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.

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

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.

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.

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

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.

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?"

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!

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.

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.

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?

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

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.

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.

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

Oh my god I love you. I do the moment of inertia with a phone demo for people ALL THE TIME

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.

Note this is very noticeable in KSP for early RP-1 rockets, which almost always have at least one spin-stabilized stage. If you start them spinning on the minimum axis, above a certain altitude, they will slowly spin out towards the maximum one due to the fact that KSP rockets are made of multiple parts that can bend and move in relation to each other. It's also an important concern when making stock props. A 3-bladed prop is stable but a 2-bladed prop wants to yank the axle out of its housing whenever you turn the aircraft.

"...this lunar landing contract came with 2.89 billion dollars, which is definitely going to speed up development..." Wow. _That_ aged like milk. Other than that, great video! Have a nice day!

excellently presented! Thanks for sharing! I'm all for going to Mars when we can travel 20 times faster than we now can. The "problem" is going to be with mental health and such. Best of luck to all of us!

Very well done! You deserve so many more views!

Haha I was thinking about the T Axis handle all the time, great that you mentioned it!

Finally! I found a video talking about the same thing I've been thinking about for years now. Yes, bone and muscle loss are the biggest physiological problems for a trip to Mars. I envisioned two cuboid shipping containers tethered together by cables (and transit ducts) about 200 feet apart, slowly rotating around their center of mass.

We had a mechanical merry go round in my local park. Only one ive seen physically. It was a wonder. I digress, it was covered with a metal dome where we could climb into once pushing it to its limits. Orienting yourself to he correct position had this same effect. You could spin full speed for 15 minutes looking any direction with no ill effects. Compared to to the 5 on the actual seats at 3/4 speed. I was instantly reminded of those memories upon seeing your video. Thanks for bringing up golden times.

Short radius is a good solution for astronauts, whom have been rigorously trained. And for a situation where all you need the gravity for is maintaining human health. It most likely is not a solution for anything else. Civilians wouldn't be able to handle the restrictions for the periods of time involved.

Well done. The medium moment of inertia of rotating bodies is a very difficult concept to understand.

Great video! Love how in depth it is for just a 16 minute video

10:15 I am SO HAPPY you used this example. When I first learned about the intermediate axis theorem, the first thing I did was realize that a smartphone can be used to easily demonstrate it. Now, whenever I'm meeting new people or talking to a stranger about the importance of understanding physics, my favorite thing to do is to take out my phone and demonstrate this. No one ever expects it to behave like that, and I always have a phone with me, so it's super cool to be able to show that to anyone any time. It really makes my point so well because of how unexpected it is for people. ^^

OK this was a great video. It anticipated most of my objections. Heinlein already described most of the single starship issues, for viewers of a certain age who've read his work; he refers to the viable single starship solution as a "tumbling pigeon". And yes, thanks to Veritasium, I knew about the intermediate axis problem so when you brought up smallstars's idea, the issue was already clear. Good citation, btw. I think you over-emphasized refuting that one commenter's plan, though. Your modification is pretty much one of the two standard versions of spin tethers I've seen, and it's not that different from smallstars's idea, so long as you reorient or reconfigure the hub ship prior to spin-up so it rotates around the correct axis. The other version I've seen is where there is no central ship, which comes with its own tradeoffs. Since Elon Musk's plan is to send a fleet of Starships, you also might want to look at the engineering issues of having multiple ships hanging together in grape clusters (eg a hub ship with, say, three ships/inflatables connected and hanging on each of the two tethers) vs flying in separate pairs/triplets. His vision is to get beyond "boots on the ground" PR stunts and pure research Big Science missions. That requires drastically larger crews and payloads per mission, and also many more missions. One consequence from a mission planning perspective is that with very long tethers (R=85m+), your crew can spend the outbound trip acclimating to martian gravity and land on the surface ready to work on day one (with minimal adaptation required to learn/unlearn 2 RPM coriolis effects at each end of the journey). Of course, that's also assuming no long-duration adverse health effects for living/working in martian gravity, which we don't know. As g-requirements go up, the practicality of spin tethers goes down. Small radius centrifuges have many problems; I get that you don't want to talk about them so I won't. They do have a place in a mars mission, even one using spin tethers. If you're sending a dozen starships, it starts making sense to leave an occasionally-manned space station in Martian orbit (or docked to one of its moons, which isn't all that different). I could totally see the utility of having a small axis centrifuge aboard such a station, especially given the intermittent crew. Most of our assumptions about mission planning stem from the idea that it's a research/PR mission funded and run by NASA. Even two years ago, Musk's ideas about cost and scale seemed optimistic to the point of lunacy. While it's still very optimistic, nobody's laughing now. I don't think anybody has fully grokked the implications of a big shift in launch costs. A shift in cost economics, and sending a fleet of ships on a working mission, changes what you expect of the crew and how you make tradeoffs between payload and cost, and that in turn affects what your ship and habitat look like.

