Forty years after the last Apollo flight to the Moon, our space correspondent examines the options facing companies and countries contemplating their own giant leap for mankind.

A long way back

It is 40 years since the last Apollo astronauts landed on the Moon, bring the total number of humans to set foot on the lunar surface to 12.

First steps

The Apollo programme was built around the Saturn V rocket – still the largest, most powerful rocket ever used. (Copyright: Nasa)

Moon shot

The first mission to the lunar surface blasted off on the 16 July 1969, when a Saturn V carried Michael Collins, Neil Armstrong and Buzz Aldrin into orbit. (Copyright: Nasa)

Flying Eagle

The awkward and angular looking Eagle lander carried Neil Armstrong and Buzz Aldrin to the surface of the Moon.

History books

On 20 July 1969 Neil Armstrong became the first human to walk on the Moon. Along with Buzz Aldrin, he spent more than two hours outside the lander.

Back to Earth

In total, the pair spent nearly one day on the lunar surface, before blasting off to rendezvous with Michael Collins who had been orbiting in a capsule above them.

View from above

The Apollo programme launched seven missions to the Moon, landing a total of 12 astronauts on the surface and introducing the world to a new view of the Earth.

Final mission

The last mission was Apollo 17, which took off from Launch Complex 39 at Kennedy Space Center in Florida on 7 December 1972.

Driving forces

The crew consisted of commander Eugene Cernan, astronaut Ronald Evans and Harrison Schmitt, the first and last scientist to land on the Moon.

End of an era

The crew left the Moon’s surface on 14 December and reentered the Earth’s atmosphere five days later, landing safely in the Pacific Ocean.

Going to the Moon is hard. And expensive. It took Nasa the equivalent of four million human-years to put twelve astronauts on the surface, at a cost of some $25 billion.

It is one of the reasons that ever since the Apollo 17 crew packed up their kit and flew home, we have not been back.

But, there now seems to be a renewed appetite for returning to the Moon. The Golden Spike Company recently announced that it can take you there by 2020 for $1.4 billion and we can only guess how much money China is putting into its lunar ambitions.

So, assuming you have the cash, what else do you need to get to the Moon? Here is BBC Future’s seven-step guide for any individual, nation or company wanting to take a giant leap:

A new rocket

Escaping the Earth’s gravity and getting people (and hardware) to the Moon requires a lot of energy. The 1960s solution, the Saturn V rocket, was a staggering piece of technology. Standing 30 stories high, the three-stage launcher was fitted with more than three million parts. But laying your hands on one may prove difficult. The only remaining Saturn V made up of original hardware intended for space, is in a giant shed in Houston. Nasa might notice if anyone tried to borrow it. And what was left of the failed Russian equivalent, the N1, has been made into bus shelters at the Baikonur Cosmodrome in Kazakhstan.

Given that there is no modern equivalent of the Saturn V or N1, and short of building a similarly massive rocket, you will need a plan B. Golden Spike proposes a multi-stage approach with multiple launches of smaller rockets (such as the Atlas 5) to ferry a lunar lander, crew capsule and two Lunar Transport Vehicles (LTV) into orbit. The LTVs will provide the power to take the lander and crew capsule from the Earth to the Moon.

Alternatively, you might choose to launch several sections of your spacecraft into Earth orbit, assemble them there and then fly onto the Moon. The various components could be launched on anything from aEuropean Ariane to a SpaceX Falcon. But you could only fly your crew on a rocket certified for human spaceflight such as a Russian Soyuz orChinese Long March.

Another way might be to use bigger rockets – or add new stages to existing rockets – to place your component parts into lunar orbit, and put the whole mission together there. Nasa is also developing a new heavy-lift rocket, the Space Launch System, which is slowly moving from the drawing board to the factory but the first tests aren’t scheduled until 2017.

Whatever you choose, the good news is that most of the technology is available and is coming down in price as private companies begin to offer alternatives.

A spacecraft

You may think that once the rocket is sorted, you are most of the way there. But that is only going to boost you into orbit. Once in space you need something to ferry you towards the Moon and land on its surface.

When they were designing Apollo in the early 1960s, Nasa engineers quickly realised that it made more sense to have two separate vehicles – an orbiter and a Moon lander – rather than a single spacecraft.

The 21st Century equivalent of the Apollo capsule is Nasa’s Orion module. It resembles a super-sized Apollo and the first test versions of this “deep space” capsule are now nearly complete. However, it will be several years before it’s ready for any crew.

If you cannot get hold of an Orion, Isle of Man company Excalibur Almaz Limited is reconditioning ex-Russian military space capsules for use in expeditions around the Moon. Joined to habitation modules, these spacecraft would be six times the size of Orion, making the journey much more comfortable.

So, when it comes to capsules, you have got some options.

But the same cannot be said of landers. There is nothing, in existence, like the Apollo lunar landers although concept designs have been developed. These include Nasa’s recent Altair craft, but that programme has now been abandoned. Still, you could dust off the blueprints and, with a bit of imagination, new materials and techniques, it should be possible to put something together. It is almost certainly going to be expensive and, as with any new space technology designed for astronauts, it is going to involve a lot of risks.

