Defunct Satellite Set to Crash to Earth After 16 Years in Space
After 16 years of operation, the European Space Agency’s (ESA) Heritage ERS-2 satellite is expected to crash back to Earth this month. Although there is a possibility of debris landing on land, the odds are that it will most likely fall into a body of water. Launched in 1995 as the successor to the ERS-1 satellite, the ERS-2 completed its mission in September 2011. During its operational years, the satellite played a crucial role in tracking various environmental changes on Earth.
The primary purpose of the ERS-2 satellite was to monitor the Earth’s polar ice, shifting land masses, rising sea levels, warming oceans, and changing atmospheric chemistry. However, since its retirement, the ESA has been gradually lowering its altitude to reduce the risk of collision with other satellites or space debris. The agency’s maneuvers have successfully depleted the satellite’s fuel and lowered its average altitude from 785 km (488 miles) to approximately 573 km (356 miles), ensuring a controlled reentry into Earth’s atmosphere within 15 years.
One notable aspect of the ERS-2 satellite is its size. Compared to other space debris, it is enormous, measuring as long as a city bus and weighing over 5,000 pounds. Currently, the satellite is at such a low altitude that it is susceptible to rapid descent due to atmospheric forces. However, since it no longer has fuel, the ESA cannot control its trajectory through engine burns.
As the ERS-2 satellite enters Earth’s atmosphere, it is expected to disintegrate at an altitude of about 50 miles above the surface. While some debris may crash onto land, the ESA predicts that the majority of it will likely land in one of Earth’s oceans, considering that water covers approximately 70% of the planet’s surface.
The issue of space junk, also known as orbital debris, has become a growing concern. This includes defunct satellites like the ERS-2, as well as small fragments of rockets or satellites and even human waste from space missions. Over the past three decades, the number of objects in Earth’s orbit has significantly increased. The European Space Agency reports that the majority of untracked space debris is smaller than 0.4 inches wide.
It is worth noting that space junk encompasses more than just missiles and satellites. Some of the more peculiar items include discarded tools, spent rocket stages, and even a lost glove. Since the beginning of the space age in the 1950s, humanity has launched nearly 50,000 tons of material into space. Approximately 10,000 tons of this material remains in orbit, according to data from the U.S Space Surveillance Network.
Out of the 16,990 satellites launched into space since 1957, around 9,000 of them are still operational as of December 2023. These satellites continue to orbit the Earth at high speeds. The chart below illustrates the number of objects cataloged in Earth’s orbit by the Space Surveillance Network.
As the defunct ERS-2 satellite prepares for its final descent, scientists and space agencies worldwide are closely monitoring its trajectory and potential impact. While the odds favor a splashdown in the ocean, the situation serves as a reminder of the growing issue of space debris and the need for responsible space exploration and debris management.