I like how this video is about the quality of youtube comments, but that's not making people think twice before posting their opinions on matter's they don't really understand very well at all.

Great show! Not previously aware of the opportunities with small radius centrifuges. Like the instability demonstrations, saw the spaces Tatiana handle previously but you provided an excellent explanation, thanks!

This just drifted through my feed, I think I just found a channel to sub to. I also really like the use of the astronaut avatar as a way to deal with the microphone. Some serious "calling it a feature" there.

this guy gotta get more recognition

Spinning the entire ship will make your control engineer hate you as your actuators change orientation all the time. I do actually like the two ship rope idea. Make the rope a winch and you have a great control tool. Hock in close bring the system to target rpm. Then let the winch increase distance while the thrusters keep the rpm to increase gravity. Would love to experience this. Having a centrifuge inside the ship is somerhing your controlengineer would love. As it stabelizes the system. Actually having two like a dumbbell would be great to control stability. While you travel speed it up to keep orientation, even if you hit something. If you want to manover regenerative brake the centrifuges, manover with little moment of inertia and spin them up again. It might be possible to rotate more efficient with coordinated acceleration of the centrifuge and thrusting. Sience fiction got his point right quite a view times. Many long travel ships have a ring rotating, the main thruster in the center of rotation and the thrusters located on a long leaver fixed on the none rotating frame. Thats basically a centrifuge but outside of the main rockets shell.

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.

Also, regarding the ring-stations - yeah, they're not very practical to build, but my favorite proposal for building a space station was one that involved the big orange fuel tanks used in the shuttle program - the idea was that rather than discarding them, they'd give them just enough extra push to get into orbit, where after numerous launches, we could send up a space-tug with some extra hardware to rendezvous and gather them all together and use them to build the segments of a ring station (of course you'd start with the dumbbell of 2, but then you can keep attaching them in pairs until you have the full ring).

Feels like they're shoehorning this into a craft that didn't have this in mind from conception.

I think for a Mars mission you would aim for 1/3 gravity. They are going to be on Mars and under that gravity for some time. And the simple two starship 500m tether gets my vote. You want the whole living space at 1/3 g.

Great explainer about the concept of moments in general. This would have been real helpful for applied mechanics class.

Just wanted to share some thoughts on your video. Awesome content! Thank you for making it. The idea of the tether is genius. It would be practical and easy to add. Each Starship could have the tether cable, winch system and its own tethering hook in the nose cone. You could have two Starships meet nose to nose in order to initiate the tether, with each ship hooking to the other one's tether. This would give you redundancy, with two tether cables, one from each ship, keeping the system connected. You can then initiate the spin with a really short radius, the length of two Starships essentially, and pay out the tether cable as you accelerate to use that centrifugal inertia to help with the acceleration process. Then disengaging those tethers at the same time when it's time for the Starship pair to separate, after they are done with their journey.

I had suspected that astronauts could adapt to short-radius centrifuges based on watching a ride operator walk around inside an amusement park centrifuge (with a radial acceleration of about 1g) circa 1970. I'm really happy to see this confirmed by the recent research you mention here. Thanks for a really excellent video. By the way, here's an idea I had a while back that I've never seen mentioned elsewhere, though I seriously doubt I'm the first person to think of it, and I would love to see someone do a video about it. Land the lunar starship upside down. The lunar engines are already going to be mounted high up the side anyway. Landing nose-down would put the astronauts and cargo near the surface and give a clear view of the terrain from the flight deck. It might even be more stable, depending how how full the tanks are at landing.

The first thing that people ask is "what happens when the tether breaks?" because that's exactly what happened during the mission TSS-1R; you also didn't considered the damage that the whiplashing cable would do

You've sold me on short radius centrigugi.

Nice. Glad this popped up on my feed. You have a new subscriber. Thanks, algorithm!

