Its in the book 2010. There is a physics principle where spin will always shift to where the longest axis is spinning like in Discovery. One of the Shuttle astronauts demonstrated it in the ISS.
The Discovery at the end of 2001 is in fact not fully lit up. The bridge is fully darkened in the last shot we see of her as Bowman departs. Even the pod bay looks slightly dimmed behind his pod’s headlights. We can surmise Bowman did shut down some systems.
The spin of the Discovery might have come about from something called the Dzhanibekov effect. Essentially, if you have an object which spins around its own axis, if said object has three different moments of inertia, depending on what axis it rotates around, it will flip eventually. This effect was discovered when a cosmonaut named Vladimir Dzhanibekov opened a box in space, which had been secured with wing nuts, which happen to fulfill this quality. It's theoretically possible, therefore, that when we find the Discovery, it is in the process of reversing its orientation from the spin, provided it, too, has three different moments of inertia.
The "T-handle experiment" recorded on ISS helped me visualize this. It's 30 seconds here and there on YT. Discovery is similar to the T-handle in the sense of mass distribution. It would continue flipping back and forth for years until eventually settling on the preferred axis, which is across the midpoint below the antenna, very close to where Max and Walter chose to board. All my future spaceship designs will have a hatch right there.
Not quite. The Dzhanibekov effect happens to objects spinning about their "intermediate axis". That is, if an object has three different moments of inertial when spinning about its three principle axes, it will be unstable if spinning about the axis with the middle moment of inertia. Discovery may not even have such an intermediate axis. It's close to being radially symmetrical on the long axis. The engine deck is wider than tall, so the ship may have a slightly higher moment of inertia when spinning in yaw than in pitch, but the difference would be very small. In any case, spinning in roll has the smallest moment of inertia, so that spin should be stable. However, spinning in roll (on the long axis) does have the highest kinetic ENERGY. Angular momentum is moment of inertia times angular velocity. It must be conserved unless it can be transferred to another object. If the ship somehow shifts from spinning on the long axis (where moment of inertia is very low) to end over end (where moment of inertia is very high), angular velocity must decrease proportionally so that angular momentum is conserved. Angular kinetic ENERGY though is one half moment of inertia times angular velocity SQUARED. If the rotation shifts so that the moment of inertia is lets say 10 times higher, and the angular velocity is 10 times lower (so that momentum is conserved), what happens to kinetic energy? The moment of inertia went up 10 times, and the velocity went down 10 times, but the velocity term is squared and the moment of inertia term is not. 10*(1/10) is 1 but 10*(1/10)^2 is 0.1 Angular momentum was conserved, but angular kinetic energy went down 10 times! That's obvious no good. Energy must be conserved, but not KINETIC energy. Kinetic energy can become a different type of energy. What if it becomes heat? Kinetic energy has been lost, but momentum must still be conserved. The only way for that to happen is for the spin to shift such that moment of inertia increases. So, if the Discovery somehow lost some kinetic energy, then its spin would have had to shift axes in order for momentum to be conserved. The spin with the highest moment of inertia would be end over end with no long axis spin, which is just what we see in the film, so the only question is what would have taken away the kinetic energy? Discovery was abandoned for years, so it needn't have been a fast process. The air in the ship could turn some of the spin energy into turbulence and that into heat which would eventually radiate into space. The spine of the ship also must flex under load and the ship won't be perfectly balanced on any axis. That flexing back and forth would absorb kinetic energy to become heat in the metal. Tidal forces would also constantly pull and push the ship as it spun, which also consumes kinetic energy. Over a long enough time span, we should expect Discovery to end up spinning its lowest energy, most stable state: end over end.
@@TonboIV Yes, this is the correct explanation for what we see in the movie. It's worth noting that this exactly what happened with the Explorer 1 satellite: it started spinning around its long axis but, due to the flexing of its antennas, it started to lose energy and ended up in an end over end rotation. It's possible Clarke drew inspiration from that. Thank you for writing the complete explanation so that I didn't have to do it myself.
@@NoahSpurrier It started rotating along the long axis due of the slowing down of the flywheel of the centrifuge, then it transitioned to an end over end spin due to the loss of angular kinetic energy
The centrifuge, the rotating part of the Discovery heavily featured ibn 2001: A Space Odyssey had motors that turned it. The Discovery (is stated in the book 2010) spins due to this rotation being induced by the centrifuge slowly running down after Dave Bowman leaves, and pre-set commands shut the Discovery down (the flight deck can be seen to be dark as Dave leaves, for example). Either he did not expect to return, or he had an override command he could give that would allow him to enter again if he did. In the book 2010, again, the guys who get aboard begin a start-up process to power-up the Discovery, which causes her to make some wild gyrations as the spinning-up gyroscope 'mopped up' the rotation. This is simplified in the movie of 2010, with little if any explanation. The author was a scientist, as was quite able to imagine based upon knowledge, check with others and describe these evolutions. He had clearly stated over the publication history of his books that he updated scientific knowledge as it comes in. One example was that mankind had existed five million years ago as a hominid, a precursor to humanity. That was a guess, as he expected more evidence to be found. Later, more evidence WAS found, pushing human ancestry back to about 5 million years.
"This is simplified in the movie of 2010, with little if any explanation." Yeah in the movie she just suddenly stops on a dime without even seeing any thrusters fire.
There'd also be other forces involved as well. Radiation pressure, gravitation from the monolith that's nearby, gas and particles from Io would also tend to induce odd motions. Though, Yarkovsky effect from solar radiation would've been quite low at a Jovian orbit. Remember the Pioneer anomaly? Just from the RTG heat it was experiencing an acceleration that took decades to explain.
except tidal forces would have nullified that rotation over a period of ten years time. Long skinny objects in orbit always end up oriented axially to the center of the planet or moon they orbit due to tidal tension creating maximal forces in that orientation.
if you look at blueprints of the ship, it has a reactor purge vent labeled on the dorsal surface of the engine pod. if at some point the reactor purged (highly likely because of lack of management) this would have introduced the exact rotation we see.
Explorer 1 originally rotated along it's long axis but due to flexing of it's antenna it eventually began to tumble end over end which was it's maximum moment of inertial axis. If Discovery One had any flex in it's structure or fluids sloshing it would end up in a rotation about it's axis of maximum moment of inertial as well.
I thought the Discovery's spinning, discoloration, and it's decaying orbit were all caused by drag when it went through the sulphur particles in Io's volcanic ejecta. I-m pretty sure that was mentioned somewhere in the novel.
I have to re-watch (and re-read) the series. About that spin. Incidentally, Discovery`s rotation is correct when we consider orbital mechanics. Shes dead in orbit above Io - that mean no gyros, centrifuges etc to stabilize her. Twice during that orbit, she will be fully facing radial in and radial out orientation (directly toward and directly opposite to Io). At those times, the end closer to the surface will be travelling prograde (orbit direction) much faster than the other one (especially when shes 400/800m long), making her spin slowly. Every orbit it would build up and eventually, she will spin as seen in the movie. Im enjoying the topics and animations in Your videos. Keep up the good work, thanks. Subbed.
I never thought why Discovery was spinning, but thanks for covering it. A little fun fact, the 2010 Discovery model was going to be thrown out by the studio, but an executive at Cartoon Network was able to get their hands on it and bring it to the CN offices in Atlanta where it was hung from the ceiling in the elevator lobby. That's where I saw it in the late 1990's. It took on a kind of greenish tint, because the orange powder they used to coat discovery was copper based. I wonder if it's still there.
HAL wasn't completely turned off but was rather "lobotomized" with destroying higher functions such as reasoning, speech, memory etc. but preserving main functions on the ship: reactor control, environment/life support, engines, navigation. It was mentioned in a book that only this way Bowman had chance to reach destination. If he just destroy HAL that meant death of Discovery as well.
Yep, the movie doesn’t convey that time jump very well. They’re still in the asteroid belt when everything goes down, shown by them passing a chunk of rock at one point.
It was supposed to have been from the fact that the centerfuge section in Discovery had seized up and transferred the rotational energy to the ship itself although it seems like it was perpendicular in its axis rotation so I don’t see why that would’ve happened. That’s what it said in the book anyway. It’s also why they didn’t try to re-create the centrifuge set in 2010.
Yes, that is the explanation in the novel. Building the centerfuge, in the mid-Sixties at the British studio, was expensive. The huge set, that could be roasted was justified by the number of scenes shot inside it. For 2010, the main sets rebuilt for the Discovery were the command deck, and the Pod-bay. Now, the centerfuge would be a digital set.
IIRC the original book described that centrifuge as being mounted equatorially in relation to the module's globe. Perhaps the size problem didn't come up while the story was in that stage, though I'll admit my reading of it was some 50 years ago! Somewhere, also, I recall Clarke explaining that the ship was supposed to feature cooling fins for its nuclear engines, but those were dropped so as not to confuse the audience over why a vessel built for airless space might appear to need "wings."
@johnbayer9795 you are correct. Recall Bowman's call to Floyd. Despite saying "look behind you," Floyd has to look down. Because the place Bowman is "standing" is aligned with the hab wheel. Here's the scene from the movie: ruclips.net/video/yv3sGHbH2DI/видео.html
I just assumed the centrifuge radius wasn’t as large as the command module’s radius 😅 because indeed I figured what the orientation should’ve been right away. Though I liked your visualisations of the alternative spins. As to the “automatic operation”, I’d always thought HAL _was_ the automatic system. I suppose it makes sense to have some kind of backups though. I admit I didn’t think Dave actually shut down the centrifuge, but just that the angular momentum slowly transferred into the flywheel bearings. As no matter how good a bearing is, it has SOME friction. And that complex would have to be affixed to the rest of the ship, so the momentum transferred through those struts into the entire body. But maybe the timeframe doesn’t quite work out that way.
The question is answered in Clarke's book "2010: Odyssey Two". Discovery I had a gyroscopic system in the forward command module that simulated gravity for the astronauts living in space, Bowman runs the whole length of the track in a circle in one scene. It shut down when power went out and its axial momentum was transferred to the ship, making it spin along its axis. Once Curnow got the power back on and restarted the centrifuge in the living section it mostly stabilized again, the remaining spin was easily dealt with using attitude control thrusters.
Did the book also explain how they achieved that the engine spin only the "track" where the simulated gravity was needed and not the whole ship? Was the spinning of the rest of the ship constantly negated by thrusters or some kind of propulsion system?
