The China National Space Administration’s Chang’e-4 lunar mission is calculated to make headlines, while raising the bar in space science. The first mission to send a lander to the dark side of the moon, it also includes a little garden supporting a flourishing ecosystem — some sprouting cotton seeds, yeast and a few fruit flies. It will not survive when the water supply runs out, and it was grown on good Chinese soil in a 3 kg canister, rather than lunar dust. Which means that China’s search for croplands in Africa will not end anytime soon. Even so, this is the first time that humans have grown anything on another world, and set up a working ecosystem. It signals the tentative beginning of an era long-anticipated by science fiction, when the human race would be able to colonise planets.
But scientifically, the achievement is unspectacular. Lunar gravity is 17 per cent that of the earth, while plants have been grown in the apparent weightlessness of the International Space Station (ISS) for the last eight years, to see if they can serve as a food supply and regulate the cabin atmosphere on long-haul space flights. Geotropism, which causes roots to grow down and shoots to grow up, has been controlled, and use of artificial lighting in photosynthesis understood. In fact, in 2017, part of a crop of Chinese cabbage was eaten with relish by the crew of the ISS.
But every part of the first biological experiment on the moon is not a success. The potato seeds have proved to be tardy in sprouting, calling into question the plot of Andy Weir’s The Martian, in which a marooned astronaut keeps himself alive by growing potatoes on Mars. He could have been better equipped with a pack of Chinese cabbage seeds to see him through his long ordeal.