Rotating Space Stations

This first video, about 1/2 hour long, has a recurring graph in it where they, item by item, put on it things that limit human comfort and habitation inside a rotating structure. In the end, you are left with a stripe of radius vs rotation rate where people would be OK. In other words, it answers things like what size your space station must be to “work”. I wish the low end of the graph was a bit more precise, but interpolating it looks like about 25 M is near the lower bound. So somewhere between 75 and 100 feet.

This is well inside the size of structures we’ve already built that rotate in a 1 G field, so ought not to be very hard to design something similar for space:

https://en.wikipedia.org/wiki/London_Eye

The London Eye is a cantilevered observation wheel on the South Bank of the River Thames in London. It is Europe’s tallest cantilevered observation wheel, is the most popular paid tourist attraction in the United Kingdom with over 3.75 million visitors annually, and has made many appearances in popular culture.

The structure is 135 metres (443 ft) tall and the wheel has a diameter of 120 metres (394 ft).
When it opened to the public in 2000 it was the world’s tallest Ferris wheel. Its height was surpassed by the 525-foot (160 m) Star of Nanchang in 2006, the 165 metres (541 ft) Singapore Flyer in 2008, and the 550-foot tall (167.6 m) High Roller (Las Vegas) in 2014. Supported by an A-frame on one side only, unlike the taller Nanchang and Singapore wheels, the Eye is described by its operators as “the world’s tallest cantilevered observation wheel”.

Then this video is from the Gateway Foundation. It’s a bit “sellers puff” at times, but it looks like these folks have a well thought out design that could be put together in space and made operational fairly quickly. I think they are ‘over selling’ the notion that there will be a need for regular folks on the station (waitresses, cops, and janitorial), but then again if they are successful in selling it as a Hotel / Hot Spot then yeah, rich people will pay up for the service and won’t be happy with just a mini-bar in the room and high grade microwaved dinners… 24 minutes:

I would hope they will succeed. Though I doubt they will need old guys fixing computers ;-)

Not to be confused with the medical “Gateway Foundation”, the Spaceport one is here:

https://gatewayspaceport.com/

It looks like they have thought things out in stages and included issues like finances…

Von Braun Station

This is a segmented spaceport that will be revenue generating at each major stage of completion. This will be mankinds first space station with artificial gravity.

The Gateway

You could call it a destination hotel, a low Earth orbit cruise ship, or a city in space with a spaceport. But the best way to understand this complex piece of infrastructure is to look to its namesake: The Gateway.

That they are selling “memberships” is a bit of a trigger for me, but the BASIC is free (but no space perks) while for $40 per year or $400 one time you can get a “Crew Membership” and enter a lotto for a trip to space, if it ever happens…

I think their design is generally OK, and having escape ships next to each cabin space is a nice touch, but just the cost of hauling 22 mini-shuttles into space is “not small”; and one picture looked like there may be two at each point, so 44 total… And will there be 44 expert space pilots on station all the time? I suppose a robotic landing would be possible, but… with emergency decent from anywhere on orbit that’s a bit of an issue too. Or maybe they have enough supplies they can just auto-dock with the ISS and wait for a big space transport to come up and fetch them ;-)

OTOH, if you have a program where visitors get to sit in the pilot seat of the flyer and look out the window while thinking about flying it it, maybe it would have ‘pay off’. I note in passing the “drivers window” is looking “straight down” given their mounted position so you would need to stand on the display panels / windshield on entry… Maybe they need a different mounting orientation ;-)

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About E.M.Smith

A technical managerial sort interested in things from Stonehenge to computer science. My present "hot buttons' are the mythology of Climate Change and ancient metrology; but things change...
This entry was posted in Human Interest, Science Bits, Tech Bits and tagged , , . Bookmark the permalink.

9 Responses to Rotating Space Stations

  1. Larry Ledwick says:

    Much of that was worked out in the papers developed to design and describe the Stanford Torus space station.

