Chinese Experts Reveal the Flag Material and Technology Used by the Tianwen-1 Lander to Deploy the Flag on Mars Last Year.
On May 15, 2021, after a journey of approximately 500 million kilometers lasting over 300 days, the Tianwen-1 lander successfully touched down on Mars and deployed the national flag, making China the first country to plant a flag on the Red Planet, reported SCMP on September 28. The flag is made of smart fabric, designed to flutter gently in the Martian wind.
The Tianwen-1 Lander Deploys China’s Flag on the Surface of Mars. (Photo: Harbin Institute of Technology).
In a study published in the journal Advances in Mechanics, Chinese scientists disclosed details about the flag material, which is expected to be used in future interplanetary missions, asteroid explorations, and other space projects.
The device carrying the Chinese flag is extremely lightweight, weighing less than 200 grams, and does not involve any motors or gears in the flag deployment process. The key moving components are made from a type of smart polymer that can change shape when heated.
The device holds the flag rolled up with a pair of clips made from elastic-like material. When heated, the “fingers” of the clips extend and release the flag, allowing it to drop and unfurl naturally due to gravity.
The image of the American flag on Japan’s Hayabusa robot first appeared on the surface of Mars in 2008. The star and stripe pattern reappeared during the Curiosity rover’s mission in 2012. In 2020, the American flag was printed on the Perseverance rover that landed on Mars. However, these printed images do not accurately meet the definition of a flag, which is typically made from fabric or similar materials.
“The deployment of the flag on the lander has made China the first country in the world to apply smart structures based on shape memory polymer composites in deep space exploration missions,” said scientist Leng Jinsong and his colleagues at Harbin Institute of Technology. The polymer can change shape freely but will return to its “memorized shape” when influenced by heat, electric charge, magnetic force, or chemical solutions.
With continuous funding from the government, Leng’s team has spent over two decades enhancing the performance of smart polymers. They have added carbon fibers to strengthen the material. They also proposed a new theory to predict the behavior of the material, tested potential materials in some of the harshest environments, and worked with manufacturers to reduce mass production costs.
“This technology is expected to be used in China’s space station, lunar exploration projects, crewed space missions, and explorations of Mars, Jupiter, asteroids, giant icy planets, and other major aerospace engineering projects,” the research team stated.
China plans to undertake several major space infrastructure projects, including a solar power station capable of transmitting high energy back to Earth. These projects were previously considered too large, costly, and complex, but smart materials may significantly reduce costs and risks associated with them.
