2001 a Space Odyssey: Good science fiction, but not perfect… the future that it imagined and the astronomy that the film got horribly wrong

If you are a space fan, almost certainly you have seen “2001 – A Space Odyssey”. I was too young to see its original release in cinemas but, more than ten years later, you could still find it projected somewhere in London. It is a remarkable film that coincided in release with the launch of the first Apollo missions and both influenced them and was influenced by them.

The scenes of the flight of Dr Heyward Floyd up to the orbiting space station and then, from the space station to the Moon have become so iconic that they are probably the most memorable sequences of any science fiction film that has ever been made. I have watched the film many times, to the point that I cannot listen to The Blue Danube without seeing mental images of that Orion flight to the space station. And, of course, the BBC theme music for all their Apollo coverage was “Zarathustra”, which was used in “2001” for the Dawn of Man scenes and at the end of the film.

There are many tales to come out of the film that show just how closely it was related to the Apollo programme and in the minds of the astronauts when they flew to the Moon. As delays in release mounted – a joke among the creative team was that the title would need to be changed to “2002” – and the schedule for the Apollo missions changed, Stanley Kubrick started to worry that Apollo 8 might genuinely find evidence of some alien artefact on the Moon that would steal the film’s thunder. Kubrick was sufficiently Running_in_Skylab4concerned to inquire about taking out insurance against such a possibility. How the insurer that he approached calculated the premium is a mystery, but the price quoted was so elevated (Arthur C. Clarke later used the “A-word” to describe it), that the idea was dropped. Later, the Skylab 4 astronauts reproduced the scene of the running track around the ring of Discovery (you can see a video of that here, as well as the animated GIF [left]).

One of the famous exchanges between the Apollo 8 crew and Mission Control came at the end of the period of 43 minutes 15 seconds of nervous radio silence as the spacecraft went behind the Moon for the last time[i]. During this period out of contact, the crew had to start the Service Module engine to send them back to Earth: if the engine failed to ignite, the mission would remain in lunar orbit for ever, becoming the crew’s tomb.

Although the Ground Station at Honeysuckle Creek, near Canberra, Australia, picked up the signal from Apollo 8, they struggled to get the signal lock that would permit voice communications and confirm that the burn had gone correctly. The nervousness shows in the following exchange with Ken Mattingly, later to become famous for being unable to fly to the Moon with Jim Lovell on Apollo 13, had this exchange with his future Commander (CapCom in magenta, Apollo 8 crew in black, my editorial notes in blue – the times are always Ground Elapsed Time… the time since launch in hours, minutes and seconds):

089:31:12 Mattingly: Apollo 8, Houston. [No answer.]

089:31:30 Mattingly: Apollo 8, Houston. [No answer.]

089:31:58 Mattingly: Apollo 8, Houston. [No answer.]

089:32:50 Mattingly: Apollo 8, Houston. [No answer.]

089:33:38 Mattingly: Apollo 8, Houston.

089:34:16 Lovell: Houston, Apollo 8, over.

089:34:19 Mattingly: Hello, Apollo 8. Loud and clear.

089:34:25 Lovell: Roger. Please be informed there is a Santa Claus.

[This is Jim Lovell’s way of saying that luck has been on their side and that the big engine that they were so worried about, has worked.]

089:34:31 Mattingly: That’s affirmative. You’re the best ones to know.

089:34:37 Lovell: And burn status report: it burned on time; Burn time, 2 minutes, 23 seconds; seven-tenths plus VGX. Attitude nominal, residuals; minus five-tenths VGX, plus four-tenths VGY, minus 0 VGZ; Delta-VC, minus 26.4.

089:35:14 Mattingly: Roger.

089:35:19 Mattingly: Apollo FLIGHT has…

[A sudden, horrible realisation falls on Mission Control that Jim Lovell has given a burn time that was far too short to bring the astronauts home safely.]

089:35:23 Mattingly: Apollo 8, re-confirm your burn time, please.

089:35:30 Lovell: Roger. We had 2 minutes, 23 seconds. Our – wait one. Stand corrected to that; 3 minutes, 23 seconds.

089:35:43 Mattingly: Thank you. [Long pause.]

Less well known is that the crew’s mischievous streak – all of them had seen “2001” – had tempted them to report, when they came out from behind the Moon for the first time, knowing full well that they were the first human eyes to see the terrain other than in photographs, that they had observed a large, black monolith on the lunar farside.

Later, of course, there are the parallels between Apollo 13’s accident and the critical scenes of Discovery’s problems en route to Jupiter. Not only was the Apollo 13 Command Module called “Odyssey”, but the crew was playing the Zarathustra theme just before the explosion.

