The story so far: Scripting history, the Chandrayaan-3 lander landed in the south polar region of the moon on August 23 at 6:03 pm IST, making India the first country to successfully soft-land in that area. The Vikram lander along with the Pragyan rover have since completed a small suite of surface tests. China’s Yutu-2 rover is the only other such instrument currently active on the moon.
Chandrayaan-3 is India’s second attempt to land on the moon. The first was Chandrayaan-2, whose lander module crashed on the moon in 2019.
China had landed a lander-rover module in the South Pole-Aitken Basin (this is not as close to the south polar region as Chandrayaan) in 2018. Both are operational as of date.
Here’s a look at China’s missions to the moon.
Chang’e
Since 2007, China has been launching lunar missions comprising orbiters, landers, rovers, and sample-return spacecraft. While Chang’e-1 and 2 launched lunar orbiters, Chang’e-3 launched the Yutu rover, which conducted a series of experiments on the lunar surface.
Planned initially as a back-up for Chang’e 3, the Chang’e 4 mission launched Yutu-2 on December 8, 2018, and it became the first rover to successfully soft-land on the moon’s far side.
After its launch, Chang’e 4 entered lunar orbit on December 12, 2018 and later completed three weeks of orbital manoeuvres before the spacecraft made a controlled landing in the Von Karman crater in the South Pole-Aitkin Basin on January 3, 2019.
The rover, on the far side of the moon, hibernates in the lunar night and functions during the day. The lander that transported it, Chang’e 4, is still operational and is a communication relay between the rover and control stations on the earth together with the orbiter, Queqiao. Details of data collected by the rover and the experiments conducted by it have not been made public by the Chinese National Space Agency (CNSA).
Chang’e 5 was launched on November 23, 2020, with two lunar orbiters, a lander, and an ascent vehicle. The primary mission objective was to collect surface samples from the Mons Rumker region of Oceanus Procellarum on the moon. After the launch, Chang’e 5 completed a lunar orbit before the descender spacecraft separated on November 29, 2020. Lowering into a circular orbit, the descender along with the lander landed on Mons Rumker, a vast volcanic plain.
The lander was equipped with a robotic arm with a scoop, a coring drill, and a chamber with a regolith storing capacity of up to 4 kg. (Regolith is the layer of soil, composed of loose rocks, dust, and other debris that covers the moon’s surface).
The lander also had the Panoramic Camera (PCAM), Lunar Regolith Penetrating Radar (LRPR), and a visible and near-infrared Lunar Mineralogical Spectrometer (LMS). With a life of one lunar day (two weeks), the lander did most of the drilling and sampling within 48 hours of landing. From a depth of 1 metre, the lander collected and stored 1.731 kg of lunar regolith and later transferred it to the ascender module.
China’s Chang’e-5 spacecraft captured this image of the lunar surface shortly after landing in the Ocean of Storms on 1 December 2020
This module then travelled to the orbiter and transferred the sample container to the return capsule, which fired its rockets and entered the earth-moon orbit before landing in Inner Mongolia in northern China on December 17, 2020. Before returning to the earth, the orbiter separated from the return capsule, fired its rockets and headed for the earth-sun Lagrange point L1 to observe the sun. (This is the same location in space to which India’s Aditya L-1 satellite is currently headed.)
China has more moon missions planned — Chang’e 6,7 and 8 in 2024, 2026 and 2027— before finally sending a crewed mission to the moon by 2030. Continuing its sample return mission, Chang’e 6, a back up to Chang’e 5, will also have a lander with a scooping arm, return container, and ascender. This mission will also land on the far side of the moon, in the South Pole-Aitken Basin.
In 2026, Chang’e 7 is scheduled to expand on lunar south pole exploration by conducting detailed surveys, analysing the terrain, and studying the geological composition, locations of water ice, and the space environment. The mission will focus on detecting water ice in parts of the moon’s permanently shadowed craters.
In 2027, Chang’e 8 will test technologies necessary to construct a lunar science base in the south pole, carrying a lander, a rover, a flying detector, and a 3D-printing module.
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Chang’e mission aims
The Chang’e lunar exploration missions have seen evolving phases of the Chinese space programme since they began in 2007. Initial missions Chang’e 1 and 2 were designed to launch an orbiter and capture high resolution photos of the lunar surface. Chang’e 3 launched in 2013 comprised of a rover (Yutu) which explored 3 sq. km of the moon for 90 earth days collecting data to understand the moon’s elemental composition and the lunar subsurface. This mission demonstrated China’s capability to soft land on the moon.
Researchers work around Chang’e-5 lunar return capsule carrying moon samples next to a Chinese national flag, after it landed in northern China’s Inner Mongolia Autonomous Region, December 17, 2020.
| Photo Credit:
Reuters
However, the programme’s aims changed with Chang’e 4, turning its focus towards the southern shadowed areas of the moon. Launching yet another lander-rover in 2018, Chang’e 4 was tasked with performing a controlled landing in the Von Karman crater in the South Pole-Aitken Basin and capture humankind’s first photos of the far side of the moon taken from the surface. Armed with spectrometers and radars, the rover studied the composition of the lunar surface there.
China then changed Chang’e mission’s aim to returning samples of lunar regolith to the earth with Chang’e 5, which brought 1.731 kg of lunar regolith back.
A representation of Chang’e 5 lander on the lunar surface
Chang’e 4’s lander and Yutu-2 rover were supposed to last for two months, but they are still functional, and have been sending data and high-resolution photos of the far side of the moon. Both the lander and rover use radioisotopic heat sources to maintain their temperatures through lunar nights.
Chang’e 5 had a specific lifetime of 23 days from launch on November 23, 2020, to return on December 16, 2020. After lunar orbit capture on November 28, the lander and descender/ascent vehicle separated and landed on the lunar surface on December 1. As the lander was capable of collecting samples for only 1 lunar day ), it lifted off via the ascender on December 3 and transferred the samples to the return capsule, before crashing to the moon’s surface on December 7.
Representation of the orbiter and returner of China’s Chang’e 5 probe after its separation from the ascender
The return capsule landed with parachutes on December 16 in northern China. Before entering earth orbit, the orbiter headed to the earth-sun L1 Lagrange point for a mission to study the sun.
As of 2021, the orbiter observed the earth and the sun, and was on its way to the moon. Some reports suggest that the Chang’e 5 orbiter may have performed a lunar flyby before heading to asteroid 469219 Kamoʻoalewa— a part of China’s asteroid sample-return mission scheduled for 2025.
