3111: Artificial Gravity

Artificial Gravity

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Title text: Low gravity can cause bone loss, so we're pleased to report that, since we initiated capsule motion, the number of bones in each crew member has been steadily increasing.

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Explanation

This explanation is incomplete: This page was created by a very unhappy astronaut. Don't remove this notice too soon. If you can fix this issue, edit the page!

In a low gravity environment, such as a spaceship taking an interplanetary or interstellar voyage, the human body will experience slow but adverse side effects. Many prototype designs have been introduced to combat this, both in science fiction and real life. One of the most common (for non-fictional purposes, or in hard science fiction) is to use a rotating system to subject the crew to centrifugal force, simulating the effects of gravity. Examples of mimicking gravity using spinning elements are: the whole wheel-like space-station and internal living ring of the Discovery, from 2001: A Space Odyssey; the extended rotating arms of the Hermes, in The Martian; the whole rotating structure of Endurance, from the movie Interstellar.

Cueball instead describes a spacecraft in which the crew quarters are being continuously shaken back and forth across an axis. Ponytail immediately sees problems with this approach, and asks if the shaking pod can be replaced with a much safer and more stable spinning wheel or cylinder. Cueball concedes this argument, but reveals that the ship has already been built, launched, and is in operation, so the crew is stuck with the shaking pod setup. Apparently, nobody pointed out that there was a much better approach during the mission development.

A shaking spaceship design would create an experience of gravity for the crew — just a very unpleasant one. When the capsule accelerates "up" (from the point of view of the picture), the crew will feel a gravity-like force pulling them "down" against the capsule 'floor'. However when the capsule accelerates "down", the crew will find themselves thrown against what was the 'ceiling' of the capsule, but has now suddenly become the 'floor', in an experience similar to falling several metres. The direction of this artificial "gravity" will keep alternating as long as the capsule keeps shaking. This will result in the crew not only repeatedly falling against one surface or the other, but also at a variable apparent gravity as the capsule's lateral velocity changes. This might make their life onboard ship, which could (otherwise) be expected to last for many years, somewhat unpleasant.^{[citation needed]}

This shaking system would also be wasteful of energy, since there would be losses due to friction at the joints between modules, as well as the energy costs of changing the motion of the crew module relative to the rest of the structure. In contrast, a rotating structure freely floating in a weightless environment tends to retain its motion, with negligible losses due to interactions with other bodies.

The title text discusses a real side effect of low gravity environments — a form of bone density loss known as Spaceflight osteopenia. The speaker claims that "the number of bones in each crew member has been steadily increasing". This is because the shaking, and subsequent multiple impacts, are fragmenting the crew members' bones. The broken pieces of bone are then being counted as bones in their own right and increasing the effective count, without telling if the pod's awkward configuration has done anything to reduce bone mass loss.

Transcript

This transcript is incomplete: Don't remove this notice too soon. If you can fix this issue, edit the page!

[Cueball and Ponytail are standing near a blueprint of a spacecraft, with Cueball pointing at the blueprint. In place of conventional conical fairing, this spacecraft has a large mechanical arm on the nose. The arm is holding an egg-shaped capsule. Two semi-transparent drawings of the arm and the capsule are depicted on either side of it with speed streaks in between, implying shaking back and forth motion of the arm.]

Cueball: To produce artificial gravity during the voyage, the crew capsule is kept in constant motion.

Ponytail: Wouldn't it make more sense to spin it instead of shaking it, so the acceleration is steadier?

Cueball: ...Listen. You, I, and the crew all wish we'd thought of that before launch.

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Discussion

Note the motion lines around the main body of the spacecraft, showing that it is also shaking to a much lesser extent. 181.214.218.76 15:26, 4 July 2025 (UTC)

That is just Newton's Third Law, which is very often taken into account in space obviously. Thehydraclone (talk) 16:04, 4 July 2025 (UTC)

I prefer to think it's using thrusters either side of the main body to slightly oscillate that back and forth, which then translates into the larger movement of the capsule through the joint. 82.13.184.33 08:17, 7 July 2025 (UTC)

Report: Total crew bone mass remains constant. 2804:7f0:bf02:c680:390e:8bb5:b4a9:db40 (talk) 16:05, 4 July 2025 (please sign your comments with ~~~~)

Now you made it sound like some bones have changed owner. Whether intentional or not, very xkcd. --Coconut Galaxy (talk) 13:28, 5 July 2025 (UTC)

"We may have made the change of direction a little too abrupt..." 82.13.184.33 15:58, 7 July 2025 (UTC)

The spinning idea reminds me of the spin drive from Andy Weir's "Project Hail Mary."136.47.216.1 17:34, 4 July 2025 (UTC)

Wait, nothing about the 4th of July today? That's odd. 2601:647:8500:1E09:55BB:EEBB:23EA:178A 23:04, 4 July 2025 (UTC)

this rocket was clearly sent up mistaken for a firework 2600:4040:52f1:300:8c1d:959a:d4c2:80be (talk) 14:07, 5 July 2025 (please sign your comments with ~~~~)

Not at all surprising - clicking through Category:Comics from July to find the relevant week each year, the only one I can see in twenty years directly referencing it is 1858: 4th of July; at a stretch, you could suggest that 285: Wikipedian Protester was also specifically timed. More notably, it's the 19th anniversary of 123: Centrifugal Force, which feels relevant. - IMSoP (talk) 10:00, 7 July 2025 (UTC)

aw, great, "steadily"--me, hi (talk) 03:37, 7 July 2025 (UTC)

This rocket design and the intent to provide artificial gravity to the crew module is similar (but not identical) to the design of the ship in Andy Weir's novel Project Hail Mary, for which the film adaptation's trailer was released on June 30. 24.85.198.95 16:36, 9 July 2025 (UTC)

Could this possibly be a reference to james bond preferring his drinks "shaken not stirred?" Especially given how the engineers never even considered spinning the capsule, despite the obvious impracticality of having it "shaken not spun," like they had some kind of personal preference. Ip36 (talk) 00:02, 10 July 2025 (UTC)

No obvious Bondian reference (saving for prior centrifugal/centripetal death-traps). And incidentally also interesting to note that stirring is also the prefered method of mixing, by anyone not solely influenced by Fleming's œuvre. 82.132.236.42 12:33, 10 July 2025 (UTC)
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