@@Atarian6502 Now that's an interesting question because without some kind of counter-rotation from something else spinning on the ship it should have introduced some yaw or roll into Discovery I's flight.
I can't find my copy of 2010. 😊🤫 So, relying on my Swiss cheese memory, I'm not sure Discovery's centrifuge had a separate flywheel. The usable area of the centrifuge is already its own flywheel and wouldn't need redundant mass. The seized bearings would be between the centrifuge and the vessel structure. If a separate flywheel were used, it would spin in the opposite direction in order to cancel out precession effects, so that Discovery could maneuver. Clarke did much better scientific research than most other authors, before or since. Having Discovery rotate end over end makes sense regardless of the orientation of the centrifuge, because of the "preferred axis" effect you mentioned. (The experiment done on ISS with a T-handle helped me visualize this.) If Discovery had a separate flywheel spinning in the opposite direction, seized bearings would stop both the centrifuge and flywheel at the same time, and the opposing angular momentum of both parts would cancel each other out.
Discovery could have shifted from a long axis spin to an end over end spin if it lost kinetic energy. Only total energy is conserved. Kinetic energy can become heat. If Discovery ended up spinning on its long axis when the flywheel stopped, and was then left like that for years, some loss of kinetic energy would be inevitable. Tidal forces would flex the structure back and forth with each spin. The ship would also not be perfectly balanced on its axis and the uneven forced would probably cause some rhythmic flexing of the spine. Air and propellant might be churned around. Slowly kinetic energy would be converted into heat and radiated into space. Angular momentum has to be conserved though. If the angular velocity is dropping, the only way to conserve momentum is for the moment of inertia to increase, and that CAN happen, if the spin axis shifts to one which maximized moment of inertia. Angular momentum is conserved, so this increase in moment of inertia decreases angular velocity proportionally. Because angular kinetic energy is proportional to the square of angular velocity, this shift in axis allows the kinetic energy to decrease, which in turn allows Discovery to discard some of its kinetic energy as heat until it reaches its lowest kinetic energy spin: end over end. That's exactly what happened to the first American satellite: Explorer 1. It was spun on its long axis during launch which it was thought would keep it stable, but the long flexible antennas consumed kinetic energy, shifting the axial spin to an end over end spin.
One other possible explanation for the rotation we see with Discovery could be the so-called "Pioneer Anomaly", where a radiation source spread unevenly across the surface of the spacecraft can, over the course of enough time, exert a rotational force on the spacecraft. Given the strength of Jupiter's radiation belts, I think it's possible that may have lead to the rotation seen on screen
a ship the size and shape of Discovery would be subject to tidal forces as well. Gravity interactions would eventually induce spin along some axis until eventually the distribution of mass would place the higher mass end (likely the engine end) point toward the major body gravity source (IO) eventually becoming tidally locked.
If the bearings in the centrifuge and/or flywheel seizing up was detected by a localized failsafe system, they may have been gracefully stopped preventing a spin along the lengthwise axis. Without that gyroscopic force stabilizing the ship, like the force keeping your bike upright from the gyroscopic force of the spinning wheels, it would now be free to spin around either of the other 2 axis. With no reaction wheel system running, the ship could no longer actively resist rotation. Anything could've given it that gentile push to start that end over end rotation. Additionally, if the detected error in the reaction wheel/flywheel system was the seizure of the wheel controlling the pitch, that rotation could've been started first before the ship scrammed the rest of the reaction wheel to prevent another failure from making it worse. I'd assume the ship has some sort of RCS system, but being that the RCS can alter the ship's trajectory, as opposed to the reaction wheels just controlling spin in place, that may have gone offline with the shutdown of HAL, as it may have been tied to some sort of autopilot system. The fail safe may have shut the wheels down expecting either manual intervention to stop the flip, or for HAL to fire the RCS to stop the roll. But neither were available in this case, and so the flip continued until 2010.
I've never read the novel. I suppose my question would be whether the flywheel explanation came from an omniscient narrator or was an explanation provided by one of the characters. It has been a while since I watched the movie. (Something I need to address.) But I seem to recall that the Discovery's orbit changed quickly. Floyd learns of the change in orbit from Dimitri at the start of the movie. When he is later attempting to explain it to Milson, the implication is that this is a sudden change and Floyd directly says that he can't explain why it has occurred. I've always felt the movie's implicit explanation for the orbit change and spin is "the Monolith did it." Either that or the Bowman/Star Child did it. Why? I have no idea. Maybe it would have been to remove a variable from the Jovian system for Jupiter's transformation. Maybe it was to bring spectators near to serve witness to the upcoming event. The Bowman/Star Child is in contact with some other intelligence(s). Perhaps it has been advocating for the human race. This may be a difference between the way the book addresses things and the way the film does. In the film, Floyd seems to be presented as a reliable perceiver of events, and he clearly sees much of what happens as the machinations of the intelligence behind or related to the Monolith.
The theoretical size of the Discovery is described in Clarke’s 1968 novel adaptation as being around 700 feet long. (The reference is the caption of a photograph of the ship as it appears in the film.) So, no, there was no significant upscaling of the ship between the two films.
When the on-board power was switched off, the centrifuge was still rotating. After reaching the desired rotation speed, the centrifuge was only driven to the extent that this value was maintained. After the on-board power was switched off, the friction losses of the axle bearings came into play. The rotational energy was transferred to the rest of the fuselage and caused it to rotate through precession.
It is explained in the film, the Io Jupiter flux tube. A electro static channel of current from Jupiter's magnetic field, and the sulfur eruptions from Io travel back and forth along that charged path. Discovery passed through it nearly every orbit. Slowing and speeding up the Discovery every passage. The spinning was from the rotating hab section getting stuck and transferring it's momentum to the rest of the ship. All of this was explained in film if you pay attention. It's also implied that the Monolith had some influence in the events and the weird aspects of the decay of the Discovery orbit because it needed us to be there for what was about to happen.
I think after Dave left the ship, the monolith shot out energy pulses at the bow of the Discovery when it sucked in the pod. The pressure from the warp field spun the whole ship and it just kept spining.
In your supposition about the onset and direction of the spin, you're forgetting 2 things, One, The flywheel bearings probably didn't seize up all at once but but just gradually slowed down once the power to the motors failed just because of residual friction in the bearings and air drag on the flywheel rotor (assuming the entire sphere, including the space for the rotor, was pressurized, but I've never seen anything to suggest it wasn't). Second is the P-factor. If a force is applied to the edge of a spinning object perpendicular to its plane of spin, the reaction force on the object will be 90 degrees ahead of the point where the force is applied in the direction of spin. We know the habitat centrifuge was spinning clockwise when seen from the front (from the scene in the first film showing Bowman and Poole entering the hab from the axial tunnel) so we can assume the flywheel was spinning anti-clockwise to conteract its torque. therefore, if the bearings had developed a bad spot somewhere around the XY plane on the port side and that bad spot created a forward "bump" on every revolution, the resulting force thru the mounts of the bearings to the structure of the ship would have caused the downward pitching moment to the command sphere. Over time, all the momentum of the flywheel would transfer to the main structure and the fact that the command sphere was way forward of the vehicles CG would result in the motion observed in the second film.
I’m not convinced that the centrifuge and flywheel would be mounted co-axially. It might be advantageous to have them offset by 90 degrees. I need to think about this some more. [edit] I withdraw this comment. Right after I made it, I realized that the flywheel rotation must be around the same axis as the centrifuge. Anything else creates instability.
During the initial exchange, Moisevitch asks Floyd if he had checked Discovery's orbit. Floyd then, I assume, verifies a change in Discovery's orbit. Some force must have acted on the ship and I always assumedthat force was the cause for the rotation.
I didn't read the book. When I saw the film in the theater I was under the impression that whoever sent the monolith had put the Discovery over IO and made it spin. Her orbit wasn't decaying. And that is what caught Floyd by surprise when he first tracked the Discovery in the beginning of the film.
The spin is correct. Cyclic gyration states that any input to a rotating mass is shown 90degress off of the input. So when the vertical centrifuge stop, the rotational force was transferred to the horizontal, since the CG of the vehicle appears to be amid ship, that is where SHE settled into showing the amid ship axis as shown in the movie. Just a theory to juxtapose the one postulated here. Any way, GREAT VIDS. Keep up the content, entertaining, if not accurate ( it is science fiction after all ). SUBSCRIBED and LIKED ! ! ! ! ! ! !
🖖😎👍Very cool very nicely done and very well executed and informatively explained in every detail way shape and form provided on the resons why for the possible rotation of the Discovery and why it did so and so forth indeed!,👌.
This is a good analysis, but you made one mistake. The Discovery was not fully powered up at the end of “2001”. When Dave Bowman leaves, the flight deck windows are dark, suggesting some of the systems are off. How much, we do not know - but she was not fully powered up. And yes you are correct, Kubrick “requested” (demanded) that the models and plans for the spacecraft were destroyed after filming. He did not want his designs used by other filmmakers in other, lesser, Science Fiction movies, such as when Universal used footage of Valley Forge from “Silent Running” in “Battlestar Galactica”, much to the chagrin of (and unsuccessful law suit by) Douglas Trumball. One model did survive, however, and this is the Aires IV that travels to and lands on the Moon. Mind you, I doubt whether the filmmakers of “2010” would have used the original filming model of Discovery as it was 54 feet long!
*Discovery* was caught between Jupiter's powerful magnetosphere and Io's violent surface (very near Lagrange). Static buildup up sulfur deposits on the surface of *Discovery* likely shorted out some electrical systems but it is also likely Bowman shut down power to most systems when he ventured out to the monolith. Sulfur has a high electronegative figure so it was very likely sulphuric atoms were easily ionized from Jupiter's magnetosphere and found itself covering *Discovery* (much like powder coatings would on metal surfaces during the powder coating paint process). The spin was due to Jupiter's strong gravitational pull and Io's gravitational pull, mimicking the "back and forth" motion that is responsible for creating some of the most violent and the largest known volcanic eruptions seen in the solar system. In the movie 2010, the concern from Floyd and others was the back and forth motion between Jupiter and Io, and this was ultimately going to tear *Discovery* apart (in addition to it being slowly deorbited as a result). So both the Soviets and Americans wanted get to the ship before this happens so they can learn what happened to Bowman.
I'm inclined to think that the centrifuge was also the stabilizing gyro for the ship, once it wound down the Discovery was at the mercy of outside forces, in particular the sulfur ejected into high orbit from Io. Her shape, two heavy weights separated by a long connection may be why she was spinning end over end.
