2001: EVA Pod Continuity

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Welcome to my documents related to the iconic space pods featured in Stanley Kubrick's 1968 film, 2001: a Space Odyssey. Check the sidebar to the left (or click on the three line icon) to see other related pages.

Introduction

Like all films, 2001: a Space Odyssey has a few minor continuity errors. Despite director Stanley Kubrick’s legendary attention to detail, the occasional inconsistency did creep in during the course of the incredibly complex production.

Why this list of obscure continuity trivia related to the film's EVA (extravehicular activity) one-person space pod? Well, basically it’s because I decided to build a small model of the pod for display as part of the Stanley Kubrick Exhibition in 2019 and as my own little 50th Anniversary of 2001 observance. And I wanted to get the thing as accurate as I could.

I noticed these inconsistencies and decided to document them. It’s not that they haven’t been observed before, but I thought it’d be useful to have this information online, for anyone else building a model. Because when you hit a continuity error you, as a model maker, basically have to decide which version to build. And there's certainly no criticism intended. Every film production has compromises and occasional issues, even one as meticulously crafted as 2001.

The photos here are from screen grabs and a variety of other sources found online. All images are copyright their respective rights holders, and are reposted here for purposes of research and criticism.

I have visited the Kubrick Archives and noted down details from some of the unpublished material they keep, but I do not have permission to publish or distribute any of that material, so this site does not include any of those images. There are complicated rights issues associated with the 2001 properties.

Multipods

Multiple pods in various sizes were used throughout the course of the film.

It’s possible a new pods were built for the purpose of filming the space and hotel scenes, but that would have added to the budget. I think recycling the pod bay props is more likely, but I've seen no evidence one way or the other.

Pod designers Frederick Ordway and Harry Lange pose for publicity photos in the pod bay set.

A continuity Polaroid of an unknown technician working with the 13.5" model.

An in-progress shot of the model, from a collection of Polaroids taken by Andrew Birkin and auctioned by Sotheby's in 2019. I have retouched the image to remove cut lines.

Amazingly it was constructed from beautifully turned laminated wood, as well as machined aluminium.

A page from Jerome Agel's 1970 book, the Making of Kubrick's 2001, describing the model pod as 13" in size, quoting Douglas Trumbull from his article in American Cinematographer.

This continuity Polaroid shows Gary Lockwood having no fun, suspended from the full-sized pod during a test setup. He obviously wore his helmet during filming of the real scene.

Note the cables going into the pod door. Because the scene was shot from below, the cables weren't visible - Lockwood's body hid them – simulating weightless conditions. However, in the final film you can see shadows of the cables appearing for a brief moment!

It's a testament to the skill of the craftspeople who made the model that it's pretty well indistinguishable on-screen from the full-sized pods, but some minor continuity errors did appear between the different versions.

Window Tinting

This isn’t arguably a continuity error per se, since it can be explained narratively, but all the pod bay pods have clear windows and all the pods in space have reflective opaque black windows.

Why? Well, the pods in the bay were never shown with moving arms. And the middle of the three pods had to have a mocked-up interior to accommodate the scenes in which the astronauts were shown climbing aboard. So the windows were clear plastic.

However the space scenes required pods with moving arms. And the mechanisms to make the arms work took up a bunch of internal space. Accordingly the space pods all had black windows to conceal the workings.

An excerpt from Agel's Making of 2001, quoting Trumbull

This apparent discrepancy was arguably explained by the scene when Bowman adjusts the tinting of his helmet visor, using a forearm-mounted button pad. This would prevent him from being blinded by unfiltered sunlight, there being no atmosphere in space. So it’s reasonable to assume that the pod windows would have had similarly adjustable polarized materials.

Cockpit interior

When it comes to continuity issues, the interior is the big one. So much so that I've basically moved all the interior-related content to its own page, as this one was getting long.

2001: EVA Pod Interior

The camera cone

Here’s one that’s not a continuity error as such, but may appear at first glance to be illogical. And that is the camera cone near the door.

