The 10 Largest Spacecrafts to Crash Back to Earth

Proton 4 was the heaviest of four Proton satellites launched by Russia from 1965 to 1968, all of which crashed back to earth at unknown locations. The Proton program launched research satellites and is considered to have played a key role in heralding a new era of Soviet space exploration.

The Saturn SA-5 was part of the U.S. Apollo program, an orbital test rocket wielding a Jupiter nose cone containing measuring instruments instead of the Apollo command module that would later be used to send American astronauts into space. The Saturn SA-5 orbited for nearly 800 days before decaying into an uncontrolled re-entry.

Part of the Russian Salyut space station program that put six crewed stations in orbit from 1971 to 1986, Kosmos 557 was later revealed to be a code name for a Salyut program station that failed to reach a stable orbit due to errors in the flight control system. Despite this failure, the Salyut program became another achievement for Russia’s space program, as it was the first to put a crewed space station in orbit.

CZ-5B-Y3 was the most recent of three uncontrolled reentries of massive Chinese Long March B core rocket stages that have plunged back to earth since 2020. In an indirect reference to China’s unwillingness to share data on the rocket’s descent trajectory, NASA Administrator Bill Nelson urged nations with space programs to “do their part to share this type of information in advance to allow reliable predictions of potential debris impact risk…to ensure the safety of people here on Earth.”

CZ-5B-Y2 is the second of three massive Chinese Long March 5B rocket stages to have crashed uncontrollably to earth since 2020 after re-entering the atmosphere above the Arabian Peninsula. Long March 5B missions have been sending payloads to China’s Tiangong space station, which is expected to be online by the end of the year.

The CZ-5B-Y1 Long March 5B core rocket stage became the heaviest object to plunge to earth in an uncontrolled manner since the 39-ton Soviet Salyut 7 space station rained debris over Argentina in 1991. Fragments from the rocket stage fell onto at least two villages in the West African country of Ivory Coast, though no injuries were reported. All three Long March 5B rocket missions have involved uncontrolled reentries of massive rocket stages.

After nine years in orbit, the Soviet space station Salyut 7 with an attached Kosmos 1686 unmanned spacecraft became at the time the largest spacecraft to plunge back to earth. Efforts by Soviet engineers to guide the de-crewed Salyut-7/Kosmos-1686 complex into the Atlantic Ocean in a controlled descent failed. The space station complexes broke up on its descent, showering debris near the Argentinean town of Capitán Bermúdez.

The massive S-II rocket stage was part of the modified Saturn V rocket that put Skylab, the first U.S. space station, into orbit. After circling the planet for nearly two years, the S-II made an uncontrolled re-entry over the North Atlantic near the Portuguese autonomous region of Madeira, an archipelago about 320 miles west of Morocco.

Skylab was the first U.S. space station, designed as a low-orbit scientific research output. Though it was initially designed to last years, the station was crewed for only a few months in 1973 and 1974. By 1978, Skylab’s orbit was decaying, and due to budget constraints NASA had failed to build any control mechanisms for a controlled re-entry. A Hail Mary attempt to force the station to tumble into the Indian Ocean by strategically firing its booster rockets almost worked, but some of the debris landed in western Australia.

The Space Shuttle Columbia is the heaviest spacecraft to have plunged back from orbit, also the only one that cost lives. (The NASA Space Shuttle Challenger explosion of 1986 occurred during takeoff.) All seven crew members were killed when Columbia exploded over Louisiana and east Texas. The cause of the disaster was later linked to a piece of foam insulation that had broken off the shuttle’s propellant tank during the shuttle’s descent to Kennedy Space Center. The shuttle was in a controlled descent until it broke apart, but the consequences — raining space debris on land — were similar to uncontrolled crashes.