BUSAN, South Korea — China has changed the launch date and target for a mission that will attempt to demonstrate the ability to deflect the orbit of an asteroid.
Speaking at the Committee on Space Research (COSPAR) 45th Scientific Assembly here July 15, Li Mingtao of the National Space Science Center of the Chinese Academy of Sciences said 2027 was the new launch date for the mission that will send one spacecraft to collide with a small asteroid and another to observe the impact.
The date is two years later than what another Chinese official announced at a conference in April 2023, stating the mission was then scheduled to launch in 2025. Li did not disclose the reason for the delay.
The mission has a new destination as well. Li said the target for the mission will be the asteroid 2015 XF261, a body estimated to be about 30 meters across. That is roughly the same size as the mission’s earlier target, 2019 VL5.
He said the two spacecraft will launch together on a Long March 3B in 2027. The observer spacecraft will make a flyby of Venus before arriving at the vicinity of the asteroid in early 2029. About three months later, in April 2029, the impactor will collide with the asteroid at a speed of 10 kilometers per second. That will take place when the asteroid is within seven million kilometers of Earth.
That schedule would mean the asteroid impact would take place the same month as another near Earth asteroid, Apophis, makes a very close flyby to Earth. Several space agencies are considering missions to study Apophis before or after the flyby. Li did not mention any plans to do so but noted that 2029 will be a year of “asteroid awareness and planetary defense.”
The goal of the mission is to demonstrate the “kinetic impactor” approach to planetary defense by showing how a high-velocity impact can change the orbit of an asteroid to prevent a potential collision with the Earth. NASA demonstrated the same concept with its Double Asteroid Redirection Test (DART) mission that collided with a moon orbiting the asteroid Didymos in 2022, changing its orbital period by more than half an hour.
One difference is that 2015 XF261 is significantly smaller than both Didymos and its moon, Dimorphos, allowing astronomers to be able to directly measure a change in its orbit. One scientist at the COSPAR session noted the possibility that the impact could completely disrupt the asteroid rather than deflect it.
“It does have the potential to disrupt the small asteroid,” Li acknowledged, stating that scientists have been doing modeling of the impact. “Even if we disrupt it, it will also provide a method, a way to deflect a small-sized asteroid. It will provide an opportunity to study the internal structure of a small asteroid.”
The mission does not yet have a name. However, he said China is considering a global competition to select a name and logo for the mission, part of an initiative that could also include design studies for future planetary defense missions.
Li said his center is looking at several additional concepts for asteroid deflection or disruption, including one that would use the launch vehicle upper stage as an impactor to increase the energy delivered. Another concept, inspired by NASA’s canceled Asteroid Redirect Mission, would seek to try to capture an asteroid. There is no timeline for those missions, he said.
China is also studying concepts for a space-based observatory to search for near Earth asteroids, similar to NASA’s Near Earth Object Surveyor mission in development for launch in 2027. Li said concepts are exploring several “novel orbits” that include the sun-Earth L-1 Lagrange point, locations leading or trailing the Earth in its orbit around the sun, and even a constellation of spacecraft in a distant retrograde orbit around the moon. There is no schedule yet for developing that observatory, he said.