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Tonight's Zoom meeting is up and running.
If there is a member who would like to participate, and who does not already have the login information, please put a note here (in this topic).
Update at 1:04 .... kbd512 joined
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The Zoom session for 2021/12/26 is officially in the history books!
Thanks to kbd512 for an interesting discussion!
A link to the recording may be requested from SpaceNut.
We'll plan another Zoom session for next week, same time, same channel.
(th)
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I chose not to join today. Actually, I slept during that time. I received 3 emails from tahanson43206 with the subject line "Document shared with you: ‘Large Ship Segment 1 of 12’". They are 1 of 12, 2 of 12, and 3 of 12. But the body of each message has a very large image that appears as a blank white rectangle. "From" says via Google Docs. Could you tell me what this is?
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Merry Christmas. I spent Christmas Day at home alone; no tree, no decorations. I did roast a 5 pound chicken, with home-made stuffing, potatoes and carrots. Used the microwave oven to thaw the frozen chicken. Scrubbed two whole raw potatoes, pealed two large carrots, threw them in the roasting pan with the chicken. Took 2 hours and 40 minutes to bake, and left the roasting pan sit on the stove closed for another 10 minutes before opening. Will have chicken for a while. When finished, I will make the leftovers into soup. After you pick the meat off the carcass, it's amazing how much meat is actually still there. I have never been able to make gravy, so add the drippings to the soup. Let the drippings gel in the fridge, peal off the fat, throw the rest into the soup. The gelatin makes a very hearty soup. And all tiny little shreds of meat from the neck, spine, etc actually add up to quite a bit. So it will be home-made chicken noodle soup.
For Boxing Day, I dropped off 3 bottles of mead that I made for my girlfriend. She didn't let me into her house. She broke up with me last spring because I couldn't fix her laptop computer after she changed her password and forgot it. I tried. I did take 2 days off work to do that, but couldn't take another day off work during a weekday, so she broke up with me. She since said she wants to get back together, but won't let me into the house with her senior citizen father. Covid. The operation she had a couple years ago gave her pancreatitis, so now she can't consume beer or whisky or anything with gluten. Mead is made from honey and sugar, so it's safe.
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For RobertDyck,
First, thanks for your description of what sounds like a delicious Christmas dinner, and plans for a number of follow on meals!
I can imagine a future in which you enjoy your golden years, supervising fine cuisine in a Large Ship where you have earned a private cabin.
I've never had to deal with a lost password on a computer, so sympathize with your attempt to solve the problem. However, I ** do ** note that a physical password is limited to a few characters. The problem would have been more severe if the entire laptop had been encrypted. Your post did not indicate if the laptop was encrypted.
And thanks for the description of your thoughtful gift!
***
Back to the business at hand ....
kbd512 is showing strong signs of ability to design (and hopefully develop) a military version of your passenger liner. He served a very useful role, by instigating the launching of the Zoom meetings, and then working with you for four hours at a time for multiple Sundays, to put Large Ship well on track.
I believe that kbd512 is no longer able to assist you with Large Ship. He will be off on his own project(s).
However, we (you and I) are on the hook for a very high quality presentation on March 12th.
The documents you received are intended to allow us to work together on the structure of the presentation.
I'm hoping you will be interested in developing 12 short YouTube videos that you would play for the March 12 audience, interspersed with brief intervals to allow audience members to put questions they have into the chat. At the end of the presentation, you (and your support team) will have time to answer the questions that came in plus any new ones that may arrive.
The key for this to work is if your "foreign" email address can work with the documents.
kbd512 has already tested the document, and he indicated that he was successful. I'd appreciate it if you were to test at least one of the documents in the next day or so.
I'll create the remaining 9 documents later today, if current plans hold.
(th)
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A Zoom session is in consideration for focus entirely on Large Ship, and specifically on the presentation March 12.
This is a dedicated topic meeting, and attendance will be by those interested in helping RobertDyck in preparation.
The time will be between the "Early" (European) meeting and the "Late" (reguolar) meeting.
(th)
Recruiting High Value members for NewMars.com/forums, in association with the Mars Society
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There are several laptop password cracker and resetting programs for linix of which I had to use one on a laptop my son had picked up. So long as the boot process allows control to the boot sequence and access to the USB or Cdrom you can jailbreak the computer.
