Big Wheel Gyroscope Space Transport

SpaceNut · 2020-08-15 10:02:46

I am hoping that this will work

posts are quote copies since we do not have true copy command

tahanson43206 wrote:

For SpaceNut re #59
For SpaceNut re new topic for Interplanetary Ship Design topic:
This is one of many images of the famous "Big Wheel" toy.
I found an article reporting on the 50th anniversary of the "Big Wheel".
(th)
SpaceNut wrote:
list post number to split out to create new gyro ship topic with respect what remains making sense to fast flights to mars....
nice human pedal powered "bigwheel"
Thanks for your encouragement!
As I understand your guidance, you'd be interested in seeing a list of posts to be copied to a new "Big Wheel Gyroscope Space Transport" topic.
I'll start working on that! My first inclination is to look for the post where kbd512 first tossed out the counter-rotating flat disk concept.
However, I'd like to start with a post that I can edit, so the top of the new topic can be updated from time to time to help future readers to understand what the topic is about, and where to find specific contributions by specific members.
***
I'm not convinced this subtopic belongs in Fast flights to Mars, because it is about a vehicle design that in itself does not necessarily contribute to speed.
What the "Big Wheel" design does do is to contribute to (1) artificial gravity for passengers and crew, (2) radiation protection for both, (3) other aspects of space flight between planets as the need becomes apparent.
Edit#1: Thanks for noting the image of an "adult" Big Wheel << grin >>
(th)

SpaceNut · 2020-08-15 10:03:10

posts to copy

tahanson43206 wrote:

For SpaceNut ...
Re #205 ... thanks for looking at that new poster!
***
Per your request, here is a list of candidate posts to be copied into a new topic, if you are willing.
The new topic would in Interplanetary Transportation, and it could have a title like: Big Wheel Gyroscopic Space Transport
I have started the series with a post I created, so that it will head up the new topic.
My idea is to edit that into an index/table-of-contents for future readers who may see the title and wonder what it's about.
Here comes the list:

http://newmars.com/forums/viewtopic.php … 16#p170616 Start
http://newmars.com/forums/viewtopic.php … 76#p170776
http://newmars.com/forums/viewtopic.php … 80#p170780
http://newmars.com/forums/viewtopic.php … 05#p170805
http://newmars.com/forums/viewtopic.php … 08#p170808
http://newmars.com/forums/viewtopic.php … 10#p170810
http://newmars.com/forums/viewtopic.php … 11#p170811
omitted
http://newmars.com/forums/viewtopic.php … 13#p170813
http://newmars.com/forums/viewtopic.php … 14#p170814
http://newmars.com/forums/viewtopic.php … 15#p170815
http://newmars.com/forums/viewtopic.php … 16#p170816
http://newmars.com/forums/viewtopic.php … 17#p170817
omitted
http://newmars.com/forums/viewtopic.php … 38#p170838
http://newmars.com/forums/viewtopic.php … 43#p170843
http://newmars.com/forums/viewtopic.php … 48#p170848
http://newmars.com/forums/viewtopic.php … 52#p170852 <- Calliban on shielding
http://newmars.com/forums/viewtopic.php … 56#p170856
http://newmars.com/forums/viewtopic.php … 57#p170857
http://newmars.com/forums/viewtopic.php … 58#p170858
http://newmars.com/forums/viewtopic.php … 65#p170865
http://newmars.com/forums/viewtopic.php … 66#p170866
http://newmars.com/forums/viewtopic.php … 70#p170870
http://newmars.com/forums/viewtopic.php … 76#p170876
http://newmars.com/forums/viewtopic.php … 96#p170896 <= RobertDyck Gyro video
http://newmars.com/forums/viewtopic.php … 01#p170901
http://newmars.com/forums/viewtopic.php … 02#p170902
http://newmars.com/forums/viewtopic.php … 03#p170903 <<= Thingiverse 3D designs
http://newmars.com/forums/viewtopic.php … 04#p170904
http://newmars.com/forums/viewtopic.php … 07#p170907
http://newmars.com/forums/viewtopic.php … 09#p170909 <<== kbd512 steel vs ceramic bearings
http://newmars.com/forums/viewtopic.php … 15#p170915
http://newmars.com/forums/viewtopic.php … 23#p170923 <<== Blender version of Gyro ship design
http://newmars.com/forums/viewtopic.php … 29#p170929 <<== GW Johnson Reminder leaks >> one piece design
http://newmars.com/forums/viewtopic.php … 36#p170936
http://newmars.com/forums/viewtopic.php … 41#p170941
http://newmars.com/forums/viewtopic.php … 43#p170943
http://newmars.com/forums/viewtopic.php … 58#p170958 <<== RobertDyck on orientation wrt Sun
http://newmars.com/forums/viewtopic.php … 63#p170963
http://newmars.com/forums/viewtopic.php … 70#p170970 <<== kbd512 on shielding
http://newmars.com/forums/viewtopic.php … 02#p171002 <<== Image of Big Wheel 3D model
http://newmars.com/forums/viewtopic.php … 05#p171005
http://newmars.com/forums/viewtopic.php … 14#p171014
http://newmars.com/forums/viewtopic.php … 16#p171016 <<== SpaceNut request for list
http://newmars.com/forums/viewtopic.php … 22#p171022
That's a lot of work if you have to copy each item separately.
If you have tools that allow you to bring a group of messages, then just start with the first in the list and copy through the last.
Then, after the new topic is set up, if it seems necessary, we can remove the posts that are not related to the new topic.
Thanks for offering to consider this request.
(th)

SpaceNut · 2020-08-15 10:05:38

SpaceNut wrote:

https://en.wikipedia.org/wiki/Artificial_gravity
radius of 10 m, a period of just over 6 s would be required to produce standard gravity (at the hips; gravity would be 11% higher at the feet), while 4.5 s would produce 2g.
Not a very uniform level over height. Also sensitive to spin time.
A larger diameter reduces these conditions.

