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Today is Zoom Day for NewMars forum.
No one has requested the European Zoom, so we will not have one today. If you would like to request a Zoom at 19:00 UTC for European members, you have all week to post a request for next week.
Meanwhile, the regular US/Canada/Mexico Zoom session is lined up with host kbd512, at 1 AM UTC.
I'll be joining at 2 AM UTC for the NightOwl session.
Last week we made progress translating the science fiction vision of RobertDyck into a Real Universe ship, by agreeing upon the dimensions and shape of the 119 hull plates for a pressure hull.
Today, with any luck, we'll continue this important work by adding ribs. I believe the terms used for these (from aerospace industry) are "formers" and "stringers".
The specifications that come out today's meeting should include a mechanical locking mechanism to set the panels in place in LEO before welding.
What I'm imagining is something like a "tongue and groove" joint used for woodworking.
However, I like the idea of a mechanical snap that holds the panels in place next to each other.
Google came up with a term: "Snap-Fit" that yields a set of drawings showing a simple mechanical joining capability.
I am imagining these joints as preliminary to position adjustment before welding.
The 119 panels ** must ** achieve perfect (to one millimeter) symmetry before welding, because they will comprise the "keel" of construction of Large Ship.
(th)
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Our North Houston contact is planning to join tonight's Zoom for a few minutes, to go over plans for Dr. Johnson's trip to Houston April 9th.
There is some confusion about start time.... the official start time is (or was) 1 AM UTC.
However, with Daylight Savings in effect, I'm not sure ** what ** time kbd512 is opening the Zoom.
All I know for certain that when I log in at 21:00 my time, the session has been in progress.
I'm hoping that GW Johnson can join the group so we can clear up plans for the various timings of the event.
If the ** real ** meeting time is 2 AM UTC, I'd be happy to make the change in the announcement.
(th)
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For the Record ... 1 AM UTC is coming up at 21:00 local time.
Hopefully the evening Zoom is in session.
(th)
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Note regarding today's Zoom meeting. I posted in the Large ship topic, here
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The surprising report of progress that showed up recently in the Hybrid Fission Fusion topic inspires this renewed invitation to our European members to consider taking advantage of the powerful Zoom communications technology provided by the Mars Society.
The US/Canada/Mexico Zoom has demonstrated repeatedly how online communication, supplemented by email and postings to NewMars during the week between Zooms can rapidly move things along.
I will be promoting a special Zoom (at the usual time US/Canada/Mexico) next Sunday, to follow up on the presentation planned for April 9th in Houston.
If anyone is interested in a Zoom at 19:00 UTC next Sunday, please let me know BEFORE Sunday.
My schedule gets locked in a couple of days ahead, so I'd appreciate some lead time.
(th)
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Today's NewMars Zoom adventure is a joint meeting with Mars Society and National Space Society.
The event is scheduled for 2 PM Houston time. That will be 3 PM Eastern for US/Mexico/Canada members.
The event is free and open to the public, and available on Zoom at northhoustonspace.org
The featured speaker today is GW Johnson, of the NewMars forum.
I am hoping that a company to provide Space Tug services will come into existence because of today's presehtation.
If anyone is unable to join the live stream but would like to see the video, it will be made available early next week, from the chapter website, as given above.
(th)
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I don't think I belong in your activities, but I would really like to see Mr. Johnsons presentation.
Done.
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For Void .... Thanks for your interest in Dr. Johnson's talk ... He is scheduled as the second speaker today.
You have plenty of time to make sure your computer is working with Zoom.
You do ** not ** need to activate either the audio or the video (of yourself) to see the presentation.
Just visit northhoustonspace.org in 15 minutes, and click on the link to the presentation.
There is an admissions person on duty to be sure you are not a spammer. Normally everyone just sails through.
(th)
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tahanson43206,
I met GW and attended his large ship propulsion presentation at the NSS North Houston meeting at Spring Creek BBQ. The lecture was well received by the audience.
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For kbd512 re #284
Thanks for attending the event, and for your support of Dr.Johnson!
I thought the presentation went well. There were no technical glitches until question time, and then the audio went out.
The recording should be ready early next week!
