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I would call it a joint ownership in that the topic was based on request branching from the large transport of Robert's.
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For SpaceNut re #101
OK ... so what way do ** you ** want to see the topic develop?
You have a simple choice ... go bigger and stay with the current dimensions and reduce the number of Starships served?
(th)
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Shapeways accepted the Fusion 360 model of the rotor of the Big Wheel Gyroscope Passenger Transport without a quibble.
https://www.shapeways.com/product/YAXHQ … 8&li=shops
This model is for inspection by NewMars forum readers who might be interested.
This model is NOT the final version, because the positions defined for Starships are too close together given the dimensions.
To achieve 1 g of simulated gravity at the level of a (presumed) floor midway through the length of each Starship in the outside ring, the rotor has a diameter of 122 meters, and it will rotate at 4 RPM.
Edit#1: It takes the computers at Shapeways a while to get around to rendering a 3D, rotatable image of a model they've approved for purchase.
The 3D rendering is now complete, so if a NewMars forum reader (or anyone) is interested, they can look at the model of the rotor from any angle.
For SpaceNut: I'm looking forward to seeing where you come down on future development.
(th)
Last edited by tahanson43206 (2020-08-23 15:08:20)
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For SpaceNut re Development of Big Wheel ...
I'll let you off the hook << grin >> The choice was to go bigger or smaller. While waiting for you to decide if you wanted to weigh in, I've come up with alternatives for the 122 meter diameter rotor that I'd like to explore.
The 66 cradle version is now available for inspection by anyone who is interested in thinking about that level of performance.
The existing design (66 cradles) featured rings of 36, 18 and 12 cradles per ring. An alternative is to reduce the count for the outermost ring to 18.
Since is is necessary to start over in any case, I'll set the cradle size to 10, and provide plenty of adjacent space for extrusions that may be needed for steering fins and landing legs.
I'm interested in moving on to design of the axle. That component is going to be subject to forces that must be communicated from the propulsion unit to the spinning rotor, but at the same time it needs to be hollow to accommodate movement of people and supplies via the docking ports on the two ends.
Beyond that lie the Yoke and the Propulsion unit, which itself will have multiple components.
Edit#1: Work is started on a 48 Docking Bay version of the 122 meter Rotor.
The rotor is recreated as an empty cylinder, and the first gear is defined for punching 18 Docking Ports in the outer ring. This time the centers of the ports will be set at 50 meters from the center. The inner rings are currently planned for 80 and 60 meters.
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Last edited by tahanson43206 (2020-08-24 15:05:25)
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The revised Big Wheel Gyroscope Passenger Transport Habitat, with capacity for 45 Starships, is complete (for the time being).
Work has started on the axle, which is currently planned as 16.8 meters in diameter and 100 meters in length.
The length includes 50 meters to span the habitat and 25 meters on either side for engagement with the Yoke.
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The 45 Docking Port version of the Big Wheel Habitat was accepted by Shapeways. Once again, this happy result seems to be related to the output from Fusion 360.
If each Starship carries 100 passengers, then the number of passengers who might be carried (and then transferred to Mars) would be 4,500.
However, as RobertDyck has shown with his design for a Large Ship, passengers who are onboard for the round trip, and the crew, would live in facilities inside the habitat, among and between the Starship Docking Ports.
As a reminder, ** this ** vehicle will not interact with the atmosphere of any planet, but instead will carry fuel and oxidizer sufficient to achieve desired navigation objectives through thrust maneuvers, combined with the Phobos Momentum Maneuver at Mars.
A 3D view is available here:
https://www.shapeways.com/product/QB2LS … 5&li=shops
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Last edited by tahanson43206 (2020-08-27 11:47:31)
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I decided to bring this topic back into view.
It was inspired by the work of RobertDyck, who has been pursuing a vision of a Unitary Rotating Space Vessel for a couple of years, and is currently preparing for a presentation on the subject to the National Space Society's North Houston chapter, on March 12th.
Thankfully, Void has found a video that addresses rotational artificial gravity. The video asserts that stability along the z axis is greater if h < 2.45r, and that stability along the z axis is LESS if h > 2.45r. The meaning (and accuracy) of this assertion needs to be addressed.
** THIS ** topic was created to explore the practicality of building a space going vessel designed to emulate a 3-axis gyroscope, of the kind that is in service around the Earth in countless navigation and vehicle stability applications.
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Here it is hiding....
per request...
normally I would compare what I know to derive the estimates and that means the mass/ payload plus fuels for a starship to send 100 people and this is a factor of 11 approximate number of ships to move the crew.
Of course the starship to mars was to send 2 cargo ships to land on mars for support with food, water, equipment to make a return trip possible once refueling and restocking the food and other supplies. Mars cargo that is 200 to 400 for those 100 people factor to add in on the large ship cargo for surface use.
With the real problem being the return had nothing but hard work to restock once on mars for the return trip.
so 2200 to 4400 for the large ships crew sizing would equal the planned starship use.
