2001 set the standard for the next 50 years of hard (and some soft) sci-fi

Finally, after almost half a century of waiting, you can welcome the mildly homicidal artificial intelligence HAL 9000 into your home. If you want.

Few of the other predictions of tomorrow's world made in Stanley Kubrick's psychedelic space epic 2001: A Space Odyssey – marking its 50th anniversary at the start of April – have come to pass.

We don't have a permanent Moon base yet, elegant shuttles manned by hostesses in elegant Courrèges outfits are still yet to announce their departure gates, and perhaps most crucially we have yet to discover any calling cards that are shaped suspiciously like high-end Sony Bravias left by Kardashev Type III civilisations buried under the Clavius crater.

But much has changed in the 50 years since Stanley Kubrick and Arthur C Clarke unleashed 2001 on an unsuspecting world.

For a start, our attention spans are shorter. A film that ran at such a resolutely languid pace would last less than a week in a modern multiplex.

2001 ran for months in 1968. Despite early mixed reviews, audiences would return again and again, often armed with mood-altering substances, in order to experience its bold, trippy, vision of the future.

Among those audiences were young film students such as George Lucas and Stephen Spielberg. It might be going a shade too far to suggest that without 2001 we wouldn't have Star Wars, ET or Ready Player One. But it's a fair bet that they would have looked very different.

Star Wars creator Lucas described 2001 as "the first time people really took science-fiction seriously".

Cinerama

2001 not only showed us possible new technologies, it depended for its very existence on the cutting-edge tech of the day. The film might never had been made in the first place were it not for MGM's desire to showcase its ultra-wide Cinerama format.

Cinerama was giant 70mm film format that was a natural fit for huge, outdoorsy films. The first few releases were travelogues, starting with This Is Cinerama in 1952, and releases continued in that vein for a while before the appearance of maxi-sized John Ford-helmed western How The West Was Won in 1962. The aesthetic was as close to a theme park ride as a conventional cinema experience.

Part of the film's appeal would be to offer a virtual simulation of space travel, in an era when a clear photo of the Earth from space hadn't been taken yet. The one everybody knows dates from 1972.

A precursor to 2001, a Cinerama "travelogue" short subject called the To Moon and Beyond, was premiered at the New Work World's Fair in 1964. One of the special effects team on that movie, Doug Trumbull, was later to find employment on the epic two-year gestation of 2001's effects.

From its beginning as a notion between Kubrick and Clarke which drew on the author's earlier works The Sentinel and Encounter In The Dawn, the project grew and doubled its initial $6.0m budget.

Shut up and take my money

It's a measure of the studio's faith in this project, in an era when feature film budgets rarely passed $2m, and profits on science-fiction properties were by no means guaranteed, that they committed so heavily to Journey Beyond The Stars, as the film was initially titled.

The initial treatment was submitted in mid-February 1965. Within days MGM executive Robert O'Brien had responded, approving the initial budget. By the end of February, MGM had issued a press release entitled "Stanley Kubrick to film Journey Beyond the Stars for MGM".

It promised: "An epic story of adventure and exploration, encompassing the Earth, the planets of our Solar System, and a journey light-years away to another part of the Galaxy."

The release made much of Kubrick's pedigree, name-checking his recent successes Lolita and Dr. Strangelove.

It was the latter film, rather than the borderline-Yewtree comedy drama, that had most connection to 2001.

The script for Dr. Strangelove initially featured a framing device presenting it as a story told by aliens discovering a ruined, post-apocalyptic Earth.

The shadow of the Cuban Missile Crisis loomed large in Kubrick's mind, and while it's not so clear in the final – often wordlessly symbolic – film, the novelisation that Kubrick and Clarke developed described the post-human Starchild returning from Jupiter and detonating mankind's entire nuclear arsenal harmlessly in space.

Kubrick was in his mid-30s when he made 2001, hugely successful but far from complacent; always looking for new ideas to put on screen.

In a telling moment, during one of his early meetings for the project with Arthur C Clarke, Kubrick was sure he had spotted a UFO zipping above his New York East Side apartment. It turned out to be an experimental NASA communications device called Echo One.

The future was coming.

In the pre-CGI 1960s, the film's pioneering effects were almost all practical. Lucas calls them "the best of the best of the first 70 years of cinema".