The novel explained it. The transfer of angular momentum as the internal centrifuge finally slowed down. I don’t remember enough basic physics to remember if the ship’s spin was in the appropriate direction.
This always bugged me for precisely the reasons discussed here. Problem is that the book explicitly says it's because of the centrifuge flywheel. Otherwise we could come up with alternative hypotheses to fit the on-screen evidence. My pet one was that sulfur dioxide emissions from Io produced unequal drag on the different structures at opposite ends. The vehicle just happened to be oriented such that the gas hit from “above” (Z+) causing rotation in pitch rather than yaw. Even then, I doubt it could impart the speed of rotation we see on screen. (The movie does have it rotating faster than the book does, to make the boarding operation more hazardous and dramatic.)
If it started spinning around its short axis then over time the loss of energy doe to the flexing of its structure would have made it transition to a end over end rotation with no component along the short axis. The same thing happened in real life to the Explorer 1 satellite due to the flexing of its antennas
If I remember correctly in the book, they referenced Skylab, how they thought there would be lots of time to repair and reactivate her when the Shuttle started. But the Shuttle was delayed, and the orbit deteriorated and wound up reentering the Earth's atmosphere. So they did something similar with Discovery. Besides Jupiter is very massive. And the orbit might not have been stable on trying to rendezvous with the Large Monolith.
I guess there was a counter rotating weight at the centrifuge, because otherwise the centrifuge would influence the trajectory of the ship if corrections where necessary. This would also simplify speeding up the centrifuge in orbit when the mission has been started. Maybe the motor was just between centrifuge and counter weight. But because they are not concentric, but side by side, I guess that the spin compensation is not perfect.
1997 I had a job interview at Boss Films. I didn’t get the job, as the company was winding down, but I did get a tour, and the discovery model was still there hanging from the ceiling of the model shop.
In the book, as well as 8th grade physics, as the centrifuge slowed its angular momentum was transferred to the main body, hence the spin. Curnow's first goal was to get the centrifuge running again to absorb the ship's spin.
The ship Leonov has two centrifugal parts counteracting any spin on the axis of the ship. For the Discovery, the flywheel has to counteract for the spin of the centrifuge. The flywheel can not spin in the same direction as the centrifuge. Though Bowman crippled HAL, some automated systems onboard could continue to work. Maybe some vents need to release build up gas which could explain the spinning.
If the nuclear reactor was a molten salt reactor, it would not require monitoring nor would it need a controlled shutdown, however it would've needed to be within it's own centrifuge to allow the separation of Xenon gas and to allow the cold plug drainage into the cooling pans yo passively shutdown. Although the model does not show any other spaces for a centrifuge, the reactor centrifuge could've been small and just rotated gimballed the reactor hence only the reactor and cooling pans spun. Note maybe it was this reactor core centrifuge that lead to the strange rotation especially as the drainage into the cooling pans during an unsupervised shutdown would also change the moment of inertia so the rotation could happen without any bearings freezing (especially given that unknown to the 60's, bearings would become ceramic or magnetic on space crafts to avoid frozen bearings). There's also momentum control wheels and or gyros which could've lead to the spin once we give up on the novel's explaination.
I think they just made the ship spin end over end for visual effects. It just looked cool to an audience. Just as the bone thrown in the sky looked cool doing the same motion in 2001. Or maybe they were just mirroring that for some reason. What I never understood was how the astronauts were able to jog on Discovery in that loop. It kind of implies that the ship was spinning like a drill bit as it moved forward. That is the only thing I can think of in order to achieve artificial gravity to the point where they could jog in that loop. But then again, that does not match up to the design of the spherical command center of the ship.
In the original novel, A.C.Clarke describes the centrifuge as situated " in the equator and between both tropics" of the spherical command module. The transferency of the movement would explain perfectly the spinning of the Discovery as we see It in the film.
I will add to the "why spinning end over end" topic that the centrifuge acted as an enormous gyroscope as far as the vehicle is concerned, and the rotational energy would have been transferred over a period of time. The bearings would have shown more and more friction, which would start transferring the rotational energy to the structure while the centrifuge continued to act as a gyroscope. It is a well-known side effect of gyroscopic motion that it can take a force applied to its structure and literally twist it 90 degrees to its incoming vector. I'd very much assume that this is how Discovery got spinning along an axis perpendicular to the rotational plane of the centrifuge. Of course, in reality, the gyroscopic effect would fade as the centrifuge slowed, so only part of its force would be twisted 90 degrees from its rotational plane. So, unless there was some other gravitational effect happening, I would have expected Discovery to be tumbling in all axes, though because of the nice, wide separation of the major masses of the Command Module and the Drive Section along the long "spine" girder, you would also expect the rates in that axis to stay the largest. But, yeah, every spacecraft people have made has ended up outgassing and leaking stuff, especially when it gets old. A spacecraft with pressurized bays all over would definitely have had propulsive venting going on as the ship deteriorated, from all sorts of places. That would introduce new vectors to the tumble over time. So, yeah, it ought to have been tumbling in all three axes.
Why would decaying fresh meat be referenced here? Due to the planned duration of the mission and limited storage as well as the meals shown in 2001, I doubt any 'fresh" stores were aboard.
If they thought Bowman had left a partly consumed meal out before going to explore the monolith it would seem to explain the statement. If you take a freeze dried meal, prepare it for eating and then leave it out the food will spoil.
In orbit, object with a long axis almost always end up orbiting in tidal lock, with their long axis pointing toward the center of the main gravitational source. This is because of tidal tension. The orbit is based on the C of G of the object, but the portion closer that than is orbiting too slow for its radial distance from the primary and so wants to drop into a lower orbit. Meanwhile the portion that is further out from the C of G is orbiting too fast for its distance from the primary and it wants to fly out to a higher orbit. This means the two ends are being pulled away from the C of G and the longest axis of the object will maximize this pull, so it ends up being the stable orbital orientation. This tidal tension is why oceans on the far side of the earth rise even though the moon is on the other side of the earth. It’s also the reason why Saturn has rings as any moon that gets close enough will literally be pulled apart, and it’s the reason the moon always has the same face towards the earth. For a ship shaped like Odyssey to be spinning in orbit, it would need some other kind of significant kick. However, Io is tidally locked to Jupiter, and so only turns exactly once every time around Jupiter. If odyssey is orbiting Io, then every time Jupiter passes by on one side, It might contribute a tidal kick that spins the ship as it passes.?
I seem to recall that, in the movie, Dr. Floyd was advised by the Soviet guy to "check the orbit". Floyd did and noticed that it was anomalous, not consistent with what would be expected. The implication was that the Monolith (and/or Bowman) might have done this to attract human attention to the ship.
So we are going with it being a gyroscopic effect caused by the spin gravity generator in the primary hull and not a consequence of atmospheric drag on a ship which has more mass a the rear than the front. ( I don't think the centre of mass is the antennae location when she's lost much of her fuel by now). especially if they ship isn't pumping it's fuel around inside anymore as Hal isn't around to maintain housekeeping functions like that. I doubt the ship would even still be in orbit after 9 years unless the ship's systems only recently gave out. it is possible there was some automated thrust control keeping it up & if it used up all the reaction mass in the last 9 years it eventually got bathed in sulphur, froze and had a partial system malfunction. It does seem likely some automated systems were installed in case Hal broke or they had to all go into stasis for a long period. (if the crew were still alive that is of course)
As far as I know, there has been a counter weight at the centrifuge which neutralizes the effect of the fly wheel to the ship's motion. Probably this counter weight is lighter than the centrifuge but has a higher speed in the opposite direction. When one of them or both slow down because of bearing friction, then there is somehow interaction between two gyroscopes. However, maybe the monolith was the reason for the malfunctions at the Discovery.
Great video, but I didn't understand the discussion about the location of the centrifuge. The movie makes It clear that it's at the back of the command sphere, behind the bridge. There's also a number of technical drawings of the ship in books like The Making of Kubrick's 2001 and others that leave no doubt as to where It was located. If It would have worked as planned is another story... In any case, great graphics, thorough explanation, good job!
Juno's orbit is also polar simply because that was its primary scientific mission, to observe the polar regions of Jupiter (there had been no good look at them previously).
Another possibility is just a tidal effect. Because it is so long, there could be a minute difference in the IO gravitational field at both ends and over time, could this accumulate? I'm wondering whether there is a stable vertical configuration in IO's gravitational field but I haven't done the Math.
When it came to position of the centrifuge, the books seemed to indicate that it was located horizontally, between the pod-bay and the flight-deck, as touched uponat 7:55 minutes in on the time tracker. See excerpt: "The equatorial region of the pressure sphere - the slice, as it were, from Capricorn to Cancer - enclosed a slowly rotating drum, thirty-five feet in diameter. As it made one revolution every ten seconds, this carrousel or centrifuge produced an artificial gravity equal to that of the Moon. This was enough to prevent the physical atrophy which would resuit from the complete absence of weight, and it also allowed the routine functions of living to be carried out under normal - or nearly normal - conditions. "
About the difference in models from 2001 and 2010: I would say that is valid, because they have different approach to make the movies. 2001 is based on the book but it have it's own artistic and philosophical approach from Kubrick's mind, while 2010 was not directed by Kubrick. 2010 is more like an adaptation from the book. Despite I like a lot Kubrick's 2001 I would love to see a remake directed by Christopher Nolan with today's technology, and also all the sequels to it.
I wonder how long mission control had contact with Discovery after Bowman left? It would seem like at least several months. Did they send signals to shut down systems?
Since Io has a very dynamic interior, there could arise significant variations in mass which can alter local gravity field strength, perturbing the orbit. These were known to exist on the moon (called masscons for mass concentrations) for different reasons from unmanned Lunar Orbiter missions that preceded the Apollo missions and had to be accounted for in mission planning.
I always assumed that the Discovery was spinning because all movement stabilization had been disabled since HAL was shut off and only the basic functions were still running. But still only very basic systems. Since HAL controlled every part of the ship and was vital to its fully automated function, he could no longer maintain the stability and course of the ship. And over the course of 9 years slight things like tiny meteorite hits or gravitational pull may have caused this spinning to start slowly and then become even stronger.
I think it makes sense that it was hit by something, either ejected from Io or from elsewhere. Jupiter is a massive gravity well. The sulfur deposits also appear consistent on all surfaces, indicating the spin did not gradually change. It probably began soon after Bowman left. Not moments after, but within a year. Otherwise the sulfur would accumulate unevenly.