One way use is 150 x 11 is 1650 mT which makes the sum min 3,850 mt and max 6,050 mT.
dry mass is 85 mT to 120 mT with a base of 100 mt to 200 mt of payload with a min amount of fuel being 1100 mT to 1200 mt.
So min mass is 185 mT with max is 329 mT to equal a dead mass of 5000 mT which makes min 2,035 mT with the max 3,619 mT for ship structure for the large ship.
adding 3,850 to 2,035 mt for the min is 5,885 mt and for max adding of 6,959 mT + 3,619 mT is 9,669 mT for the structure and payloads.
So fueled up 1100 x 11 min is 12,100 mT to max 13,200 mT to get that mass to mars with the cargo supplies and structure.
restock and refuel is the same for fuel 12,100 mT to 13,200 mT but for the food and water we only need the trip outs quantity to be brought up to the large ship for payload just 1,650 mT.
So we are high for the dead mass structure and cargo at the max end of the spectrum, which makes the fuel requirement even higher.
So if we shoot for the average we do not really impact the ships probable fuels but the other would be less than the dead head mass number.
basically tie 11 starships together in orbit and stuff it with the supplies for surface stay and you end up with the monster we are building. That has no support to get it to the surface and no capability to restock or to refuel the large ship for the return home.
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For SpaceNut re #1201
Your idea in Post #1201 seems (as I understand it) to be to rig 11 Starships in a ring...
As a suggestion, may I suggest you consider making that 12? You'll need to maintain momentum balance, and 12 seems (to me at least) to be a better bet than 11. Any number divisible by 3 or 4 should work. 11 could be made to balance, but why make the lives of your crew more difficult?
Note: if you were to proceed with your idea (which I find quite interesting), then your statement about "no support to get" to the surface seems (to me at least) hard to understand .... why wouldn't you just separate individual Starships from the ring and use them for travel to the surface and back?
Please develop your ideas further ... I'm assuming (hoping!) Post #1201 was just the opening of a remarkable variation on the theme of Large Ship.
Your suggestion would certain cut down on work required to design Large Ship ... all you'd need to develop is the set of girders that will secure the Starships.
If you look back at the Gyroscope Vessel I was working on, you'll find that I was thinking about almost the exact same concept.
I used Fusion 360 for that work, and show various configurations of Starships.
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Yes I remember the docking plate with holes. The question is we need at a minimum 2 points on each hull to stabilize the ring of them keeping the ring attachment as far apart as possible. Its got to be easy to do as we need to get them apart when approaching mars. The big thing with the plate is its going to stay in orbit with the cargo to return with. I also think we need drop cargo containers to off load some more of that cargo that is eaten and used on the way out. That means each staship must hold the goods for 1/2 the surface stay while 12 ships for cargo already been sent.
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As of last year the starship had these performance to cost values.
The fully reusable rocket could have a per flight cost of $2-5 million for its 150 ton capacity.
There is currently a payload size of 18 meters height by 9 meters wide for 1000 cubic meters of volume.
There will be a taller payload faring option with 22 meters in height. This could provide 1200 cubic meters of volume.
The down mass was 50 ton with a dry mass approximately 120 tons.
https://en.wikipedia.org/wiki/SpaceX_Starship
Strikes against a starship is not designed for rotation, has no radiation protection shield.
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SpaceNut wrote:basically tie 11 starships together in orbit and stuff it with the supplies for surface stay and you end up with the monster we are buiding. That has no support to get it to the surface and no capability to restock or to refuel the large ship for the return home.
Actually no. With 11 Starships you get cylinders, each with one pointy end. That makes interior space very awkward, and you have to add floors. You can't simply stuff it with supplies, because you will never be able to stuff enough supplies to keep 1,000 people alive and breathing for 6 months. No recycling life support, no Mars.
It was for mass and people estimating as you said the pointy nose makes it difficult to utilize as a transport long term.
Starship really does need a super large version of a Cygnus to make it more functional for long duration.
One of the issues is the cargo for a single trip to mars is provided by 2 ships to the surface and that causes the main issue for even this design. The cargo in an occupied ship is greatly reduced as compared to the cargo ships that land on mars separately. So how can we solve for that greater loading to support that quantity of resources.
Since its that pointy nose that allows for the atmospheric entry for a starship to function with the belly flop heat shield use.
Sure ever inch of the starship could be used once cargo was put into it but there is the addition fuel requirement to support that extra down mass for a single ship to make use of.
It is unknown as to how much area is empty at that point to make use of from a support cargo pod design to make use of for that short duration support function for each starship. The initial quantity of food and resources would be near zero once reaching mars so we have that much room to restock but how much of a 200 mt to 300 mt is remaining to transfer is unknown.
If this could be done we have reduced the ships to mars by 24 on a single mission design as these are all cargo landers.
Next would be refuel of a starship for use as a single ship back to orbit to a waiting system for return home as the 1000 people could be brought up to orbit in a short term duration transfer. So how much fuel does it take an empty ship just with people for a 1 week transfer to that ship unit....
The station which has the fully fueled return has cargo to make it possible.
Need to think about how many items we need to make some different happen.
