There is a story, no doubt apocryphal, about a European company which signed a contract with a Japanese manufacturer of televisions. The contract allowed for 1% wastage, or 1 in 100 defective televisions sets. Come the day the first batch was delivered, and the CEOs of the two companies stood and watched as ninety-nine brand-new televisions were transported into the warehouse. The Japanese then presented the European CEO with a box containing a smashed up TV. When asked what it was, the Japanese CEO explained that it was the one defective television set from the hundred, as stipulated in the contract.
With CNC robots and CAD/CAM, manufacturing in the 21st Century is a sophisticated, precise and cost-efficient process. Back in the early 1960s, the Apollo command modules were built by hand by North American Aviation. The first one, CM 012, contained so many faults, Apollo 1 commander Gus Grissom intended to hang a lemon from the control panel. No more than a few days later, Grissom was dead, along with his crew, Ed White and Roger Chaffee, killed by a fire inside the command module during a plugs-out test.
In order to navigate to the Moon, much of the course calculations for Apollo were performed by rooms full of computers at Mission Control in Houston, Texas. Aboard the spacecraft, there was only the Apollo Guidance Computer, a device considerably less sophisticated than an average mobile phone of today. The AGC required the astronauts to enter "verbs" and "nouns" using a DSKY (display/keyboard) in order to start programs. It had a vocabulary of around 38,000 words. In Carrying the Fire, Michael Collins' autobiography, he describes having to make 850 key-strokes in order to enter the necessary data and program calls for Columbia and Eagle to rendezvous on the Lunar Module's return from the lunar surface.
Even cruder was Gemini's radio-control "encoder" for the Agena target vehicles, which used a "little box topped by two concentric wheels and a lever". All instructions "ended in either a one or a zero, and were formed by setting up the first digit on the outer wheel and the second digit on the inner wheel, and transmitting all three by turning the lever from center to either the left (for zero) or the right (for one)" (also from Carrying the Fire).
The technology to return to the Moon not only exists, but is a great deal more sophisticated and effective than it was in 1969. True, the same laws of physics still apply, and the solutions to the problems those laws present have not changed. But in the tools and instruments used to implement those solutions, there is really no reason why Project Constellation should not be able to put one or more astronauts back on the lunar surface in relatively short order. In the 21st century, the hardware can be built to better engineering tolerances, with less faults, for less cost and in shorter time. The entire trip can be managed by computers onboard the spacecraft, using software which does not require data to be read out over the radio to the crew and then laboriously inputted by them.
But it's not the hardware and software which have prevented return trips to the Moon. Some might say it's the lack of public will - and yet, there were still those criticising and demonstrating against Apollo when Neil Armstrong and Buzz Aldrin landed on the Sea of Tranquility. There are many since who have complained that the money spent on Apollo could have been better spent on other things. Perhaps it's the lack of political will. When President Kennedy gave his famous speech, "we choose to go to the Moon in this decade and do the other things, not because they are easy, but because they are hard...", he may have been motivated by a desire to win the Cold War in at least one area, but he made it happen. I see no reason why a later president could not have managed something similar - providing they had the will, their motivation is irrelevant.
Money is often cited as another stumbling block. The Apollo programme up to Apollo 12 cost $16.1 billion in 1969 dollars - about $112 billion in 2005 dollars (figures from Return to the Moon by Harrison Schmitt). By 1969, the US Administration had spent approximately $83 billion on the Vietnam War, and $214.4 billion in Iraq by 2005. So money is clearly not a problem.
What about expertise? The Mercury, Gemini and Apollo programmes were designed, managed, built and staffed by young people, who frequently put in long hours to get the job done. It's been said that no equivalent workforce exists today, and that people now are unwilling to work the necessary hours. Which is plainly rubbish. Look in any large corporation and you'll find a workforce which often puts in ridiculous - and unpaid - hours to finish projects and meet deadlines. There is certainly enough expertise throughout the world in computing and information technology for a return to the Moon - after all, the bulk of the work in the 21st century version will lie there and not in hand-engineering hardware.
There is perhaps one element of the Apollo programme which no longer holds true, and might in part explain why it has never been repeated. NASA at that time was dominated by a large number of strong-willed and charismatic leaders - not just the astronauts, but also the administrators and chief engineers. Many of them were ex-military, or had fought in World War II. The entire organisation's culture was very much based on personal leadership. People's careers could be ruined by saying the wrong thing to the wrong person in a meeting. It could be argued this mindset had been forged during half a decade of global war; certainly no such comparable event happened in the second half of the 20th century. NASA is now a bureaucracy, with systems and procedures and checks and balances. Many critics have complained that it this which is holding back Project Constellation - take the recent decision by NASA to convert from Imperial to SI units... which they subsequently abandoned because it would have been too difficult and costly to implement. I don't necessarily agree that the leadership/organisational model used by NASA during Apollo is necessary for a return to the Moon, but it's certainly clear that the compromises foisted on the organisation in the decades since then have severely jeopardised its operations.
Yes, I think we should return to the Moon. And then travel onwards to Mars, and the planets, dwarf planets and moons beyond. It doesn't matter if there is no immediately obvious benefit to doing so. Not all of the benefits of Apollo were plain at the time. I'm not much bothered whether the next set of astronauts on the Moon are American, Chinese, Indian, Russian or European. But it is a little embarrassing to see NASA floundering as it tries to implement a programme they have already implemented once before and which should be so much easier to do now. Even worse, they're failing in other areas - the International Space Station will likely not last much longer than 2016.
It's been said that landing on the Moon killed science fiction. I suspect the reverse is true. The Apollo programme demonstrated that space is not the benign environment advertised by science fiction short stories, novels and films. Far from it. As a result, one branch of sf turned inwards - the New Wave - while another slid further into fantasy - Star Wars and its ilk. Space has become a place of dreams and fancy, and so unreachable. There is a hardy few dipping their toes in the water, so to speak, in the International Space Station and aboard Shuttle missions. But, by and large, space is an environment, a setting, which exists chiefly in books and films.
Not so long ago we had the Mundane sf Manifesto, which insisted on "stories set on or near the Earth, with a believable use of technology and science as it exists at the time the story is written". It was, and remains, controversial. Perhaps now, on the 40th anniversary of the first landing on the Moon, we should re-introduce the sub-genre of Space Fiction, stories set in space which treat the setting honestly and accurately. Perhaps the sub-genre could be used to re-introduce space as it actually is to the public, perhaps it might even rekindle interest in it as something achievable and conquerable - because only when you have identified the problems, can you start working on solutions....