The deteriorating orbit is blamed on the TMA-2 Monolith in Clarke's book, NCA had taken Io's sulfur ejections into account in their projections. The orbital decay was much too rapid to be natural.
Nicely done video. I would disagree about the sulfur being the cause of the Discovery's decaying orbit. If themat were the case, her acceleration toward Io would have primarily remained steady or increased. Any direct deceleration from a sulfur plume would likely be easily accountable. However, Floyd speaking to Melson in front of the White House specifically said that the Discovery seemed at times to be accelerating, and at others seemed to have stopped entirely. He also said they had no idea why. I believe it was the Monoliths' interference specifically to get the Americans' attention. That ultimately allowed them to transmit their message to Earth. Without the Leonov and her personnel, the message may not have carried the nessisary weight. Just my thoughts on the matter.
I just want to point out that you are oversimplifying the problem, and neglecting torque. A spinning disc causes torque along the direction of the axis of the spin. If the flywheel seized up, it would cause a torque either in the direction of travel, or against it. So yes, there would be a slight roll on the ship which could easily be corrected, and a pitch/tumble/orbital change which might get worse over nine years. Some other people have commented that spins do funny things in space. Also, adding sulpher to the ship irregularly changes its mass and mass distribution. Plus, I think the film makers had the EXACT effect they wanted to by tumbling the ship. It was frightening, just as you said. I agree with you there!
It's possible that the centrifuge stopped spinning as the ships power failed. Also as stated forces like the sulfur plums would possibly have caused the spin. Back in 1984 when they made the movie 2010 the spin was included for dramatic affect. Who knows but it's fun to speculate.
The spin was caused by the gravity wheel stopping without proper braking or attitude control. This was explained actually. the rotational energy would make the Discovery spin
3:19 it was determined that as Discovery passed through the flux tube between Jupiter and Io it was perturbing its orbit. 5:45 No, the centrifuge rides on magnetic bearings while near frictionless there is still drag to the rest of the ship which is countered with RCS corrections. 7:36 I believe in the novel Curnow talks about this and belives gyroscopic precession is why the ship is spinning end over end as the centrifuge spun down and transfered its momentum into the rest of the ship
Any aerospace engineer or astronomer well-versed in orbital mechanics will tell you that a long extended spacecraft will not spin like that near a large gravitating body like Jupiter. What will happen instead is that gravity gradient (tidal forces) will cause the spacecraft to align along the local vertical and rotate with the orbit. It can spin a bit along its long axis, but it is unstable. Structural vibrations will transfer the energy of rotation about this axis to one of the side axes, where the gravity gradient and structural friction will dampen it.
I'm old and my memory in question. But i thought Frank Poole's pod was used by HAL to kill him and spun off into space (exit stage right) then Bowman retrieves Poole with second pod but due to HAL blocking his return had to abandon Poole and fire himself into the airlock .Opposite and equal reactions pod #2 gone ? then Bowman leaves in pod #3 not to return ..... Wasn't there a pod in the pod bay in 2010?
correction, after reviewing film clips I now see the pod that Bowman blows himself out of remains on station at the airlock door . I must commend future spaceship design as the pod doesn't appear to move at all after the explosive decompression but it is what it is so I concede Bowman may have been able to retrieve the pod allowing Bowman to leave one pod on Discover .... my error
My understanding has always been the centrifuge thing. However, such a long slender ship would be especially susceptible to tidal influence, which would cause it to tumble end over end in its orbit. This effect could be nullified by imparting a roll on the long axis, like a football.
You're wrong about the spin. And centrifugal forces. It would indeed spin end over end as the centrifuge energy dissipated. Its a well known phenomenon of progression. And has been seen in satellites as their gyros fail. This is exactly why it's in the movie.
It might be pedantic, but would the Discovery technically be in orbit of Io if Bowman left the Discovery at the LaGrange Point between Jupiter and Io (a spot where an object would stay in one spot due to overlapping gravity)?
Yes, eg the JWST is still considered to be in Earth orbit. Since it is in Earth’s L2, not Mars’ L2 or Venus’ L2. Therefore, being in one of Io’s Lagrange Points is still in orbit of Io.
@@kaitlyn__L Sorry, but you're wrong. The JWST s orbiting the Earth, not the Moon, being carried along with the Moon at the further-out L2 Lagrange point. Bowman 'parked' the DISCOVERY-1 at the Jupiter-Io L1 Lagrange point, the unstable point in-between the two bodies, which is far closer to Io than to Jupiter. Thus, it was orbiting Jupiter in lock-step with Io, orbiting that gas giant at the same rate that Io was orbiting it. The trouble is, though, that only L4 and L5 Lagrange points are stable. L1 -- as well as the L2 and L3 Lagrange points (there being only 5 such points) -- are unstable and require "station-keeping" engine burns to keep things there. The close approaches of the other Galilean moons of Jupiter would be enough to perturb the object perched at L1, nudging it away from its position. Jupiter's equatorial radius is 71,492 kilometers, with the semimajor axis of Io's orbit being 422,000 km, about 5.9 Jupiter radii away. By contrast, the Moon's average distance from the Earth is 384,400 km, about 60.268 Earth radii away, the Earth's radius being 6,378.14 km. Jupiter's magnetic field alone would perturb any spacecraft parked at Io's L1 spot, which is one of the things Clarke's novel mentions, what with the magnetic flux tube connecting Io and its sulfurous eruptions to Jupiter in the first place. An object parked for 9 years at the Earth-Moon L1 Lagrange point -- sans any station-keeping maneuvers -- would be perturbed away from that unstable location, so its no surprise that the DISCOVERY-1 spaceship, parked at the Jupiter-Io L1 spot, would have its position rendered so precarious. I would say that the close approaches of Europa (especially), orbiting Jupiter at 9.8566553 Jupiter radii out (i.e. 671,000 km away), would be the main reason that the ship was perturbed in its L1 'parking' spot. Io orbits Jupiter every 2,548 minutes, with Europa orbiting Jupiter every 5,114 minutes -- i.e. they're in an orbital resonance of 2:1, with Io orbiting Jupiter twice for every Europa orbit around Jupiter. That's a closest-approach of Europa to Io every other Io orbit of Jupiter, every 3.5513888... days. That gravitational 'tug', repeated every 3 and a half days or so over the course of some 9 years (i.e. from 2001 to 2010) would amount to almost a thousand such 'tugging' moments. Even the slightest tendency of the ship to tumble -- let's say a complete turn over the course of a week, initially -- would be reinforced such that the spin rate would gradually accelerate . . . taking less than a week after the first year . . . then perhaps a day-long spin-rate by the end of the 2nd year . . . etc. etc. That spin-rate HAD to have been accelerating over the course of the 9 years in-between Bowman leaving the ship in the Pod and the LEONOV arriving at the same L1 spot, since Bowman certainly didn't leave in that Pod with the ship ALREADY spinning so fast! That once-every-3.55-day nudge provided by Europa's further-out orbit is the main source of the extra energy required to accelerate the spin of that rotating, tumbling vehicle, I think. The other Galilean satellites -- Ganymede and Callisto -- would also add their gravitational nudges to the spinning ship, but Europa would have the greatest effect on it.
There’s another poster remarked, originally the centrifuge was positioned equatorially…. If the fly will malfunction with that, not in part a moment of inertia perpendicular to the spin, and therefore pause the end over in rotation?
Simple physics transference of rotation or momentum of the centrifuge in the capsule through minisculenergy energy transferences by, however, miniscule frictional forces did this
The Discovery's spin isn't wrong. The result of Explorer 1 introduced new physics we simply didn't know yet. If it has a way to lose mechanical energy it will convert its on axis spin to cross axis spin. This isn't that hard. Anything that can vibrate can do it. (Vibrations -> heat energy)
Bowman probably didn't shut down the systems aboard Discovery. That would have happened because the ionized cloud of sulfur atoms it was orbiting within would have built up an electrical charge on the hull and infrastructure until it discharged and popped the circuit breakers. With HAL shut down and no one aboard, there was nobody to reset them. The same sort of thing happens to electronics on the ISS whenever it passes over the South Atlantic Magnetic Anomaly, except in that case people are there to reboot.
I suspect the reason she's spinning is partly down to it being a visual reference to the Movie and the bone scene. I guess the Fly wheels may look nothing like they are speculated to look may of them mounted in a gimbles they could be used to move the ship instead of thrusters. Acreative
To combat radiation space craft could use optronics, at least in unshielded sections then convert to electronics in safe areas. That would make systems more reliable.
Yes, initially the spin of discovery would have been along its longitudinal axis. However, I advise you to look up the bizarre phenomenon of rotating bodies. Over time they periodically go through a period of reversal where they flip around/through different axis. It's very unintuitive because most people can go through life without witnessing the effect, so it seems very unintuitive. Of course, in the book/movie the Discovery was depicted as going through one of these inversions and flipping end over end instead of spinning along its axis.
Its in the book 2010. There is a physics principle where spin will always shift to where the longest axis is spinning like in Discovery. One of the Shuttle astronauts demonstrated it in the ISS.
Came here to say that
The Discovery at the end of 2001 is in fact not fully lit up. The bridge is fully darkened in the last shot we see of her as Bowman departs. Even the pod bay looks slightly dimmed behind his pod’s headlights. We can surmise Bowman did shut down some systems.
Good point.
Yes, in fact, IIRC, the book mentioned something about Dave shutting down some of the systems.
The spin of the Discovery might have come about from something called the Dzhanibekov effect. Essentially, if you have an object which spins around its own axis, if said object has three different moments of inertia, depending on what axis it rotates around, it will flip eventually. This effect was discovered when a cosmonaut named Vladimir Dzhanibekov opened a box in space, which had been secured with wing nuts, which happen to fulfill this quality. It's theoretically possible, therefore, that when we find the Discovery, it is in the process of reversing its orientation from the spin, provided it, too, has three different moments of inertia.
The "T-handle experiment" recorded on ISS helped me visualize this. It's 30 seconds here and there on YT. Discovery is similar to the T-handle in the sense of mass distribution. It would continue flipping back and forth for years until eventually settling on the preferred axis, which is across the midpoint below the antenna, very close to where Max and Walter chose to board. All my future spaceship designs will have a hatch right there.
Not quite. The Dzhanibekov effect happens to objects spinning about their "intermediate axis". That is, if an object has three different moments of inertial when spinning about its three principle axes, it will be unstable if spinning about the axis with the middle moment of inertia.