SpaceNut · 2020-08-15 10:18:17

not all of each posts content applies

kbd512 wrote:

Calliban,
Since we'd only refuel the ship after it returns to Earth, its load of Deuterium and Tritium should be nearly depleted by that point. Our water-cooled nuclear reactors here on Earth are always making more of that stuff, so there should be a healthy supply available. My overall thought process about how this would work is to use the fusion drive for impulsive burns that supply just enough energy to complete the orbital transfers and insertions. It'll also have some reserve fuel for contingencies. I plan to supply ~600t of Aluminum or Lithium fuel, with a preference for Aluminum due to ease of handling and cost, providing ~6.2km/s of dV capability with the FDR's expected 5000s Isp. By my count, a fully loaded frigate needs 37 fusion engines to provide the same TWR as the version using the TransHab and Orion as a payload. The difference between my plan for how to use this new technology and their plan is that their plan calls for 49km/s worth of dV (yes, you read that correctly), whereas mine requires a little over ~4km/s using minimum energy transfers and elliptical orbits.
A 5,000t ship, with an airliner's structural mass fraction, should provide adequate radiation shielding for its crew and artificial gravity, so movement between orbits, however slow, isn't a major health concern. The habitable space will consist of a pair of contra-rotating decks entirely contained within the hull. Those two decks will be protected by thicker hull plates. A central solar storm shelter / water tank will protect the crew from the most severe solar storms. The habitable / rotating section will have a little more than double the pressurized volume of an AN-225's cargo bay, dictated by the minimum rotation diameter / height to clear heads / rpm combination for human comfort while providing 1g of artificial gravity. The ship will be built on Earth, more or less gutted internally, and launched like an upper stage of a rocket, albeit one time only. SpaceX's original ITS booster was about the correct size. Once the ship is in orbit, it's staying in orbit. Any repairs will be done using a space station. The ship will be shaped like a giant lifting body, sort of like a spear head. It will be capable of reentry and landing on a dry lake bed runway after installing a flexible single-use fabric heat shield, though this feature will never be used in normal operations, unless someone can think of a good reason to use it. I can't think of any, but just in case (there's always something I never thought of), the design will be minimally capable of gliding, just as our Space Shuttle was.
The best visualization I can provide is here (a more aerodynamic and smaller version of this):
Star Trek Stingray Starship Concept Artwork
Why not just build a giant metal tube and call it a day? Well, I suppose we could, but that would be more of a miniature O'Neill space station with no possibility of return to Earth. In much simpler terms, sleek starships inspire wonder and excitement, whereas giant metal gas tanks do not. If landing is ever required, then this lifting body design could feasibly do that.
It will feature a particle deflector shield, though perhaps not akin the giant glowing dish model from Star Trek, but it will be a cryogenically cooled electromagnet that uses the hull and an ionized gas to project / inflate a miniature magnetosphere. When it's not thrusting, it'll be pointed in the direction of the Sun to provide a protective ionized plasma bubble (largely created by protons from our Sun becoming trapped in the electromagnetic field) around the vehicle when it's in interplanetary space. From testing, the power required to do this is nominal and it deflected all protons with the energies that those given off by the Sun have and better than 95% of the protons with GCR energy levels. In short, highly effective, but because of the electrostatic repulsion from particles with like-charges, rather than magnetism. Charged particle repulsion force is something like 10^39 more powerful than magnetism or gravitation, thus why gravity is called the "weak force".
Since a ship of this size will be about as maneuverable as a battleship is here on Earth, it will feature a very powerful fiber-based laser array to deflect or vaporize chunks of space debris that might strike and penetrate the hull. I presume Lockheed-Martin or Raytheon will provide the laser. No "photon torpedoes", though. Sorry sci-fi fans, but this is an interplanetary transport, not a warship. However, it will contain small "ejector tubes" to dispense atmospheric or in-space exploration probes. A sophisticated suite of onboard optical sensors will monitor the space around the vessel to avoid having to use that laser. Radio waves will likely be attenuated by the deflector shield, hence the need to use optical sensors and communication. The other prominent Star Trek-type feature will be escape pods based upon our Cygnus cargo containers. In normal operations, these naval frigate-sized ships will travel in convoys of 2 to 5 ships to provide mutual protection / search and rescue. Total complement will include 250 crew and colonists, remarkably similar to a large naval frigate.
Here are a few of the big numbers associated with this ship:
2000t dry mass
600t of Aluminum foil fuel for the fusion engines
150t of food for 2 years of operations (when the colonists depart for the surface of Mars, then most of this will be offloaded there unless colonists are also brought back to Earth)
250t of potable water
260t of pure water to supply the PEMFC with O2/H2 with 480MWh worth of power for the impulsive burns
1MW of solar power for life support and ship's functions
20MW PEM fuel cells (10t total for a redundant array of 20 1MW fuel cells; only ~6.26MW required; extra power provided for shorter burn times and reduced gravity losses; burn times of no more than a day expected in normal operations; nominally, 6 burns per round trip- TMI, MCC, MOI, TEI, MCC, EOI)
So, why no nuclear reactor? This is a small ship that only requires a little over 6MW of electrical power for a handful of days per mission. The additional power output from the fuel cells is to shorten the burns and the fuel (what will become water at the end of the burn) contributes redundancy. A reactor capable of providing equivalent surge power would increase the deadweight tonnage due to shielding mass and it probably wouldn't be redundant. About 99% of the time, the power that a fission reactor could deliver is simply not required. There's plenty of power over time from the solar array to re-split the water in-transit to Mars or Earth and to provide life support. We must have reserves of water for life support at all times, no matter where we go. If the ship was 10,000t or more, then a small fission reactor would make more sense.
I figure we have enough mass budget for 1,000t of cargo per crewed flight. The remaining tonnage is devoted to various crew survivability features not present in other spacecraft. The stripped (of human habitation features) RPV may provide ~2,000t of cargo. However, even 1,000t of cargo is equal to 10 SpaceX Starships per flight. I think that's an absolute minimum delivered tonnage capability to create a second self-sustaining branch of human civilization on another planet. Even my plan presumes we source most of materials from Mars, but in order to do that, we need to bring in lots of heavy machinery. In short, we need big ships.
I'm not a fan of windows in spacecraft, but each vessel will include an ALON-enclosed observation deck for truly spectacular unobstructed views of space.
Certain variants of this ship will be remotely piloted and all of the available internal volume will be dedicated to provisions or cargo or fuels. I figure a convoy would have four crewed ships and one remotely piloted ship carrying provisions and/or very large pieces of equipment to robotically deliver to the surface of Mars. Examples of such equipment might include nuclear reactor cores, tanks for chemical storage pieces of construction or mining equipment, drilling rigs to drill for water or other subsurface volatiles like Methane, etc. The RPV would contain the propellants for landing the equipment and humans, rather than placing humans in unnecessarily close proximity to massive quantities of rocket propellants for months at a time.
A combination of thin film photovoltaics laminated onto the hull and batteries will provide life support power. A fuel cell stack will supply surge power to the super capacitor bank and fusion engines for the impulsive burn maneuvers. The burn times are essentially a function of how fast the power source can recharge the super capacitor banks since the entire rear end of the ship will be a gigantic integrated aluminum radiator to absorb the thermal load from the fuel cells and engines. A pair of redundant 10MW PEM fuel cells will recharge the super capacitors. Each fuel cell can supply 40% more power than the original FDR concept required, so burn times will typically be shorter in normal operations. Scaling to the power levels required for this ship, I determined that PEMFC supply more power at a faster rate than equivalent rigid PV panels could supply (dictated by the force of the impulsive events and the size of the PV array required), for no significant increase in mass over PV. The O2/H2 required will be split into reactant tanks in orbit, just prior to departure, turned back into water during the burn, split back into O2/H2 during the lengthy transit, and then turned into water again during the insertion burn. Since the hull is primarily constructed of Aluminum alloy, the radiator mass is essentially the ship's rather healthy structural mass.
The FDR reference mission is a 210 day total mission time has a payload mass fraction of 46% and a total mission dV of 49km/s. It's 134t IMLEO with a 61t payload and requires a 180kW PV array providing at least 200W/kg. My mission is a 180 day transit, each way, and I want to put a 5,000t ship in LEO (built and launched in pieces, obviously). To enable a similarly speedy departure on a minimum energy trajectory, I presume I would need a 6.7MW power source.