In the film, at the top of page 40 of the script, HAL states:

Sorry to interrupt the festivities, Dave, but I think that we’ve got a problem.

While, aboard Apollo 13 (with the Lunar Module docked, the call-sign was “Apollo 13”: it was only “Odyssey” when the Lunar Module was undocked), Jack Swigert made the famous call:

055:55:19 Swigert: Okay, Houston…

055:55:19 Lovell: …Houston…

055:55:20 Swigert: …we’ve had a problem here. [Pause.]

The Swigert quote, often attributed, wrongly, to Jim Lovell, who started to report simultaneously, is often misremembered as “Houston, we have a problem”, with people combining HAL and Swigert. When the mission report came out, NASA Administrator, Tom Paine sent a copy of the report to Arthur C. Clarke. He underlined Swigert’s words and, on the cover of the report, wrote:

Just as you always said it would be, Arthur

Many people have wondered why the book of 2001 – A Space Odyssey and the film version are so different in some respects. In the novelisation, written by Arthur C. Clarke, Discovery heads to Iapetus, the 8th moon of Saturn, for the encounter with the monolith while, in the film version, the encounter takes place in orbit around Jupiter. Douglas Trumble, who produced the special effects for 2001, filmed the Saturn encounter first, before Stanley Kubrick changed his mind and decided to re-shoot the scenes at Jupiter, changing the script to make Discovery a Jupiter mission. What Douglas Trumble thought of this is not recorded but, it was not all wasted effort because he was able, later, to draw on his 2001 experience in the film Silent Running, which was set around a Saturn flyby. Arthur C. Clarke, however, based the novelisation on the earlier version of the script and, with filming and novel being produced in parallel and both with long lead-up times, it was impossible for late changes in one to be reflected in the other.

When Stanley Kubrick approached Arthur C. Clarke with the idea of making “a good science fiction movie”, Clarke looked back at his short stories for inspiration and found half a dozen examples of his early writing that he classed as “the story of how the solar system was won”. Almost all the stories appear in the collection “The Other Side of the Sky”. In the six vignettes that make up the set that give their name to the whole collection, one can recognise clearly the Catherine wheel space station that is being constructed still in the film. Other elements of 2001 are visible in another set of six vignettes “Venture to the Moon” that appears in the same collection. However, the key story is one called “The Sentinel” that he wrote in 1948 for a BBC Short Story competition. 226363main_2001_station_t_fullTo Arthur C. Clarke’s surprise, the story did not even get a commendation, but it was published five years later in his collection “Expedition to Earth”.

The Sentinel in Clarke’s story was a relatively small tetrahedron, not the 1:3:9 rectangular parallelepiped of the movie. Many other things in the plot of 2001 changed over the years and through the successive re-writings, as was recounted in Arthur C. Clarke’s book “The Lost Worlds of 2001”. One of the more bizarre ideas that Kubrick and Clarke kicked around early in the process of writing the script was the suggestion that the tetrahedral Sentinel was an ambassador, who would be brought back to Earth and accorded a ticker-tape parade in an open-top limousine. Similarly, in early versions of the 2001 novel, HAL was a humanoid robot called Athena and not a computer at all.

One potential criticism of 2001 is that it did not predict the future successfully: despite its spectacularly accurate depiction of videocalls, twenty years past the millennium there is no base in Clavius crater on the Moon; PanAm does not fly scheduled services to Earth orbit (although private company, SpaceX does!), nor connections from the Space Station to the Moon; Barron Hilton does not have a hotel in a space station and less still in the wheel-shaped station of 2001; there are no crewed flights to the planets and will not be for probably a couple of decades at very least; and hypothermia technology for spaceflight is still a long off. However, this misses the point of science fiction, particularly good science fiction. A writer does not set out to predict the future: he or she sets out to answer the question “what if…” What if crewed flights to the planets are possible? What if we can travel to other stars? What if it is possible to travel faster than light? The writer tries to imagine a plausible future in which these things could happen (not “will happen”), how they might happen and what their impact could be.


A point that Arthur C. Clarke has made forcefully in his forward to his novel “The Songs of Distant Earth” is that there is a sharp dividing line between what is science fiction and what is science fantasy. One uses plausible science, or its extrapolation, the other violates the fundamental laws of the universe and thus describes things that are pure fantasy. Faster than light travel is a case in point: there is, at least at present, no plausible way that it can happen; in fact, one hundred years after relativity, there is no hint that the speed of light is not the absolute speed limit in the universe. Any story that uses faster than light travel is science fantasy, not science fiction. Unless our ideas are wildly wrong, no future Captain Kirk will be able to order “ahead, Warp Factor 5”, nor request “Scotty, beam me up”: like time travel, it seems that the universe has fundamental issues with beam transporters and travel between distant stars that takes just a few hours[ii].

