How fast does Overture spin?

Sunday, May 15th, 2016

The latest in a series of posts in which I obsess over a tiny little ginormous fictional spaceship. including a Read More as a courtesy for the non-obsessed.

As previously discussed, Overture seems to be designed to spin on its axis to make artificial gravity. Looking “back” at the ship from “ahead” in terms of its direction of travel, it looks like this:


I was curious how fast it spins. So I did some math.

According to this post, Overture has a diameter of 448 meters. I wasn’t sure if that was just for the big donut with its presumably-habitable pods, or if it includes the antenna structure sticking out to the side. Fortunately the space shuttles docked on the hub provide a handy yardstick:


Using copy-and-paste, I confirmed that Overture’s big donut is about 19 shuttle wingspans across, or 456 m, which is close enough to the official figure of 448 m for me to assume that the difference is due to my sloppy measuring.

According to the Wikipedia article on artificial gravity, the following formula is what we need:


I’m going to assume that Overture is designed to produce 1 g at the outermost (lowest) deck of the inhabited big-donut pods. That gives:

R = 224 m, a = 9.81 m/s/s

Plug those in and do the math, and you end up with:

T = 30 seconds

So Overture spins at 2 rpm.

I bet it would look pretty out the windows. I think those might actually be windows in the two big-donut pods at either end of the gantry that connects the donut to the hub; they’re the only two pods that have them:


If those actually are decks it looks like there are 10 of them in the pod. Using my handy shuttle-wingspan yardstick, it looks like the decks are about 15 feet apart, which sounds a little big, but maybe it makes sense if the ceilings are high or there’s a lot of stuff taking up space between the decks.

Each deck would have slightly less artificial gravity than the one below. If I did the math right the middle of the pod would have 8.25 m/s/s, or about 84% of normal, while the top deck would have 6.67 m/s/s, or about 68% of normal.

I also figured out the gravity for the smaller donut’s pods: 6.05 m/s/s (62%) at the bottom (outermost) part of the pod, 4.74 m/s/s (48%) in the middle, and 3.42 m/s/s (35%) at the top. So the crew will definitely feel a lot lighter if they spend time in there.

Interestingly, if a crewmember were to travel around the rings that connect the pods in the donuts, going in the direction the ship is spinning would make them heavier, while going in the opposite direction would make them lighter. That in turn made me wonder: If they had a bicycle on the ship, and Dr. Blasto rode it as fast as he could through the big donut’s connecting ring in an anti-spinward direction, could he achieve weightlessness and just sit there, floating, while the ship turned past him?

The answer turns out to be no, for several reasons.

For one thing, he’d need to have an uninterrupted passage to ride through, and I bet the ship’s designers wouldn’t make that easy. There probably isn’t a breathable atmosphere throughout the ring’s 1,181-meter circumference. Even if there is, the pods are probably isolated with airtight bulkheads for safety.

But on a 25-year shift I can imagine boredom setting in. After a while those fussy safety rules might start to look more like guidelines than hard-and-fast rules. So maybe Blasto would wait until Commander Gartner was asleep or busy doing Oort Cloud observations and open all the hatches to he could try his weightless biking stunt.

The faster he goes, though, the lighter he becomes. He’d still have air resistance holding him back, but there’d be less and less friction with the deck for the bike’s tires to push against. At some point before he’d achieved weightlessness he’d be unable to go any faster.

The real problem, though, is that he can’t go fast enough regardless. At the 188 m radius that I estimate for the outer ring, he’d need to go 39.4 m/s, or 87.9 mph, to cancel out Overture’s rotation. I don’t think he can pedal that fast.

But that figure of 87.9 mph made me think of something else: What if Dr. Blasto has a flux capacitor? Then all he has to do is go 0.1 mph faster and he can travel through time! And for that all he has to do is descend to a lower deck. Way before he reaches the lowest deck, where the ship’s rotational velocity is a brisk 104.9 mph, he would hit the magic 88 mph and vanish in a burst of blue-white light, bound for temporal glory!

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Okay, but: Edgar Allan Poe… in SPACE!

Monday, May 2nd, 2016

Okay, but: Edgar Allan Poe… in SPACE!

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The page at some interesting hints…

Sunday, April 17th, 2016

The page at has some interesting hints about where they’re planning to go story-wise. I’m getting a very cool transmedia/meta vibe. And, well, you know how I feel about that sort of thing.

Also, what exactly are The Poe Diaries, and how can I watch them? :-)

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