Space exploration, a spacefaring nation on a scientific mission to Mars

One proposed mission, Mars One, plans to send volunteers to the planet on a one-way trip, while SpaceX CEO and business magnate Elon Musk has set out his plans for the colonisation of Mars, allowing people to travel back and forth from Earth. Nasa have also put a project in place for a colony on the planet by the 2030s. But with so many unknowns, and a recent Mars mission ending in disaster when a probe crash landed on the planet's surface, just how close are we to getting there – and are we really prepared for life on another planet?

The mission to Mars

There have been 53 missions to Mars since the 1960s, including flights around the planet and landing rovers, but only 23 have been successful. Of those successes, the majority were American, with the US safely landing seven robots on the surface.

No-one has attempted a manned mission yet, but Nasa chief Charles Bolden believes it is very close to becoming a reality, saying the current goal of getting astronauts to Mars in the 2030s is "eminently achievable".

Bolden said: "We are farther down the path to sending humans to Mars than at any point in Nasa's history. We have a lot of work to do to get humans to Mars, but we'll get there."

Elon Musk, CEO of SpaceX, has a much more ambitious plan. He wants to send a manned mission to Mars by 2022 and to put one million people on the planet within 40 years.

While funding the expensive mission is a massive hurdle for SpaceX, Musk claims that his main aim is to "make Mars seem possible – like it’s something we can achieve in our lifetimes".

Announcing his plans earlier this year, he added that there were “two fundamental paths” facing humanity today. “One is that we stay on Earth forever and then there will be an inevitable extinction event,” he said. “The alternative is to become a spacefaring civilization, and a multi-planetary species.”

Meanwhile, the controversial Mars One project run by entrepreneur Bas Lansdorp, has been recruiting volunteers for its one-way mission since 2013 and says it plans to use technology which already exists to get its travellers to Mars. However, experts argue that the technology does not exist and the project is unlikely to ever get off the ground.

How do we get there?

As part of its plans, Nasa will test drive craft in the space around the moon in the first instance. The space agency is currently developing a crew capsule called Orion that will eventually fit onto a massive, heavy-lift rocket called the Space Launch System. The Orion has been undergoing tests for the last two years, while parts of the rocket were tested earlier this year.

The first test flight combining the two is scheduled for 2018.

SpaceX's proposals meanwhile involve launching a rocket with a reusable booster that can be used to get back to Earth. On top of the booster will be the “interplanetary module” where those travelling to Mars will live during the journey. The module will be nearly as long as two Boeing 747 aircraft and could initially carry up to 100 passengers. SpaceX's estimated current cost of sending someone to Mars is around $10bn per person.

Mars One, on the other hand, will outsource the launching phase of its mission before sending its Mars Transit Vehicle off to the red planet.

The problems facing each of these proposals is the efficiency of getting a manned spacecraft off the ground and the hefty costs involved. As Andy Weir, author of best-selling novel The Martian, told National Geographic: "If we have any chance of getting to Mars, we need to be able to get off Earth better."

The other hurdle is landing on Mars. After travelling through space at such high speeds, slowing down and stopping a spacecraft without crashing into the planet is a major obstacle to overcome.

Experts believe that craft would need to carry enough fuel to slow it down on landing, again adding to costs and complexity.

The journey

The journey time to Mars will vary depending on the technology eventually used for manned missions. While Nasa's plan does not give timescales, SpaceX believes its ship will be able to do it in as little as 80 days, while Mars One predicts it will take seven or eight months.

The timing of the journey is also crucial, as Earth and Mars only align favourably for interplanetary missions once every 26 months. Astronauts will need to take all the food, water and other resources needed for the journey, while their bodies will need to be able to withstand the reduced gravity and increased radiation in deep space. Experts also say they will have to find a way to deal with boredom in order to protect their mental health.

Tara Ruttley, a program scientist for the International Space Station (ISS), said: "We're all beings of the 1-G (gravity) environment; that's what we're built for. The second you take that away, we become new and changed, and the body is very efficient at getting rid of what it doesn’t use.

"This means muscles will atrophy, bone density will decrease and the immune system will become depressed."

Nasa is already trying to solve some of these problems by sending astronauts on a year-long mission to the ISS. One study also involves a set of twins and will look at the differences between the twin who spent a year in space and the one who remained on Earth.

Surviving on the planet

Strictly speaking, humans cannot survive on Mars as it is a hostile environment to human life.

While it is believed that the planet once had an atmosphere and lots of water, that was billions of years ago and it is now extremely cold – the average temperature is -60C – with an unbreathable atmosphere and intense radiation.

This means yet more technology is needed to allow humans to land and live on the planet.

In order to survive, pressurised and heated habitats would need to be built, while habitants would also need a spacesuit every time they went outside. Every trip outside would also add to radiation exposure, bringing obvious health complications.

In the long term, humans would need to develop a way to extract water from underground supplies and create their own food sources.

While Martian soil is toxic, experts believe it could be used to grow plants once some of the harsher chemicals are removed. Care packages could be shipped up from Earth in the earlier days, but these would come with a hefty pricetag. Humans would also need to adjust their calendars as a year on Mars is about 1.88 Earth years, with a day lasting a little more than 24 hours and keeping in contact with friends and relatives would be an issue, with a 15 to 20-minute delay on messages getting back home.

Pioneering the planet

To take things to the next level and allow humans to live on the planet without the need for bottled oxygen, protective suits and pressurised domes, Mars itself would need to be changed through a process known as terraforming. Largely the stuff of science-fiction, this would involve releasing megatons of greenhouse gasses to warm the planet and unleashing the red planet's frozen water reserves, transforming it into a planet with an Earth-like atmosphere.

This might take thousands, or even millions of years and the costs involved would be massive.

Scientists in both the public and private sector believe it can be done – however their views differ on exactly how it could be achieved.

SpaceX's plan involves repeatedly detonating nuclear weapons in the now-thin Martian atmosphere. Describing the planet as a "fixer-upper", Elon Musk said: "First you're going to have to live in transparent domes, but eventually you can transform Mars into an Earth-like planet. You'd warm it up. There's the fast way and the slow way. The fast way to drop thermonuclear weapons over the poles."

However, Chris McKay, a planetary scientist at Nasa, said it was a mistake to think there is a lot of energy in nuclear weapons.

He said: "If you take all all the nuclear weapons on Earth, all the countries summed together, that adds up to about half an hour of Mars sunlight. You don’t change a planet by detonating nuclear weapons, you change a planet by harnessing sunlight."

What would this mean for humankind?

Aside from satisfying the human desire for exploration and fascination with space, establishing a human colony on Mars would also provide a security blanket for humanity.

In the event that life on Earth becomes untenable due to things like climate change, Mars would offer a backup location. It could also provide additional resources like water, precious metals, or additional farmland in case we can no longer feed ourselves.

As Barack Obama said earlier this month as he backed Nasa's plan: "If we make our leadership in space even stronger in this century than it was in the last, we won't just benefit from related advances in energy, medicine, agriculture and artificial intelligence, we'll benefit from a better understanding of our environment and ourselves."