A European satellite named Envisat, launched in 2002, has been drifting in low Earth orbit since April 8, 2012, without responding to signals from Earth. Envisat, which was used for observing Earth, was the largest satellite of its time, weighing 8.2 tons and measuring about 25 meters in length. It was officially declared out of commission in May 2012 after a power supply failure, though the exact cause of the failure remains unknown.
Envisat is currently orbiting at an altitude of 768 kilometers, a height where it will not naturally reenter Earth's atmosphere for about 150 years, potentially until 2160–2170. This has raised concerns among experts, as the satellite's long stay in orbit increases the risk of collision with other spacecraft. Such a collision could trigger a Kessler syndrome—an event where a chain reaction of collisions creates thousands of new debris fragments, making space more hazardous for future missions.
The satellite follows a polar orbit, which means it frequently passes over the Earth’s poles and crosses paths with many active satellites. Due to its high speed—over 25,000 kilometers per hour—Envisat comes within less than 200 meters of two cataloged objects each year. This close proximity, though brief, highlights the potential dangers of its uncontrolled movement in a crowded orbital region.
The European Space Agency (ESA) had explored the e.Deorbit project, which aimed to use a specialized spacecraft to capture Envisat and guide it into a controlled reentry. However, the project was eventually abandoned due to technical and financial difficulties. Other proposed solutions, such as robotic arms, capture nets, and ground-based lasers, have not yet been tested on a satellite as large as Envisat. The International Institute of Space Law has criticized the ESA for not foreseeing the long-term risks of Envisat's uncontrolled orbit. This situation underscores the growing need for better strategies to manage space debris and develop reliable methods for safely removing defunct satellites from orbit.
European Space Agency's Envisat Satellite Remains Uncontrolled in Orbit Decades After Failure
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