A year ago, the first seeds sprouted on the Moon. China’s Chang’e-4 mission was the first to land on the far side of the Moon, which faces away from Earth. The lander carried a sealed container filled with soil, cotton, rapeseed, Arabidopsis (rock cress) and potato seeds, yeast and fruit fly eggs. The aim of the experiment was to form an artificial, self-sustaining environment – a mini biosphere. The six components were chosen to act “producers, consumers and decomposers”, with the plants producing oxygen and food to sustain the fruit flies. The yeast was to process waste from the flies the dead plants to create more insect food.
Professor Xie Gengxin, the experiment’s chief designer, explained that these six species were chosen because they were small and could grow in a confined environment and were hardy enough to withstand extreme conditions on the lunar surface. Professor Liu Hanlong, head of the experiment, said that potatoes could be a source of food for space explorers, with rapeseed as a source of oil and cotton could be used for clothing.
“We have given consideration to future survival in space. Learning about these plants’ growth in a low-gravity environment would allow us to lay the foundation for our future establishment of space base.”Professor Liu Hanlong, head of the experiment
The biosphere canister was just 18cm tall and weighed 3kg. It was designed to test photosynthesis and respiration and contained a supply of air, water and nutrients. The seeds inside were kept dormant for the 20-day trip to the Moon.
Chang’e-4 touched down on 3rd January 2018, and mission control centre sent a command to the probe to water the seeds to start them into growth. China announced that the cotton seeds had grown buds 12 days later, stating this was “the completion of humankind’s first biological experiment on the Moon”.
[Although most reports say that only the cotton seeds germinated, the South China Post quotes a mission scientist as saying that the rapeseed and potato seeds also sprouted.]
The temperature on the Moon varies widely, from -173°C to over 100°C, and the Chinese scientists behind the mission admitted that keeping the temperature favourable for growth would be a challenge. Sadly, just 24 hours after their announcement that the first Moon plants had sprouted, the scientists confirmed they had died. However, those little seeds have been responsible for germinating some big hopes.
“If we want to live longer-term off the surface of the Earth, could we take along the biology that we use to keep us alive? How do you become a good gardener in space? It’s fantastic to be able to sort of say, yeah, it’s a first tiny step down that path.”Simon Gilroy, Professor of Botany at the University of Wisconsin-Madison, via NPR
In September 2019, the project team released a 3D image of the plant from image processing and data analysis, which showed that two cotton leaves grew.
They’re also planning to send larger biological payloads, with more complex organisms to the Moon. China’s Chang’e 6 mission, scheduled for the early 2020s, may be the next opportunity for them to do so.