This is NOT how you make Artificial Gravity

Today we're talking rotational stability and Artificial Gravity! This video has been a long time coming, and not just because it took 47 hours to edit, I took my first pass at this script about a year ago but wasn't sold on the final product. A very busy year later I've finally decided to cut the video down to a (slightly) more simple discussion about rotational stability in the context of artificial gravity. Nevertheless, this ended up being my longest science video ever, and definitely one of the most taxing for my ten-year-old computer.

I think these are some of the best visuals I've done even though they are still fairly simple, but there is still so much to talk about. I did a lot of research for that first draft, including how you can perform maneuvers while spinning, and even a way to jumpstart the rotation using gravity gradient stabilization.

Enjoy!

Starship SN10 Footage is used with the permission of Cosmic Perspective:
Thank you Ryan!

Intro Music: "Tornado" by Wintergatan
Thank you Martin!

Main Music: Lone Wolf by Dan Lebowitz
Available in the YouTube Audio Library

(0:00) - Intro
(1:31) - What is Artificial Gravity?
(2:41) - Small Radius AG
(4:44) - Large Radius AG
(5:26) - Single Starship AG
(6:39) - The Rotational Stability Problem!
(8:51) - Multiple Starship AG
(12:05) - What if the Tether Breaks!?
(14:55) - What's the Best Option?
(15:43) - Outro

[kestrelwings]

Centrifugal force isn't just about health. It is also about hygiene. Water and dirt going "down" might make cleaning easier and reduce the risk of inhaling dirt.

[AlpineTheHusky]

The cool thing is you can basically simulate this VERY accurately in Kerbal Space Program....as long as the kraken doesnt get to you

[FrigidDeadline]

I think an advantage of whole ship gravity over short radius is crew sanity, it would feel a lot more comfortable and natural to just have 'gravity' all the time.

[shawnmikeska]

Just looking at the small centrifuge, it looks like the most likely issue with the pressure in the eyes is that there is a force gradient from the feet to the head. The surface tension of the liquid below is pulling it down slightly but not meaningful force is being applied to the head. A large centrifuge has a smaller gradient.

[fxzn]

bro FINALLY. when i first saw that concept with the 3 starships, i was just thinking.. what??? its so overcomplicated when you could just use a massive rope. and NO one was talking about it.

my very first thought and solution to the art grav problem was just tethering two starships, and personally, i still think that's the best option. either way, i'm glad someone actually made a video about it. thank you.

[klatbaraada]

This gives new meaning to the term "I'm going to take Starship out for a spin"

[ThomasHojack]

The phone flipping analogy was the coolest interactive thing I've seen to demonstrate a concept, well done.

[GreyAcumen]

I love how absolutely absurd the way that "works" looks. This is the type of thing that would show up in Star trek and have the entire crew spend 15 minutes going "WTF is going on with their ship?"

[...]

something i don't understand about short radius centrifuges:
wouldn't they apply significantly less acceleration to your upper body, and especially your head?
and aren't those also the areas which are the most negatively affected by low gravity?

[Vicvic]

The tether concept was experimented with and was found out that due cable stretching and pulling back like a spring the space craft is pulled towards the center then a inertia pulls the craft away from the counter weight creating an impact load on cable and makes the center of rotation unstable meaning gravity will be as well. This is a reason why solid structures are required in between the ships. As for small diameter centrifuges, they will work for research purposes and small scale transport but the selling point is colonization.

[TheChromeRonin]

The precession problem is why I thought the design of the Hermes cycler in the Martian was epic, as the plane of rotation for the gravity hab modules is isolated to the bearing at the point where it intersects the main hull. This means you get that flat plane of rotation because the main hull is NOT rotating. It also gives you a stationary point to mount antenna, telescopes, thrusters and heavy stuff like fuel.

[Almandar]

I would think short-radius centrifuges have major disadvantages vs the tethered starships option:
1.) Uneven: Different spin and therefore uneven G-force applied from top-down on the body.
2.) Stationary: Movement around the cabin and useful work is limited to near zero: inactive astronauts.
3.) Periodical: This is a guess, but I can hardly imagine that anyone could so much get used to the rotation that sleep could be accomplished: only periodical use vs continuous.

[TheRecord]

They could put a small one up on the ISS or Gateway to be used as sleeping quarters. It spins with the beds positioned to the sides, allowing you to sleep like you're on Earth, but also letting your body recover from zero gravity.

[achillesa]

Alright I was ready to come in here and defend the tether design but you actually said it makes sense so now I don't know what to complain about. I hadn't considered the other designs, but I learned a lot from your analysis. These small radius centrifuges look very interesting and I'd love to see them developed more, but artificial gravity on the whole ship is some hard to beat quality of life. Anyway, subbed!

[aneyesky]

Love the “ Honest, this is the truth” animation of the astronaut placing his hand on his heart, every time you make a good point, lol.

[peterhart]

Recently I watched a youtube video were it showed some astronauts in space doing an experiment where they spun a crew member in a chair. It was to compare the results to that of spinning a person in a small centrifuge on Earth. The result was none of the crew got sick when spinning inside the spacecraft where there is no gravity, but they did when on the Earth? The conclusion was that gravity affected the inner ear and that was what made people sick when spinning. I am not sure how this relates to artificial gravity in space, but maybe the human body can tolerate a faster spin rate in space than what is presently accepted. I don't know the answer, just food for thought.

[seasidescott]

I love the way you went about this discussion. Don't give up on snapping the tether as NASA has proven fairly good at projecting trajectories and wasting all that momentum would be a shame.

[space_artist_real]

Allright, so as a soon to be mechanical engineer I can say that the short centrifuge AT FIRST looks dizzying, with the head near the center of rotation, but really it's genius. The way it's built is *chef's kiss*. I even mistook the linear rails for an aluminum ladder, but linear rails are better. Linear rails are cheap as hell in these large quantities and you need only simple hardware like:
a)Wood
b)Bolt
c)Matress

Also it's so goddamn simple :D I feel like doing the structural analysis would be the best experience in the world since even hand calculations would end up near exact.
Bruh why they say it's a waste of funds lmaoooo

[andrewcliffe]

Always liked this choice of a cable. With 2 starships you can rescue each other if necessary that far safer

[fredamber]

Artificial gravity caused by rotation has an important advantage:
You can go to the toilet normally and take a shower normally.