Robotic exploration: China has great plans

Month after month, China takes more and more steps toward space superpower status. We’ve just seen them complete a three-module space station, and perform the first handover from one crew to another. This also set a new record: six Chinese people in orbit simultaneously. This year they are also on a steady path to being the second nation by orbital rocket launches, only behind the USA. However, there is another field where China is scoring great success: robotic exploration.

The beginnings

Chinese robotic exploration started relatively late, with the Chang’e 1 lunar orbiter launched in 2007. The name comes from the Chinese goddess of the Moon. The spacecraft used its camera and laser altimeter to produce some very accurate 3D maps of our satellite. Chang’e 2 repeated the mission in 2010 and visited the Sun-Earth L2 Lagrange point and asteroid 4179 Toutatis. Next, in 2011, the People’s Republic tried to launch an orbiter to Mars, Yinghuo-1 (“Luminous fire”, and similar-sounding to the ancient word for Mars). It rode along Russia’s Fobos-Grunt spacecraft. Unfortunately, the failure of the Blok-D upper stage of the Proton launch vehicle doomed both spacecrafts.

In 2013, Chang’e 3 landed on the Moon, making China the third nation to accomplish such a feat, after the USSR and the USA. The probe studied the lunar soil and deployed a small rover, Yutu (“Jade rabbit”). A similar mission took place in 2019, when Chang’e 4 and Yutu 2 landed on the lunar farside, a world first. Communications continued thanks to the Quequiao relay satellite, orbiting in a halo orbit around the Earth-Moon L2 Lagrange point. Such a trajectory had already been explored in 2014 by Chang’e 5-T1, a demonstrator for a surface sample return capsule.

These tests allowed the latest mission of the Chinese lunar exploration program to take place in late 2020. Chang’e 5 landed on the lunar surface, gathered some surface samples, and then brought them back to Earth. The mission was the first lunar sample return since Luna 24 in 1976. It used an ambitious lunar orbit rendezvous profile, just like the Apollo program. In the same year, China launched its first successful Mars mission. The Tianwen-1 (“Heavenly questions”) spacecraft included an orbiter, a lander, and the Zhurong rover. The landing went perfectly, and the three spacecrafts are now studying the red planet.

The future of lunar exploration

After so much progress in the last decade, China is set to continue robotic lunar exploration in the next few years. In 2024 a new relay satellite, Quequiao 2, is scheduled for launch. In 2025, this satellite will support a second sample return mission, Chang’e 6, this time from the lunar South Pole. The mission will also include experiments from other countries, namely Italy, France, ESA/Sweden, and Pakistan. They will allow laser ranging of our satellite, and look for ice, volatiles, and negative ions.

Next, in 2026 and 2028, the Chang’e 7 and 8 missions should take off. Both of these will land at the South Pole, and look for ice deposits using rovers and small hoppers that will be able to fly to several locations. The latter mission will also include an instrument to produce oxygen from the lunar regolith, demonstrating In-Situ Resource Utilization. These probes will test key technologies for China’s future ambitions, which include landing a crew on our satellite and establishing a permanent base.

The future of interplanetary exploration

The second Chinese interplanetary spacecraft should leave Earth around 2025 and head for near-earth asteroid 469219 Kamoʻoalewa. The space probe, dubbed Tianwen-2, will travel using electric propulsion and will land on the asteroid to gather a sample of its surface. From there, it will set course for an Earth fly-by and drop off the sample in a reentry capsule. After the delivery, the spacecraft will reach the 311P PanSTARRS main-belt comet. This object is a big chunk of ice and rock, but it doesn’t circle around the Sun in a highly elliptical orbit like a regular comet. Instead, it’s located in the main asteroid belt between Mars and Jupiter. Thus, studying such an object from up close will be a great first in the field.

Tianwen-3 is a proposed Mars sample return mission. Two vehicles should leave Earth in 2028: a lander and launcher, and an orbiter to bring back the samples. If everything goes according to plans, the mission would bring back martian soil in 2031. Interestingly, it would be in competition with the joint ESA/NASA attempt to do so, which should also take place at the end of this decade. The two spacecrafts would both use existing launch vehicles: Long March-3B for the lander and Long March 5 for the orbiter. There will be no attempt to select samples in advance (like the Perseverance rover is doing right now): the soil around the lander will be what is brought home. Interestingly, there is a proposal to use a small robotic dog for sample gathering, to try and get the most scientifically significant rocks from the area.

The last mission which is planned in some detail is Tianwen-4. This will be China’s first mission to the outer planets. The main spacecraft will orbit Jupiter and its moon Callisto. During the encounter with the king of the planets, a smaller spacecraft will begin autonomous flight and use the gas giant’s gravity to propel itself up to an encounter with Uranus. It will possibly be the first and only spacecraft to reach the ice giant since Voyager 2 in 1986. The launch should take place around 2030, but anything so ambitious and so far out in the future is at high risk of seeing delays and changes in plans.

We cannot know for sure if these launch dates will be met and if everything will go smoothly. We don’t even know if other minor missions will go from proposals to flight hardware in the meantime. What is certain is that it will be exciting to see a decade of exploration unfold before our eyes, and to follow every landing and fly-by.