(th)
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tahanson43206,
The battery in GW's mic died, and then their attempt to provide audio through a cell phone resulted in some feedback through the computers. They did their best with what they had to work with. No matter how good your equipment is, sometimes it will fail.
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For kbd512 re #286
Thanks for the on site reporting! Everything considered, I think this venture was a resounding success! I would like to thank GW Johnson for all the time and expertise and effort he put into the presentation, to Mrs. Johnson for taking the risks of an automobile trip from McGregor to Houston, and to the members of the leadership team of the North Houston chapter of NSS for all the work they did ahead of the event, during the event, and after!
Today is Zoom day for NewMars.
No one in our European membership asked for a Zoom session, so there will not be one.
The regular US/Canada/Mexico Zoom will start at the usual time, noting that Daylight Savings is in effect in the US.
There is a chance someone from the North Houston NSS chapter may drop in.
This is the Second Sunday, so the Seattle Chapter of the Mars Society will hold it's meeting at the usual time, so the NewMars meeting will last only two hours.
Last month we were invited to attend the Seattle Chapter meeting, and hopefully that will happen again.
(th)
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I heard some kind of weird feedback about the time the questions started. I wondered what it was. But us ex-slide rule guys know little about this computer stuff. For one thing, we think quite differently.
At first I didn't recognize Kbd512, and for that I apologize. Looking at him on the zoom screens, the lighting is quite different, and he looked different in person from those screen images. Plus, I am old and getting slow. There is no help for that.
One of the zoom participants was a NASA retiree who contacted me by email. He had the same question as somebody else in the room asked: why I did not look at lunar ISRU propellant? Short answer: my studies are non-comprehensive. I still might go look at that yet. If I can figure out how to do it.
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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I just created an account on Slack for the Moon Society. I asked...
Could I start a conversation? Is there fuel on the Moon? Traditional thinking is no. A few years ago, scientists found water ice at the bottom of craters at the poles where sunlight never touches them. Estimates from Lunar Prospector was a cup of water over an area the size of a football field. That's hardly worth it. LCROSS impacted the most concentrated deposit of water that Lunar Prospector could find. Ok, I guess 2009 is a little more than a few years ago. LCROSS found more water than expected, but still low concentration. In the 1980s John Wickman proposed "Lunar Soil Propellant". That's powdered aluminum and liquid oxygen as a bipropellant. The powdered aluminum would be blown into the rocket combustion chamber with nitrogen gas. This requires smelting regolith, forming aluminum and oxygen. The problem is the Moon doesn't have any nitrogen. Well, some nitrogen compounds in those same polar craters, but even less than water ice. So, is there propellant on the Moon? Yes/no? If yes, then how much? My thinking when LCROSS data was published is the little water that does exist should be reserved for life support and industry for future Lunar settlements. Something that doesn't consume water, but recycles it. Whether a chemical/mechanical life support system or greenhouse, water is recycled. Smelting anorthite from regolith for aluminum requires water, but that's recycled. Smelting ilmenite for titanium also requires water. The reason I ask is anything in space requires propellant. The most convenient source to fill a propellant depot in Earth orbit would be the Moon. Nature is often not convenient. So convince me... is there propellant on the Moon, where and how much?
A couple answers so far. Non-committal. They're holding that discussion themselves. Second person pointed out you need solar panels to "splice aluminum oxide". I think he meant to split aluminum oxide; we'll attribute that to autocorrect.
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I have heard discussion of aluminium/LOX being used as propellant before. I believe in hybrid rockets. But making it requires electrolysis of bauxite or anorthite in a flux. And it consumes carbon electrodes in the process and requires around 20kWh of electric power per kg Al.
Silane is an option, but it wouldn't be easy to source purified silicon. And hydrogen would have to be sourced from Earth. It is present in concentration 100ppm in lunar regolith. It is drier than the Sahara. Carbon is present in lunar regolith at concentration about 100g/m3 from memory. Given that the Starship runs on methane, they may need to import it from Earth. Oxygen can be made by reducing iron oxide in ilmenite. Iron is energetically the easiest oxide to reduce. But it is available in high concentration only in the mare. Ethane may be easier to store if we are importing it from Earth.
Last edited by Calliban (2022-04-10 14:33:53)
"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."
