The city's space enthusiasts had a wonderful experience on Thursday, when three of the nation's astronauts visited Hong Kong to talk with local students.

They encouraged them to pursue their dreams and embrace scientific innovation.

The talk, held at Victoria Park, was a highlight of the ongoing science and technology exhibition themed "Innovation in Science and Technology, Realization of Our Dreams". This is part of a series of events to mark the 20th anniversary of Hong Kong's return to the motherland.

One of the speakers were Yang Liwei, the first Chinese astronaut to go into space in the Shenzhou VI along with Chen Dong and Jing Haipeng. Chen and Jing also completed the Shenzhou XI mission in 2016.

On Thursday, the trio shared their experiences, revealing interesting things witnessed in space.

Chen also said he was impressed by the Hong Kong students' powers of observation and imaginations.

He said today's Hong Kong young people may one day "land on Mars and shake hands with creatures from outer space".

During their mission last year, astronauts Chen and Jing conducted scientific experiments at space station Tiangong II. Among these were formation of multi-purpose porous polymer membrane under zero-gravity; cultivation of silkworms in space; and experiments with a double pendulum. These were devised by Hong Kong secondary school students.

Form-6 students Chan Chui-shan and Ho Yik-lung of Shun Tak Fraternal Association Yung Yau College, developed the porous membrane idea. They also set up a booth at the science and technology exhibition.

Chan Chui-shan said five samples they created were taken to the space lab by the astronauts. They were then successfully removed to form a membrane in space. "This proved our hypothesis was right," Chan said.

"Yesterday, the astronauts met us and brought us the good news," Chan added

"They showed us the video shot during the experiment in the space lab. The process was so miraculous we held hands and yelled," said Chan.

Membranes formed on earth were usually poor quality with unevenly distributed pores. They also had inconsistent pore sizes due to the forces of gravity, the science enthusiast explained.

This inspired them to think that the experiment should be done in space. The membranes shaped in space had a smooth even surface with well-distributed pores. This would be much more efficient when used as artificial skin to treat burn patients or performing a filtering function during dialysis.

But Chan said there were limitations to these experiments. The student added that they were determined to find ways to improve them.

Many Hong Kong young people dream of becoming an astronaut when they grow up; their parents support them despite the risks and demanding tests they will have to endure.

Chim Zi-yin and Chim Zi-lok, 10-year-old twin brothers were grateful to attend the morning session with the astronauts. They are both fascinated with astronomy books and science fiction movies. The pair is also doing regular physical training. They realize being an astronaut requires a strong body and will.

Aware of the risks astronauts face, their parents insist they will help them face future challenges.

jenny@chinadailyhk.com

(HK Edition 06/30/2017 page3)