First cotton plants sprout on the Moon

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When China’s Chang’e-4 spacecraft landed on the lunar far side on January 3, 2019, it made history. It was the first spacecraft to visit that part of the Moon, and among its payload was a 2.6 kg mini-biosphere called the Lunar Micro Ecosystem (LME).

The sealed, cylindrical biosphere is only 18 cm long and 16 cm in diameter. The LME carried six lifeforms, kept in mostly earth-like conditions except for micro-gravity and lunar radiation.

The Chang’e-4 lander.

A sprouting cotton seed on China’s Chang’e 4 lunar lander is the first plant ever to germinate on another world, heralding a new era for life in space.

The LME carried: • Cotton seeds; • Potato seeds; • Rape seeds; • Yeast; • Fruit fly eggs; and, • Arabidopsis thaliana, a common, hardy weed.

This ground-breaking work by China is the first biological growth experiment on the Moon. Only the cotton seeds produced positive results.

At first, the team behind this experiment thought that there was only one cotton leaf, but now data indicates there were two.

The LME was unheated, so after the first lunar day – about 14 earth days – the cotton sprout died when the temperatures plunged to minus 190°C But the experiment continued, to test the longevity of the LME itself.

In the past, experiments have been conducted aboard the International Space Station (ISS) and China’s Tiangong-2 space lab – where plants, rice and arabidopsis were cultivated. But these experiments took place in Low-Earth Orbit (LEO), which is a microgravity environment. The planners of the Chang’e-4 mission therefore sought to include an experiment that would test how organisms fared in lunar gravity.

According to Professor Liu Hanlong – the Dean of Chongqing University’s School of Civil Engineering, who is leading the experiment – the first thing to sprout were the cotton seeds. An image sent back by the lander provided a glimpse inside of the experiment and showed a cotton sprout that was growing well, though no other plants appeared to be growing at the time.

The results were then compared to an Earthbased control experiment, which showed much more substantial growth. While air pressure and a constant temperature of 25°C (77°F) are maintained inside the LME (as with the control group), the fact that it has to contend with less than 17 per cent of Earth gravity had some detrimental effects.

On the next Chinese Moon mission, they hope to send more complex life forms, though they haven’t specified what they’ll be.

The bad news is that the Moon is as dry as the Murray-Darling basin at the moment, so doesn’t represent a potential new cotton production area.