SpaceNut · 2020-08-15 10:19:07

tahanson43206 wrote:

For kbd512 re #24
SearchTerm:CounterRotatingHabitatSections
First time I've seen this suggestion. Nice!
Edit#1: Are you interested in seeing drawings of your design for a large vessel?
RobertDyck has a parallel track going, where he's posted an illustration or two.
I went back over the entire topic, and found numerous illustrations but no drawings.
It might be possible to draw younger folks with the needed skills into the mix, if you were to undertake a process of sketching your design.
It's possible your thinking might intersect with that of RobertDyck at some point.
(th)

SpaceNut · 2020-08-15 10:20:37

tahanson43206 wrote:

For lbd512 re Counter Rotating habitats in a saucer shaped form ...
The shape of the Enterprise came to mind, as I thought about the benefits of your proposal ...
This image shows the Enterprise (or something similar) under construction on Earth.
The design would (presumably) be modified in your version, with a thicker saucer to accommodate the habitat disks.
Still, the propulsion units mounted externally, with thrust transferred to the habitats via the central load bearing shaft seems appropriate for the hybrid fusion rockets you've described.
The propulsion pods would (presumably) contain chemical thrusters in addition to the hybrid fusion units.
(th)

SpaceNut · 2020-08-15 10:21:13

kbd512 wrote:

tahanson43206,
Something that looks like the Enterprise would be awesome, but I had a more aerodynamic design in mind that at least has the possibility of landing after appropriate stripping and outfitting. Maybe that capability is unnecessary. What I know for sure is that real ships inspire people, whereas giant gas tanks don't. If we built these ships, it would help our economy bounce back. At the end of the construction process, we'd also have real ships for Mars colonization to carry the many thousands of tons of consumables and equipment required to get a sizable colony up and running in a reasonable amount of time. I can't see how we could colonize Mars using giant gas tanks carrying tiny payloads.

