By 
April 28th, 2024
China’s Chang’e-6 lunar mission atop a Long March 5 carrier rocket at its departure site in Wenchang, Hainan province.
Image credit: CCTV/Inside Outer Space screengrab
Launch preparations are quickening for China’s next spacecraft sendoff to the Moon – the Chang’e-6 mission.
The spacecraft now sits atop a Long March 5 carrier rocket at its departure site in Wenchang, Hainan province.
Chang’e-6 is reportedly to launch at 3:50 PM, May 3rd Beijing Time (3:50 AM, May 3rd, Eastern Time).
The 8.2 metric ton Chang’e-6 is targeted for a touchdown in the South Pole-Aitken Basin on the lunar far side. The overall mission spacecraft consists of four components: an orbiter, a lander, an ascender and a reentry module.
Image credit: CNSA
First-time try
If all goes as planned for this first-time attempt at gathering dust and rocks from the Moon’s far side, then placed on the ascender for transport from the surface into lunar orbit, followed by transfer into a reentry module that hauls the collectibles to Earth.
In the past, both the former Soviet Union and the United States have brought lunar samples to Earth, but none has ever obtained specimens from the far side of the Moon.
China scored the first soft landing on the far side of the Moon with its Chang’e-4 lander/rover mission back in early January 2019.
Between Chang’e-6 and the earlier Chang’e-5 lunar sample mission, the most significant difference is that the soon-to-launch mooncraft is conducting sample-return from the far side of the Moon.
Photo taking during Chang’e-5 moon surface sampling session in December 2020.
Credit: CNSA/China Central Television (CCTV)
In mid-December 2020, the Chang’e-5 mission made use of similar spacecraft components to return near-side specimens from Mons Rümker, in the region of Oceanus Procellarum.
Image credit: CCTV/Inside Outer Space screengrab
Design and control
“The Chang’e-6 aims to achieve breakthroughs in the design and control technology of the Moon’s retrograde orbit, intelligent sampling, take-off and ascent technologies, and automatic sample-return on the far side of the Moon,” Ge Ping, deputy director of the Center of Lunar Exploration and Space Engineering for the China National Space Administration told China Central Television (CCTV).
“At present, the Long March-5 carrier rocket and the Chang’e-6 probe are in good condition,” Ge added. “All preparations for the launch are progressing in an orderly manner, following normal working procedures.”
Liao Guorui, an engineer at the Wenchang Spacecraft Launch Site, told CCTV:
“At present, the launch site has ensured the normal testing of Chang’e-6 and the Long March-5 Y8 carrier rocket. Our Hainan launch site features high temperatures, high humidity, and high salt mist. We have made corresponding preparations for the environmental conditions, and we have also prepared some typhoon prevention plans to adapt to the weather in Hainan.”
Image credit: CCTV/Inside Outer Space screengrab
Narrow launch window
Details of the launch window were spotlighted by Zhu Haiyang, a staff member with the China Academy of Launch Vehicle Technology.
“The signature feature of the Chang’e-6 mission is that it has extra high requirements for the launch window, mainly due to the lunar orbit. In order to achieve an optimal energy, it has a high requirement for the launch time of the rocket and the time of delivery to the Lunar Transfer Orbit [LTO], so the launch window is relatively narrow,” Zhu told CCTV. “We have carried out some verifications for the ‘narrow window and multi-orbit’ technology.”
Chang’e-5 return capsule holding lunar specimens.
Image credit: National Astronomical Observatories, CAS
Transfer point
For this Chang’e-6 launch, 10 lunar orbits for the rocket have been designed. Chang’e-6 probe needs to enter the LTO with a perigee of 200 kilometers and an apogee of 410,000 kilometers, and the requirement for orbit entry accuracy is also extremely high.
“As for the rocket, we mainly need to send it to the LTO transfer point,” Zhu added. “In terms of process coordination before launching at the launch site, coordination and drills were also carried out around the narrow window multi-orbit technology. With higher accuracy in orbit insertion, less propellant will be consumed by Chang’e-6 for its attitude adjustment, including orientation, orbit elevation, and orbit change.”
Scoop and drill
According to James Head, noted lunar scientist at Brown University, the Chang’e-6 mission is very similar to the Chang’e-5 spacecraft and its operational strategy, acquiring scoop and drill samples, perhaps up to 4.4 pounds (2 kilograms.)
Image credit: CCTV/Inside Outer Space screengrab
The recently launched Queqiao-2 far side communications satellite is in lunar orbit, tested, and is fully functional to support, not only the Chang’e-6 mission, but also follow-on Chang’e-7 and Chang’e-8 robotic expeditions, in support of placing an International Lunar Research Station (ILRS) on the Moon, Head said.
Near side–far side dichotomies
According to Xingguo Zeng, a key member at the Laboratory of Lunar and Deep Space Exploration at the National Astronomical Observatories, Chang’e-6 is designed to address questions about the multiple lunar near side–far side dichotomies and to provide new insights into both the early impact history of the Solar System and the geological evolution of the Moon.
Image credit: Xingguo Zeng, et al.
To that end, the Chang’e-6 landing zone has been selected to lie within the lunar far side South Pole–Aitken (SPA) basin in the southern part of the Apollo basin, Xingguo observed, a site that provides access to a diversity of SPA material.
Go to this informative video regarding the upcoming liftoff of Chang’e-6 at:
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