Discovery may not even have such an intermediate axis. It's close to being radially symmetrical on the long axis. The engine deck is wider than tall, so the ship may have a slightly higher moment of inertia when spinning in yaw than in pitch, but the difference would be very small. In any case, spinning in roll has the smallest moment of inertia, so that spin should be stable.
However, spinning in roll (on the long axis) does have the highest kinetic ENERGY. Angular momentum is moment of inertia times angular velocity. It must be conserved unless it can be transferred to another object. If the ship somehow shifts from spinning on the long axis (where moment of inertia is very low) to end over end (where moment of inertia is very high), angular velocity must decrease proportionally so that angular momentum is conserved. Angular kinetic ENERGY though is one half moment of inertia times angular velocity SQUARED. If the rotation shifts so that the moment of inertia is lets say 10 times higher, and the angular velocity is 10 times lower (so that momentum is conserved), what happens to kinetic energy? The moment of inertia went up 10 times, and the velocity went down 10 times, but the velocity term is squared and the moment of inertia term is not. 10*(1/10) is 1 but 10*(1/10)^2 is 0.1
Angular momentum was conserved, but angular kinetic energy went down 10 times! That's obvious no good. Energy must be conserved, but not KINETIC energy. Kinetic energy can become a different type of energy. What if it becomes heat? Kinetic energy has been lost, but momentum must still be conserved. The only way for that to happen is for the spin to shift such that moment of inertia increases. So, if the Discovery somehow lost some kinetic energy, then its spin would have had to shift axes in order for momentum to be conserved. The spin with the highest moment of inertia would be end over end with no long axis spin, which is just what we see in the film, so the only question is what would have taken away the kinetic energy? Discovery was abandoned for years, so it needn't have been a fast process. The air in the ship could turn some of the spin energy into turbulence and that into heat which would eventually radiate into space. The spine of the ship also must flex under load and the ship won't be perfectly balanced on any axis. That flexing back and forth would absorb kinetic energy to become heat in the metal. Tidal forces would also constantly pull and push the ship as it spun, which also consumes kinetic energy.
Over a long enough time span, we should expect Discovery to end up spinning its lowest energy, most stable state: end over end.
@@TonboIV Yes, this is the correct explanation for what we see in the movie. It's worth noting that this exactly what happened with the Explorer 1 satellite: it started spinning around its long axis but, due to the flexing of its antennas, it started to lose energy and ended up in an end over end rotation. It's possible Clarke drew inspiration from that.
Thank you for writing the complete explanation so that I didn't have to do it myself.
But the Discovery would itself have to have been rotating along its longitudinal axis first.
@@NoahSpurrier It started rotating along the long axis due of the slowing down of the flywheel of the centrifuge, then it transitioned to an end over end spin due to the loss of angular kinetic energy
The centrifuge, the rotating part of the Discovery heavily featured ibn 2001: A Space Odyssey had motors that turned it. The Discovery (is stated in the book 2010) spins due to this rotation being induced by the centrifuge slowly running down after Dave Bowman leaves, and pre-set commands shut the Discovery down (the flight deck can be seen to be dark as Dave leaves, for example).
Either he did not expect to return, or he had an override command he could give that would allow him to enter again if he did.
In the book 2010, again, the guys who get aboard begin a start-up process to power-up the Discovery, which causes her to make some wild gyrations as the spinning-up gyroscope 'mopped up' the rotation. This is simplified in the movie of 2010, with little if any explanation.
The author was a scientist, as was quite able to imagine based upon knowledge, check with others and describe these evolutions.
He had clearly stated over the publication history of his books that he updated scientific knowledge as it comes in.
One example was that mankind had existed five million years ago as a hominid, a precursor to humanity.
That was a guess, as he expected more evidence to be found. Later, more evidence WAS found, pushing human ancestry back to about 5 million years.
"This is simplified in the movie of 2010, with little if any explanation." Yeah in the movie she just suddenly stops on a dime without even seeing any thrusters fire.
There'd also be other forces involved as well. Radiation pressure, gravitation from the monolith that's nearby, gas and particles from Io would also tend to induce odd motions.
Though, Yarkovsky effect from solar radiation would've been quite low at a Jovian orbit.
Remember the Pioneer anomaly? Just from the RTG heat it was experiencing an acceleration that took decades to explain.
except tidal forces would have nullified that rotation over a period of ten years time. Long skinny objects in orbit always end up oriented axially to the center of the planet or moon they orbit due to tidal tension creating maximal forces in that orientation.
if you look at blueprints of the ship, it has a reactor purge vent labeled on the dorsal surface of the engine pod. if at some point the reactor purged (highly likely because of lack of management) this would have introduced the exact rotation we see.
Explorer 1 originally rotated along it's long axis but due to flexing of it's antenna it eventually began to tumble end over end which was it's maximum moment of inertial axis.
If Discovery One had any flex in it's structure or fluids sloshing it would end up in a rotation about it's axis of maximum moment of inertial as well.
2010 is criminally underrated.
I thought the Discovery's spinning, discoloration, and it's decaying orbit were all caused by drag when it went through the sulphur particles in Io's volcanic ejecta. I-m pretty sure that was mentioned somewhere in the novel.
The discoloration and decaying orbit, yes, but the rotation is attributed to the centrifuge running down.
I have to re-watch (and re-read) the series.
About that spin. Incidentally, Discovery`s rotation is correct when we consider orbital mechanics. Shes dead in orbit above Io - that mean no gyros, centrifuges etc to stabilize her. Twice during that orbit, she will be fully facing radial in and radial out orientation (directly toward and directly opposite to Io). At those times, the end closer to the surface will be travelling prograde (orbit direction) much faster than the other one (especially when shes 400/800m long), making her spin slowly. Every orbit it would build up and eventually, she will spin as seen in the movie.
Im enjoying the topics and animations in Your videos. Keep up the good work, thanks. Subbed.
I never thought why Discovery was spinning, but thanks for covering it.
A little fun fact, the 2010 Discovery model was going to be thrown out by the studio, but an executive at Cartoon Network was able to get their hands on it and bring it to the CN offices in Atlanta where it was hung from the ceiling in the elevator lobby. That's where I saw it in the late 1990's. It took on a kind of greenish tint, because the orange powder they used to coat discovery was copper based. I wonder if it's still there.
HAL wasn't completely turned off but was rather "lobotomized" with destroying higher functions such as reasoning, speech, memory etc. but preserving main functions on the ship: reactor control, environment/life support, engines, navigation. It was mentioned in a book that only this way Bowman had chance to reach destination. If he just destroy HAL that meant death of Discovery as well.
Yep, the movie doesn’t convey that time jump very well. They’re still in the asteroid belt when everything goes down, shown by them passing a chunk of rock at one point.
It was supposed to have been from the fact that the centerfuge section in Discovery had seized up and transferred the rotational energy to the ship itself although it seems like it was perpendicular in its axis rotation so I don’t see why that would’ve happened. That’s what it said in the book anyway. It’s also why they didn’t try to re-create the centrifuge set in 2010.
Yes, that is the explanation in the novel. Building the centerfuge, in the mid-Sixties at the British studio, was expensive. The huge set, that could be roasted was justified by the number of scenes shot inside it. For 2010, the main sets rebuilt for the Discovery were the command deck, and the Pod-bay. Now, the centerfuge would be a digital set.
IIRC the original book described that centrifuge as being mounted equatorially in relation to the module's globe. Perhaps the size problem didn't come up while the story was in that stage, though I'll admit my reading of it was some 50 years ago! Somewhere, also, I recall Clarke explaining that the ship was supposed to feature cooling fins for its nuclear engines, but those were dropped so as not to confuse the audience over why a vessel built for airless space might appear to need "wings."
From memory too this was the explanation given, the centrifuge had slowed to a stop and transferred its momentum to the structure.
@@Tom_RUclips_stole_my_handle same
@@Tom_RUclips_stole_my_handle This. They mentioned it in the 2010 novel.
The long 'winged' spaceship from the Gerry Anderson movie 'Into Infinity' (also seen in 'Space: 1999') would qualify.
@johnbayer9795 you are correct. Recall Bowman's call to Floyd. Despite saying "look behind you," Floyd has to look down.
Because the place Bowman is "standing" is aligned with the hab wheel. Here's the scene from the movie: ruclips.net/video/yv3sGHbH2DI/видео.html
I just assumed the centrifuge radius wasn’t as large as the command module’s radius 😅 because indeed I figured what the orientation should’ve been right away. Though I liked your visualisations of the alternative spins.
As to the “automatic operation”, I’d always thought HAL _was_ the automatic system. I suppose it makes sense to have some kind of backups though.
I admit I didn’t think Dave actually shut down the centrifuge, but just that the angular momentum slowly transferred into the flywheel bearings. As no matter how good a bearing is, it has SOME friction. And that complex would have to be affixed to the rest of the ship, so the momentum transferred through those struts into the entire body. But maybe the timeframe doesn’t quite work out that way.
The question is answered in Clarke's book "2010: Odyssey Two". Discovery I had a gyroscopic system in the forward command module that simulated gravity for the astronauts living in space, Bowman runs the whole length of the track in a circle in one scene. It shut down when power went out and its axial momentum was transferred to the ship, making it spin along its axis. Once Curnow got the power back on and restarted the centrifuge in the living section it mostly stabilized again, the remaining spin was easily dealt with using attitude control thrusters.
Did the book also explain how they achieved that the engine spin only the "track" where the simulated gravity was needed and not the whole ship? Was the spinning of the rest of the ship constantly negated by thrusters or some kind of propulsion system?
@@Atarian6502 Now that's an interesting question because without some kind of counter-rotation from something else spinning on the ship it should have introduced some yaw or roll into Discovery I's flight.
I can't find my copy of 2010. 😊🤫 So, relying on my Swiss cheese memory, I'm not sure Discovery's centrifuge had a separate flywheel. The usable area of the centrifuge is already its own flywheel and wouldn't need redundant mass. The seized bearings would be between the centrifuge and the vessel structure. If a separate flywheel were used, it would spin in the opposite direction in order to cancel out precession effects, so that Discovery could maneuver.
Clarke did much better scientific research than most other authors, before or since. Having Discovery rotate end over end makes sense regardless of the orientation of the centrifuge, because of the "preferred axis" effect you mentioned. (The experiment done on ISS with a T-handle helped me visualize this.) If Discovery had a separate flywheel spinning in the opposite direction, seized bearings would stop both the centrifuge and flywheel at the same time, and the opposing angular momentum of both parts would cancel each other out.