A portentous spectacle

Keir Dullea, who played astronaut Bowman, told The Guardian how some of the memorable zero-gravity shots were obtained.

"The rotating living quarters of the Discovery spacecraft were built by Vickers," he said. "They were 70ft across and turned at 3mph. The camera tricks the crew used to simulate centrifugal force were ingenious. There's a scene where I climb down a ladder and, at the other side of the screen, you see the other astronaut sitting at a table upside-down. It looks as if I walk round towards him, until I'm upside-down too, but they actually rotated the set, and him, round to me.

"He seems to be eating normally – but only because they'd glued his food to his fork."

The entire apparatus creaked and groaned horribly as it rotated and bulbs on the lighting rig were forever blowing as a result of the strain placed on the studio's electrics.

Clarke, who was on set for much of the filming, described it as: "A portentous spectacle, accompanied by terrifying noises and popping light bulbs."

The colossal centrifuge was not the only out-sized piece of special effects kit.

Camera trickery

The slit-scan method that brings to life Bowman's journey through a wormhole to a distant alien "zoo" is based on a trick developed by Victorian-era photographers.

The 1843 Ellipsen Daguerrotype was intended for use as a panoramic camera with a 150° field of view. It was an early example of slit-scan, exposing a narrow section of the plate at a time until the full panorama was developed.

Like its contemporaries, though, it depended on unwieldy, rigid photographic plates so it was something of a niche product.

When flexible film was introduced in the early 1900s, panoramic photos using slit-scan became more commonplace.

2001 effect wizard Doug Trumbull recalled the work of another member of the To The Moon and Beyond crew, John Whitney, who had been involved in Saul Bass's pioneering opening credits of Alfred Hitchcock's Vertigo – one of the first examples of a computer being used to render animation on film.

Another detail that remains unexplained is what happens at the end. Astronomer Carl Sagan, who was recruited to give advice on the production, later wrote: "They had no idea how to end the movie."

Whitney's experiments with long-exposure rostrum camera work inspired Trumbull to create his own variation on the slit-scan technique, where a camera shot through an external moving slit while a psychedelic gel background was moved on the other side of the slit, creating a vertical "tunnel through space-time" effect.

The apparatus he built was nearly 10 metres long and six high. The final sequence was the result of Trumbull's giant slit-scan machine running 24 hours a day for over two months.

Nowadays, of course, you can get much the same effect by downloading a glitch camera filter such as Hyperspectiv onto your iPhone.

You will still see something like the original slit-scan technique in use wherever sporting events require a photo finish.

From the glacial pace of a largely wordless hard sci-fi masterpiece to the split-second capture of a fast-moving sporting event is not as far as you might think.

2001 looks like hard science-fiction at first glance. It makes no efforts to compress the long and boring aspects of space travel into something zippy and exciting for the screen.

But there's little time spent on understanding how of the exciting technology on show actually works. Setting aside the Sunny Delight pouches of food for consumption in low gravity, a trip on the Orion space shuttle is pretty similar to a conventional airline journey.

Thanks for your help, IBM

IBM were hired as consultants, both to help visualise the future technology that underpinned ship's computer HAL and to help devise a computer-based quality control system that could help Kubrick keep track of the details on images destined to be projected on 30-metre screens.

Neither task panned out.

IBM responded to Kubrick's quality control system request with a note that said: "There's no way, Stanley. There's too many things changing every day." And Kubrick described IBM's schematics of a potential shipborne AI as "useless and totally irrelevant to our needs".

The film opens with a lengthy prologue depicting the alien monolith's influence on a band of Australopithecus (filmed under tight security for fear of spies from the near-contemporary shoot of Planet of the Apes) and then skips forward to the near future for the discovery of a similar – or possibly the same – monolith on the Moon.

There's another time-jump, of 18 months, before we get to the section of the film that comes closest to explaining its narrative. This, presumably, is the section of the movie that's actually set in 2001, although it's never explicitly said.

Another detail that remains unexplained is what happens at the end. Astronomer Carl Sagan, who was recruited to give advice on the production, later wrote: "They had no idea how to end the movie."

2001 has next to no dialogue; it has only the loosest narrative arc, no hero and not really a villain either unless you count a malfunctioning computer.

It's a film with no universally agreed ending and asks many more questions than it answers, yet is widely acknowledged as one of the greatest achievements in science-fiction film making.

And it predicted Siri and Alexa. What else do you want? ®