer Gomes dos Santos, head of the ITA’s Space Object Observation Laboratory (LMOE), they plan to expand the system in the future by acquiring a larger telescope with an aperture of about 1 meter (m) in diameter.
“Telescopes with larger apertures are able to detect fainter space debris. They are also used to identify and characterize objects that have not yet been catalogued,” explains aerospace engineer Carlos Amaral, member of LMOE-ITA and a captain in the Brazilian Air Force (FAB). “Small aperture telescopes, when used in conjunction with larger instruments, are mainly used for preliminary orbit determination. Their data are used to correlate with other objects already catalogued,” he adds.
The three telescopes will focus on observing objects in medium orbits, between 2,000 kilometers (km) and 35,786 km from Earth, and high orbits, above 35,786 km. The latter height defines the so-called geosynchronous orbit, in which a satellite moves through space at the speed of the Earth’s rotation so that it is stationary over a point on the planet’s surface. The Geostationary Satellite for Defense and Strategic Communications (SGDC), for example, operates in this orbit (see Pesquisa FAPESP issue nº 256). “Although not the intended use, the telescopes will also be able to observe objects in low orbit,” explains the captain.
Alexandre Affonso / Pesquisa FAPESP
Once the telescopes have been purchased, installation is expected to take one year. One of the telescopes will be integrated into the Pico dos Dias Observatory, which is part of the National Astrophysical Laboratory (LNA) in Brazópolis, Minas Gerais. The other two will be installed in São Paulo and Goiás.
The risk management system has already been acquired and has been operating since January of this year. Called the GSTT Orbit Guard, it is software developed by the Italian company GMSPAZIO, which uses information collected by telescopes and other sensors, such as radar, to predict and prevent the risk of collisions.
In Brazil, the system operates in two distinct forms, with one information platform at the FAB Space Operations Center in Brasília, which is responsible for monitoring, controlling, and operating Brazilian military satellites. The other platform is installed at LMOE-TIA, which focuses on research, development, and training for the defense sector and the Brazilian aerospace industry.
“We are already processing data from other sensors, such as the ROBO40 automated telescope with a 40-cm diameter lens installed at the LNA,” says Amaral. The equipment is mainly used for astronomical observations—tracking space debris is a secondary activity.
PanEOS Telescope: the only equipment in Brazil dedicated to monitoring space debrisComunicação LNA
Aiming for 15 telescopes The ITA project also envisages monitoring low orbit telescopes, up to an altitude of 2,000 km. Most of Brazil’s 30 active satellites, including the China-Brazilian Earth Resources Satellites (CBERS), the government’s Amazonia 1 (see Pesquisa FAPESP issue nº 300), which uses remote sensing to monitor deforestation and agricultural activity in the Amazon, and the VCUB1 nanosatellite for Earth observation and data collection from Visiona, a joint venture between Embraer Defense & Security and Telebras.
“A good configuration for a national space debris monitoring network should consist of at least 15 dedicated instruments, with different diameters, installed at different locations,” says astrophysicist Wagner Corradi, director of the LNA. “Brazil is very large. We need information collected at different places for good data triangulation, which allows us to correctly determine the objects’ trajectory and speed,” he states. The researcher explains that tracking the trajectory of space debris enables precise satellite maneuvers, thereby helping to avoid potential collisions.
Most of the telescopes dedicated to tracking space debris are located in the northern hemisphere, and there are many observation gaps below the equator. In Brazil, the only instrument dedicated to this task is the Panoramic Electro Optical System (PanEOS), which belongs to the Roscosmos State Corporation for Space Activities (Roscosmos). It has been installed at the Pico dos Dias Observatory since 2017, following an agreement with the Brazilian Space Agency (AEB), and it is co-managed by the Industry Research and Consulting Foundation based in Itajubá (MG).
The instrument, which comprises a series of cameras, is made up of a main telescope with a 75-cm diameter lens, complemented by two 25-cm and two 13.5-cm telescopes. As Corradi explains, Roscosmos determines the focus of PanEOS observations, as it is the recipient of the data collected. “We have full access to the data generated by PanEOS. It is stored and available for anyone to use. But we do not have the prerogative a priori to choose the telescope’s targets. The national network was set up precisely to give us the freedom to choose these targets,” says the LNA director.
The opportunity to use PanEOS allowed Colombian physicist William Humberto Úsuga Giraldo to develop the first Brazilian digital “mask” for detecting space debris in telescope images. It was the subject of his master’s degree in aerospace engineering and sciences at the Federal University of Rio Grande do Norte’s (UFRN) School of Science and Technology in 2022.
The mask consists of a computational process capable of analyzing the telescopic images to filter out and distinguish between space debris and stars in the sky. They are exclusively used for the telescopes for which they have been created. But PanEOS already has Russian masks. According to astrophysicist José Dias do Nascimento Júnior, Giraldo’s master’s thesis advisor, the project paves the way for Brazilian research with PanEOS and provides training to assist Brazilians in developing new masks to read space debris data.
A debris observation telescope at the Paraíba Astronomical and Geospatial Observatory, at Sítio Unha de Gato, near Juazeirinho (PB) is expected to be operational in 2025. The project is the result of an agreement between the State University of Paraíba (UEPB) and the Shanghai Astronomical Observatory in China. The FocusGeo instrument consists of three telescopes with a diameter of 18 cm.