SpaceNut · 2020-08-15 10:21:39

tahanson43206 wrote:

For kbd512 re #29
The Enterprise ** was ** designed for flight through atmosphere.
I don't recall now if the first series included a flight through atmosphere, but later episodes (including the movies) certainly did.
Your idea of counter-rotating habitat disks lends itself to an aerodynamic configuration, as you suggested.
Do you need the assistance of an architect with vehicle training? Your expertise is wide and deep, but it can't include everything.
If you can break the design of this vehicle into portions you want to handle, and portions you want to farm out, it will give SpaceNut an opportunity to reach out beyond this tiny group to invite others to assist.
Edit#1: The gyroscopic effects of the counter-rotating habitat design would be interesting to work with, I would think. Thrust applied directly perpendicular to the axis of rotation should be free of consequences. The navigator would presumably rotate the vehicle so that the vector needed for thrust is perpendicular to the axis of rotation.
The engineering of counter-rotating masses has been going on since the first design for helicopters, and (it turns out) long before.
Edit#2: Engineering of counter (or contra) rotating propellers has been going on for a while:
From Wikipedia:
A contra-rotating propeller was patented by F. W. Lanchester in 1907.[9]
(th)

SpaceNut · 2020-08-15 10:22:34

RobertDyck wrote:

tahanson43206 wrote:
The Enterprise ** was ** designed for flight through atmosphere.
I don't recall now if the first series included a flight through atmosphere, but later episodes (including the movies) certainly did.
Star Trek distraction. Enterprise from The Original Series was built in space. It was never intended to land. Here's an image from the first movie showing the refit.
Season 1, Episode 14, "Tomorrow is Yesterday": Enterprise is sent back in time to the 1960s (current time when it was produced). Enterprise encounters a problem and enters upper atmosphere. A fighter jet (F-104A Starfighter) is scrambled to intercept and take pictures. That doesn't mean Enterprise is designed to do this.
Digitally remastered, with modern CGI

SpaceNut · 2020-08-15 10:23:21

tahanson43206 wrote:

For RobertDyck re #31 and terrific images!
I bow to your knowledge of the initial series, but return with the observation that later versions of the Enterprise were built on Earth.
I offer as evidence a scene from the Startrek movie which featured a brash young recruit (who became Captain Kirk). I remember the scene in which the "citizen" was arrested by a very official looking officer ... in that same stretch there were scenes of the factory .
However, to the point I was trying to make ...
kbd512 seems (to me at least) to be developing a reasonable approach to offering artificial gravity.
Without going back to look, I am recalling a sketch from your Large Ship topic in which you showed a rotating habitat around a central vehicle body. Your design (as I remember it) is traditional, in that it assumes the axis of rotation of the habitat will be exactly the same as the axis of the centers of mass of the vehicle.
If I understand kbd512's design correctly, it would indeed look a lot like the Enterprise, and the engineering solutions will include dealing with the gyroscopic effects of a mass rotating at right angles to the direction of thrust.
In a search via Google, I found an Aircraft Owner's site, which included a mention of a Navy document:
https://blog.aopa.org/aopa/2012/01/29/g … recession/
One of the best explanations I’ve found for it is in the Navy’s Introduction to Helicopter Aerodynamics workbook (P-401) available here https://www.cnatra.navy.mil/pubs/folder5/TH57/P-401.pdf It starts on page 103 of the pdf, section 405 and 406. This is also a valuable resource for a lot of other rotor aero subjects.
The bulk of the useful comments around the core article were about how helicopter propellers are ** not ** pure gyroscopes, since the individual blades participate in the dynamic process at work. As an example, several authors pointed out that a factor of 90 degrees, which would be predicted for a pure gyroscope, is much less than 90 degrees, because of the aerodynamic forces that are involved.
However, getting back to kbd512's vision ... ** That ** WOULD be a pure gyroscope situation, because the habitats would be rotating inside an enclosure that would have vacuum as the surrounding.
Thus, an engineer planning an application of thrust while the habitat is in full operation will need to insure that the axis of rotation of the habitat is at precisely 90 degrees to the desired vector, so that the thrust can be applied equally to the rotor bearings at both ends of the habitat shaft.
The fact that (in kbd512's design) the habitats are counter-rotating will have a useful effect, but I suspect that the navigator will need to be conscious of the rotating mass inside the vessel while planning maneuvers.
I am hoping others active in the forum will give thought to this concern.
(th)