The pod is covered with a bunch of recessed dishes. Some - notably the ones on the “earmuffs” - are painted black and are obviously meant to be small rocket engines. Those have faint lines radiating out from the centre, though you can't see those in the movie and only one or two photos show them. But some are painted white and contain fluted silver tubes or rings. And within each ring is a curved lens.

The white recesses thus contain cameras, which provide visual coverage to the pilot for areas away from the window. Quite ingenious, though of course it made more sense in the 1960s when video cameras were quite big. Modern cameras would actually be tiny, equipped with wide-angle “fisheye” lenses, and wouldn’t be anywhere near as large as the fluted metal rings seen on the space pod. The recessed dish idea is clever, since it’s intended to be a protective solution for the cameras, but of course would restrict the angle of view visible by each lens. This is one area where real life technology has vastly surpassed the technology of 2001.

Incidentally, the camera cylinders are interesting. They're seemingly identical to the ones seen on the Space Station V set - the videophone camera and the voiceprint ID cameras. Were these recycled prop pieces? Or are they different enough in some way – maybe different sizes – that each camera is a one-off?

Anyway. One of the cameras, interestingly enough, is at the tip of a projecting cone and not in a recessed dish. I’ve always wondered about this - why have just one of the cameras sticking out?

The cone is at the rear starboard side. So it seems likely that it was a solution for door clearance problems. A recessed dish would have protruded down into the area where the door rotates internally.

Pod cameras and HAL eye

That said, there is actually a continuity error involving cameras! And that's the camera mounted on the very front of the vehicle, beneath the window.

The pods in the bay all feature a recess with a silver camera cylinder.

However the pods in the space scenes have a black and red-lit HAL eye instead of a silver tube. It appears that Kubrick decided to emphasize HAL’s surveillance capabilities to the audience, but after the pod bay scenes were shot.

Interestingly enough, the shot of the pod in the alien hotel room shows a pod with a silver tube camera. This despite the fact that the hotel room was apparently one of the final live-action scenes to be filmed. So perhaps they took one of the two non-space pods out of storage to film this scene, but never changed out the front lens.

Incidentally, the theory that perhaps one of the pods had a HAL lens and the other pods didn't is incorrect. Photos exist of the pod bay showing all three pods in one frame, and none have HAL lenses.

Front panel detail

During the pod attack scene, when HAL hijacks Poole’s innocent pod and turns it into a callous weapon of murder, the craft is shown turning towards the camera and lunging forward with arms outspread. This is followed by a rapid sequence of increasingly close views of the pod’s front panel.

Surprisingly, this jump cut sequence actually features two different props. Most of the sequence depicts one of the full-sized pods. But the last clips, the closeup views, briefly show a rebuilt front panel, which has increased detail and more obvious fine print on the lettering.

There are thus physical differences in detail between the full-sized pods and the rebuilt front. The projecting thingie inside the round recess on the starboard side, for example, is noticeably different – it's kind of a vertical paddle for most of the pods, but a horizontal diamond for the closeup view. The trellis-type thing on the port side is considerably more built up in the closeup view. And the lower panel of the closeup view is nearer to the horizontal shelf-type structure (ie: it extends upwards further, and the "shelf" supports extend further down) than on other pod versions. Finally, there are obvious black and red Harry Lange-type curved lines around each circular object. These appear in the pod shot above, but the pod bay pods lack these lines.

Incidentally, what are all these thingies supposed to be? The camera lens is obvious, but what about all the other stuff? The thing at the lower left might be some sort of electrical socket. Maybe the recessed round things are kind of fuel connectors for hooking up fuel hoses. Or exhausts when the machine is in an atmosphere? But the other stuff? Who knows!

Clearly Kubrick never figured on a far-off future where people would have high-rez copies of his movie at home, and religiously analyze them.

Writing

There seem to be subtle differences between the pods in terms of the writing on the outside. The most obvious is the word “CAUTION” in red above the top headlights. It exists on some pods but not on others.