Glad to see all are ok after such a filling holiday meal and that we are awake to communicate so soon after it.
Zoom session links are on the way....
Edit
Had a chance to view a small bit of a couple of the videos recording and it looks fun to do. Maybe someday I will but for now I will settle for reruns.
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For SpaceNut re #132
First, thanks for the timely reminder Linux can be used to crack a lost password on a laptop.
If the laptop with the locked password is still available, then I would be happy to participate in the operation. While I haven't run that specific software, I ** have ** booted laptops (and desktops) using USB sticks into Linux, so the process is familiar.
Second, thanks for your support of the Large Ship Presentation initiative.
We have two possible presentations shaping up ... the first is already booked, for the Large (passenger) Ship with RobertDyck.
The second is a possibility but not yet clearly defined.... that would be a military vessel designed (by kbd512) to be nimble, lightweight, free of material comforts, and intended for the US Space Force.
I am hoping that kbd512 is serious about this latest ehthusiasm, and that it lasts longer than a few days.
(th)
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For SpaceNut (primarily) ... all others welcome....
The links you requested from Executive Director James Burk arrived, and I have made a bit of progress working with them.
The key appears to be to download the four files that Zoom creates for each Zoom session.
In the case of the most recent Zoom meeting, it is at 1 hour and 23 minutes in that kbd512 reveals the secret of how a massive bearing for a counter-rotating space habitat would work. He explains that the principle to be used is exactly the same as is used in an internal combustion engine. The piston head is driven by a structure that holds onto the crank shaft with a clamp that is secured with bolts. There are NO bearings in that interface. Instead, the entire "bearing" function is performed by a fluid (oil) that can withstand the pressures exerted by the crank shaft on the piston, and by the piston on the crankshaft.
For the information of anyone who might be wondering what Zoom creates, here are the file names and sizes for the most recent Zoom meeting:
/home/tahanson/Downloads/GMT20211227-003451_Recording_gvo_1280x720.mp4 437.8 MB
/home/tahanson/Downloads/GMT20211227-003451_Recording_avo_640x360.mp4 246.1 MB
/home/tahanson/Downloads/GMT20211227-003451_Recording.m4a 120.2 MB
/home/tahanson/Downloads/GMT20211227-003451_Recording.txt 122 bytes
I played the 1280x720 mp4, and was able to advance the time pointer without difficulty.
Audio for kbd512 was better than mine, but his contributions are far more interesting (I would think)_ so all is good.
(th)
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tahanson43206,
No secrets were revealed, merely what engineers have known for a very long time. Every highly stressed component, such as a bearing material, has a deterministic fatigue life, beyond which it fails. The empty weight of each fabric torus is 187.5t, so despite the low rotational speed of 5.4rpm (exact rotational rate is about 5.37rpm for 1g), the bearing surfaces are placed under considerable stress. There are 525,600 minutes per year and these counter-rotating habitat modules will rotate at 5.4rpm for the better part of 25 years. That works out to 70,956,000 cycles over the projected service life of the bearings.
An engine run at a relatively low 3,000rpm completes approximately 1.5 billion cycles over 1 full year of continuous operation, so that's far less realistic than our use case. There's no such thing as a metallic or ceramic ball or roller bearing material with a fatigue life of 71 million cycles, much less 1.5 billion cycles. That is why no such bearings are used to support the loads generated crankshafts, camshafts, and connecting rod bearing surfaces- they simply wouldn't last long enough in operation before deformation (yielding) or cracking resulted in a catastrophic failure. Fluid bearings don't have such short fatigue life, although eventually heat and pressure will break down the protective fluid film that prevents destructive metal-on-metal contact.
The ball and roller bearings used in large / low-speed electric motors can last for up to 5 to 7 years tops before replacement is required. That's not long enough for our application. Gigantic bearing replacement in space is likely to be complicated since bearings are typically press-fit in place using extreme force. Even if replacement was easier and cheaper, fluid bearings are still the only type of bearing that will last for the projected service life of the vehicle. In the end, simple physics and known materials science dictates which solutions are practical or merely feasible and which are not. We already know well how this works.
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For kbd512 re bearing description in Zoom
Thanks again for your explanation of this important design feature of the vessel you will (if all goes well) be able to present to a customer for funding.
