Confused question about Discovery's spin in 2010

[Staiduk]

'Lo!
I've been trying to work out some of the details of the ship in my novel, and in order to visualize it I've been visualizing the majestic Discovery One. The two ships are of similar size; both long and narrow, etc. (In fact, cut the Command Module off the Discovery and bolt on a luxury yacht; replace the AE35 with two great big whomping round fuel tanks and let the ends of the ship extend on 50m booms so it doesn't need to spin too fast to provide gravity, and you've pretty much got my ship. OK? Moving on...)

Anyway, I was thinking about the way Discovery was spinning when Leonov found her at Jupiter. (Still one of the most heart-stopping moments on the Big Screen IMO - it still rocks me every time I see it.)

Anyway, I was pouring a cuppa just now when I realized there was something odd about it and I thought I'd ask here.

In the book Clarke tells us that the reason the derelict is spinning is that over the years, the centrifuge - still running when Bowman left the ship - seized up; transferring its inertia to the Discovery's superstructure. But the thing that I find odd is this: The centrifuge was mounted laterally in the Command Module; horizontally across the module's widest point. When it seized, Discovery should have begun rolling, not pitching.

Granted, seeing Discovery spinning like an arrow in flight wouldn't have been very impressive visually, but that is what would have happened, right? Just curious.

Of course, I'm also thinking that the centrifuge was 65m forward of the ship's CoG, so is there some effect relating to precession that would have induced that violent pitch?

Ah - gotta go watch 2010 again; just to see that shot. :thumbup:

Thanks!

 

[PhantomCruiser]

That was a great cinematic moment.

I had a physics guy explain this to me once, but it was years (and several bottle of wild turkey) ago.

One of the smart people here can answer it better, but I seem to remember that Discovery would have started an uncontrolled yaw once the centrifuge seized up as the energy was transferred to the structure; but over time the "spin" induced would wind up as the end over end motion shown in the film. Something about the conservation of energy and some kind of torque. Like I said, there was alcohol involved... But the guy's a physics guru and I had no reason to doubt him.

I'll try to find him on FB. If I can get him I'll see if he's changed his mind or if his baton twirling motion of Discovery One has held up over the years.

 

[dgatsoulis]

I had read something similar a couple of years ago. I think that a rotation on all three axes, would be a more accurate result, if a ship like the Discovery was left stranded in Io orbit for several years.

Edit: here is the link

 

[Staiduk]

I had read something similar a couple of years ago. I think that a rotation on all three axes, would be a more accurate result, if a ship like the Discovery was left stranded in Io orbit for several years.

Edit: here is the link

Hey that was a great thread and pretty much explained it to my satisfaction. That one guy got it wrong though; (NERD ALERT!! :lol the centrifuge is definitely mounted laterally, not horizontally. We can see this in 2010. When Bowman appears to Floyd on the flight deck, he walks down a short corridor to the pod bay. He doesn't pass through the centrifuge which was accessible only by the hub. Had it been mounted horizontally; they'd have had to crawl butt-first through the hub to get to the bay. Which would be OK for Floyd; but when you're a noncorporeal entity representing a hyperadvanced alien civilization, you have a certain dignity to maintain. :rofl:

Cheers!

 

[Izack]

I'm inclined to attribute the movie-Discovery's spin to artistic license on the director's part. As you said, a rolling Discovery would have been a much less instilling picture than a pitching one. It also set up the following scene rather nicely, with Floyd and the cosmonauts suffering in the high acceleration.

I didn't know of Clarke's explanation of this, having never found those books. Thanks for sharing.

It's not hard to imagine, either, that at some point, late in the long line of technical failures aboard that cursed vessel, that some control system placed Discovery in that pitching motion, or some ACS propellant was accidentally expelled. Would make it difficult to explain the ship's controlled behaviour later in the film, though... :hmm:

 

[movieman]

Isn't the centrifuge way too big to fit in Discovery anyway?

 

[Kyle]

f you've read 2001 A Space Odyssey, Discovery was always pitching for artificial gravity. When the crew of the Leonov reach Discovery, they're in a perfect 1g setting. This was a mistake made in the movie adaptation of 2001 that was corrected in the 2010 adaptation of the respective book.

 

[jedidia]

I think it's got to do with torque... The centrifuge is a lot further from the center of mass in the long axis, so more of the momentum would be aplied to that axis...?

 

[Keatah]

The two best explanations for what we see are artistic license for drama and a malfunctioning attitude control.