    One of the interesting issues is the longest sight line necessary for humans to feel comfortable. In a torus habitat you have the strange effect of the horizon climbing upward as your gaze passes down the axis of the tube of the torus.

    Other interesting items is that you could perform human powered flight as you moved near the hub of the station. as gravity would decrease as you “rose” above the 1G surface on the outer rim of the station. This might also have some interesting effects regarding internal micro weather from convection.

    https://www.rockwell-center.org/student-research/the-stanford-torus-as-a-vision-of-the-future/

    https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19770014162_1977014162.pdf

    Personally my biggest concern with the spinning torus design is the all eggs in one basket problem, with no segmentation of the torus with bulk heads a large breach in the pressure hull would be catastrophic.

    I would be much more comfortable (at least on the first few constructions) if the torus tube was broken up into 6 to 8 segments, or because of the structural problems involved with creating large pressurized tubes, instead of a single tube, perhaps a bundle of several smaller diameter tubes.

    Large pressurized tubes fail by ripping length wise down the tube so there is a risk a large penetration could result in the tube “unzipping” along its length as a fracture propagated down the hull due to the hoop stress around the tube being the largest force to control.

  2. Larry Ledwick says:

    I think the entry level test type should be a rotating dumbell style, much easier and cheaper to build and would allow testing of some of those threshold values at reasonable cost. Put a zero g station in the center hub and have living quarters in the dumbell ends.

  3. p.g.sharrow says:

    To preserve the human anatomy 1G is specially needed during rest or sleep periods so the rotating station could be made of habitation “sausages” arrayed with an end at a central docking structure and the berthing area at the “bottom” near the rim.
    Any structure created can be quite large but must be created a bit at a time so modular construction planed to be added to over a very extended period must be the design…pg

  4. E.M.Smith says:

    The “Gateway” design (see the video….) has isolated individual sections around the ring. It looks very survivable to me. They connect via a separate “tunnel” that runs around the ring next to them. So each “sausage link” can close their door and be isolated, and have a separate route to their individual escape pod / craft; or you can go into the transit ring and walk to the restaurant / bar without going through other folks “sausage links”.

    Per “entry level”: I like the idea of a couple of small room sized units on a tether. It would take a bit of care getting it up to speed (as flexible things are dodgy until taught…) but perhaps a tether inside a small pipe to keep initial position established. This would not be a permanent set up (as you would need to stop it spinning to enter / exit the “cans on the end”) but would be very easy to do for a week or three as a test of what we think is “enough radius”. You could even vary the radius and see what folks thought. Heck, you could even just use two dragon capsules and a tether for a first quick test.

    @P.G.:

    While 1 G is ideal, I think we’ll find that folks do OK at reduced G down to about 1/2 G. So even just running at 2/3 G would be a big savings in weight and stresses. Similarly running a 7.5 psi atmosphere and 40% O2 ought to work (with some care on flammables – but not nearly as much as needed for 100% O2). Finding out just how much G gets you 90% of the benefit is something a first cut station would be valuable for.

    @Larry:

    Well, remember that if you just fly opposite the direction of rotation at about the speed of rotation you become weightless… Call it a 300 m ring, rotations of 1 / min (as a guess), so that’s about 300 x pi ~= 942 m /minute or 16 m / second. Hmmm… 51 ft / second or about 35mph. A bit fast for a human powered… So I guess you would need to be up nearer the hub. But an ultralight could become VERY ULTRA LIGHT ;-) Then, taking your motorcycle the back way around the ring could become challenging ;-)

    Hmmm…. You know, there’s a whole new future of experiences coming in Space Roller Coasters ;-) Go one way you are weightless, the other 2 G, now wobble it up and down ;-)

  5. Steve C says:

    I wonder what sort of signals the crew’s semicircular canals would be sending to their balance centres in some of these proposed rotating systems. Normal earthly gravity is a steady unidirectional force, but rotatory systems’ net forces can’t be. I would think that a “you are rotating” message which changed direction as you changed orientation in your surroundings could be rather disruptive to a “standard 1g spec” nervous system.

