Chang’e-5 orbiter embarks on extended mission at Lagrange Sun-Earth point

HELSINKI – The Chinese orbiter Chang’e-5 is heading for a stable gravitational point in space on an extended mission after delivering fresh lunar samples to Earth.

The spacecraft is now heading to a Sun-Earth Lagrange point to conduct observations of the local environment, the Sun, and to conduct operational tests.

The Chang’e-5 orbiter left the lunar orbit late on December 12 to the east, along with a return capsule containing monthly samples. The two spacecraft separated about 5,000 kilometers from Earth on December 16, and the return capsule re-entered the atmosphere. Return capsule has landed at 12:59 east December 16 with 1,731 kilograms of monthly materials.

Meanwhile, the blinding man made a avoidance burn. Initially, it was unclear whether the avoidance combustion was meant to avoid the return capsule or the Earth’s atmosphere.

Amateur radio operators the first confirmed that the Chang’e-5 orbiter was still in space and dressing to the moon. Official confirmation of the condition of the spacecraft has now been provided.

Hu Hao, chief designer of the third phase (sample return) of the Chinese monthly exploration program, told China Central Television (Chinese) December 20 that the orbiter is now on an extended mission to a Sun-Earth Lagrange point.

Hu said the extended mission was made possible by precise orbital injection by March 5th launch of the vehicle, the same missile that failed in July 2017 and delayed Chang’e-5 by three years. The Chang’e-5 orbiter has more than 200 kilograms of fuel left for subsequent maneuvers.

Although unspecified, it is believed that the Chang’e-5 orbiter will enter orbit around L1, based on the reference to the planned solar observations. The orbiter is equipped with optical imaging.

The team will decide on another destination after tests and observations have been made, Hu said.

Image of the Earth and the transiting moon, made by NASA’s DSCOVR mission from point 1. Lagrange Sun-Earth. Credit: NASA

Chang’e mission extensions

Chang’e-2, which orbited and mapped the moon in 2010, later visited the Lagrangian Earth-Sun L2 point to test tracking networks and the ground. He then performed a flyby of the asteroid 4179 Toutatis.

The orbit of the 2014 Chang’e-5 Q1 2014 mission to test a return capsule re-assignment also received an extended mission after completing its main tasks. This spacecraft entered a halo orbit around Lagrange-Earth point 2, taking pictures of the Earth and the moon, but also indicating that China could align an unprecedented monthly side landing with the Chang’e-spacecraft. 4, then a backup successfully used Chang’e-3. CE5-T1 also imagined candidate landing sites for the actual Chang’e-5 mission.

Chang'e-5 ascension vehicle approaching the orbit of the mission in lunar orbit.
Chang’e-5 ascent vehicle approaching the orbiter. Credit: CNSA / CLEP

Possible future scenarios for the Chang’e-5 orbiter could include visiting the L4 or L5 Sun-Earth points. These triangular release points are more stable than the other three points and could house objects near Earth. Imaginaries could be used to explore the region in connection with speculated Earth Trojan asteroid objects.

Such objects would co-orbit the Earth, but are 60 degrees in front (L4) or behind (L5) of the planet. In October 2021, NASA will launch LUCY, a first mission to visit Jupiter’s Trojans.

A paper submitted to the 2018 International Astronautical Congress suggested that Queqiao, the relay satellite that facilitates lateral earth-moon communications for the Chang’e-4 mission, could be sent to the L4 or L5 post-primary Earth-moon mission for a similar survey, citing great value for both astronomers and engineers.

Meanwhile, on Earth, the re-entry capsule has since been transferred to Beijing. The box containing the monthly samples was handed over to the Chinese Academy of Sciences before preparation, analysis and storage at a specially built facility.