When humans first walked on the moon in 1969, our place in the Universe changed forever. Neil Armstrong may have fluffed his lines when stepping onto the lunar surface, but it truly was 'a giant leap'.

Space technology and exploration has continued, with advances like the International Space Station, the Hubble Space Telescope, Mars rovers finding water on the Red Planet, the Global Positioning Satellite system and Elon Musk's car launched from a re-usable rocket to name a few.

But we haven't been back to the Moon since 1972, and many consider a human mission to Mars a pipe dream. Fifty years from now, toward the tail end of the 21st century, will anything we have done reach the level of excitement that captured the world's attention in July 1969?

Associate Professor Michele Trenti, astrophysicist at the University of Melbourne is unsure of the future of human space exploration.

"The Apollo program was truly inspirational, an epic challenge for the times. I'm hoping that we can dream big again, but it's not clear to me how we can do this."

"I would love to see something truly inspirational in space exploration in the next 50 years, but I am not sure that it will happen."

Andrew Wetherell is Managing Director of the Melbourne Space Program, says we should look to the two main visionaries in space exploration for clues about where the big advances will come in the next 50 years.

"There's Elon Musk, who's all about making humanity an interplanetary species. And you've got Jeff Bezos, who takes a bit of a different view, which is essentially that all our heavy industry is going to move off-world, so Earth becomes a residential place, and you do all your mining and manufacturing in space."

"And I think the reality is probably both are partly right. In the next 50 years, what you're going to see is a shift in terms of the power of rocketry, and that will see us go to Mars, and will see us return to the Moon.

"And there are already companies that are starting to manufacture fibre optic cables in space, because it's higher quality. Other planets, even the moon, will become facilities for this kind of manufacturing."

Professor Rachel Webster, who leads the Astrophysics group at the University of Melbourne, has similar thoughts but gets her inspiration from another, less well-known visionary, Professor John S. Lewis, and his 1996 book, Mining the Sky.

"In this he's basically saying, 'we've got our feet off the planet. Where can we go from here?'," says Professor Webster.

Professor Lewis is a space chemist and currently Chief Scientist with Deep Space Industries.

He took his inspiration from earlier, pre-space flight visionaries like Konstantin Tsiolkovskii, Robert Goddard and Arthur C. Clarke. The book explores a future where the Moon and Near Earth Asteroids are mined for minerals and water.

Water is the key ingredient of space travel, as it can both be used to sustain life, and also be split into its constituents, hydrogen and oxygen to power space ships as they explore the Solar System and beyond.

"You need energy, resources, food," says Professor Webster.

"Once we get off the planet we can go anywhere and get this stuff. We can go to the Moon, that's the obvious place, but also asteroids are dead easy to mine, because you can just cruise up to them and park and take what you want. There's no having to land or take off because there's no gravity, and they are rich in exactly the resources we want."

A single two kilometre diameter asteroid, according to Professor Lewis, contains around $A20 trillion worth of minerals, enough, he wrote, "for a space program tens of thousands of times larger in scale than anything we could afford without the use of space resources".

"I'm astounded it's taken us so long to go back to the Moon, but it's going to happen again very soon," says Professor Webster.

"We're not just talking about the Americans and the Russians here. The Chinese are going absolutely gangbusters, and India isn't far behind. Everybody is in the game. It's not hard to do this, it's just a matter of committing the resources and doing it."

While Associate Professor Trenti is sceptical of a Moon-landing scale event in the near-term, he says we are entering a new and exciting era for space developments, where the economies of scale, and major advances in miniaturisation have democratised space.

Dr Trenti leads the SkyHopper cubesat program, that is preparing a miniature space telescope for launch in 2022.

"The first computers took up a whole floor of a building. They were bulky expensive, of limited access, slow to design and construct, and challenging to operate," he says.

"Space technology has been similar, where launching a satellite was a big deal and only a large team and a few space agencies could pull it off.

"In the last few decades, computing has really taken a giant step forward in terms of miniaturisation and capability and availability in the market. And I think we are probably at the point in space exploration where we are getting this transition – even school kids can now build and launch a small satellite."

Mr Wetherell agrees.

"I can now launch a satellite that's functional for about $A300,000. And those satellites will get smaller and smaller," he says.

"In June, the Melbourne Space Program, a not-for-profit education organisation, successfully launched the ACRUX-1 cubesat, which was designed and built by students from universities across Melbourne

While a return to the Moon, a human visiting Mars or the mining of a nearby asteroid are all feasible, a humanity-defining event that would outstrip all of these would be the discovery of life on another planet.

And it could happen in the next 50 years.

Unexplained methane recently found on Mars gives a tantalising clue that life could exist in our Solar System, but even more tantalising is the thought that complex, intelligent life exists elsewhere in the galaxy.

"There are ideas out there for the next generation of space telescopes capable of taking an image of another Earth-like planet and establishing that it has an atmosphere, that it has conditions suitable for life, and maybe even seeing some signs of organic molecules – signs of life," says Associate Professor Trenti.

As to who might put their hands up for these dangerous voyages out in space, Professor Webster thinks the pool will be large.

"Periodically I ask my third-year astrophysics class, 'if I could give you a one-way ticket to Mars tomorrow, would you go?' And I am always shocked because most of them say 'yes, I'd go in a heartbeat'," she says.

"When people got in boats and went and sailed around the Earth, they didn't know if they were coming back. I just don't think people are going to really hesitate to hop in their spaceships and head out into the Universe.

"I think in the next 100 years we will see substantial activity in the rest of the Solar System."

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