That said, Star Trek has had a huge influence on our modern world in ways that Gene Roddenberry would never have imagined when he set out to produce a “good science fiction series”. Star Trek did not predict the future: it made it!

When the US Department of Defence wanted to know what the bridge of its future warships should look like, a deputation of senior officers went to the studio to be given a tour of the bridge of the Starship Enterprise. As a result, William Shatner or Patrick Stewart would feel remarkably at home on the bridge of a modern aircraft carrier. Other things were just as influential: we are now used to computerised voices that can recognise and answer our questions in the same way that the computer of the Enterprise can and library computers that, like the one on the Enterprise, can store and recover in an instant masses of knowledge that were inconceivable with the pea-brained computers of the mid-1960s. Even more mundane things though have influenced: people were envious of the sliding doors on the Enterprise that opened when someone approached; now, of course, we see automatic, sliding doors everywhere but, in the 1960s, they were just a fantasy (two stagehands where hidden out of sight, opening and closing the doors on command in front of the actors).

When you imagine something that is plausible, possible and attractive, as Star Trek did so many times, someone will find a way to make it work in real life. One of the few exceptions so far are the diagnostic beds and medical tricorders of Doctor McCoy and his team: despite all efforts and prizes offer for the development of a real-life medical tricorder that can diagnose a patient with a quick scan of the body, no one has yet cracked the problem (but you can be sure that they will… one day).

Coming back to “2001 – a Space Odyssey”, the film has aged remarkably well. Many television series and movies of the 1960s and ‘70s are really showing their age now: awful special effects, eye-watering costumes and terrible cardboard and plastic sets – you could get away with a lot when a series was being watched in black and white on a 405 lines television – but 2001 is still remarkably watchable. The exteriors and sets on board the spacecraft are believable, the representation of weightlessness still looks seamless, the computer graphics of the instruments would not be out of place today (computer graphics were barely starting in the late 1960s) and the technology still stands up well. A straw poll of colleagues showed that we liked the space suits of Frank Poole and Dave Bowman far more than the ones that Doug Hurley and Bob Behnken wore on their recent flight to the ISS.

The film made tremendous efforts to try and get the spaceflight right and, because of that, the film remains so watchable. Kubrick and Clarke did, however, make one deliberate omission: the nuclear drive of Discovery would have needed huge cooling fins but, they decided that putting giant wings on a spacecraft designed for airless flight would be too confusing to film-goers and so decided not to include them [the irony of 2001 trying not to confuse spectators in this was, perhaps, lost on Stanley Kubrick].


It is because of the tremendous attention to detail that Stanley Kubrick and Arthur C. Clarke showed that I was surprised to notice a couple of really bad examples of continuity in the film. They are so glaring that I am astonished that I had not noticed them previously. Then I watched the sequences again, paying closer attention and found no fewer than ten major continuity errors in the moonflight sequence of the film. So, for those movie nit-pickers out there and many of my colleagues admit that they cannot watch a science-fiction film without picking-apart the science, here are the ones that I have spotted.

We recall that, in the moonflight sequence, Dr Heywood Floyd is travelling from the Space Station to Clavius Base to talk to Senior Staff and to inspect the monolith, which has just been uncovered and has not yet been illuminated, having been unearthed (unmooned???) during the current two-week lunar night.

Let’s follow the sequence of timings of events established in the various lunar scenes between  his departure from the Space Station and the signal beacon emitted by the monolith:

  1. Minute 32:25 of the film. We see the Moon Shuttle in transit. The Moon is gibbous, about 3 days from Full Moon. Sinus Iridium – the stunningly beautiful Bay of Rainbows where the first Chinese Jade Rabbit rover landed – is fully illuminated. And Clavius, one of the largest craters on the Moon and, to me, one of the most spectacular, a mere 225km across, is also fully illuminated (we see it bottom-centre of the lunar disk) as, we see clearly, is the floor of nearby Tycho, where the monolith is standing. The interior of Tycho will remain illuminated for the next 11-12 days.

