Levitating frog inspires China to make a mini ‘moon’

China has built a research facility that simulates the low-gravity environment on the moon – and it was inspired by experiments using magnets to levitate a frog.

The facility could provide valuable research for lunar exploration activities, according to scientists involved in the project.

Located in the city of Xuzhou, in Jiangsu province, the simulator is expected to be officially launched in the coming months.

Lead scientist Li Ruilin, from the China University of Mining and Technology, said it was the “first of its kind in the world” and would take lunar simulation to a whole new level.

The simulator could make gravity “disappear”, Li said in an interview yesterday. While low gravity could be achieved in an aircraft or a drop tower, it was momentary; Li said in the simulator that effect could “last as long as you want”.

At its heart is a vacuum chamber that houses a mini “moon” measuring 60cm in diameter.

The artificial lunar landscape is made up of rocks and dust that are as light as those on the moon – where gravity is about one-sixth as powerful as the gravity on Earth – partly because they are supported by a magnetic field.

When the field is strong enough it can magnetise and levitate things – from a living frog to a chestnut – against the gravitational force.

Li said the idea came from Russian-born physicist Andre Geim’s experiments to levitate a frog with a magnet – for which he won an Ig Nobel Prize, celebrating science that “first makes people laugh, and then think”, in 2000.

Geim, from the University of Manchester in England, also won a Nobel Prize in Physics in 2010 for his work on graphene.

China wants to land astronauts on the moon by 2030, and to set up a joint lunar research base with Russia. Chinese space authorities said last month that construction of the research station could start as soon as 2027 – years ahead of schedule – amid concerns over US-led moves to set the rules for lunar activities.

The Xuzhou facility was expected to play a key role in China’s future lunar missions, including building infrastructure on the moon, Li said.

It will allow scientists to test equipment – and potentially prevent costly miscalculations – in a simulation of the extreme lunar environment. The Chang’e 5 mission returned with rock samples in December 2020, but there were not as many as planned because the drill hit unexpected resistance. Missions by the Soviet Union and US have had similar issues.

Experiments on a smaller prototype simulator suggested drill resistance on the moon could be much higher than predicted by theoretical models, according to a paper by the Xuzhou team published in the

Journal of China University of Mining and

last week.

Technology

Li said that the moon simulator could be used to test whether new technology such as 3D printing could be used to build structures on the lunar surface.

It could also help assess whether a permanent human settlement could be built there, including issues like how well the surface trapped heat, he said.

“Some experiments conducted in the simulated environment can also give us some important clues, such as where to look for water trapped under the surface,” he said.

Simulating the harsh lunar environment on Earth was no easy task – the magnetic force needed is so strong that it could tear apart components like superconducting wires.

Li said the team came up with innovations to get around these challenges, including simulating lunar dust that could float more easily in the magnetic field.

He said the Chinese facility would be open to researchers from around the world.