“We are in the process of drawing up the telescope’s operating manual,” says physicist Lourivaldo Mota Lima, from the UEPB’s Physics Department and project coordinator. However, he says, the information collected will belong to the Chinese observatory, which has the discretionary power to make the data available to Brazilian institutions and researchers or to international space debris monitoring systems. “UEPB’s aim is to use the images generated for research once the telescope is operational,” explains Lima. “According to the agreement signed, for the first five years, the images will be available to the researchers involved in the project, both in Brazil and abroad.”
Alexandre Affonso / Pesquisa FAPESP
Millions of pieces of debris in space In addition to operational autonomy, the creation of its own network for monitoring and tracking space debris will give Brazil privileged access to international initiatives that monitor these fragments, such as the US Space Surveillance Network and the European Space Operations Centre. According to Corradi, nations and institutions that share information with international networks have broad access to the data collected by other countries, while those that do not share can only access public data.
In a bulletin published in July 2024, the European Space Agency (ESA) estimated that there are 40,500 pieces of space debris larger than 10 cm, 1.1 million objects between 1 cm and 10 cm, and 130 million pieces of debris between 1 millimeter (mm) and 1 cm in Earth’s orbit. Only 36,860 of the largest objects are regularly tracked and catalogued by space surveillance networks.
Most of the fragments are the result of around 650 collisions, explosions, and ruptures caused by space artefacts, such as the 2009 collision of the defunct Russian satellite Kosmos 2251 with the US satellite Iridium 33, which produced 2,000 pieces of debris larger than 10 cm and thousands of smaller fragments.
“A millimeter-sized object travelling at more than 20,000 kilometers per hour can cause significant damage if it collides with a satellite, a space telescope, or the International Space Station,” says astrophysicist Roberto Dias da Costa, from the Institute of Astronomy, Geophysics, and Atmospheric Sciences at the University of São Paulo (IAG-USP). “A broken satellite can have a significant impact on telecommunications, territorial monitoring, and weather forecasting.”
As far as life on Earth is concerned, space debris has yet to cause any real damage. To date, only one individual, American Lottie Williams, is known to have been struck by space debris—an incident that occurred in January 1997 and resulted in no injury. “There are no records of significant material damage,” says Costa. According to the USP professor, the majority of objects lost in space are relatively small, which causes them to burn up and disintegrate when they enter the Earth’s atmosphere. Larger debris that survives reentry has generally fallen in remote desert or oceanic regions. “But potential risks remain,” he warns.
Casing of the Delta 2 rocket’s engine, which crashed in Saudi Arabia in 2001NASA
Unknown environmental impact One issue that remains insufficiently measured is the impact of space debris on the environment and life on Earth. “This is information that agencies do not disclose,” asserts mathematician Jorge Kennety Silva Formiga, a researcher at the Department of Environmental Engineering at São Paulo State University’s Institute of Science and Technology (ICT-UNESP) in São José dos Campos. “We know that the material reaching Earth contains titanium, aluminum, iron, lead, and other substances. But what is the long-term environmental impact and who is accountable for it?” questions the professor.
The researcher highlights that while it is straightforward to identify who owns and is legally responsible for a rocket or satellite, the situation becomes more complex when dealing with fragments of objects that have exploded or collided with other debris. These fragments, which often collide with other space debris during their trajectory, make it challenging to ascertain clear accountability.
Formiga, along with mathematician Denilson Paulo Souza dos Santos, head of the Department of Aeronautical Engineering at UNESP’s São José da Boa Vista School of Engineering (FESJ), coauthored a mathematical model designed to predict the trajectory of space debris, including reentry dynamics and potential impact points on Earth. “The mathematical model plays a crucial role in debris monitoring, particularly since many objects in orbit are not continuously tracked. […] One potential application of this research is in the collection of space debris, thereby mitigating the challenges posed by the growing accumulation of debris in Earth’s orbits,” they note in an article published in 2021 in the Brazilian Journal of Development.
The duo’s proposal focuses on analyzing the life cycle of space debris, with particular emphasis on satellite fragments. “We aim to study the dynamics of debris following an explosion or collision,” says Santos. After such an event, he notes, a cloud of fragments is generated. The algorithms being developed will track the propagation of this cloud, the trajectories of the objects, and, when necessary, their reentry points into Earth’s atmosphere. “By understanding the entire life cycle of the debris, we will be able to determine its origin, assess its risks, and establish legal responsibility for the resulting waste,” adds Formiga.
With support from FAPESP, the two professors have also proposed a preventive strategy to mitigate the impact of space debris, focusing on maneuvers to alter the objects’ trajectories. This approach would utilize pulses emitted by a ground-based laser system; a technique originally suggested by American physicist Claude Philipps in a 2014 article published in Acta Astronautica.
Formiga and his colleagues developed a mathematical model that incorporates data on the trajectory of space debris and the gravitational forces acting on it to calculate the necessary propulsion from a laser and assess the impact of the laser pulse on the debris’ displacement. The findings were published in The European Physical Journal in 2023. The article demonstrates that a laser pulse can induce a slight change in the debris’ velocity, thereby altering its reentry path into the atmosphere and preventing potential collisions.
The story above was published with the title “Trash in Earth’s orbit” in issue 346 of December/2024.
Projects 1. Space debris: Life cycle analysis and preventive mitigation (nº 23/01391-5); Grant Mechanism Regular Research Grant; Principal Investigator Denilson Paulo Souza dos Santos (UNESP); Investment R$46,497.07. 2. Space debris mitigation: Dynamics based on maneuvers combined with ground-based laser and space blower propulsion (nº 22/13228-9); Grant Mechanism Regular Research Grant; Principal Investigator Jorge Kennety Silva Formiga (UNESP); Investment R$48,123.46.
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