China is now looking to launch its first planetary defense test mission a year earlier than planned and on a larger rocket.
Like NASA did on its recent Double Asteroid Redirection Test (DART) mission, China wants to test changing the orbit of a potentially hazardous asteroid with an impactor spacecraft and also accurately measure how much its orbit is altered.
DART partnered with a successor mission from the European Space Agency called Hera, which is due to launch in 2024 and will study the impact site in detail. China, however wants to attempt both the impact and close observation in one shot. The country first announced plans for the mission in April and later revealed that the test would target a space rock known as 2020 PN1, a "potentially hazardous" asteroid roughly 130 feet (40 meters) wide. The mission was to launch on a Long March 3B rocket around 2026.
Wu Weiren, chief designer of China's lunar exploration program, told CCTV on Nov. 24 that the new plan will see the mission launch in 2025 atop the larger, more powerful Long March 5 rocket.
"We will launch two probes," he said. "The first one is for surveying. Having studied it [the asteroid] thoroughly after a period of survey, the other one, an impactor, will follow our orders to collide with the asteroid and hopefully divert it three or five centimeters [one or two inches] away from its course."
The spacecraft will launch together, but after separating from the rocket they will enter different trajectories to 2020 PN1. The surveyor will rendezvous with the asteroid first, allowing it to make observations both before and after the planned impact.
While small, the planned alteration in the orbit would be enough to significantly alter the asteroid's path over time.
"A deviation of three or five centimeters would change the trajectory by over 1,000 kilometers [620 miles] after around three months," Wu said. "The longer the time, the bigger the change of the trajectory."
Wu underlined the importance of being able to eliminate potential threats of collisions with Earth.