A detail that I hope you will add to your new Practical Vessel topic is the nature of the fluid you will choose for deep space service.
I would assume the kind of oil we (humans) use in our internal combustion engines will not be the best choice for the counter-rotating space vessel you've started to design.
My hope is that someone has already done the research (and possibly even testing) to be used.
Come to think of it, rotating machinery has been in use in space since the Apollo days. Your application would be on the larger end of the spectrum.
In that sense, your design will be breaking new ground, so it will be fun/interesting to follow your progress in the Practical Vessel topic.
(th)
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This report is primarily for GW Johnson and RobertDyck ...
For GW Johnson ... congratulations on success in adding text to Large Ship Segment 2 of 12.
I found it just now while adding a new Share for RobertDyck.
For RobertDyck ... the new share you requested is installed in 10 of the 12 documents, and it will be installed in the remaining two shortly.
Please test the new links when you have time.
In addition, I'd like to suggest (subject to your approval of course) that you set up #1 for "What this vessel is!" , and #2 for "What this vessel is NOT!"
Tentatively (and again with your approval needed) I have tagged #4 for Atmosphere, and invited GW Johnson to upload his study of the topic.
SpaceNut has suggested Funding and Construction as topics, so they might go in the higher numbers.
(th)
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Merry Christmas and Happy New Year, guys! Or Hanukkah, or whatever! Just so you are enjoying the season.
I did manage to copy and paste the email I sent TH about the atmosphere into that #4 google document. The real details, with illustrations and numbers, I am still working on, and hope to post on "exrocketman" just after New Year.
I had the no-pre-breathe and fire danger issues under control in an "exrocketman" posting 3 years ago. That was "Suit and Habitat Atmospheres 2018", posted 16 March 2018. What I have found out recently was what the altitude criteria were, to avoid long-term hypoxia effects living at high elevations here on Earth. I converted the 2500 m elevation criterion into a wet in-lung oxygen partial pressure, in order to generalize the altitude criterion into something that applied to reduced pressures and higher oxygen percentages. The long term health criterion is more restrictive at 0.14 atm Pp O2 wet in-lung, than the short-exposure criterion based on oxygen masks requirements that I had in 2018. The long-term restriction is what prevents both chronic mountain disease (CMS) and pregnancy/childbirth problems.
I use the wet in-lung Pp approach because it is partial pressure differences that drive diffusion across the lung membranes. At least every textbook I ever saw on the subject of diffusion said so. You have to reduce the Pp of O2 from what is in your breathing gas mix by the Pp of water vapor at body temperature (some 0.06193 atm), because of the wet environment inside the lungs. That water vapor displaces some of the breathing gas you inhale.
There is a CO2 displacement effect as well, for CO2 diffusing out of the blood into the lung spaces, but it is at least an order of magnitude smaller than the water vapor effect, and so is safely ignorable for design purposes. The water vapor is a significant effect, and more so at reduced total breathing gas pressures, as it does not reduce as pressure is reduced.
Anyhow, watch for the posting. There may be charts or tables in there that you can use. There is no paywall on my site.
GW
Last edited by GW Johnson (2021-12-28 11:20:06)
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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For all who may be thinking about Zoom Collaboration this coming Sunday...
We offer a session at 19:00 UTC on Sunday for the convenience of our European members. If anyone is interested in such a session, please post a request in this topic. We need at least two people who want to participate, and we need a volunteer host. The time should work well for members in Canada/US/Mexico, because it is earlier in the day on Sunday.
We are offering a special Large Ship session that would precede the regular Zoom session. This would require coordination between GW Johnson and RobertDyck. I can probably adjust to whatever time they decide upon. The focus would be on preparation for the Large Ship presentation to the North Houston chapter of the National Space Society. The purpose would be to provide whatever assistance we can to RobertDyck as he prepares for this one hour long presentation.
The regular Zoom session will (if plans hold) begin promptly at 1 AM UTC Monday in London, as usual.
This session has turned into a marathon exchange lasting four hours or more, depending upon the stamina of the participants. NewMars members can drop by as their time permits, and leave when convenient. The session itself is held up by a workstation that patiently waits 40 minutes after the last participant leaves before closing down. All sessions are recorded, so if something is of particular interest to a NewMars member, a link to the recordings can be provided through SpaceNut.
