But while the former International Space Station (ISS) commander loved his space visits, life on earth is still his preference.

‘’We’ve evolved quite a long time to be here on the ground, so we are naturally suited to be here and the food is a lot better here too,’’ Dr Chiao joked to the Mercury ahead of speaking at the University of Wollongong on Monday night.

NASA certified Master Science teacher Jami Sunkel also addressed the ‘Inspiration through space exploration’ public lecture.

But much attention was on Dr Chiao, who logged  229 days in space over four missions, including six spacewalks supporting ISS design and construction.

‘’It definitely is a life-changing experience to fly in space and to look back at our earth,’’ he said.

‘’The earth is very beautiful. The colours are very bright. It makes you really start to think about what’s important in life. What it’s all about.

‘’But against the backdrop of that, you've still got a job to do...important experiments to run, you’ve got a space station to build or something like that.

‘’It is definitely a unique experience.’’

This is the second time the Houston-based trained engineer, who also speaks Mandarin, Chinese and Russian, has been invited to speak in Wollongong by Professor Anatoly Rozenfeld from UOW’s Centre for Medical Radiation Physics (CMRP).

In 2010 he came alone. This time around Dr Chiao brought along his Oneorbit co-founder Jami Sunkel to encourage young people to start thinking about what they want to do with their life.

‘’Our tagline is make the most of your one orbit. It is kind of a metaphor for life, ‘you've got one go around so make the most of it’,’’ Dr Chiao said.

‘’That’s the message we want to impart at these talks.

‘’I will share some of my adventures from space and give a status of the current NASA plans and where I think we are heading in the future.

‘’The new administration [Trump] is kind of turned more centric towards the moon, which in my opinion is the right way to go. The moon I think is an important stepping stone as we get ready to go to Mars.’’

Ms Sunkel raised the recent discoveries of seven earth-like exoplanets.

‘’We found this system of planets that are 40 light years away so they're still pretty far from us but we think they have a lot of components similar to earth to be able to have an habitable zone and host life,’’ she said.