Discovery could have shifted from a long axis spin to an end over end spin if it lost kinetic energy. Only total energy is conserved. Kinetic energy can become heat. If Discovery ended up spinning on its long axis when the flywheel stopped, and was then left like that for years, some loss of kinetic energy would be inevitable. Tidal forces would flex the structure back and forth with each spin. The ship would also not be perfectly balanced on its axis and the uneven forced would probably cause some rhythmic flexing of the spine. Air and propellant might be churned around. Slowly kinetic energy would be converted into heat and radiated into space.
Angular momentum has to be conserved though. If the angular velocity is dropping, the only way to conserve momentum is for the moment of inertia to increase, and that CAN happen, if the spin axis shifts to one which maximized moment of inertia. Angular momentum is conserved, so this increase in moment of inertia decreases angular velocity proportionally. Because angular kinetic energy is proportional to the square of angular velocity, this shift in axis allows the kinetic energy to decrease, which in turn allows Discovery to discard some of its kinetic energy as heat until it reaches its lowest kinetic energy spin: end over end.
That's exactly what happened to the first American satellite: Explorer 1. It was spun on its long axis during launch which it was thought would keep it stable, but the long flexible antennas consumed kinetic energy, shifting the axial spin to an end over end spin.
One other possible explanation for the rotation we see with Discovery could be the so-called "Pioneer Anomaly", where a radiation source spread unevenly across the surface of the spacecraft can, over the course of enough time, exert a rotational force on the spacecraft. Given the strength of Jupiter's radiation belts, I think it's possible that may have lead to the rotation seen on screen
a ship the size and shape of Discovery would be subject to tidal forces as well. Gravity interactions would eventually induce spin along some axis until eventually the distribution of mass would place the higher mass end (likely the engine end) point toward the major body gravity source (IO) eventually becoming tidally locked.
If the bearings in the centrifuge and/or flywheel seizing up was detected by a localized failsafe system, they may have been gracefully stopped preventing a spin along the lengthwise axis. Without that gyroscopic force stabilizing the ship, like the force keeping your bike upright from the gyroscopic force of the spinning wheels, it would now be free to spin around either of the other 2 axis. With no reaction wheel system running, the ship could no longer actively resist rotation. Anything could've given it that gentile push to start that end over end rotation. Additionally, if the detected error in the reaction wheel/flywheel system was the seizure of the wheel controlling the pitch, that rotation could've been started first before the ship scrammed the rest of the reaction wheel to prevent another failure from making it worse. I'd assume the ship has some sort of RCS system, but being that the RCS can alter the ship's trajectory, as opposed to the reaction wheels just controlling spin in place, that may have gone offline with the shutdown of HAL, as it may have been tied to some sort of autopilot system. The fail safe may have shut the wheels down expecting either manual intervention to stop the flip, or for HAL to fire the RCS to stop the roll. But neither were available in this case, and so the flip continued until 2010.
I've never read the novel. I suppose my question would be whether the flywheel explanation came from an omniscient narrator or was an explanation provided by one of the characters.
It has been a while since I watched the movie. (Something I need to address.) But I seem to recall that the Discovery's orbit changed quickly. Floyd learns of the change in orbit from Dimitri at the start of the movie. When he is later attempting to explain it to Milson, the implication is that this is a sudden change and Floyd directly says that he can't explain why it has occurred.
I've always felt the movie's implicit explanation for the orbit change and spin is "the Monolith did it." Either that or the Bowman/Star Child did it.
Why?
I have no idea. Maybe it would have been to remove a variable from the Jovian system for Jupiter's transformation. Maybe it was to bring spectators near to serve witness to the upcoming event. The Bowman/Star Child is in contact with some other intelligence(s). Perhaps it has been advocating for the human race.
This may be a difference between the way the book addresses things and the way the film does. In the film, Floyd seems to be presented as a reliable perceiver of events, and he clearly sees much of what happens as the machinations of the intelligence behind or related to the Monolith.
The theoretical size of the Discovery is described in Clarke’s 1968 novel adaptation as being around 700 feet long. (The reference is the caption of a photograph of the ship as it appears in the film.) So, no, there was no significant upscaling of the ship between the two films.
When the on-board power was switched off, the centrifuge was still rotating. After reaching the desired rotation speed, the centrifuge was only driven to the extent that this value was maintained.
After the on-board power was switched off, the friction losses of the axle bearings came into play. The rotational energy was transferred to the rest of the fuselage and caused it to rotate through precession.
It is explained in the film, the Io Jupiter flux tube. A electro static channel of current from Jupiter's magnetic field, and the sulfur eruptions from Io travel back and forth along that charged path. Discovery passed through it nearly every orbit. Slowing and speeding up the Discovery every passage. The spinning was from the rotating hab section getting stuck and transferring it's momentum to the rest of the ship. All of this was explained in film if you pay attention. It's also implied that the Monolith had some influence in the events and the weird aspects of the decay of the Discovery orbit because it needed us to be there for what was about to happen.
Your sci-fi science videos are so interesting. Thank you!
I think after Dave left the ship, the monolith shot out energy pulses at the bow of the Discovery when it sucked in the pod. The pressure from the warp field spun the whole ship and it just kept spining.
In your supposition about the onset and direction of the spin, you're forgetting 2 things, One, The flywheel bearings probably didn't seize up all at once but but just gradually slowed down once the power to the motors failed just because of residual friction in the bearings and air drag on the flywheel rotor (assuming the entire sphere, including the space for the rotor, was pressurized, but I've never seen anything to suggest it wasn't). Second is the P-factor. If a force is applied to the edge of a spinning object perpendicular to its plane of spin, the reaction force on the object will be 90 degrees ahead of the point where the force is applied in the direction of spin. We know the habitat centrifuge was spinning clockwise when seen from the front (from the scene in the first film showing Bowman and Poole entering the hab from the axial tunnel) so we can assume the flywheel was spinning anti-clockwise to conteract its torque. therefore, if the bearings had developed a bad spot somewhere around the XY plane on the port side and that bad spot created a forward "bump" on every revolution, the resulting force thru the mounts of the bearings to the structure of the ship would have caused the downward pitching moment to the command sphere. Over time, all the momentum of the flywheel would transfer to the main structure and the fact that the command sphere was way forward of the vehicles CG would result in the motion observed in the second film.
I’m not convinced that the centrifuge and flywheel would be mounted co-axially. It might be advantageous to have them offset by 90 degrees. I need to think about this some more.
[edit]
I withdraw this comment. Right after I made it, I realized that the flywheel rotation must be around the same axis as the centrifuge. Anything else creates instability.
During the initial exchange, Moisevitch asks Floyd if he had checked Discovery's orbit. Floyd then, I assume, verifies a change in Discovery's orbit. Some force must have acted on the ship and I always assumedthat force was the cause for the rotation.
Because back then, that's how Arthur C. Clarke wrote it. That's all you need to know.
I didn't read the book. When I saw the film in the theater I was under the impression that whoever sent the monolith had put the Discovery over IO and made it spin. Her orbit wasn't decaying. And that is what caught Floyd by surprise when he first tracked the Discovery in the beginning of the film.
In the film I had just assumed either she had been hit by an object or cloud or a thruster had malfunctioned. This is a good in-depth video. Thanks.
The spin is correct. Cyclic gyration states that any input to a rotating mass is shown 90degress off of the input. So when the vertical centrifuge stop, the rotational force was transferred to the horizontal, since the CG of the vehicle appears to be amid ship, that is where SHE settled into showing the amid ship axis as shown in the movie. Just a theory to juxtapose the one postulated here. Any way, GREAT VIDS. Keep up the content, entertaining, if not accurate ( it is science fiction after all ).
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🖖😎👍Very cool very nicely done and very well executed and informatively explained in every detail way shape and form provided on the resons why for the possible rotation of the Discovery and why it did so and so forth indeed!,👌.
This is a good analysis, but you made one mistake. The Discovery was not fully powered up at the end of “2001”. When Dave Bowman leaves, the flight deck windows are dark, suggesting some of the systems are off. How much, we do not know - but she was not fully powered up.
And yes you are correct, Kubrick “requested” (demanded) that the models and plans for the spacecraft were destroyed after filming. He did not want his designs used by other filmmakers in other, lesser, Science Fiction movies, such as when Universal used footage of Valley Forge from “Silent Running” in “Battlestar Galactica”, much to the chagrin of (and unsuccessful law suit by) Douglas Trumball. One model did survive, however, and this is the Aires IV that travels to and lands on the Moon. Mind you, I doubt whether the filmmakers of “2010” would have used the original filming model of Discovery as it was 54 feet long!
Yes, the original large Discovery model was pretty big. Difficult to store, too, I would think!
@@WeTravelbyNight Space Station V was 6 feet in diameter, even the Orion was 3 feet long. Oh and the aforementioned Valley Forge was 25 ft long!
*Discovery* was caught between Jupiter's powerful magnetosphere and Io's violent surface (very near Lagrange).
Static buildup up sulfur deposits on the surface of *Discovery* likely shorted out some electrical systems but it is also likely Bowman shut down power to most systems when he ventured out to the monolith.
Sulfur has a high electronegative figure so it was very likely sulphuric atoms were easily ionized from Jupiter's magnetosphere and found itself covering *Discovery* (much like powder coatings would on metal surfaces during the powder coating paint process).
The spin was due to Jupiter's strong gravitational pull and Io's gravitational pull, mimicking the "back and forth" motion that is responsible for creating some of the most violent and the largest known volcanic eruptions seen in the solar system.
In the movie 2010, the concern from Floyd and others was the back and forth motion between Jupiter and Io, and this was ultimately going to tear *Discovery* apart (in addition to it being slowly deorbited as a result). So both the Soviets and Americans wanted get to the ship before this happens so they can learn what happened to Bowman.
I'm inclined to think that the centrifuge was also the stabilizing gyro for the ship, once it wound down the Discovery was at the mercy of outside forces, in particular the sulfur ejected into high orbit from Io. Her shape, two heavy weights separated by a long connection may be why she was spinning end over end.
The novel explained it. The transfer of angular momentum as the internal centrifuge finally slowed down. I don’t remember enough basic physics to remember if the ship’s spin was in the appropriate direction.
Fascinating. I wondered why discovery was spinning. I assumed it was due to an unstable orbit.