Sadly most published photos aren't high enough resolution to reveal what most of the writing actually read, with the exception of the aforementioned "CAUTION", the text on the higher-rez front panel in the photo above and, of course, the famous "EXPLOSIVE BOLTS" text on the door.

There are a few high-rez medium format transparencies in the Kubrick Archives. Not all are publicly available, but these mostly show the mid-sized lettering like "DEST DETON INSTALL", "GHV SVC", "MAN ARM REMOVAL, "LENS INSTALL", "TELEM SDL", "ELECT MOD INSP ACC", "NOTICE USE ONLY 4V3 REPLACEMENT", and so on. The tiny blocks of text are still blurs.

It's quite likely that the small blocks are boilerplate. Elsewhere – the pod interior and the spacesuit backpacks – the fine print text is actually application instructions and patent numbers of the Letraset dry transfers that were used for the lettering.

Underside: the jet engine

The underside of the pods isn’t clearly shown in the film. Nor are there any still photos of the underside of any pod that I’ve been able to find, and this includes a search I conducted in the Kubrick Archives.

It's clear that the underside was supposed to have a recessed rocket engine. This is visible from the first crude mockup models used as maquettes for setting up the shots of the EVA pod with the Discovery. (photos of the small maquettes are in the Kubrick Archives, and I've seen them, but I'm not sure if they're publicly available. The large maquette was auctioned recently.) And various other sources, such as Robert McCall's promotional painting below, show a rocket-powered pod. Of course this painting is obviously hardly canon and, despite looking awesome, has a lot of deviations from the movie pod, such as a protruding engine bell and various stripes on the front.

The storyboards also show a base-mounted recessed engine.

This idea of a big rocket engine down there, like the engine of the Apollo Lunar Excursion Module, has always puzzled me. In the film the pod is shown moving forward, as it were. Not “upwards” relative to the pilot's seated position. So it would be propelled by the reaction control engines on the side-mounted “earmuffs”. Even when Bowman is rushing out to try and rescue Poole he doesn't use the big engine on the bottom.

So why have an engine down there at all? 2001 fan and model maker Paul Bodensiek suggests that maybe they were thinking the pods could be used on the Jupiter mission to land on Jovian moons for science exploration. Arthur C. Clarke's novel says that "The main rocket drive produced an acceleration of one-fifth of a gravity - just sufficient to hover on the Moon - while small attitude-control nozzles allowed for steering."

The moon exploration idea is a plausible theory, though of course the pods lack any form of landing gear, and are quite small vehicles, which suggests they were designed for brief maintenance jaunts around the Discovery, not for long treks out to a moon, where lots of fuel, air and water would be required. So who knows?

Navigation thrusters

Of course, one questionable aspect to the overall pod design is the lack of logically positioned thrusters in general. Actual spacecraft always have at least 12-16 separate rocket thrusters, pointing in various directions and usually paired to avoid unintended vehicle rotation. These are used both to move the vehicle through space (translation) and spin it around to face different directions as required (attitude control).

This NASA diagram shows how the RCS (reaction control system) worked on the Gemini space capsule. 

The 2001 EVA pod has a bunch of thrusters on each earmuff (5 large ones and possibly 4 to 8 small ones) which could be used for translation and attitude control, but notably there's no obvious way for the pod to control its pitch. (thanks to Piers Bizony for pointing this one out!) In an aircraft, pitch is the movement of the plane which raises the nose and lowers the tail, or vice-versa.

This side view of a pod shows the port-side “earmuff” which contains half of the main rocket thrusters. There are five main thrusters on the spherical section. There are also four mid-sized and four small recesses, each with silver rings around them, on the flat portion of the earmuffs. These might be fine control thrusters, as I can't think what else they'd supposed to be. If the mid-sized ones had gimballed (tiltable) internal bells they might work for pitch control, I suppose, but they don't look like they're designed that way in these photos. The two lower pipes/tubes (see lower) might conceivably be used for pitch up, but there's nothing for pitch down.