The right stuff

Going to the moon is not going to be fun. It is likely going to be tiring, cramped and most of all dangerous. So, even if you have the cash, you will need the “right stuff”.

Have you thought about the risks you are taking? How your family will cope if things go wrong? Have you even considered what to say when you get there? Will you come in peace for all mankind or are you just in it for personal glory?

For astronauts, the psychological aspects of being a spacefarer are every bit as important as the physical.

And then there is the training. An ability to work in a close-knit team and respond to emergencies in a calm, professional manner is vital if you want to get back alive.

Even Apollo’s only scientist-astronaut, geologist Harrison Schmitt, was a fully trained jet pilot. The other Apollo astronauts were, for the most part, super-fit flying aces and many of today’s astronauts are still from a flying background. Rookie UK astronaut Tim Peake, for instance, is a military helicopter test pilot – hardly a desk job.

If you plan to fly to the Moon before this decade is out then start training now. Even if you decide to employ professional astronauts to do most of the work, you still need to put in the hours. Apart from a rigorous fitness regime, you will have to learn how to fly the spacecraft, work in weightlessness and train for what to do when something goes wrong.

The right clothes

Once you and your hardy crew have escaped Earth’s orbit and touched down on the surface, you are going to want to step outside the capsule. And for that you need a spacesuit.

These are effectively miniature spacecraft – containing everything you need when planting flags, hitting golf balls or just taking in the views from the lunar surface. To cram all the life support, communications and computers in, spacesuits are bulky. This does not matter so much if you are on a spacewalk outside the International Space Station in zero gravity. But if you are attempting to bounce around on the Moon, you will need something that is relatively compact and light. It will also need to be strong enough to avoid getting torn on rocks or damaged by lunar dust.

Apollo spacesuits were individually tailored to each astronaut and sewn and glued together by seamstresses. They consisted of multiple layers – from a mesh of coolant pipes near the body to a tough outer protective suit of fire-proof Teflon cloth. The iconic Apollo helmets featured gold-plated visors to protect the astronauts from the Sun and the gloves were made as thin as possible to maintain flexibility.

Thanks to the development of new lightweight materials, future spacesuits should be a lot less bulky but they will still need to be immensely complex. Try the funky new ones being developed by the University of North Dakota’s Spacesuit Laboratory, for instance, which promise much greater range of movement and flexibility.

The maths

After President Kennedy made his 1961 pledge to put men on the Moon, Nasa drew up a list of all the challenges that would need to be overcome to make that goal possible. The gap between the tiny Mercury capsule, in which astronaut Alan Shepard had become the first American in space (but not even orbit) three weeks earlier, and the goal of men walking on the Moon seemed almost laughably insurmountable. There was so much that had to be figured out, with one of the biggest challenges being space navigation and rendezvous.

A lunar mission, then or now, involves spacecraft docking on the way to the Moon or in lunar orbit. If, for instance, Apollo astronauts failed to dock their command module with the lander, then the mission would be off. Worse, if on returning from the Moon, the lander failed to rendezvous successfully with the command module, then two astronauts would end up stranded, forever, in lunar orbit.

The maths of orbital mechanics and rendezvous became one of the primary objectives of the mid-60s Gemini missions, with MIT graduate Buzz “Dr Rendezvous” Aldrin taking a leading role. Although the navigation computer developed for the Apollo spacecraft was a marvel of 1960s engineering, astronauts still used sextants to verify their position.

Even with advances in computing, the challenges of space navigation remain. The spacecraft needs to know where it is. A glitch in the software and you could find yourself completely lost in space. China recently proved its orbital navigation capabilities, with its spacecraft docking to the Tiangong-1 space lab but if you want to go to the Moon, you must get your maths right. Half a degree out and you will never be seen again.

Mission control

Building, launching and flying a rocket to the Moon takes tremendous organisation. The genius at the heart of Apollo was mission control. Bringing together specialists from every aspect of the flight – from engine control to life support – and having a single Flight Director in charge, kept everything on track. The concept proved its worth when, during Apollo 13, things were going catastrophically wrong and the collected expertise at mission control saved the crew’s lives.

Even today, the International Space Station has a room full of people on the ground to keep the astronauts in orbit safe. For your flight to the Moon you will need a skilled team of experienced personnel and a communications system capable of reaching the crew during every minute of the mission. You will also need engineers, back-up astronauts and a public affairs staff to keep those journalists happy.

Money

Okay, so we’ve mentioned this once, but it is worth reiterating. Going to the Moon is going to need money. Lots of it.

The Apollo programme was initially estimated at $7 billion but this was quickly revised to around $20 billion. In the end, the final cost was reported to be  $25.4bn.

All of which should make any budding lunar travellers take estimates with a pinch of salt. If you have ever employed builders, you will know that final costs tend to be a great deal more than the original estimates. And, as with builders, you should consider getting some other quotes.

Golden Spike estimates $1.4 billion for a trip. But here at BBC Future, we reckon we could do you a mission to the Moon for $1.3 billion. Cash in hand.

Source:NASA