Three Chinese astronauts have safely returned to Earth after a nine-day delay caused by space debris damaging their original spacecraft. The incident has left the new crew aboard the Tiangong space station temporarily without a viable return vehicle, highlighting the growing risks of orbital debris for all space missions.
The Shenzhou-20 crew, who had completed a six-month mission, landed in Inner Mongolia on Friday. They were forced to use the recently arrived Shenzhou-21 capsule for their journey home after their own vessel was deemed unsafe following a collision with an unknown object in orbit.
Key Takeaways
- Three Chinese astronauts from the Shenzhou-20 mission returned to Earth nine days behind schedule.
- Their original Shenzhou-20 capsule was damaged by space debris, causing "tiny cracks" in a window.
- The crew used the Shenzhou-21 spacecraft for their return, leaving the new crew on the Tiangong space station without a return vehicle.
- China's space agency will launch a new rescue spacecraft, Shenzhou-22, to serve as a lifeboat for the stranded crew.
- The event underscores the increasing danger that orbital debris poses to all spacefaring nations.
An Unexpected Return and a New Dilemma
The Shenzhou-20 crew touched down at the Dongfeng landing site at 4:40 p.m. local time, concluding a mission that began in April. Their return was originally planned for November 5, but ground controllers detected an issue with their spacecraft during final checks.
Officials from the China Manned Space Agency (CMSA) later confirmed the cause. The Shenzhou-20's return capsule had sustained damage from a collision with space debris. The impact resulted in small cracks forming in one of the capsule's windows, compromising its structural integrity for the intense heat and pressure of atmospheric reentry.
A Logistical Challenge in Orbit
Standard procedure for China's space program involves an in-orbit handover. The departing crew welcomes their replacements, and for several days, two Shenzhou spacecraft are docked to the Tiangong station. This overlap provides redundancy, but the damage to Shenzhou-20 disrupted this carefully planned sequence.
With the Shenzhou-20 capsule declared unfit for travel, the decision was made for the returning astronauts to use the Shenzhou-21, which had brought their replacements to the station just two weeks prior. While this ensured a safe return for the outgoing crew, it created a significant logistical problem: the three astronauts who recently arrived on Tiangong are now in orbit without a designated lifeboat.
The CMSA has announced that it will launch an unmanned Shenzhou-22 spacecraft at a future date to dock with the station and serve as the new crew's return vehicle. Until its arrival, the Shenzhou-21 crew remains on the station without an immediate means of emergency escape.
The Growing Threat of Space Junk
This incident is a stark reminder of the escalating danger posed by orbital debris, often called "space junk." Decades of space activity have left a cloud of defunct satellites, spent rocket stages, and fragments from past collisions circling the Earth at high speeds.
Even a tiny object, like a paint fleck, can cause catastrophic damage when traveling at orbital velocities, which can exceed 17,500 miles per hour (28,000 kilometers per hour).
A Crowded Sky
Estimates suggest there are hundreds of thousands of pieces of debris large enough to damage or destroy a satellite or spacecraft. The sudden breakup of an old Russian satellite last year created at least 180 trackable pieces, while a spent Chinese rocket stage generated nearly 1,000 pieces of junk after a suspected collision.
The problem is not unique to China. The International Space Station (ISS) has had to perform dozens of avoidance maneuvers over the years to steer clear of debris. SpaceX's Dragon capsules, which ferry NASA astronauts, have also had to dodge potential threats during flight.
"Due to the sharp increase in orbital debris, the likelihood of damage to spacecraft and space stations of all countries has risen significantly," explained Igor Marinin, a member of the Russian Academy of Cosmonautics.
The incident has renewed calls for greater international cooperation between space powers, including the United States and China, to track debris and establish traffic management rules for orbit. While U.S. law largely prohibits direct collaboration between NASA and China's space program, some informal coordination on space safety has reportedly increased in recent years.
A Test for China's Space Program
The Shenzhou-20 debris strike marks a rare and highly public challenge for China's otherwise remarkably successful manned space program. The program, known as Shenzhou or "Divine Vessel," has achieved major milestones in recent years, including the completion of its permanent Tiangong space station and plans to send international astronauts into orbit.
The situation mirrors a recent incident involving American astronauts. Last year, two NASA astronauts were stranded on the ISS for nine months after their intended ride home, a Boeing Starliner spacecraft, experienced propulsion system issues.
China's ability to respond by preparing and launching the Shenzhou-22 rescue mission will be a critical test of its operational flexibility and emergency protocols. The successful and safe return of the Shenzhou-20 crew demonstrates the program's resilience, but the grounding of their original capsule serves as a powerful warning that the hazards of orbit are a shared risk for all who venture into space.