A member of the Chang'e-6 lunar mission's ground team examines equipment for capturing the probe's return. /CMG
Imagine trying to film a rapidly falling object. As physics dictates, the velocity of an object in freefall increases with time, making the process difficult to capture in its entirety.
Yet, as shown in the livestream of Chang'e-6's return, mission control received a live video signal well before touchdown. How was this achieved?
"We deployed seven trajectory measurement devices within a five-to-seven-kilometer radius of the aiming point," explained An Xueguang from the landing site's trajectory measurement team.
These devices are equipped with high-resolution cameras and sensors capable of capturing every detail of the return of humankind's first samples of the moon's far side, according to a China Media Group (CMG) report.
Members of the ground team review the plan for trajectory measurement. /CMG
The mission faced challenges due to the capsule's small size and high descent speed, making it difficult to track. The unpredictable summer weather conditions in Inner Mongolia also presented another hurdle.
"The Chang'e 6 return capsule is one-eighth the volume of its manned counterpart," An's teammate Jia Peng told CMG. "Furthermore, its descent speed is two to three times faster."
To overcome these obstacles, the team strategically deployed a combination of optical, radar and communication equipment. They also meticulously planned for the mission and practiced for various potential scenarios.