Underside: the greeblies

Anyway. Although no surviving photos seem to exist, the pod underside is briefly visible, and in shadow, twice in the actual movie. And the views are quite different. Both show the recessed cone of the engine bell, but one shows odd detail bits ("greeblies" in Star Wars parlance) and the other does not. Since the two views are supposed to be of the same pod (the one Bowman rushes out in, during his ill-fated attempt to rescue Poole) this is a continuity error.

Here are some screen grabs from the BluRay movie of those two moments, brightened and contrast-altered to eke out more detail. Note that the bases look grey in colour in these shots, but I don't think they were. I think it's purely a matter of lighting – I suspect they were white like the pods as a whole. Note also that this pod also has the red and black curved coloured stripes around the front details, as seen in the attack sequence.

The surviving blueprints don’t help. In fact, they show aspects to the design that were never built – parallel rails running along the side of the pod bottom, and a pair of recessed round handgrips.

Here are excerpts from the blueprints published in Piers Bizony's The Making of 2001, and Adam Johnson's 2001: the Lost Science. They're not the final design, and include features not seen in the screen-used pods.

Sadly the brief glimpse we get of the greeblies isn’t very well defined, especially for the stuff on the starboard side of the vehicle. Even examination of a 4K disc doesn’t reveal that much more detail because of the shadow.

Should I include the greeblies?

So one of the major decisions I had to make when making my pod model was whether to include the underside greeblies or not. The basic choices are:

Greeblies Yes!

Greeblies No!

What did I do in the end? I added the greeblies to my 65mm pod, because I thought they were kind of fun, and the underside of my model would be highly visible when on display in the museum. I modelled them after the frames visible in the 4K BluRay transfer. Unfortunately there are some areas where I wasn't able to make out a lot of detail, and so I based the greeblies on known model kit parts used on the Aries 1B. This decision does mean that my model has a few details that weren't on the actual movie props, of course.

I'm currently working on a larger pod and will not be including the greeblies on that one. Mainly because we just don't have enough detailed information to replicate them accurately at a larger scale.

The pipe thingies

Immediately below the rear step are a pair of round cylinders. It's not obvious what these are supposed to be. They can't be exhaust pipes, because such things make no sense in the vacuum of space. They're not cameras, since there are two cameras beside them. They're not lights, as they have black covers. They're not rocket jets or vernier thrusters as they look nothing like any of the other ones, plus they're so off-centre (away from the pod's centre of gravity) that they would cause the whole pod to spin crazily if fired.

Now, in one of the Archives photos I was able to make out the word “COUPLING” visible, slightly offset implying another word preceded it, over the starboard tube. So perhaps that's what they were meant to be, though they're never shown connected to anything in the film.

Anyway. In the pod bay and alien hotel scenes, these cylinders have horizontal slots. In the outer space scenes they seem to have vertical ones. Mostly, anyway. There's one brief moment where round inserts are seen in the cylinders, not vertical vanes.

The handwheel and the red blocks

One ancient mystery of the EVA pod has been the function of the small handwheel on the port side (left side from the pilot's point of view) of the the door. This recessed six-sided wheel has long been presumed to be some sort of emergency door release thing, mainly because of its location next to the door and hatch. But no closeup photos of this part of the pod seem to exist. I've even searched the Kubrick Archives and haven't found anything.

However, now that 4K film scans are available of the movie in the form of a Blu-ray UHD disc, we can finally read the text next to the wheel. Thanks to 2001 enthusiast Karl Tate's research, we can see the words "REACTANT CELL INSERT". The black L-shaped area beneath the recessed wheel is also delineated by two lines, and the handle has a recessed marker line on its surface. The left-hand position is marked with some text, possibly the word "LOCK", and the right-hand position also has some fine text - possibly "UNLOCK". The small text is too blurry to read, but those words are certainly possibilities.

Finally, the square frame to the left of the wheel contains a red rectangular block in some scenes – notably the scene of Frank boarding the pod for the first spacewalk, the space scenes, and the alien hotel scene. But in at least one pod bay scene it's apparently empty and showing a black socket.

