China's National Space Science Center is proposing to launch more than 20 rockets to alter the trajectory of asteroid Bennu, a potential threat to Earth.
If Bennu sounds familiar, it's because NASA's OSIRIS-REx mission recently visited it. Launched from Florida four years ago, the probe successfully collected at least 60 grams of samples from the 500-meter-wide asteroid—over 330 million kilometers from Earth—in October. The spacecraft began its return journey last May and is set to arrive back on Earth on September 24, 2023.
These Bennu samples are invaluable to scientists. As a pristine relic from about 4.6 billion years ago, they offer key insights into the formation of our solar system. Moreover, they may hold molecular precursors that contributed to life on Earth, analyzed using cutting-edge technology.
Bennu poses risks beyond its scientific value. It will pass within 7.5 million kilometers of Earth's orbit between 2175 and 2199. While the impact probability is low (1 in 2,700), a collision could release energy equivalent to 1,200 megatons—roughly 80,000 times the Hiroshima bomb.
Anticipating this, experts at China's National Space Science Center aim to act preemptively by diverting Bennu now.
Their strategy involves launching 23 Long March 5 rockets, each weighing 992 tons, to collide with the asteroid simultaneously. This could shift its path by nearly 9,000 km. The study, led by Mingtao Li, will appear in the November issue of Icarus.
“Asteroid impacts pose a major threat to all life on Earth,” said Li, a space science engineer at the Beijing center and lead author. “Deflecting an asteroid from an impact trajectory is key to mitigating this threat.”
No timeline is set for this mission, but it may take years. Meanwhile, NASA and ESA's DART mission will pioneer kinetic impactor technology against the Didymos system.
