On the 7th December 2018, an intrepid explorer set out on a mission that would be a first for the scientific community.
Launched from the Xichang Satellite Launch Centre in China, a probe called Chang’e-4, named after the moon goddess of Chinese mythology, became the first man-made craft to land on the far side of the moon on the 3rd January. After a period of standby, the rover contained within the probe woke up and sent its first images to Earth on the 11th January. Named after the jade rabbit which accompanied the moon goddess, the Yutu 2 rover will be the first craft to explore this little-known region.
Often referred to as ‘the dark side of the moon’, despite the fact that it experiences daylight, the far side of the moon never faces Earth as the moon is tidally locked with us. It has a much thicker and older crust, pockmarked with craters like an acne-ridden teenager. These craters were caused by asteroid impacts over the years and range in size.
The Von Kármán crater, where the probe landed, is located within an even larger crater called the South Pole-Aitken Basin. The crater is 2,500 km across and 13 km deep, and was formed billions of years ago when an asteroid around 500 km in diameter ploughed into it, even reaching the layer below the crust known as the mantle. To put that in perspective, the asteroid believed to have brought an end to the age of the dinosaurs was a measly 12 km across.
One of the mission’s objectives will be to examine the moon’s geological history and take photos of interesting locations, which will help us learn more about how our only natural satellite formed. In addition, experiments in radio astronomy will also take place. The focus is on low frequency radio waves, as these can be extremely difficult to pick up from Earth due to the level of background noise from our technology. A map of the radio waves across the sky at these low frequencies will be made and the lander’s equipment will even be able to study the Sun’s behaviour. These studies may well return data that could never have been obtained otherwise.
But how will we be able to communicate with the lander if the moon blocks direct signals from Earth? A relay satellite will help us out. Following the mythological theme, it is called the Magpie Bridge, a reference to the story of two lovers who were banished to opposite sides of the Milky Way by the girl’s mother, a goddess who didn’t approve of the union. Magpies felt sorry for them and decided that they would make a bridge once a year to connect the couple.
As if the poor old lander and rover didn’t already have enough to do, German researchers have provided equipment to perform the Lunar Lander Neutrons and Dosimetry Experiment. Known as LND, this experiment will assess the radiation on the moon, which will not only study particles that originate in the Sun, but will help researchers to understand if the radiation on the moon will be dangerous to any humans who decide to visit in the future. This experiment is therefore absolutely vital for man taking any more “small steps” on the moon itself.
The lander has also brought some tiny passengers from Earth: seeds of cotton, potato, rapeseed, yeast, Arabidopsis and some fruit flies. Just a few days ago the cotton germinated, making it the first plant to grow on the moon.
This mission is an impressive feat for any country, but perhaps even more so for China, which only sent its first astronaut into orbit in 2003. It was the third country to do so, after traditional space superpowers: the Soviet Union and the US.
Because of this history, and because this is a first for space science, there have been some mutterings that this is the restart of the competitive “Space Race”, originally started by the US and Russia. However officials have stated that this is not the case, and say that China is willing to share its discoveries with other countries in the interest of advancing science.
In planning this mission, China has already worked with NASA, the US space agency. This collaboration had to be fought for, as the US Congress banned NASA from working with China in 2011 and an exception was only granted once the FBI and Congress were satisfied that no leaks of information pertaining to their national security could take place.
The findings from this cooperation could aid further moon landings and will be shared with the international research community at the UN space gathering in February. The mission has had input from European researchers too.
Despite the collaborative effort from nations around the world, this is an impressive show of what Chinese scientists can do. Of course there is the incentive that the potential resources present on the moon would provide its discoverers with fabulous wealth, as well as potentially provide our energy needs for at least 10,000 years.
Regardless of the motives, this lunar mission is a very significant step and opens up various options for the Chinese space agency, who have hopes to build a station on the moon and send missions to Mars, despite being smaller in both size and budget than NASA. Despite this, its plans and funds are less liable to change than its American counterpart, as the Chinese government is more consistent in its goals than the States.
Indeed, the Trump administration has suggested ending funding for the International Space Station by 2025, and if this comes to fruition the Chinese space station, Tiangong-2, could be the only one of its kind in orbit.
This lunar mission signals a great step forward in space exploration that will no doubt deepen our understanding of our nearest and dearest extra-terrestrial body and what lies beyond it. Potentially even more importantly, this could signal the beginning of increased cooperation between foreign space agencies for the benefit of us all.