Failed Soviet-era spacecraft appears to have crashed back to Earth overnight

Cosmos 482, the Soviet probe that was supposed to land on Venus but ended up stuck in Earth's orbit for decades, appears to have crashed back to Earth in the early hours of Saturday morning.

The European Space Agency reports that the lander "was not spotted by radar over Germany at the expected" during an anticipated pass at 3:32 am ET. They concluded that "it is most likely that the reentry has already occurred."

The location and exact time of the landing are still uncertain. Other satellite tracking stations have not provided updates on potential landing sites as of Saturday morning.

In March of 1972, the Soviet Union launched the probe that was supposed to land on Venus. It was part of the country's ongoing Venera program (Venera is Russian for Venus). Ten probes would eventually make their way to the surface of the second planet from the Sun. One lander only survived 23 minutes in the harsh 900-degree Fahrenheit environment, while another lasted two hours. Photos beamed back to Earth showed a barren and rocky landscape and a sky of yellow, likely made up of sulfur.

But Cosmos 482 never escaped Earth's orbit. A technical problem believed to be a failure of the rocket's upper stage left it stuck in an elliptical orbit around Earth. That orbit has been slowly decaying over the last 50-plus years. And because it was built to survive Venus' harsh atmosphere and environment, there were concerns that it could come down in one big piece.

The lander, which was about 3.3 feet wide and weighed 1,190 pounds, may have landed in the ocean, as 70% of the planet is covered in water

The European Space Agency (ESA) says the risk of being hurt by space debris is under one in 100 billion. In comparison, the agency says a person is about 65,000 times more likely to be struck by lightning. The ESA says more than 1.2 million pieces of debris are orbiting the Earth, with 50,000 larger than 4 inches across.

Cosmos 482, launched in 1972 as part of the Soviet Union's Venera program, which intended to explore Venus, is forecasted to return to Earth around 2:30 a.m. ET, plus or minus four hours, according to SatTrackCam Leiden, a satellite tracking station in Leiden, the Netherlands. Estimates from The Aerospace Company and the European Space Agency indicate similar timings for reentry.

As of Thursday, the landing location was estimated to be anywhere between 52 N and 52 S latitude, according to NASA. This large swath contains the United States, as well as most of the continents on Earth.

Since 70% of the planet is covered with water, it’s likely the probe will land in the ocean but there is a small chance it could hit a populated area.

The craft is about 3.2 feet across and weighs about 1,190 pounds.

"No need for major concern, but you wouldn't want it bashing you on the head," McDowell wrote.

Cosmos 482 experienced a successful initial launch on March 31, 1972, and temporarily orbited Earth.

However, the unmanned spacecraft did not achieve sufficient velocity to launch into a Venus transfer trajectory, NASA said, and the payload -- or the portion of the craft significantly related to the craft's primary mission -- was unable to exit Earth's orbit.

Astronomers hypothesize that a malfunction on a timer caused the engine to burn prematurely, NASA said.

The spacecraft separated into four pieces. Two of the pieces, which remained in low orbit, decayed within 48 hours. Orbital decay refers to an incremental decrease in altitude, gradually closing a craft's distance to Earth, according to NASA.

The other two pieces -- including the large lander probe -- became stuck in Earth's higher orbit. It has experienced orbital decay for decades, NASA said, and that decay has brought it close enough to reenter the planet's atmosphere around May 10.

Because the probe was designed to withstand entry into Venus' atmosphere -- which is 90 times denser than Earth's -- it is possible that parts of it could survive reentry and continue onward to the planet's surface, according to NASA.

Astronomers are increasingly monitoring space junk left near Earth during launches of satellites and other spacecraft. There are currently more than 1.2 million known pieces of space debris, 50,000 of which measure more than 4 inches across, according to a 2025 report by the European Space Agency.

"Even if we created no new space debris, it would not be enough to prevent a runaway series of collisions and fragmentations," the ESA said in a statement.

ABC News' Matthew Glasser contributed to this report.