SpaceNut · 2020-08-15 10:23:52

kbd512 wrote:

tahanson43206,
I'm talking about gliding to a landing without invoking matter-antimatter reactors or impulse drives or other fictional technology that doesn't exist. To accomplish that using the airframe I posted a link to, it would be stripped of equipment and engines, landing gear would be installed, and a single-use disposable fabric heat shield would be wrapped around the Aluminum to prevent it from melting during reentry.
If anyone else is interested in the design of this vehicle, they should feel free to contribute. My personal interest is in establishing the basic feasibility of a realistic design that's many times larger than the giant gas tank designs we've been playing with. The primary purpose of this ship is as an interplanetary people and cargo transport. It's not intended to be an absolute speed machine and that makes the design infinitely more practical than these intellectual curiosity experiments NASA is constantly running without producing any flight qualified hardware. The speed and payload is intended to be an analog to that of the early WWII era ocean going cargo ships that we used to deliver supplies to our British allies across the pond. It's obviously going quite a bit faster than the "sizzling six knots" of our pre-WWII merchant fleet, but it's also crossing a much bigger "pond".
The general design goal is to produce a durable and maintainable open source interplanetary merchant ship design that most technologically advanced countries could actually build with appropriate tooling and a reasonably well trained labor pool. The defense-related hardware is already mostly shared amongst us, so the technology transfer is minimal. The advanced fiber lasers may not be distributed to everyone, but the rest of the technology is already pervasive. It's aerospace manufacturing at an industrial scale, similar to what happened in WWII, using many of the same materials and methods, with some changes to account for modern manufacturing technology. They don't need to launch it on their own, either. America can and should assist with that. Humanity won't become a space-faring civilization until we build the ships required to take us into the abyss.
Aluminum hull construction - cheap and easy to come by, doesn't require advanced composite molding know-how or associated costs, and serves as a gigantic radiator for dissipating thermal power
Sr90 RTG - cheap and easy to come by in massive quantities, provides adequate electrical power for the fusion engines
Linear implosion fusion engines - in use for plasma and fusion experiments in many countries since the 1980's, actually works for initiating fusion but not for producing 1 lousy watt of electrical power (thankfully, that's not the goal here), and we've had an unchecked 100% success rate with losing plasma containment (we're doing it intentionally this time around)
Deuterium / Tritium fusion fuel fuel - again, easy to come by since most technologically advanced countries have operating nuclear reactors
Aluminum foil fusion jet power fuel - cheap and easy to obtain in massive quantities, abundant on other planets like Mars
Super capacitors - a pervasive technology capable of storing adequate electrical charge to initiate fusion
SCO2 gas turbines - already in a very advanced state of development for commercial electric power for molten salt solar and nuclear reactors, very compact size and low weight thanks to the density of supercritical CO2
CO2 working fluid - again, cheap and easy to come by, both here on Earth and on other planets
There could always be reasonable technology changes to suit the needs / wants of partner nations, just as there's a bunch of specialized software running on F-35 fighter jets to interoperate with the weapon systems that other countries wish to employ from their fighters. We could have core computer and sensor technology that individual nations could then further develop specialized software for, for exploring their own targets of interest, such as hunting for resources on near-Earth objects or colonizing Venus vs Mars, etc. As long as fundamental things like hatches and communications and whatnot interoperate between ships produced by different nations, then tweaks and fixes are fine.
Mostly, there are reasonably well known costs for the selected materials and technologies because nearly all of them are readily available for commercial or governmental purchase if you have the money. The universities can produce the fusion engines to teach plasma physics to prospective doctoral candidates. Who knows, maybe one of them will figure out how to get electricity out of it. Stranger things have happened. In the interim, highly efficient interplanetary propulsion will be worth the money. It's about time we produced a practical working fusion device, even if it doesn't produce electrical power.
An aerospace engineering team would have to work on something like this, but I don't have the tens of millions of dollars to pay them. If I did, I would be spending it to keep them employed, with the goal of eventually putting a lot of people around the world to work, a respite from COVID-19, if you will. In aerospace engineering, if you want to make a small fortune, then you start with a large fortune.
Anyway, of course I'd love to exchange ideas to see if there's any broader interest in this concept.

SpaceNut · 2020-08-15 10:24:24

tahanson43206 wrote:

For kbd512 re topic and your interesting idea in particular ...
I just tried to reply to RobertDyck when your long post arrived, so I've only had a chance to glance at it.
One point I would like to make is that the talent needed for a project like this is available in massive numbers of trained and experienced practitioners who earned enough while working to live long lives away from the daily grind.
In addition, there are (I am confident) thousands of young people with plenty of energy to learn, and not yet bogged down by the demands of a full time job.
It would be stupendous waste of all that talent and experience to fail to enlist at least ** some ** of it on behalf of an innovative idea such as you have offered.
RobertDyck would appear to be someone well qualified to help with living accommodations aboard ship.
If SpaceNut ever gets power back after the hurricane caused outage in his home state, I hope he will be interested in considering how talent can be attracted to support development of your idea.
In my opinion, the ability to land in an atmosphere is not a high priority for a design team for a large passenger vessel for the space trade.
(th)

SpaceNut · 2020-08-15 10:24:51

RobertDyck wrote:

tahanson43206 wrote:
I bow to your knowledge of the initial series, but return with the observation that later versions of the Enterprise were built on Earth.
I offer as evidence a scene from the Startrek movie which featured a brash young recruit (who became Captain Kirk). I remember the scene in which the "citizen" was arrested by a very official looking officer ... in that same stretch there were scenes of the factory .
The first episode I saw was TOS season 1, episode 11, "The Menagerie". Live, first run.
Those of us who grew up with TOS choose to ignore the abomination which is the Kelvin timeline.
https://redshirtsalwaysdie.com/2018/04/ … lvin-kirk/
Prime Kirk
...TOS Kirk credited his father as his inspiration for joining Starfleet. He began and completed a five year officer training program. A long story short, he went through the ranks and at 32 was made a captain. Kirk was given command of the USS Enterprise and lead it on its famous five year mission.
Kelvin Kirk
Kelvin Kirk however, never knew his father. His father was killed on the day of Kirk’s birth. Kirk was dared into Starfleet. During his time at the academy, he was suspended from the academy. Within what seems like a day, he was promoted to first officer, then became acting captain, then he and the Enterprise crew saved earth from destruction.
It has often been asked, what soldiers would ever follow command of the spoiled brat that is the Kelvin timeline Kirk.