    With rather queasy memories of “that” fairground ride, where the turntable you’re all standing on spins up to speed, then cranks its axis around until you are spinning vertically, I think I’ll hold off on the space travel for now …

  6. p.g.sharrow says:

    Establishing “Gravity” with electro-static warpage might be easier…pg

  7. p.g.sharrow says:

    On Gravity: From pg’s blog, https://pgtruspace.wordpress.com/2012/01/25/on-gravity/


    Does gravity really suck?

    Gravity causes exactly the same warpage as charge fields in atomic structures. Gravity behaves exactly the same as charge fields as to effects over distance. Charge fields are created by gravity. The potential for acceleration in an earth gravity field is 32ft per second for each second of acceleration, the charge field of earth is an linear accelerator. Investigations conducted in the 1800s established an average charge field of 300 volts per meter average in dry air. In a boring week I created a number of gravity batteries of oil, paper and foil. In all cases the batteries were positive on top and negative on the bottom. The voltage over distance was about .50 milivolts per 10 mils or 300volts over 1 meter. This was dielectric warpage as in a condenser, no current flow measured as this was a device to measure potential created by gravity. Do not confuse voltage potential with current flow! You have to gather the charge bodies as well as develop potential and create a controllable current flow as well as allow for recharge of the device. Dielectric warpage is the displacement of the nucleus from the center of the electron shell. The electron shell is the atomic surface and the nucleus the atomic mass or center of gravity. Whether gravitational fields or electrical charge fields the effect is the same, atomic warpage.

    More gravity really sucks.

    Gravity is a form of energy.

    All energy moves from high concentration towards low concentration.

    All matter produces gravitational attraction.

    Gravity obeys all the laws of energy except it appears to move in the wrong direction or does it.

    The movement of electricity appears to move from high charge to low charge but it actually moves in a curious manner. The charge units fall into low charge spaces in a cascade from low charge toward high. A lightning strike starts at the ground and the charge units cascade into the lowered charge areas and create a conductive plasma to continue the strike as the higher charged regions unload into the lower drained areas. The movement in a conductor is in the same manner. In solid state electronics an area is doped to have “holes,” positive, low charge areas next to “filled,”negative, high charge areas so a small charge change can cause charge units to fall into the holes and start current flow.

    A visual representation is a pile of sand at angle of repose. If some is removed from the base, the sand will cascade to fill the hole from the bottom toward the top of the pile.

    In an Aether universe the flow of all energy including gravity flows in the correct manner. In cascade from low charge toward high charge. The aether is in high charge (negative) condition and matter is in low charge (positive) condition. Over 200 years of experiments have shown that the charge gradient of the earths’ atmosphere is about 300 volts per meter elevation increase in a dry atmosphere with no clouds.

    . Do not confuse the movement of energy from high concentration towards low with the cascade of energy in the opposite direction. In gravity we see and feel the effects of the cascade towards matter but the energy travels in the other direction within and through the aether

  8. E.M.Smith says:

    @Steve C:

    The first video addresses that in some depth. That’s the graph I was talking about. They’ve measured what rotation rate and circumference makes people queaz (or not) and that puts the limits on size and rate.

    FWIW a significant number of people get very queazy (space sick) and up-chuck in zero-G, so rotating is better…

    @P.G.:

    Interesting idea… I’ve seen frogs suspended with a really strong magnetic field, so clearly there are electro-magnetic ways of making force on a body. Using the electric axis is intriguing. But inside a metal can, 300 V / meter might be an issue. Can’t imagine all the electronics would be keen on it. then preventing ground loop currents in the metal from causing variations in “gravity” could be interesting.

    But if there is any place well suited to giving it a try, it is a tin can in space ;-)

  9. philjourdan says:

    Then there is the issue of the sterile environment and the effects on the immune system.

    Lots of areas for innovation.

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