This always bugged me for precisely the reasons discussed here. Problem is that the book explicitly says it's because of the centrifuge flywheel. Otherwise we could come up with alternative hypotheses to fit the on-screen evidence. My pet one was that sulfur dioxide emissions from Io produced unequal drag on the different structures at opposite ends. The vehicle just happened to be oriented such that the gas hit from “above” (Z+) causing rotation in pitch rather than yaw. Even then, I doubt it could impart the speed of rotation we see on screen. (The movie does have it rotating faster than the book does, to make the boarding operation more hazardous and dramatic.)
If it started spinning around its short axis then over time the loss of energy doe to the flexing of its structure would have made it transition to a end over end rotation with no component along the short axis. The same thing happened in real life to the Explorer 1 satellite due to the flexing of its antennas
If I remember correctly in the book, they referenced Skylab, how they thought there would be lots of time to repair and reactivate her when the Shuttle started. But the Shuttle was delayed, and the orbit deteriorated and wound up reentering the Earth's atmosphere. So they did something similar with Discovery. Besides Jupiter is very massive. And the orbit might not have been stable on trying to rendezvous with the Large Monolith.
I guess there was a counter rotating weight at the centrifuge, because otherwise the centrifuge would influence the trajectory of the ship if corrections where necessary. This would also simplify speeding up the centrifuge in orbit when the mission has been started. Maybe the motor was just between centrifuge and counter weight. But because they are not concentric, but side by side, I guess that the spin compensation is not perfect.
Fine work. Thank you for your efforts. I keenly enjoyed your observations and commentary. Keep up the good work! High desert Southern California.
1997 I had a job interview at Boss Films. I didn’t get the job, as the company was winding down, but I did get a tour, and the discovery model was still there hanging from the ceiling of the model shop.
In the book, as well as 8th grade physics, as the centrifuge slowed its angular momentum was transferred to the main body, hence the spin. Curnow's first goal was to get the centrifuge running again to absorb the ship's spin.
The ship Leonov has two centrifugal parts counteracting any spin on the axis of the ship. For the Discovery, the flywheel has to counteract for the spin of the centrifuge. The flywheel can not spin in the same direction as the centrifuge. Though Bowman crippled HAL, some automated systems onboard could continue to work. Maybe some vents need to release build up gas which could explain the spinning.
If the nuclear reactor was a molten salt reactor, it would not require monitoring nor would it need a controlled shutdown, however it would've needed to be within it's own centrifuge to allow the separation of Xenon gas and to allow the cold plug drainage into the cooling pans yo passively shutdown.
Although the model does not show any other spaces for a centrifuge, the reactor centrifuge could've been small and just rotated gimballed the reactor hence only the reactor and cooling pans spun. Note maybe it was this reactor core centrifuge that lead to the strange rotation especially as the drainage into the cooling pans during an unsupervised shutdown would also change the moment of inertia so the rotation could happen without any bearings freezing (especially given that unknown to the 60's, bearings would become ceramic or magnetic on space crafts to avoid frozen bearings). There's also momentum control wheels and or gyros which could've lead to the spin once we give up on the novel's explaination.
I think they just made the ship spin end over end for visual effects. It just looked cool to an audience. Just as the bone thrown in the sky looked cool doing the same motion in 2001. Or maybe they were just mirroring that for some reason.
What I never understood was how the astronauts were able to jog on Discovery in that loop. It kind of implies that the ship was spinning like a drill bit as it moved forward. That is the only thing I can think of in order to achieve artificial gravity to the point where they could jog in that loop. But then again, that does not match up to the design of the spherical command center of the ship.
In the original novel, A.C.Clarke describes the centrifuge as situated " in the equator and between both tropics" of the spherical command module. The transferency of the movement would explain perfectly the spinning of the Discovery as we see It in the film.
I will add to the "why spinning end over end" topic that the centrifuge acted as an enormous gyroscope as far as the vehicle is concerned, and the rotational energy would have been transferred over a period of time. The bearings would have shown more and more friction, which would start transferring the rotational energy to the structure while the centrifuge continued to act as a gyroscope. It is a well-known side effect of gyroscopic motion that it can take a force applied to its structure and literally twist it 90 degrees to its incoming vector. I'd very much assume that this is how Discovery got spinning along an axis perpendicular to the rotational plane of the centrifuge. Of course, in reality, the gyroscopic effect would fade as the centrifuge slowed, so only part of its force would be twisted 90 degrees from its rotational plane. So, unless there was some other gravitational effect happening, I would have expected Discovery to be tumbling in all axes, though because of the nice, wide separation of the major masses of the Command Module and the Drive Section along the long "spine" girder, you would also expect the rates in that axis to stay the largest. But, yeah, every spacecraft people have made has ended up outgassing and leaking stuff, especially when it gets old. A spacecraft with pressurized bays all over would definitely have had propulsive venting going on as the ship deteriorated, from all sorts of places. That would introduce new vectors to the tumble over time. So, yeah, it ought to have been tumbling in all three axes.
Why would decaying fresh meat be referenced here? Due to the planned duration of the mission and limited storage as well as the meals shown in 2001, I doubt any 'fresh" stores were aboard.
If they thought Bowman had left a partly consumed meal out before going to explore the monolith it would seem to explain the statement. If you take a freeze dried meal, prepare it for eating and then leave it out the food will spoil.
In orbit, object with a long axis almost always end up orbiting in tidal lock, with their long axis pointing toward the center of the main gravitational source. This is because of tidal tension. The orbit is based on the C of G of the object, but the portion closer that than is orbiting too slow for its radial distance from the primary and so wants to drop into a lower orbit. Meanwhile the portion that is further out from the C of G is orbiting too fast for its distance from the primary and it wants to fly out to a higher orbit. This means the two ends are being pulled away from the C of G and the longest axis of the object will maximize this pull, so it ends up being the stable orbital orientation. This tidal tension is why oceans on the far side of the earth rise even though the moon is on the other side of the earth. It’s also the reason why Saturn has rings as any moon that gets close enough will literally be pulled apart, and it’s the reason the moon always has the same face towards the earth.
For a ship shaped like Odyssey to be spinning in orbit, it would need some other kind of significant kick.
However, Io is tidally locked to Jupiter, and so only turns exactly once every time around Jupiter. If odyssey is orbiting Io, then every time Jupiter passes by on one side, It might contribute a tidal kick that spins the ship as it passes.?
What I find chilling is the idea that TMA2 was somehow involved with Discovery's spin. But that is the mystery of the monoliths, and 2001 as a whole.
Curious regarding the centrifuge: If in space, how do you make sure the engine spins just the room you want and not the whole ship?
I seem to recall that, in the movie, Dr. Floyd was advised by the Soviet guy to "check the orbit". Floyd did and noticed that it was anomalous, not consistent with what would be expected. The implication was that the Monolith (and/or Bowman) might have done this to attract human attention to the ship.
So we are going with it being a gyroscopic effect caused by the spin gravity generator in the primary hull and not a consequence of atmospheric drag on a ship which has more mass a the rear than the front. ( I don't think the centre of mass is the antennae location when she's lost much of her fuel by now). especially if they ship isn't pumping it's fuel around inside anymore as Hal isn't around to maintain housekeeping functions like that.
I doubt the ship would even still be in orbit after 9 years unless the ship's systems only recently gave out. it is possible there was some automated thrust control keeping it up & if it used up all the reaction mass in the last 9 years it eventually got bathed in sulphur, froze and had a partial system malfunction. It does seem likely some automated systems were installed in case Hal broke or they had to all go into stasis for a long period. (if the crew were still alive that is of course)
This is superb 👍. All of Clarke's work was wonderful.
I agree. As a Clarke fan, I cannot wait for 2025 when Denis Villeneuve makes "Rendezvous With Rama". It's been a long time coming!
As far as I know, there has been a counter weight at the centrifuge which neutralizes the effect of the fly wheel to the ship's motion. Probably this counter weight is lighter than the centrifuge but has a higher speed in the opposite direction. When one of them or both slow down because of bearing friction, then there is somehow interaction between two gyroscopes.
However, maybe the monolith was the reason for the malfunctions at the Discovery.
Great video, but I didn't understand the discussion about the location of the centrifuge. The movie makes It clear that it's at the back of the command sphere, behind the bridge. There's also a number of technical drawings of the ship in books like The Making of Kubrick's 2001 and others that leave no doubt as to where It was located. If It would have worked as planned is another story...
In any case, great graphics, thorough explanation, good job!
Juno's orbit is also polar simply because that was its primary scientific mission, to observe the polar regions of Jupiter (there had been no good look at them previously).
Another possibility is just a tidal effect. Because it is so long, there could be a minute difference in the IO gravitational field at both ends and over time, could this accumulate? I'm wondering whether there is a stable vertical configuration in IO's gravitational field but I haven't done the Math.
When it came to position of the centrifuge, the books seemed to indicate that it was located horizontally, between the pod-bay and the flight-deck, as touched uponat 7:55 minutes in on the time tracker. See excerpt: "The equatorial region of the pressure sphere - the slice, as it were, from Capricorn to Cancer - enclosed a slowly rotating drum, thirty-five feet in diameter. As it made one revolution every ten seconds, this carrousel or centrifuge produced an artificial gravity equal to that of the Moon. This was enough to prevent the physical atrophy which would resuit from the complete absence of weight, and it also allowed the routine functions of living to be carried out under normal - or nearly normal - conditions. "
About the difference in models from 2001 and 2010: I would say that is valid, because they have different approach to make the movies. 2001 is based on the book but it have it's own artistic and philosophical approach from Kubrick's mind, while 2010 was not directed by Kubrick. 2010 is more like an adaptation from the book. Despite I like a lot Kubrick's 2001 I would love to see a remake directed by Christopher Nolan with today's technology, and also all the sequels to it.
Perhaps a flywheel, used to store the centrifuge's momentum, was at a different orientation to the centrifuge itself, connected via a gearing.
The spin was cinematic.
I wonder how long mission control had contact with Discovery after Bowman left? It would seem like at least several months. Did they send signals to shut down systems?
Since Io has a very dynamic interior, there could arise significant variations in mass which can alter local gravity field strength, perturbing the orbit. These were known to exist on the moon (called masscons for mass concentrations) for different reasons from unmanned Lunar Orbiter missions that preceded the Apollo missions and had to be accounted for in mission planning.