Here is the first error. Floyd has been called to the Moon at short notice because the monolith has been found. The monolith is a “fire alarm” designed to emit a signal when exposed to sunlight for the first time: this signal will reveal to its creators that an advanced civilisation capable of travelling to the Moon has appeared on the Earth. Either the monolith has not yet been uncovered and Heywood Floyd’s voyage is being made almost a month too soon or, despite the intentions of its creators, the monolith failed to react the first time that it was illuminated by the Sun’s rays. Either way, there is a rather glaring plot-hole in the script.

  1. Minute 33:20: We see a beautiful perspective of the Earth and Sun from the PanAm Moon Shuttle. The Earth’s phase, correctly, perfectly mirrors the Moon’s phase from the previous shot (the illuminated part of the Earth from this perspective should correspond to the shape of the unilluminated part of the Moon). So, Tycho is still fully illuminated.
  2. Minute 35:19: The scene switches from the Moon Shuttle’s zero-gravity toilet, to the its final approach to the Moon. We now see a waxing crescent Moon, about 5 days old. The terminator – the line between light and dark -is crossing Mare Nubium and is about to reach the Apollo 11 landing site. Tycho and Clavius will remain dark for another 2-3 days until sunrise. The implication is that more than three weeks have passed between the previous scene and this one, although the Moon Shuttle journey will be no more than two days long.

However, this shot is now consistent with the intended chronology: Floyd lands at Clavius in darkness; gives his presentation to senior staff and then sets out on his journey by moon-hopper to Tycho – a trip that will take the best part of a day, judging by the stately progress of the moon-hopper over the landscape – arriving in time for sunrise over the monolith.

  1. Minute 35:30: The shot changes and now we see the Moon Shuttle on final approach to a waning Half Moon. Tycho and Clavius are still illuminated although, in both cases, the shadows are creeping down the western ramparts of the craters to their respective floors as lunar night approaches. To be consistent with the previous scene another seventeen days must have passed.

This scene is, obviously, totally inconsistent in timing with the previous one and, worse also, inconsistent with the the chronology established by first two lunar scenes.

  1. Minute 35:56: We see a lovely image of a brilliantly illuminated Tycho crater with the halo that appears at Full Moon through the windows of the Moon Shuttle, as Heywood Floyd views the landing at Clavius Base. This image corresponds to a phase of the Moon some three weeks after the previous scene. If the monolith has been exposed already, as the film supposes, it will have been in full sunlight the entire time.
  2. Minute 36:34: The Moon Shuttle lands at Clavius in darkness, with the scene illuminated only by the of the waxing gibbous, almost full Earth. The Moon’s phase will be the inverse of the Earth’s so, roughly consistent with the phase shown at minute 35:19, save for one detail: the image shows Earth about 4 days before full when, to be consistent with the earlier scene, it would have to be about 4 days after full.
  3. Minute 37:16: Lo and behold, the Moon Shuttle is landing and, suddenly, we see now a waning gibbous Earth so, apparently, about another 8 days have passed since the previous scene!!
  4. Minute 38:23: The waxing gibbous Earth is back. Another three weeks appear to have passed for the Earth to have passed from waning gibbous to waxing gibbous phase in the last minute of action.
  5. Minute 44:21: We see a waxing gibbous Earth, consistent with the previous scene.
  6. Minute 44:39: The waning gibbous Earth is back. Another three week jump in apparent time.
  7. Minute 47:36: And now, a waxing gibbous Earth is visible in the sky over the base at Tycho crater. Another eight-day leap in time. The shadows in the crater indicate that the Sun is about to rise, but the phase of the Earth indicates that the Sun just just set and that the best part of four weeks will pass before sunrise.
  8. Minute 48:48: Heywood Floyd arrives at the monolith and we still have a waxing gibbous Earth, but the approaching line of sunlight is clearly visible, which is physically impossible as the floor of Tycho would have been in darkness now for several days, so the line of sunlight would be receding and far below the horizon.

So, I conclude that, despite all the efforts of Stanley Kubrick and Arthur C. Clarke, some important and totally avoidable science errors did creep into the film, but it is still a massive tour de force and will continue to be remembered and watched still for decades to come. At the same time, 2001 just like Star Trek, has influenced our lives and will continue to influence them, as people try to turn the future that they have imagined into a reality that we can live.


[i] The flight log records the internal conversations on board Apollo 8 during this communication blackout, recorded on the Command Module tape recorder. Bill Anders switched it off at 089:24:13 GET, leaving a seven minute gap with no record of any crew conversation. The flight log records these conversations in dark red to distinguish them from communications with the ground.

[ii] In one episode, Chekov reports, “it’s only a tenth of a parsec away, we’ll be there in a couple of minutes, Captain”. That indicates that the Enterprise’s cruising speed is around 100 thousand times the speed of light.

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