Chinese astronauts have installed protection against space junk aboard the permanently inhabited station Tiangong, according to China’s manned spaceflight authorities, a month after a docked vessel was damaged for the first time.
Early last month, a tiny piece of debris traveling at high velocity cracked the window of the Shenzhou-20 spacecraft’s return capsule, just before the vessel was set to leave Tiangong carrying a trio of Chinese astronauts back to Earth. The damage was deemed severe enough that China’s space authorities made the unprecedented decision to delay the return and send the crew back on the only other available vessel, the Shenzhou-21, triggering the country’s first emergency launch mission.
The Shenzhou-21 crew was left without a flightworthy vessel for 11 days. The entire saga, unprecedented for China’s rapidly advancing space program, highlighted the risks posed by space debris to countries aiming to explore and eventually colonize the reaches beyond Earth.
Eight-hour spacewalk installs protection
According to state media network CGTN, astronauts Zhang Lu and Wu Fei endured an eight-hour spacewalk earlier this week to install debris protection panels on the space station’s outer hull. Using Tiangong’s robotic arm, they mounted the countermeasures while also performing an inspection of the station’s exterior and other minor repairs.
The astronauts also inspected and photographed the damaged window of the Shenzhou-20 spacecraft, which remains docked at Tiangong, waiting to be sent back uncrewed to a landing site in China for further examination. According to the China Manned Space Engineering Office, the vessel’s cracked window could be reinforced by the Shenzhou-21 crew on future spacewalks.
Emergency mission delivers new return vessel
The China Manned Space Agency pulled off an impressive feat following the damage discovery, launching an uncrewed emergency flight to Tiangong in under two weeks. The crew who arrived aboard the Shenzhou-20 had to use the Shenzhou-21 craft to return, leaving the newly-arrived crew without a return vehicle. The emergency flight successfully delivered a new return vessel, the Shenzhou-22, which presumably carried the debris protection materials.
Growing threat from orbital debris
Orbital debris has become a major issue for space agencies worldwide. The disintegration of old, defunct satellites, mishaps with active ones, and anti-satellite weapon tests create vast fields of space debris that remain in orbit for years.
Your average piece of space junk can travel as fast as 15 km per second, or over 10 times the speed of a bullet on Earth. With over 25,000 tracked pieces of space garbage floating about and as many as 170 million bits too small to track, this combination could prove deadly for manned space missions.
Traditional and emerging solutions
For decades, space agencies have used barriers called Whipple shields to protect vehicle hulls from impact. These are incredibly bulky, however, and have a tendency to break into “secondary debris” on impact with space junk, which only kicks the can further down the road.
Stateside, startups like Atomic-6 are working on materials like “space armor,” composite-to-resin tiles meant to protect satellites and manned craft alike from the ever-growing threat.
With any luck, China’s countermeasures will help the agency prevent further catastrophe, though the danger is far from over.
