To infinity and beyond: How mankind is plotting a route to Mars
When humans landed on the moon the possibilities appeared limitless.
Regarded by many as mankind's greatest achievement, the famous mission in 1969 had star-gazers dreaming we would go bigger and bolder.
The logical next step was Mars and while man-made machines have touched down on the Red Planet, for human beings that particular giant leap never came.
After America won the race to the moon, Presidents found it harder to justify investing millions of pounds in space exploration due to political pressures on the ground.
Those who gathered around their televisions in awe to watch the moon landing would probably have found it hard to believe that more than half a century on that feat would not be topped.
But that could all be about to change.
Last week's launch of SpaceX, fronted by the billionaire Elon Musk, has reignited discussion about manned space travel to Mars and beyond.
The fact it was a commercial flight makes it all the more exciting and, just like that summer of 69, the opportunities seemingly endless.
The first SpaceX launch has sent astronauts to the International Space Station (ISS) but the flamboyant Musk, who co-founded the electric car and clean energy giant Tesla, has made no secret of his desire to go to Mars.
Virgin's Richard Branson has also dabbled with space travel, while Boeing and Amazon supremo Jeff Bezos are also entering the market.
Many scientists believe this is the key to sending a manned mission to Mars.
Governments often find ploughing millions into space travel hard to sell to voters more concerned about issues that affect their daily lives, and this has proved a barrier to going further than the moon.
But a super-rich businessman, without these concerns holding him back, is now talking about making it a reality.
Couple that with a deeply nationalist President currently residing in the White House who never misses an opportunity to take pleasure in getting one over China and Russia - and, crucially, doesn't have to foot the bill - and there is plenty of new-found optimism for space travel.
As groundbreaking a moment the launch to the ISS was - the first time astronauts had been sent into space from US soil since 2011 - there's a sense that it's only the precursor to something much bigger.
Bosses at SpaceX have not been shy about stating their ambitions - even talking about 'cities on Mars'.
Colonisation of other planets has always seemed like the stuff of science fiction, but some scientists believe it could be key to extending the survival of the human race.
Uncrewed missions to Mars have been talked about as early as 2022. Even if that date sounds a tad ambitious, humans touching down on the Red Planet seems to be closer than ever.
Experts have spoken about rockets refuelling at stations in Earth's orbit and attempting to cut journey times from six months to four months to decrease radiation.
Dr Gareth Dorian, a space science research fellow at the University of Birmingham, believes the launch of SpaceX is a stepping stone to much bigger things in the future.
He also says the involvement of private companies could open up space to more people in the future.
"It's pretty big. It increases access to space for far more people and that's the big selling point for me. It means more people can go to space independently of state or anything else," he said.
"But also because SpaceX is owned by Elon Musk, and he has a particular vision for human space flight in the future, this enables people like him and others who want to see a multi-planetary civilisation at some point in the future, and this is a stepping stone.
"Absolutely it is. This is a multi-decadal or multi-generational project, you have to have the continuity and this shows that it's possible."
Dr Dorian believes a manned mission to Mars is now likely, but warned there are significant hurdles to be overcome, including the safety of those humans involved.
He said: "I think it will happen, the big question is when. Once you've got a system in place that's working you can refine the design.
"In terms of the physics, it takes more energy to get to low-Earth orbit than it does to get from low-Earth orbit to the moon so in many ways that's the hard part, if you like, and they've done that now.
"There's obviously many other hurdles to overcome and the astronauts still have to be returned safely to Earth as well, that's another huge hurdle to overcome, but it certainly makes it more likely in the medium term."
Dr Dorian acknowledged cities on Mars and beyond would likely be centuries away, if it is ever to happen. But he says private businesses entering the space race opens up endless possibilities, potentially helping to answer the ultimate question: are we alone?
For any of that to be possible though, Dr Dorian insists there must be people ready to continue the visions of Musk and other company bosses entering the market when they are no longer here.
"The way that it's always been phrased is a trip to Mars is always 30 years away. It's been that way since the 1970s," Dr Dorian said.
"After the Apollo mission people were saying we'll be on Mars in 30 years, then the 1990s and 2000s came.
"Timescale depends on a lot of things. One of the big things, frankly, is you need someone with the vision of Elon Musk and the passion of Elon Musk to make this happen.
"If this was just a normal commercial enterprise, a company just looking to make profits, that's fine. He's got a very specific dream and a very specific vision and he's obviously able to use his wealth and resources to spark that future and drive it.
"If he's not there, or someone like him is not there, then other people will come along and their vision might be totally different. There is a huge potential, I think, for someone to come along and say well let's just use SpaceX to make money, so you have to have people with the determination to see it through no matter what.
"It's the same with any great leap forward in civilisation. You have to have people there with the drive to make it happen.
"Whether it's the start of a new era, I think it is as long as the will is there."
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