In the case of a space station, beyond the ISS, I think a thin cylinder shape, probably a quarter of the diameter thick, would make sense to have enough space for people to live in with plenty more in addition. Instead of thrusters, I'm thinking an equivalent to reaction wheels for the spin and moveable weights along the edge to maintain a consistent center of gravity with a docking bay in the center which would decrease in RPM to match the incoming ship to allow for a proper connection. After the ship departs, the center will start to spin after those who entered are along the outside until it's matched the RPM of the station when they're able to exit the dock and go elsewhere. There's more to the idea, but this should be enough for now.

My criticism of short radius centrifuges is that they solve a subset of problems and also tend to be more effective in loading the lower body. Spin gravity applied to the whole vehicle has other worthwhile benefits. One of those is simply to create a sense of "up" and "down" within the crew cabin which has psychological benefits. There is also the practical benefit of ensuring objects will fall. That makes a lot of activities, like eating, a lot less complicated. (Ok, so you still need zero g procedures for when you're not spinning). Again, the intangible here is psychological benefit. Speaking of which, I don't think it too much of a luxury to have a normal shower and spin gravity is essential to this (you need the water to head down and be collected, not float). So while I get the idea of centrifuges in some contexts, I still feel that spin gravity, if its practical to implement, should be implemented. And while I'm here, I'll point out that a lot of people seem to be fixated on creating exactly one Earth g. Much of the benefits noted above work at fractions of an Earth g. Also, wearable masses (imagine for instance a radiation protection vest) would increase musculoskeletal loading and would be applicable in the range of 0.5 to 0.8 Earth gs. So you may be able to seek a reasonable compromise at below 0.8 g. Again, something to factor in when you're doing the real engineering trades.

Yay, finally somebody has reminded us all of what I learned 50 years ago in year 12 physics about rotational motion.

I don’t think the problem with tethers is them snapping, it’s that if any slack develops at any time it becomes chaotic. Gordon of Gemini X (Space tether mission) - “Oh, look at the slack! . . . It's going to jerk this thing all to heck."

The first challenge to overcome is Elon Musk.

I very much appreciate you not brushing off what if the tether snaps. Human history is literally the story of shit failing over and over again until we find something acceptable. It would extreme arrogance to act like the tether would never fail ever, and there should absolutely be plans addressed in case it does.

Incredible video! So well done. I'm saying for years that short arm centrifuges are the way to go for science missions. They allow the ship to keep its orientation (solar cells, antenna, thermal management all depend on that!), are relatively easy to install in a ship like Starship and are super usuful for supplementing daily workout to keep the astronauts in shape.

Going on a tangent while talking about spinning in circles made me chuckle.

Use a combination of short radius centrifuges at the axis for workouts at higher gravity with lower gravity (lunar level) at larger radius with slower spin rate.

Don't worry, small scale centerfuges will probably be used when we come to our senses and stop letting business narssists run everything and actually let the engineers who do the real work, yk, DO THE REAL WORK

"What if the teather breaks?" As if we can't build huge suspension bridges.

What a wonderful video with simple explanations of things so many common misconceptions! I agree that tethered spacecraft definitely appear to be the best, the cheapest, the most lightweight and the most practical solution. This is especially the case if the generated 'artificial gravity' is lowered to less than one G, allowing for smaller diameters and much lighter (tethering) structures while still providing major benefits for physical and mental health (along with other measures like fitness workouts weightlifting etc) similar to those astronauts conduct in 0G environments to remain healthy for longer periods. I would strongly suggest considering tethering more than just two spaceships (or space modules rather) though! The most likely solution that I personally think will prove most practical, is tethering at least four, maybe even 5 or more modules together into a structure (maybe with some modules experiencing near 0 or low gravity in/near the center of the structure). The result would be a modular structure which is in a way very similar to the ISS, but with the modules tethered and rotating. Such a type of vehicle design would not only allow for final assembly in space, but it would also allow for a similar strategy as the Moon landings with modules of the vehicle remaining in orbit, and just one or two of the spaceships/space modules detaching for the trip down to the planet. Such a design would of course also allow for each of the sections to be optimized for their special purposes, and it would allow for at least some limited implementation of a few mission critical redundancies, greatly improving mission safety aspects. Furthermore can the tethering structures (easily) be designed for transfer of resources (fuel, water, oxygen food), energy, and data from one module to another during the trip, in return for waste products going back the other way to maintain balance of the rotating masses. Maybe even more importantly though, would it allow for some of the sections to be left behind at various stages of the journey. This (just like any other viable design will similarly require to be practical and efficient) allows to leave structures containing large portions of waste, (used) fuel, (used) food, and other used up resources or equipment behind. This will make the vehicle for the return trip much smaller and much lighter (and it would even already allow reducing the ship's mass before 'decelerating' or entering the orbit of Mars). This will make the overall concept very (fuel) efficient, while at the same time retaining all the necessary (tethering) dimensions of the artificial gravity design concept, only with (far) fewer tethered (and spinning) modules on the return trip.