I always assumed that the Discovery was spinning because all movement stabilization had been disabled since HAL was shut off and only the basic functions were still running. But still only very basic systems. Since HAL controlled every part of the ship and was vital to its fully automated function, he could no longer maintain the stability and course of the ship. And over the course of 9 years slight things like tiny meteorite hits or gravitational pull may have caused this spinning to start slowly and then become even stronger.
We also don’t know what type of food preservatives they have in 2010. Meat may not spoil in 3-5 days.
My favorite part was the Enterprise, but I liked the rest of the video too!
Could thermal expansion from the sun-facing side be translated into movement?
I think it makes sense that it was hit by something, either ejected from Io or from elsewhere. Jupiter is a massive gravity well. The sulfur deposits also appear consistent on all surfaces, indicating the spin did not gradually change. It probably began soon after Bowman left. Not moments after, but within a year. Otherwise the sulfur would accumulate unevenly.
The deteriorating orbit is blamed on the TMA-2 Monolith in Clarke's book, NCA had taken Io's sulfur ejections into account in their projections. The orbital decay was much too rapid to be natural.
Nicely done video. I would disagree about the sulfur being the cause of the Discovery's decaying orbit. If themat were the case, her acceleration toward Io would have primarily remained steady or increased. Any direct deceleration from a sulfur plume would likely be easily accountable. However, Floyd speaking to Melson in front of the White House specifically said that the Discovery seemed at times to be accelerating, and at others seemed to have stopped entirely. He also said they had no idea why. I believe it was the Monoliths' interference specifically to get the Americans' attention. That ultimately allowed them to transmit their message to Earth. Without the Leonov and her personnel, the message may not have carried the nessisary weight. Just my thoughts on the matter.
I just want to point out that you are oversimplifying the problem, and neglecting torque. A spinning disc causes torque along the direction of the axis of the spin. If the flywheel seized up, it would cause a torque either in the direction of travel, or against it. So yes, there would be a slight roll on the ship which could easily be corrected, and a pitch/tumble/orbital change which might get worse over nine years. Some other people have commented that spins do funny things in space. Also, adding sulpher to the ship irregularly changes its mass and mass distribution. Plus, I think the film makers had the EXACT effect they wanted to by tumbling the ship. It was frightening, just as you said. I agree with you there!
Good video on an interesting subject!
It's possible that the centrifuge stopped spinning as the ships power failed. Also as stated forces like the sulfur plums would possibly have caused the spin. Back in 1984 when they made the movie 2010 the spin was included for dramatic affect. Who knows but it's fun to speculate.
OMG! It's full of stars.
The spin was caused by the gravity wheel stopping without proper braking or attitude control. This was explained actually. the rotational energy would make the Discovery spin
The real reason was probably the aliens came back and spun it themselves just to mess with us.
Another factor is precession caused by an unbalanced spinning mass. Especially if it is shaped like a dumbbell.
The spin of the Discovery was caused by a writer who wanted to make it difficult and dramatic to get on board the ship.
3:19 it was determined that as Discovery passed through the flux tube between Jupiter and Io it was perturbing its orbit.
5:45 No, the centrifuge rides on magnetic bearings while near frictionless there is still drag to the rest of the ship which is countered with RCS corrections.
7:36 I believe in the novel Curnow talks about this and belives gyroscopic precession is why the ship is spinning end over end as the centrifuge spun down and transfered its momentum into the rest of the ship
Left in orbit for years with nothing to do - it takes far less boredom than that to set me spinning.
Any aerospace engineer or astronomer well-versed in orbital mechanics will tell you that a long extended spacecraft will not spin like that near a large gravitating body like Jupiter. What will happen instead is that gravity gradient (tidal forces) will cause the spacecraft to align along the local vertical and rotate with the orbit. It can spin a bit along its long axis, but it is unstable. Structural vibrations will transfer the energy of rotation about this axis to one of the side axes, where the gravity gradient and structural friction will dampen it.
I'm old and my memory in question. But i thought Frank Poole's pod was used by HAL to kill him and spun off into space (exit stage right) then Bowman retrieves Poole with second pod but due to HAL blocking his return had to abandon Poole and fire himself into the airlock .Opposite and equal reactions pod #2 gone ? then Bowman leaves in pod #3 not to return ..... Wasn't there a pod in the pod bay in 2010?
correction, after reviewing film clips I now see the pod that Bowman blows himself out of remains on station at the airlock door . I must commend future spaceship design as the pod doesn't appear to move at all after the explosive decompression but it is what it is so I concede Bowman may have been able to retrieve the pod allowing Bowman to leave one pod on Discover .... my error
Personally i always found the Orbital decay to be the more interesting question .
My understanding has always been the centrifuge thing.
However, such a long slender ship would be especially susceptible to tidal influence, which would cause it to tumble end over end in its orbit. This effect could be nullified by imparting a roll on the long axis, like a football.
You're wrong about the spin. And centrifugal forces. It would indeed spin end over end as the centrifuge energy dissipated. Its a well known phenomenon of progression. And has been seen in satellites as their gyros fail. This is exactly why it's in the movie.
A movie about life on Earth, after Jupiter has been turned into a star, and knowing aliens do exist, would be interesting.
that would be 2061 by A C Clarke......
it was spinning as a throwback to the opening of 2001 with the caveman throwing the bone in the air....
It might be pedantic, but would the Discovery technically be in orbit of Io if Bowman left the Discovery at the LaGrange Point between Jupiter and Io (a spot where an object would stay in one spot due to overlapping gravity)?
Yes, eg the JWST is still considered to be in Earth orbit. Since it is in Earth’s L2, not Mars’ L2 or Venus’ L2. Therefore, being in one of Io’s Lagrange Points is still in orbit of Io.
@@kaitlyn__L Sorry, but you're wrong. The JWST s orbiting the Earth, not the Moon, being carried along with the Moon at the further-out L2 Lagrange point.
Bowman 'parked' the DISCOVERY-1 at the Jupiter-Io L1 Lagrange point, the unstable point in-between the two bodies, which is far closer to Io than to Jupiter. Thus, it was orbiting Jupiter in lock-step with Io, orbiting that gas giant at the same rate that Io was orbiting it.
The trouble is, though, that only L4 and L5 Lagrange points are stable. L1 -- as well as the L2 and L3 Lagrange points (there being only 5 such points) -- are unstable and require "station-keeping" engine burns to keep things there. The close approaches of the other Galilean moons of Jupiter would be enough to perturb the object perched at L1, nudging it away from its position.
Jupiter's equatorial radius is 71,492 kilometers, with the semimajor axis of Io's orbit being 422,000 km, about 5.9 Jupiter radii away. By contrast, the Moon's average distance from the Earth is 384,400 km, about 60.268 Earth radii away, the Earth's radius being 6,378.14 km. Jupiter's magnetic field alone would perturb any spacecraft parked at Io's L1 spot, which is one of the things Clarke's novel mentions, what with the magnetic flux tube connecting Io and its sulfurous eruptions to Jupiter in the first place. An object parked for 9 years at the Earth-Moon L1 Lagrange point -- sans any station-keeping maneuvers -- would be perturbed away from that unstable location, so its no surprise that the DISCOVERY-1 spaceship, parked at the Jupiter-Io L1 spot, would have its position rendered so precarious.
I would say that the close approaches of Europa (especially), orbiting Jupiter at 9.8566553 Jupiter radii out (i.e. 671,000 km away), would be the main reason that the ship was perturbed in its L1 'parking' spot. Io orbits Jupiter every 2,548 minutes, with Europa orbiting Jupiter every 5,114 minutes -- i.e. they're in an orbital resonance of 2:1, with Io orbiting Jupiter twice for every Europa orbit around Jupiter. That's a closest-approach of Europa to Io every other Io orbit of Jupiter, every 3.5513888... days. That gravitational 'tug', repeated every 3 and a half days or so over the course of some 9 years (i.e. from 2001 to 2010) would amount to almost a thousand such 'tugging' moments. Even the slightest tendency of the ship to tumble -- let's say a complete turn over the course of a week, initially -- would be reinforced such that the spin rate would gradually accelerate . . . taking less than a week after the first year . . . then perhaps a day-long spin-rate by the end of the 2nd year . . . etc. etc. That spin-rate HAD to have been accelerating over the course of the 9 years in-between Bowman leaving the ship in the Pod and the LEONOV arriving at the same L1 spot, since Bowman certainly didn't leave in that Pod with the ship ALREADY spinning so fast! That once-every-3.55-day nudge provided by Europa's further-out orbit is the main source of the extra energy required to accelerate the spin of that rotating, tumbling vehicle, I think. The other Galilean satellites -- Ganymede and Callisto -- would also add their gravitational nudges to the spinning ship, but Europa would have the greatest effect on it.
There’s another poster remarked, originally the centrifuge was positioned equatorially…. If the fly will malfunction with that, not in part a moment of inertia perpendicular to the spin, and therefore pause the end over in rotation?
Simple physics transference of rotation or momentum of the centrifuge in the capsule through minisculenergy energy transferences by, however, miniscule frictional forces did this
The Discovery's spin isn't wrong. The result of Explorer 1 introduced new physics we simply didn't know yet. If it has a way to lose mechanical energy it will convert its on axis spin to cross axis spin. This isn't that hard. Anything that can vibrate can do it. (Vibrations -> heat energy)
Bowman probably didn't shut down the systems aboard Discovery. That would have happened because the ionized cloud of sulfur atoms it was orbiting within would have built up an electrical charge on the hull and infrastructure until it discharged and popped the circuit breakers. With HAL shut down and no one aboard, there was nobody to reset them. The same sort of thing happens to electronics on the ISS whenever it passes over the South Atlantic Magnetic Anomaly, except in that case people are there to reboot.
I think it's because it looks cool on the screen!
I suspect the reason she's spinning is partly down to it being a visual reference to the Movie and the bone scene.
I guess the Fly wheels may look nothing like they are speculated to look may of them mounted in a gimbles they could be used to move the ship instead of thrusters. Acreative
To combat radiation space craft could use optronics, at least in unshielded sections then convert to electronics in safe areas. That would make systems more reliable.
Yes, initially the spin of discovery would have been along its longitudinal axis. However, I advise you to look up the bizarre phenomenon of rotating bodies. Over time they periodically go through a period of reversal where they flip around/through different axis. It's very unintuitive because most people can go through life without witnessing the effect, so it seems very unintuitive. Of course, in the book/movie the Discovery was depicted as going through one of these inversions and flipping end over end instead of spinning along its axis.