On Tuesday morning (Jan. 15), China released a picture of a cotton seed that sprouted on the Moon’s far side, marking humans’ first successful attempt at growing living things there. But the joy was short-lived as the plant died shortly after as the night’s freezing temperatures set in.
Cotton seeds had embarked on a journey in the Chang’e-4 spacecraft to the Moon in early December, as part of China’s mission to test life sustainability as it prepares to build a lunar base.
The seeds were placed within a seven-inch-tall tin filled with air, water, and soil containing potato and arabidopsis seeds—the latter is a plant in the mustard family—as well as fruit-fly eggs and yeast. In theory, they should have created a “mini lunar biosphere,” as plants grown inside could emit oxygen, while fruit flies could feed on yeast and emit carbon dioxide for plants to grow, according to Chongqing University, which is in charge of designing the experiment. The institute selected the species based on a number of criteria, including tolerance of low gravity, strong radiation, and large temperature fluctuations.
Soon after Chang’e-4 touched down on Jan. 3 during the lunar day, scientists on earth instructed the tin to activate its systems for adjusting temperature, light, and water. The systems worked until Saturday (Jan. 12), when night started to fall on the landing site, the Von Kármán crater. A night on the Moon is about as long as 14 days on Earth.
Scientists then powered off the tin, ending the experiment as the seeds, yeast, and fruit-fly eggs froze when temperatures fell below -50°C, said the experiment’s director Liu Hanlong (link in Chinese) at a press conference on Tuesday. When the next lunar daytime comes, the rising temperatures will cause the frozen matter to thaw and decompose in the tin.
Scientists didn’t find any obvious changes on the other organisms aside from the cotton seeds as of Tuesday, Liu noted. It’s unlikely anything inside the tin will grow in the following six days because temperatures will rise above 30°C, which isn’t suitable for seeds to sprout, Liu said.
China will carry on with other lunar experiments, including detecting signals that might reveal the universe’s origin with the help of its relay satellite Queqiao, and explore the Moon’s composition with Yutu-2, the rover that traveled with Chang’e-4. The rover is in sleeping mode during the lunar’s nighttime.
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