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OK, I just posted the new habitat/spacesuit atmosphere article on "exrocketman". Its titled "Habitat Atmospheres and Long-Term Health", dated 1-1-2022. 0.45 atm habitat oxygen-nitrogen mix at 45% oxygen. Still safe leaked down to 0.40 atm. Min 3.031 psia pure oxygen suit. Still safe leaked down 10%.
Be aware that I have since developed a spreadsheet design analysis tool for this, which makes iteration easy. I have since refined that 0.45 atm 45% oxygen selection, but only slightly, to 0.43 atm and 43.5% oxygen. Still safe leaked down 10%. It also sizes the minimum pure oxygen suit pressure that meets the "no pre-breathe" criterion: 2.975 psia. Suit is still safe leaked down 10%. All the long-term and short-term hypoxia criteria are built in, along with the pre-breathe factor, and the fire danger criterion.
Unless I hear differently from Rob, I plan to get on at 7 PM central Sunday (1 AM UTC Monday) as usual.
GW
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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For GW Johnson re #140 (and private correspondence)
Confirming ... the Sunday regular Zoom will start at 1 AM UTC London Time Monday.
The ID and passcode are permanent. They will not change. Thanks for planning to attend.
It should be interesting to see what happens as we enter the new (Earth) year.
(th)
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I have posted a second "exrocketman" article describing the "best case" (0.43 atm 43.5% O2) and "rule of 43" (0.43 atm and 43% O2) habitat atmospheres and the resulting min pressure specs for suits that meet the "no pre-breathe" criterion. It is dated 1-2-22, and titled "Refining Proposed Suit and Habitat Atmospheres". The basic method is described fully in the "exrocketman" article dated 1-1-22 and titled "Habitat Atmospheres and Long-Term Health". The min suit pressures that meet pre-breathe for feasible habitat atmospheres are higher than the utter minimum suit pressures that are feasible as independent designs. Those just fail to meet pre-breathe with long-term habitat atmospheres that are safe for pregnancy and childbirth. Y'all should go look at those two articles before we start tonight's zoom meeting.
GW
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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it is UTC :36 (or so) /// The Zoom session will be active shortly before 1 AM London time.
(th)
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The Zoom session is running at 00:54:35 UTC
I'll be setting up a second workstation shortly.
The session is in progress... attending are:
RobertDyck
kbd512
GW Johnson
Anyone who is a NewMars member and would like to join this session, please post a note in this topic.
I'll check the topic from time to time. It will be necessary to send login information to your email address of record.
End of forum checking .... I'll be continuing to listen to the Zoom using headphones.
Update at 22:50 local time ... the Zoom session is as lively as ever.
GW Johnson just brought up his recent work on Atmosphere.
(th)
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Meeting Highlight ... there are many moments when interesting sequences occur...
During a discussion of the relative merits of aluminum and fiberglas for construction, GW Johnson gave an illustration of the relative features of an aluminum canoe vs one made of fiberglas using the aluminum canoe as a form. While on a canoe trip in the aluminum canoe, GW Johnson observed an encounter between a human and a snake which fell into the canoe from a branch under which the canoe passed. A human (not GW Johnson) stood up and pounded on the snake with his paddle. The force of the blows was so great the rivets popped in the canoe hull, and the crew had to bail the rest of the trip.
The point of the story was that a fiberglas canoe is more resilient than an aluminum one. I don't recall how this anecdote was woven back into the discussion of manufacture of Large Ship in orbit, but it certainly made a lasting impression on me!
Related to this anecdote is the experience of GW Johnson making resilient fiberglas canoes with his family. What seems worth pursuing further from this snippet of the Zoom session, is the question of whether a similar technique, perhaps adapted for the conditions of space, might prove worth developing.
Here-to-fore (to the best of my knowledge) every human created structure that showed up in space had been fabricated on Earth. There will surely come a time when structures are constructed in orbit.
Construction of Large Ship will occur in space. The example of the ISS and the Russian and Chinese space stations all featured components built on Earth and connected in orbit. Large Ship could be constructed the same way, although RobertDyck has expressed an interest in attempting on-orbit construction.
The use of metal components vs non-metal components remains very much open for discussion. It is possible that experiments carried out on the various space stations and in short flights of various space craft might provide useful insight into which materials and techniques might be useful for large scale construction. To the best of my knowledge (admittedly limited) no actual construction has ** ever ** occurred on orbit, other than bolting components together or plugging components into receptacles.
