The Soviet probe 'Cosmos 482' crashed in the Indian Ocean after going out of control half a century ago.

The Soviet probe Cosmos 482 has finally fallen to Earth. After wandering in Earth orbit for more than half a century, the craft, launched in 1972 as part of a mission to Venus, re-entered the atmosphere this Saturday and, according to Roscosmos, the Russian space agency, crashed into the Indian Ocean shortly before 8:30 a.m. (Spanish time). In a Telegram message, the Russian agency indicated that, according to calculations by specialists at the Russian Rocket and Space Center TsNIIMash, part of Roscosmos, the craft entered the atmosphere at 9:24 a.m. Moscow time (one hour behind in mainland Spain), “560 kilometers west of the Middle Andaman Island, and fell into the Indian Ocean, west of Jakarta.” The European Union's Space Surveillance and Tracking Operations Centres have also confirmed that, according to their analysis , the probe disintegrated within a time window that coincides with the time indicated by the Russian agency.

The world's major space agencies were monitoring the uncontrolled reentry of the Soviet probe Cosmos 482. For days, and although predictions have been refined as the planned date approached, uncertainty about the exact location and time of re-entry has remained high until the very last moment. A few minutes after 8:00 a.m. this Saturday, the radars of the European Space Agency's (ESA) Space Debris Office detected the craft over Germany. According to their forecasts, it should have returned to fly over Germany around 9:30 a.m., but the radars picked up nothing. "Given that the craft was not detected by radar over Germany at the expected time of 9:32 a.m. [Spanish Peninsular Time], it is very likely that re-entry has already occurred," the European agency reported in a blog post where they were monitoring the re-entry.

The Soviet probe Cosmos 482 is a device launched 53 years ago that never reached its destination: Venus. This is the main reason why the fall of this piece of space junk to Earth is special. The craft was designed to withstand the enormous pressures of the atmosphere of the hottest planet in the solar system, so it could survive in one piece its reentry into Earth's atmosphere, scheduled for early Friday morning.

A few days ago, the monitoring protocol of the International Committee for Space Debris Coordination was activated. This organization represents 13 space agencies, including the ESA, its US counterpart, NASA, as well as agencies from the United Kingdom, France, Italy, Russia, Ukraine, China, and Japan, among others. Although all are members of the committee, the exchange of information between some of them is practically nonexistent. Russia, for example, has not provided data for some time, although its radars keep a detailed track of space objects that periodically fall to Earth. The largest source of information for the Western world comes from NASA with its radar network, although both ESA and some European agencies have their own instruments.

The uncontrolled probe completes one orbit of the Earth every hour and a half. Each radar can observe this object about four times a day and estimate when and where it will fall. The problem is that it is very difficult to predict this object's behavior in the layers of the atmosphere between 100 and 200 kilometers above sea level. Added to this is the uncertainty of solar activity and other unknown factors, such as whether the capsule has a parachute, and whether it will deploy, or if it has already done so, explains engineer Benjamín Bastida Virgili, who works at ESA's Space Debris Monitoring Service in Darmstadt, Germany. All these factors mean that the margin of error in the fall date was almost a day earlier or later, and that almost the entire Earth was within the fall trajectory.

Cosmos 482 was launched in March 1972. It never managed to escape low-Earth orbit. After reaching a parking orbit around Earth, the craft apparently attempted to launch itself onto a transfer trajectory to Venus. However, it separated into four parts: two of them remained in low-Earth orbit and decayed within 48 hours, while the other two pieces, presumably the lander and the separated upper stage engine unit, entered a higher orbit between 210 and 9,800 kilometers from Earth, according to NASA . A glitch is believed to have caused the engine ignition to fail to reach the speed needed for the transfer to Venus, leaving the payload in this elliptical Earth orbit that has been decaying over time until it falls away in the coming days.

The 495-kilogram lander was designed to withstand 300 times the acceleration of Earth's gravity and a pressure 100 times that of our planet, ESA explains. As a result, it could survive re-entry into the atmosphere.

Space agencies have embraced reentry as a valuable experiment. The craft's aerodynamic shape makes it an ideal object for measuring air density in very low Earth orbits. Each time the elliptical orbit passes through perigee, its closest point to Earth, it loses altitude at apogee, its highest point. This difference in altitude allows us to infer the atmospheric drag the object faces right up until reentry. The design of most spacecraft is too complex for such studies, but the descent capsule's nearly spherical shape makes it possible, turning its reentry into an "accidental" scientific experiment.

The fall of large pieces of space debris is common. Moderately sized rocket parts re-enter almost daily, while smaller, tracked pieces of space debris do so even more frequently. The surviving pieces rarely cause damage to the ground. With increasing space traffic, the frequency of these re-entries is expected to increase in the future.

The risk of injury from satellite reentry is extremely small, ESA explains. The annual risk of a person being injured by space debris is less than 1 in 100 billion.