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For SpaceNut ... your interest in the option of binding a flotilla of passenger Starships in a ring protected by a radiation shield is close enough to the purpose of this topic so that I am able to support it.
Elon is most definitely going to build his passenger version of the Large Ship, if he succeeds at all with Starship, so it is timely for you to show up with a plan to give his passengers Mars gravity (per RobertDyck model) and Galactic scale Radiation protection, which is NOT provided by Large Ship (Prime).
I ran a quick calculation, and if you mount 12 Passenger Starships in a ring of 75 meters radius, they have an average span of circumference of 20 meters.
That gives you plenty of room between Starships for auxilliary services in the hub, along the lines of the recycling that is a part of Large Ship (Prime) design.
The scale of the ship provides plenty of sun facing area for solar panels and green houses.
The radiation shield would be outside the passenger ring, or course.
There's a lot to like in your concept.
There may even be an image in this topic that shows what 12 Starships in a ring would look like, although this topic was set up for 1 full G at the outer ring.
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The current version of the starship has the access docking port on the side part way down with a panel hinged door that would open and then you need to have something akin to an air terminal seal to the docking location that is on the edge of the disk since starship has those wings for the glide to avoid.
If we are able to make an extra large version of a Cygnus then cargo would dock in the center of then with a docking ring as it does at the ISS. These cargo units would arrive with engines and fuel for the mars landing which under current starship is just 100 mT on the belly flop to land vertically.
At this point I am thinking that the BFR starship should be morphed into a 3 stage so as to make the cargo unit possible other wise we are towing a lot of mass to mars that has little value if using a complete cargo starship.
That makes the disk the holding of crew and goods for the journey similar to the large ship ring.
we need to solve the 200 plus starship cargo needs so as to lessen the fuel same as the large ships as we are way to heavy....
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12 starships spread out on the edge to seat into a half 9 meter diameter with air lock connection and latching system to hold the ship into the half circle.
so a 75 m radius is 471.2 m circumference.
To make use of the ring in the large ship means making it a bit wide so as to allow a straight down the middle corridor to move things in and out of the disk to ship.
https://en.wikipedia.org/wiki/Docking_a … spacecraft
https://en.wikipedia.org/wiki/NASA_Docking_System
The docking port on the ISS for the shuttle was capable of the approximate 120 mT but we may need something even stronger than that in the 350 mT.
That air lock docking might look something like these
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For SpaceNut ... it is ** so ** easy to lose track of details of Large Ship (Prime) .... The diameter is 75 meters ... the radius is 238 (give or take).
This doesn't change the overall direction of your post above ... To find the dimensions of Large Ship, you can search multiple locations in the archive.
The best place to start is at the top of Large Ship ...if you're ever in doubt in future, just go to the top post of the topic:
Updated math with more precision. Mars acceleration for the ship, so 38.0% that of Earth gravity. Radius 37.76 metres from centre of rotation to surface of the floor, 3 RPM. One deck. Circumference 237.25 metres. Ring width 19 metres. This allows 2 isles for cabins, corridors 1.5 metres wide, outside cabins have a window, inside cabins do not. Standard cabin size 4x2.4 metres.
It will save RobertDyck getting ulcers, if we (NewMars members) can try to stay reasonably close to his vision).
kbd512 has branched off to look at counter rotating habitat rings, so he has (by definition) left the original Large Ship behind.
However, I'd like to see the rest of us who are working the problem try to stay as close as we can to the original specifications.
GW Johnson has added a mass figure (5000 tons) because RobertDyck has not provided one, and because GW Johnson needed a value to work with to compute propulsion options. I like the 5000 figure because it is large enough to give everyone working on this problem some mass to work with.
You've done a nice job of allocating those 5000 tons beween habitat ring, spokes and central shaft. Those allocations are helpful to get a handle on planning for structure and loading, but of course they are just starting numbers.
***
On the ** other ** hand, since this ** is ** the Big Wheel topic, the numbers for Big Wheel are quite different from Large Ship, since Big Wheel was intended to provide 1 G at the outer ring.
If you were working with Big Wheel numbers, I apologize.
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Here is more on the refueling of a waiting disk that would have all 12 starship return from mars back to.
I am wondering how much fuel can be brought to orbit by a starship cargo to refuel a tug since we know that a fully loaded is 1200 mT plus more in a payload if it have tanks to bring it up to the waiting station space tug.
What I had found is that it takes for a zero cargo playload just the 20 mt of consumed for a crewed 85mT starship that its only going to need 340 mT to get home so we must be able to bring quite a bit from mars back up to mars orbit for refueling.
The starship would need slightly more than that since we will bring up a minimal quantity of payload and safety fuels but its still less than what we needed to leave from earth.
Thinking about landing back on the mars surface from orbit would seemingly require less fuel since we would be empty of payload which was requiring 100 mT but we can leave that so we are guaranteed a safe re-landing of a starship back on its surface.
1200 mt - 440 mT for round trip leaves 760 mT minimum for refueling if using a GW space tug.
That sure is a large order with how many trips we need not to say nothing to how long it will take to make the fuel.
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