A topic devoted to construction on orbit may come into being in the NewMars forum. If it does I hope fiberglas is included as a subtopic to explore.
(th)
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This is an update regarding preparation of YouTube videos from Zoom recordings.
I am contemplating working in this arena to lay up a set of videos about Large Ship, ahead of the March 12th presentation to North Houston chapter of the National Space Society. We have roughly 8 weeks to put in place a presentation as backup, in case RobertDyck is unable to make the date due to the nature of his on-call employment.
Today, I pulled up Corel Video Studio on an ancient Windows XP instance. To my delight, the software still runs, and I could see a history of video projects done for another non-profit organization in the 2011/2022 time frame.
My (tentative) strategy is to import Zoom recordings (courtesy of SpaceNut >> Executive Director James Burk) and to edit them down to three minutes for posting on YouTube, in a NewMars channel (if I can figure out how to create one).
If RobertDyck is unable to give his talk on the 12th of March, we would have these recordings in reserve to play for the audience.
***
GW Johnson is considering an offer I've made to help him to set up online seminars using the Mars Society Zoom.
While there are many subjects which Dr. Johnson is qualified to explore with suitable students, I am focused at the moment upon his Orbital Studies, supported by software running in the uniquely accessible form of an ordinary spreadsheet.
My vision of how this would work is:
1) Dr. Johnson has already created spreadsheets ... we need to store them where the public can download them (working on that)
2) We have Zoom to make recordings of seminars
3) We need students ... i am looking for persons who want to learn how to use the spreadsheets to calculate flight parameters
4) I am NOT looking for persons who want to lead the seminars. if you want to lead a seminar, contact me here.
5) We need a time slot that works for everyone. It would be between 19:00 UTC Sunday and 1:00 UTC Monday.
(th)
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It is 13:18:10 per time.is/UTC ... We offer a Zoom meeting for European members at 19:00:00.
At present we've seen no interest but that could change any time. To ask for a Zoom meeting at 19:00 UTC, just post a request here.
Two participants are needed to get the ball rolling, and at that point we will look for a host to take on that time slot.
A special Zoom meeting for Large Ship presentation planning is an option if RobertDyck is interested. Otherwise the offer will remain unused.
The regular Zoom meeting is on schedule, and a host is available.
Regular attendees will connect at 1 AM UTC Monday as usual. The host will be a dedicated workstation which will hold up the session as long as there are participants, plus 40 minutes for time-out.
If a NewMars member would like to attend, and has not already done so, the procedure is simple enough. Just post a note here. I'll send the login information via your email address as shown in the Profile page for your ID. You'll need to be able to run Zoom on your computer.
Courtesy in Zoom meetings is pretty simple ... activate your video if you have one, keep your audio off unless you will be speaking, and use the "Raised Hand" icon to ask for the group's attention.
Members are free to come and go as their time and circumstances permit.
(th)
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It was 18:12 UTC a short time ago ... it appears that a meeting for our European members would work out well for people in my time zone. No one has asked for a meeting at 19:00 UTC, but the option is very much open.
The later meeting, at 1 AM UTC Monday remains on track for US/Canada/Mexico members.
(th)
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19:00 UTC came and went without a European session. If anyone in Europe would like to set something up for next week, just post a request here.
***
The US/Canada/Mexico session is coming up in (about) 90 minutes ... time.is/UTC says 23:23:53 right now...
The session will open a few minutes before 1 AM UTC Monday, and remain open as long as folks want to keep it going.
(th)
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The evening Zoom session is open, at 55:55 UTC in London.
I'll set up a second system shortly. All who arrive now can start discussions as you are inspired.
GW Johnson just sent a pdf file about the Tug to shove Large Ship on it's way to Mars, and to give in a soft "landing" in orbit back around Earth.
Large Ship will still have to do a small amount of the work, but it is a fraction of the initial requirements.
Update at 20:33 local time ... kbd512 and RobertDyck are holding down the fort! I've added FM headphones and will be listening in while doing chores.
Any member with the access codes is welcome to join in.
Update at 21:32 local time ... GW Johnson just joined the Zoom
For much of the past hour, kbd512 and Robertdyck were comparing notes on military aircraft ...
(th)
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