So. Perhaps the thing on the left is a removable module of some sort, for a depletable chemical energy cell. In that case, the rotating handle on the right, with its large finger recesses for a gloved hand, would be the release mechanism to allow the astronaut to remove said module. The black rectangles above and below the red thing might be hold-down clamps. Perhaps in the space scenes the module was in place. When the pod was in the bay, the module is seen removed for service or charging/replenishing.

Naturally this is all conjecture of what the designers of a fictional spacecraft had in mind, but I think it's a reasonable theory! It does seem like a pretty tiny module, though. It'd be like a motorcycle battery.

Of course, maybe they just forgot to put a red block back in there, and it's a simple continuity error after all.

Window shape

This isn't a continuity issue per se, but the windows have been the subject of a lot of debate over the years. Were they:

1. Flat

2. Curved in a cylindrical form (ie: curved on the horizontal axis but not the vertical axis)

3. Curved as a flattened sphere (ie: curved in both directions)

I believe the pod bay pod windows were sheets of acrylic, curved in one direction like a piece of a large horizontal cylinder. There are a lot of pod bay shots showing straight overhead reflected lines of the ceiling lights, so they couldn't have been spherical. And there are a handful of behind the scenes photos where you can see overhead equipment reflected in a window, but flattened slightly. This flattening says to me that the windows were curved in one direction.

Consider this behind the scenes shot. You can see that the overhead light fixture is a straight line, indicating that the window glass wasn't spherical. However, you can see a dark curved line in the middle of the window, indicating the surface curvature. In addition, the ceiling tank thingie reflected in the lower section of the window is compressed vertically. This shows that the window was curved as a cylinder.

The door and the explosive bolts

How was the emergency opening of the door supposed to work? This is an area of uncertainty that suggests a potential inconsistency.

Rotating door

First of all, the door on the back rotates. That's pretty clear, and is shown in the film during one of the pod bay sequences. The round cap on the top of the pod sphere is also the top rotation point of a slice-shaped door which rotates counter-clockwise. The bottom edge of the door probably rested on some sort of curved track. When fully open a small triangle of door remains in the upper-right section of the opening – it doesn't retract all the way inside the pod.

How was the door operated on the set? Now that is a mystery. Most likely a stagehand turned it rather than relying on an expensive mechanical device, but where the operator would have been sitting I have no idea. Perhaps there was an electric motor with a sort of rack and pinion mechanism on the lower track.

By the way - this photo shows a rarely noticed feature of the door - a series of raised details that protrude out from the edge of the door itself. These also reveal the door to be quite thick. The protrusions fit into notches or recesses on the left side of the inner doorframe; another detail that's hard to spot because the black notches vanish in the shadows.

Explosive bolts

For emergency egress, the door was meant to be equipped with electrically operated "explosive bolts". These are marked on the outside by 10 red squares with recessed metal cylinders. The squares have corresponding points on the inside.

If you look closely you'll see that the red squares delineate a rectangular groove in the door surface. This rectangle represents the door's emergency hatch. It's also a slightly darker shade in the photo below.

Emergency door hatch

Interestingly enough, at least one of the full-sized pod sets had a removable emergency hatch set within the door. In other words, the rectangle marked out by the red squares was a separate section that could be taken out by the filmmakers.

How do I know this when it doesn't appear open in the film? Well, a series of 35mm black and white photos taken by Dmitri Kessel shows Keir Dullea and Gary Lockwood in the pod bay, next to the backside of a pod. It must have been a hot day, as Dullea is holding a little battery-powered fan. Anyway. The pod that they're standing next to has the emergency hatch removed, but the door itself is shut! These photos are in the Archives but have not, to my knowledge, ever been published.

The Explosive bolts

So. This brings us to the scene when Dave Bowman backs his pod up against the emergency hatch on the Discovery, then blows the back door of the pod to enter the airlock. If you watch the scene carefully you'll see the pod by the airlock with its door shut, a sudden explosive cloud, and then the pod has a missing door.