SpaceNut · 2020-08-15 10:25:20

kbd512 wrote:

tahanson43206,
I likewise think that a lot of brainpower is being wasted on trivial pursuits that are unlikely to lead humanity to a better future. I'm primarily fighting against short-sighted and inward-focused thinking that hasn't generated better outcomes thus far. We seem to have a growing number of people who exhibit an unhealthy fascination with the otherwise meaningless superficial physical characteristics of other people and far too many plain old bad ideas that simply don't work whenever humans are involved. Right now we're stuck in a funk that isn't helping anyone and we need to break free of that so everyone can get back to living life and advancing our collective human cause.
We need to get off this planet so we can go forth and explore the unimaginably large universe we actually live in. There seems to be this objectively wrong idea that says you need to be or do "X" in order to contribute. It's funny how Elon Musk doesn't believe that and has accomplished so much without caring that he didn't "know how" when he started. Ultimately, we all learn by doing. Theory is good to know, but then there's actual practice. Medicine is actually called "a practice", because at least the doctors who came up with the term weren't so foolish as to believe that they actually understood everything that they were doing. The first people to engineer rocket engines didn't know a damn thing about rocket engines and sure, they made lots of mistakes along the way, but now we have reliable rocket engines as a result of them not believing that they had to know all the answers ahead of time. I'm not sure where the idea came from, but from talking to young people these days, that "I have to know everything about some task before I even try" idea seems to be very pervasive and it's disabling them. Maybe they have so much information now, yet not a clue as to what good it is to them, that they don't understand how to use their imaginations and basic logic. That was something I never thought would be a problem. Getting people to think about how to solve complex problems is like pulling teeth, but they still wonder why nobody wants to pay them what they think they're worth. We've never built interplanetary spaceships before, either, yet that seems like a poor excuse to not even try. Until we can get "the professionals" involved (that was only a joke, there aren't any), some amateur attempts will simply have to suffice.
I agree that landing is not a high priority, but it might be necessary from time to time (hopefully infrequently), which is why it should still be a fully functional ground-to-orbit machine. We presently lack ship yards in space or highly efficient orbital class launch propulsion systems, which is why I was thinking that the gutted hull would be launched first and then fitted out in orbit using assemblies that bolt-up to mounting brackets.

SpaceNut · 2020-08-15 10:26:09

tahanson43206 wrote:

For SpaceNut re kbd512's idea of counter-rotating habitat disks in Enterprise form factor ...
kbd512 came up with a vision for a deep space passenger transport I have not seen before. In the ordinary course of events it would flow under the bridge into the NewMars archive, never to be heard of again.
I'd like to see that idea developed on its own merits. In a recent post I tried to imagine how having a massive counter rotating saucer shaped personnel compartment would challenge the navigator of a space vehicle. It seems to me that the physics of attempting to accelerate a vehicle like this would be worth exploring.
A quick check with Google confirmed that counter rotating propellers have been "with us" since at least 1907. Applications include marine use as well as atmosphere, and fixed wing aircraft as well as helicopters.
The helicopter case is closest to kbd512's concept, because the disk of rotation is parallel to the flight path instead of perpendicular as is true for fixed wing aircraft.
Issues that could be explored in a separate topic would include:
1) How to orient the spacecraft before applying thrust
2) How to mount the disks so that they can be started into rotation, maintained at a desired rate of rotation, and slowed to a stop when necessary.
3) How to design the system so that humans can safely move from the non-moving part of the ship to either of the rotating disks and back
4) How to design gas and fluid seals between moving and non-moving parts of the ship.
The closest example of a large scale project along these lines is the restaurants at the top of towers in various cities.
I've been in the one in Toronto and the smaller one in Indianapolis. Those are aligned with the axis of rotation of the disk parallel to the axis of the towers.
kbd512's design is distinctively different, because the axis of rotation of the disk is perpendicular to the axis of the vehicle.
Engineering for kbd512's design would be quite challenging.
(th)

SpaceNut · 2020-08-15 10:26:42

kbd512 wrote:

