BUSAN, South Korea — China has changed the launch date and target for a mission that will attempt to demonstrate the ability to deflect an asteroid’s orbit.
Speaking at the Committee on Space Research (COSPAR) 45th Scientific Assembly here on 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 a 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 briefing in April 2023, saying the mission was then scheduled to launch in 2025. Li did not disclose the reason for the delay.
The mission also has a new destination. Li said the mission’s target will be asteroid 2015 XF261, a body estimated to be about 30 meters across. This is roughly the same size as the mission’s previous target, 2019 VL5.
He said the two spacecraft will launch together on a long Mars 3B in 2027. The observation spacecraft will make a flyby of Venus before arriving in 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. This will happen when the asteroid is within seven million kilometers of Earth.
This schedule would mean that the asteroid impact would occur in the same month that another near-Earth asteroid, Apophis, makes a very close flyby. Several space agencies are considering missions to study Apophis before or after flyby. Li did not mention any plans to do so, but noted that 2029 will be a year of “asteroid awareness and planetary protection.”
The purpose 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 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 Didymos and its moon, Dimorphos, allowing astronomers to be able to directly measure a change in its orbit. A scientist at the COSPAR hearing raised the possibility that the impact could completely disrupt the asteroid rather than deflect it.
“It has the potential to disrupt the small asteroid,” Li admitted, stating that scientists have done impact modeling. “Even if we break it, it will also provide a method, a way to deflect a small asteroid. It will provide an opportunity to study the internal structure of a small asteroid.”
The mission doesn’t have a name yet. However, he said China is considering a global competition to choose 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 deflecting or disrupting the asteroid, including one that would use the launch vehicle’s upper stage as an impactor to increase the energy delivered. Another concept, inspired by NASA’s aborted Asteroid Redirection 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 under development for launch in 2027. Li said the concepts are exploring several “new orbits.” that include the sun-Earth L -1 Lagrange point, locations leading or following the Earth in its orbit around the sun, and even a constellation of spacecraft in a distant retrograde orbit around the moon. There is still no plan for the development of this observatory, he said.