The lunar samples collected by China's Chang'e 5 robotic mission have set out on their journey to Earth after the craft conducted late Thursday night the first-ever moon-based space launch by any Chinese space vehicle.
The lunar rocks and soil gathered by Chang'e 5's lander-ascender combination are scheduled to land at a preset site in North China's Inner Mongolia autonomous region in mid-December, completing the world's first endeavor in 44 years to bring lunar substances back to Earth.
According to the China National Space Administration, the ascender carrying the samples activated a 3,000-newton-thrust engine at 11:10 pm on Thursday to lift itself to an elliptical lunar orbit, marking the first time for a Chinese spacecraft to blast off from an extraterrestrial body.
Before the ascender was launched, the lander-ascender combination erected a small Chinese national flag to honor the country, the administration said.
The ascender will later rendezvous and dock with Chang'e 5's orbiter-reentry capsule combination, which is now traveling in lunar orbit at an average altitude of about 200 km. Next, it will transfer the lunar samples to the reentry module and then separate from the combination.
The orbiter-reentry capsule combination will later return to Earth orbit, where the pair will separate, and the reentry capsule will conduct a series of complicated maneuvers to return to Earth's land.
Chang'e 5, China's largest and most sophisticated lunar probe, was launched by a Long March 5 heavylift carrier rocket early on Nov 24 at the Wenchang Space Launch Center in Hainan province, setting out on the world's first mission since 1976 to return lunar samples to Earth.
The spacecraft has four main components－an orbiter, lander, ascender and reentry capsule.
The spacecraft separated into two parts－the orbiter-reentry capsule combination and the lander-ascender combination－while in lunar orbit early Monday morning.
On Tuesday night, the lander-ascender combination landed on a region north of Mons Ruemker, a mountain overlooking a vast lunar mare called Oceanus Procellarum, or the Ocean of Storms, on the western edge of the moon's near side, becoming the third spacecraft to successfully touch down on lunar surface this century. The first two to achieve this feat－Chang'e 3 and 4－were also from China.
Shortly after the touchdown, the lander began to use a drill to obtain underground samples from 2 meters beneath the surface. It finished the underground operation at 4:53 am on Wednesday. The craft then started gathering surface soil with a mechanical arm. Samples were packed into a vacuum container inside the ascender.
All of the collection and packing processes ended at 10 pm on Wednesday, having taken a total of nearly 19 hours, much sooner than expected.
Project planners have allowed the lander-ascender combination to work about two days on the moon to accomplish the gathering and packing tasks.
Experts said that planners needed to leave sufficient time for the craft to perform the sophisticated collection operations in case of possible malfunctions, adding that completion ahead of schedule indicates the apparatus worked very well.