The three-starship solution seems to have the same problem like the rotating wingnut in zero gravity, that in regular intervals flips around 180 degrees.

I still think constant acceleration with plasma/ion engines (Like VASIMR) is the best option for artificial gravity. The gravity is toward the base of the starship and you just need to rotate 180 degrees during the deceleration half of the flight. Just build the damned radiant heat exchangers so you can run a nuclear generator about the size we already have on nuclear submarines and you have sufficient power for VASIMR engines. You may still not get enough acceleration for a full 1G but that probably is not necessary to maintain health anyway, especially since with constant acceleration the trip to Mars is shortened to like 40 days. If you can generate 1/3 G everyone is already acclimated by the time you get to Mars.

I liked the design of the hail Mary for smaller-scale ships

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

Small spinnes are health risk for the crew in long term missions. Better will be to use the whole ship version, but go for lower G than 1. Spincalc mostly covers all situations. By the way, the best "spinner ship" would be either equivalent of tyqoon "station" from ixion pc game, or Nauvoo from expanse sci-fi universe.

Not sure if you have mentioned this in any of your more recent videos, but I suspect that the eye pressure problem on the short radius centrifuges is most likely due to the gradient offset of the G-forces. The subject's head is close to the centre point of the rotational axis meaning that the head is closer to the zero G point. If the short radius centrifuge is just a bit longer such that the subject's head is closer to 0.5 G it might help with the eye pressure problem. But, I'm no physicist, so I might be wrong on this, it's just what made logical sense to me. 😅

We dont need artificial gravity at all. We just need magnet shoes and a metal walkway. I've been thinking about this for years and i feel like NASA should hire me.

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

Nice video! While I agree that short-radius centrifuges may be more practical to build, I don't see them more practical to use. Living in gravity is far more than organic health and our bodies function better in ergonomic terms when something is pulling us "down". From eating (with your digestive system benefiting from gravity as a bonus) to writing, walking, playing basketball (with very large radii, this would be possible without significantly twisted throws), using untethered tools, drinking water... the list goes on. Adding to it, I definitely hope no one builds a ring station, though... if they do, we can throw the old trope at them: "Well done, FLIPPER!" :D

I'm a big fan of the two-Starships-connected-by-cables concept for a Mars mission. One passenger and one cargo (with the cargo Starship also acting as a lifeboat). Two things. One, there is no need to create an artificial gravity greater than Mars' gravity (.375 g). There will already be a gravity gradient between decks that can be put to some use. Second, I have a concern if the cable breaks it will snap back on the Starship and damage it or wrap around it. It will be under 80 tons of tension, and I have no idea how it will react when suddenly going to zero.

3 years on musk has missed every projected milestone, and starship can't even get into a lunar orbit, let alone to Mars. Waist of money giving that conman the contract.

As someone with horrible short term memory, i really appreciate the secon reminders at the end

Ok, so to jump in on the questions about the small centrifuge. Is this something that can only be used for sleep? What would you suggest for an implementation of a small centrifuge on Starship? Can people on this solution do useful work, or are they just going to be lying down while their body fluids drain back to places where they should be? I have generally been on the anti-small camp, but I'm really curious as to what a recommended implementation might look like, and how it might help Starship travelers. Also, most importantly, can you poop within the small centrifuge?

Tethers are lighter than a rigid trusswork, but are there secondary stability issues with a flexible tether? Such as wobbling or twisting of the load, "crack the whip" scenarios, etc.? Is some sort of shock absorbing and dampening system necessary?

I really like this guy, he taught me things

I find the idea of humans using explosives to launch starships into space then flinging them around each other in circles while traveling to Mars hilarious.

Man you put a ton of effort into this 👏

The two vehicles connected by a tether has been my favorite for many years. I am no expert, but my intuition tells me that that is the easiest, cheapest, and most stable large radius set up. I hope that someone sets this rig up in orbit around earth for experimental purposes. Would it be possible to deliver and retrieve people and cargo to that rotating system without stopping it? Some sort of creeper car stationed on the axis point that creeps down the tether to the vehicles?