tahanson43206,
1. Spin-down the gravity wheels for the very brief periods of time when you're using the fusion engines. Exposing people to micro-G for a few days every couple of years won't hurt them.
2. I intended to use electric motors mounted between the wheels, but I'm sure there are lots of ways it could be done.
3. The two gravity wheels are connected to the rest of the ship by a micro-G center section that both stores consumables and provides access to the rest of the ship. If the humans have to leave the gravity wheel, the only other places to go on the ship are the escape pods or the unpressurized engineering section that contains the power and propulsion systems. The ship has a fair amount of "void space" for unpressurized cargo, but also because it's a giant gas tank when it's launched into space. The saucer section contains escape pods and cargo pods. The engineering section contains the RTG cores, gas turbines, propellants, radiators, and large cargo.
Rather than sending everyone to the surface using a single giant lander, the escape / cargo pods (Cygnus cargo capsules) are sent to the surface individually, in sequence (landings coordinated by the orbiting ship), where they become pressurized storage / "Mars homes" on the surface. They're collected and connected, for later burial, to a series of subsurface or partially buried tunnels / airlocks that form a larger settlement. The heavy equipment from the primary cargo bay is also sent to the surface using disposable fabric heat shields like ADEPT or HIAD. The propellant required for these low-dV landing operations is siphoned off from the upper atmosphere of Mars and collected in tanks aboard the ship, where it is split into CO / O2. By the time it's time to leave, all the passengers have been "kicked off" or brought back aboard for return to Earth.
Once we get molten salt concentrated solar and molten salt fission reactors and Aluminum smelters up and running on Mars, Mars will provide all or nearly all of the propellant, D-T and Aluminum and CO2 for landing operations. That way, none of the D-T will be older than 6 months upon first use. Only fresh food, new Cygnus capsules / Aluminum Mars homes (for burial on Mars) and of course new colonists, will be brought in from Earth. Earth will obviously provide the colonists, the ships, maintenance facilities and maintainers (some of this will eventually become the responsibility of our new Martians), and propulsion hardware for the ships until Mars makes their own.
We will use the same 10MWe CO2 gas turbines to power the ships and solar thermal (base power, with no restricted areas as with fission reactors) and fission reactors (relocatable industrial power for mining and refining, and to provide the fission products for the ships to use) present on the surface. First priority is to get the solar thermal power plant built to power the colony, then adding greenhouses and storage of working gases and fluids, next producing the propellants required for self-sustainment, and finally, adding more colonists.
4. Umm, maybe we don't do that and just have the power / water / air connections running through the spokes that tie the gravity wheel / torus to the micro-G center sections where most of the pressurized consumables are stored. I could be wrong, but this seems unnecessary.

SpaceNut · 2020-08-15 10:27:48

SpaceNut wrote:

Rotating space habitat, usually consisting of a pair of counter-rotating cylinders. A pair of cylindrical orbital space colonies that rotate around their respective axis to produce simulated gravity (one rotates clockwise and the other counter clockwise to minimize torques).
.
https://en.wikipedia.org/wiki/O%27Neill_cylinder
typical orbiting station
the Et tanks reused
says that its a lifeboat
single ring rocket
this speakers to two rings rotating

SpaceNut · 2020-08-15 10:28:23

adding content not in list

Tom Kalbfus wrote:

How much do you think it would cost to build this space station? It is the design from the movie 2001 A Space Odyssey. According to this diagram, it rotates enough to simulate Mars gravity in the outer ring, about 1.6 times a minute at this given diameter. I can find some uses for a station like this. According to the specifications, it could house 600 people in orbit under 1 Mars gravity in Low Earth orbit. Suppose we actually tried to build it as a real space station, not as a movie prop, it was designed by Werner Von Braun after all! A whole bunch of little details would have to be added to make it a functioning space station. If we built it, what uses could it have? I think as a Space Hotel, it could be useful. People could experience Mars gravity without going to Mars.
You can read it better if you go directly to the site:
http://www.starbase79.com/images/2001Sp … tation.JPG
As you can see it states a gravity of 0.38 that of Earth, other versions of it give it a rotation rate of 1 per minute and a lunar gravity in the outer rings..

Calliban wrote:

Whilst wheels like this are the optimum solution for minimising gravity gradients, they are non-optimum for cosmic ray shielding. We actually want stubby cylinders, with as much shielding per unit area as possible. The cylinders would be decked out inside, with different gravity on different decks. Shielding is expensive because of its enormous mass. We want solutions that get the most habitable volume for the minimum shielding mass. The best shape would be spherical. But it is difficult to fit decks into a sphere that make best use of internal volume. So a stubby cylinder may be better.
The rotating sections could in fact be entirely within the pressure hull. A centrifuge within it, capable of producing Martian levels of gravity. The lower the artificial gravity, the lower the gravity gradients and the less problem with motion sickness for any particular spin radius. What can we get away with? We actually don't need space based experiments to work this one out. We can build compact centrifugal habitats on Earth on thrust bearings. Decks would be tapered, as the effective gravity is the vector sum of Earth gravity and centrifugal gravity.

SpaceNut · 2020-08-15 10:29:01

SpaceNut wrote:

https://www.ride-extravaganza.com/inter … gravitron/
When the automated door closes the fun really begins – riders barely realise they’re moving (everything they can see is moving with them). The ride quickly starts to rotate reaching its top speed of 24 rpm in less than 20 seconds. (fast given its wide diameter).
At this speed (turned with a 33kW 3-phase motor), the 45 panels that riders stand against rise upwards leaving people stuck to the wall with their feet off the ground. Regular riders will always move into position as the ride gains speed, sometimes turning sideways or upside down.
http://www.artificial-gravity.com/sw/Sp … inCalc.htm

SpaceNut · 2020-08-15 10:30:14

RobertDyck wrote:

In the movie "2001: A Space Odyssey" the station was named Station 5. The hub was fixed, so both wheels rotate together.

