Chang'e-2: From Lunar Backup to Asteroid Flyby and Solar Orbit
China launched Chang'e-2 in October 2010 as a backup to its first lunar orbiter, then flew it beyond the Moon after its primary mission. The spacecraft traveled to the Sun-Earth L2 point and passed asteroid 4179 Toutatis in December 2012 before entering orbit around the Sun. Its catalog entry still lists an extended mission, but the orbital data stopped updating soon after launch because Earth-based tracking could not follow it to the Moon and beyond.
Chang’e-2 began as a spare for Chang’e-1. After the first lunar orbiter succeeded, engineers repurposed the backup for its own flight. It launched on October 1, 2010, from Xichang aboard a Chang Zheng 3C, built by CAST on the DFH-3A bus and operated by CASC.
Its catalog entry, NORAD 37174, remains marked as an extended mission, yet only one element set exists, from about an hour after liftoff. That launch-day orbit was roughly 264 by 277 km at 29.19°. The spacecraft later reached Sun-Earth L2, passed 4179 Toutatis in December 2012, and entered solar orbit.
Chang’e-2’s extended journey may show how a backup spacecraft can be repurposed for additional science, potentially influencing how agencies plan lunar and deep-space missions. Researchers and engineers could gain experience in tracking, navigation, and asteroid encounters, while the public may see a clearer example of reuse and international scientific interest. Its frozen catalog record also highlights data limitations that satellite trackers and historians may encounter.