What do you mean, "successful landings...or not"? You showed a successful landing right in the video and, even more amazingly, a takeoff immediately afterwards, without even having to refuel! I had no idea that Starship was so advanced.

I was not expecting the wintergatan jumpscare

Thought this was an sfs video💀

i cant do the actual math myself, but using spincalc, 500 meter radius to get 1g is about 1.3 rpm. also i'd imagine they dont even NEED 1g. i wonder how low they could get away with and still stave off the effects of 0g life.

After watching Real Engineering's video on the SpinLaunch, I am fascinated by the discourse on design concerns that people have for certain things. I know some people do comment with their credentials and a really well thought out argument for their point, but I'm really interested in how sometimes the discussion gets side tracked by assumptions in the proposed solution. For example, people were dismissive of SpinLaunch's vacuum chamber based on aerospace testing vacuum chambers, which were orders of magnitude more complex and expensive than the actual needs of the SpinLaunch system. I wonder if the concerns about the tether or the centrifuges could be similar in this case, or if it's all just a reaction from ignorance on the actual science

Lets take a moment to appreciate the quick remote camera work at arecibo tht gave us some once in a lifetime footage!

Very interesting. Would spinning up a "small"ish centrifuge inside of Starship affect the ships movement?

Nice discussion and it changed my mind about tethered artificial g. Now I see how unworkable it is. I can only imagine the negative long term effects of short radius artificial g though. Permeant ear changes at the least. Fast transport is the only solution to Mars travel.

RIP Arecibo. You were something else.

Surely accelerating the ship throughout it's journey will eliminate the need for all these dodgy fixes

Hey, thank you for the insight on rotational stability problem. I really liked it. As layperson I have a question regarding the segment around 12:20: if the all 500m apparatus was rotating at 2 rpm, shouldn't the starships rotate faster than that after the tether is cut because of conservation of angular momentum?

I just uploaded a follow up video on Thrust based gravity, check it out! Q: How much time do astronauts need to spend in artificial gravity? A: Short exposures seem to be adequate to counteract zero-g, the 2nd paper on the right around 0:22 demonstrated that 30 minutes a day was enough to offset the muscle losses we usually see during bed rest studies. "Aerobic exercise capacity" was not maintained but this is probably because they were not moving while in AG, 30-60 minutes on a bike is pretty reasonable given current astronaut schedules and would likely do a better job maintaining "cardio.” I think the best implementation is for use during exercise similar to the MIT concepts around 15:16. This would take the form of an exercise bike or something similar that is on an arm within the starship's 9m diameter. This would further limit balance and motion sickness issues as you'd be on a bike seat and not moving your head side to side.

I'm glad someone finally discussed tethered options. I've thought about this for years, but never saw any analysis of it. My thought was to have your utility stuff at the other end of the tether (like say, and unshielded nuclear reactor) where 1km of separation could be really helpful. Although when it comes to artifical gravity, I tend to think longer term (space stations, deep space missions), not a trip to Mars.

This is a really objective video that shows the root of the problem!

Apart from worrying about gravity, radiation shielding is more important. Cosmic radiation goes through everything and destroys DNA. This is a very destructive radiation that exists in all space. The earth's atmosphere protects us and it cannot be replicated easily.

If Lord God Philosopher King Musk says we can spin around like gerbils in a cage then it is written.

10:35 All 4 thumbs up 👍👍👍👍for this short but lifelong experience of throwing my phone in all 3 axes and fully confirming your prediction after 10 seconds

In that spinning table the head itself is right at the pivot point - meaning the head is not experiencing gravity. This surely would have an impact on the results of the experiment.

Great video. Great explanation

Thanks, Con, interesting video!

Thanks for telling us about the short radius centrifuge research - i really believed that would never work

I see SOOO many mainstream media, high dollar movie productions, Disney or similar style cartoon, have a bad habit of drawing a flag backwards on a uniform. Yet this small (compared to the other examples) KZfaq video got it right now problem. Idk why this bothers me, but great job!

You reminded me I miss Tom Scott's videos. 😕 I know he has other channels, but his location/science videos were (are still!) awesome! 😎🤘☮️

I would definitely go with developing a dedicated spaceship for routine journeys to Mars. The mission parameter differences between launching from a planet and voyaging through space are quite wide.

That "small" centrifuge takes up a lot of realestate in the context of a small spaceship. Plus the crew would have to take turns getting access to it to take the turns.

The footage of Arecibo observatory breaking felt like a personal attack /j