SpaceNut · 2020-08-15 10:30:47

tahanson43206 wrote:

For RobertDyck re #44
Thanks for that neat GIF from the movie! Out of curiosity, if you were designing that station now, all these years later, would you have recommended counterrotating habitat sections?
It seems to me that precession is a predictable consequence of the original design.
The vehicle that SpaceNut found would have a problem with seals leaking at the joints between the habitat sections and the central shaft.
(th)
The fixed hub certainly solved the problems that would arise from kbd512's concept of counter-rotating habitats in a space vehicle.

(th)

SpaceNut · 2020-08-15 10:31:32

RobertDyck wrote:

The question is how much does the station move? If the station remains in fixed orbit, never moving, and always rotates in the same direction, then precession is not an issue. But there's another problem: if the rotating bit is asymmetrical, you can get the "Intermediate axis theorum". With Station 5 rotating while the second ring is only partially constructed, mass will not be perfectly balanced. This could result in the "flip" behaviour explained in this video. (14 minutes, 48 seconds)
The Bizarre Behavior of Rotating Bodies, Explained
https://aspenxchange.com/wp-content/uploads/2019/10/Bioprocess-Alert-Image-100219.jpg

SpaceNut · 2020-08-15 10:32:15

RobertDyck wrote:

tahanson43206 wrote:
The vehicle that SpaceNut found would have a problem with seals leaking at the joints between the habitat sections and the central shaft.
The fixed hub certainly solved the problems that would arise from kbd512's concept of counter-rotating habitats in a space vehicle.
Yea. Now we have conflicting design criteria. This is where engineers have to get creative. I don't have a solution, but will describe the problems. Yes, a spin stabilization is an issue. But it's more than that. A spacecraft has to manoeuvre. How does the craft make turns? Yes, it can make turns easily within the plane of rotation, but to navigate you have to control trajectory in 3 dimensions. How do you turn against the axis of a large rotating body? And yes, SpaceNut's spacecraft with counter-rotating rings does negate the problem. But as you said, you then have a problem with seals at the joints which could leak. And friction at the joints will tend to slow rotation, with the two wheels rotating in opposite directions. Maintaining rotation would require an electric motor to actively overcome friction, maintaining rotation.
My design with the cargo hold, propellant tank and main engine all on one side of the wheel would create the "intermediate axis theorem" problem. :'( Solving my ship design would require the axle have an equal mass on either side of the wheel. But I wanted one face of the wheel to be covered in thermal fabric to form a heat shield for aerocapture and aerobraking. No way around it, mass will have to be distributed. Physics is physics.
But all designs with a single rotating mass have the problem of steering. How do you turn against the axis of rotation?
Oh! Another concern: radiation. My design was to have the aft end of the ship (rocket engine end) always pointed toward the Sun. That means one side wall of the ring will always face the Sun. That sunward wall would have radiation shielding.

SpaceNut · 2020-08-15 10:32:49

RobertDyck wrote:

Steering. A ship with a spinning wheel for artificial gravity. Could we deliberately produce precession, cause it to precess 180°, then stop precession? Could we control it? Use precession to turn a spinning wheel against its axis? How do we do that?

SpaceNut · 2020-08-15 10:33:27

tahanson43206 wrote:

For RobertDyck re recent posts about rotating habitats and design considerations ...
Thank you for your several helpful additions to this topic ... Your analysis so far is of the case of parallel axis designs.
Would you be willing to take a look at kbd512's concept, of habitats arranged like counter rotating helicopter propellers?
It is that design I found intriguing, perhaps because I've not seen it on offer before. The design would (it seems to me) help to address radiation protection, because the disk could be oriented edge on to the solar radiation, and thus the volume of mass needed for radiation protection would be reduced to the thickness of the habitat section, and to 1/2 of the circumference of the disk if the budget is tight.
It seems to me better to design for thrust to be applied while the habitats are in motion. Someone suggested recently that the habitats might be spun down before a thrust maneuver, but I think that would be a use of energy (and potentially fuel) that is not necessary. It should be possible to design the system from the outset to achieve all objectives, including accepting thrust while rotating.
Your suggestion of causing precession to orient a vehicle to the vector desired for a thrust maneuver reminded me immediately of the mechanical action needed to change the aspect of a helicopter propeller. The difference between a helicopter propeller and a rotating habitat is significant, of course, because a helicopter interacts with the atmosphere to assist itself with movement in plane of rotation, while a rotating habitat would be a pure gyroscope.
As a reminder, Dr. O'Neill and his students used the counter-rotating habitat design concept to plan for adjustment of the habitat orientation as it orbits the Sun. As I remember the technique, the two habitats are joined at both ends by girders which allow for adjustment of the spacing between the habitats. As one end is pinched, the complex will be caused to rotate in a direction resulting from the combination of the forces at work.
I ** think ** something similar is done in spacecraft with gyroscopic attitude control equipment. Working from memory, I believe that some major telescopes have been held to a desired orientation by gyroscopic systems, and those systems have been subject to failure which reduced the ability of ground controllers to maintain the desired orientation.
Google came up with this item about Hubble when I asked:
NASA's Hubble Space Telescope. NASA took great strides last week to press into service a Hubble Space Telescope backup gyroscope (gyro) that was incorrectly returning extremely high rotation rates. The backup gyro was turned on after the spacecraft entered safe mode due to a failed gyro on Friday, Oct. 5.Oct 27, 2018
NASA's Hubble Space Telescope Returns to Science ...www.nasa.gov › feature › goddard › update-on-the-hu...
(th)

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