In other words, the door hasn't swivelled back, because the triangle in the corner isn't visible. But neither has the emergency hatch been blown out, since the rest of the door isn't visible. And, if the emergency hatch had been blown out using the bolts, then the loose hatch would have been violently propelled into the airlock! (quite dangerous for the astronaut in this scenario, as the hatch would have then careened around, slamming into stuff) But the hatch isn't shown leaving the pod. Thus, how the door's emergency system was supposed to work remains a mystery!

Indeed, arguably the pod shouldn't even be hanging around outside the door after the hatch or door are opened. Not only is Dave blown out into the airlock, but all the air would also have been evacuated from the pod's interior. The pod would have been propelled uncontrollably away from the Discovery. Unless, perhaps it was on some sort of magic autopilot that maintained the vehicle's attitude the whole time!

Filming the explosive SCENE

You can see how the scene was filmed if you examine the footage frame by frame. The pod was positioned with its door closed, the charges or whatever was used to make the cloud of smoke were set off, and a cloud emerges from the outer edges of the airlock (rather than the supposed explosive bolts). Then the scene cuts to a second sequence. In this one the pod has no door, and Bowman is flung forward into the airlock. The cut between the two shots is very close, and of course happens so rapidly that nobody could ever notice the transition without viewing the scene frame by frame.

Famously this scene was filmed upside-down, with the camera at the bottom of the airlock set, pointing upwards. The pod was hung from the studio ceiling, with its door pointing down. Because his face would be plainly visible, Keir Dullea bravely shot the scene himself – it's not a stunt double. He was dropped out of the pod, through the cloud of smoke, into the airlock set itself. He was attached to a harness held by a man that Dullea described as a "circus roustabout," who had knotted the rope appropriately. Just before he was to slam into the bottom of the set, the roustabout hauled on the safety rope, yanking Dullea back up to the airlock ceiling. You can't see the rope in the final scene because Dullea is dangling downwards.

1. Pod with closed door is in position.

2. Cloud of smoke starts to appear.

3. The smoke has entered the "airlock" part of the set, as the red-tinted area indicates. The door is still closed.

4. This frame appears immediately after frame 3. Note how it's a separate take since the cloud is a different shape, and the pod door is now missing.

5. The smoke dissipates into the airlock, clearly revealing the missing pod door.

6. Keir Dullea as Bowman falls downwards into the airlock, since the scene was filmed "sideways" with the camera pointing up. Dullea's body hides the wires that he's hanging from.

7. Now we can fully see the pod doorframe, and its missing door.

Another fun piece of trivia: did you notice that the airlock actually contains a spare spacesuit? It's to the right of the airlock door. This is why Bowman wears a green helmet with his red suit during the HAL disconnection scene, even though there are no green suits in the pod bay – the green suit is in the airlock. It just doesn't look green in the airlock scene because of the red lighting.

Making a pod model

The most logical approach to making a nice pod model is to replicate the internal set used for the cockpit at a smaller scale, so that it can physically fit inside the model of the outside of the pod. This mostly works reasonably well, assuming you don't pay close attention to certain discrepancies of size, especially related to the depth of the windowframe and the width of the doorway.

But this approach does yield certain problems, such as the width of the control/indicator panels on the back wall of the cockpit. (you can't get these panels' proportions to match the internal cockpit set while still fitting in the space available in the scaled-down set installed in the pod) The geometry of the back door area is another intractable problem. It's basically impossible to get a back door and tunnel (the stuff covered in fake black leather) that has proportions matching both the exterior and interior views, given the need to cram the control panels and window recess in there.

It also means that any pilot figure inside the pod will have to be scaled down in size to fit, and can't be the same size as a figure on the outside of the pod that's scaled to the published dimensions of the model. (eg: the exterior of the pod might be scaled to 1:8, but the interior figure would have to be 1:9 or 1:10 or so)

Thanks

Thanks to Piers Bizony and Paul Bodensiek for their comments and assistance. Big thanks to the Stanley Kubrick Archive for access to original material. Additional thanks to Thomas Reddie for his excellent research and CGI models, and Karl Tate for 4K images and additional observations.