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I presented a paper at the Mars Society convention in Chicago in 2004 about aluminum. I showed how you could smelt anothite by reversing the pH of the Bayor process. That's used for bauxite. After the convention I discovered a company in Sweden was already doing it. I reinvented the wheel. At least it works.
Part of my presentation was to recycle carbon. At least that part was new. Carbon anodes will combine with oxygen from aluminum oxide, forming CO2. Use RWGS to combine CO2 with H2 over a catalyst to carbon soot and H2O. Split water with electrolysis, recycle H2. Byproduct is O2. Soot is piled on top of the carbon anodes where it's heated by aluminum electrolysis. The soot is pressed. The heat and pressure turns soot into graphite. It's poor graphite, but only needs to hold itself together long enough to be consumed. This is a modification of Soderberg anodes.
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The US/Canada/Mexico Zoom is in session. RobertDyck and kbd512 are engaged in saving the world as usual.
kbd512 spent a few minutes describing his conversations with several of the folks he met at the North Houston chapter meeting yesterday.
As a note, the regular meeting US/Canada/Mexico is (apparently) starting at Midnight UTC.
(th)
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Was hoping to discuss the Large Ship, but didn't get to it. Tom joined late, and James cut us off early.
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Big ship propulsion talk went very well at North Houston NSS section. We had a good time, talk was well-received, and discussions went for 2 hours after meeting. Long trip, but a good one. The only significant question was why I did not look at propellants from the moon to supplement or replace propellants sent u from Earth. I guess I'd better starting thinking about how I might figure doing that.
GW
Last edited by GW Johnson (2022-04-11 09:18:40)
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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The Sunday NewMars Zooms are coming up.
I am willing to host the European Zoom. I'm willing to open a session for as few as one person.
If there is interest, put in a bid before midnight Saturday.
The regular US/Canada/Mexico Zoom is hosted by kbd512, and it will start at Midnight UTC.
I'm planning to join at the usual time of 1 AM UTC Monday.
In a recent Zoom, the need for a PERT chart was identified.
https://lucid.app/pricing/lucidchart#/p … coreBundle
This commercial product has a free trial offer ... We can have up to three charts and use of up to 100 symbols.
The Large Ship project is on hold at the moment, due to discovery of a variety of issues.
One issue appears to be the lack of a PERT chart.
(th)
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Re post 294: I have it mostly figured out how I will do the propellant-from-the-moon thing. It will take a custom spreadsheet, similar to the one I did the space tug thing, but a bit different.
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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The Large Ship project is on hold at the moment, due to discovery of a variety of issues.
The big issue is tahanson43206 (Tom) insisted on contacting manufacturers to fabricate sections of hull. I pointed out we don't have any money. You will lose credibility immediately if you ask a commercial company to do work for you when you have no money.
There is no reason for this project to be on hold. We have to start with reality. That includes ways to reduce cost, to raise money, we need detailed engineering for the entire ship before any parts are fabricated, and we definitely cannot fabricate parts intended to be launched into space until our ride to space is ready. The whole project depends on SpaceX Starship; which isn't ready to carry commercial payloads, the first orbital test flight hasn't happened yet, and the FAA hasn't even decided if they will allow Starship to launch from Boca Chica. Elon Musk has said he already has authorization to launch from LC39A in Florida, but the FAA has said he doesn't. That could be resolved amicably, but it could also get very very bad. So we're no where near ready to fabricate parts.
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For RobertDyck .... glad to hear you are planning to resume work.
I provided a link to a free PERT chart service, so I hope it looks like a good fit for Large Ship.
Without concrete steps toward a firmly defined goal, everything is just so much hot air.
Looking forward to your concrete plans, and for your specific plans to delegate responsibility.
This project would ultimately require thousands of people.
A leader of a project that size needs to be able to delegate responsibility.
(th)
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For GW Johnson ... thanks for working on the Lunar propellant supply problem.
I'm hoping you'll be able to go over it with the Zoom audience.
In another topic, Calliban suggested using the new Spin Launch system to toss propellant from the Moon's surface.
This could greatly reduce cost and complexity of a Lunar supply system, if it works.
(th)
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Doesn't matter whether you look at spin launch, mass drivers, or anything else, as long as you look at anything below escape speed, your effective elliptical transfer orbit has a periapsis speed equal to the launch speed, and a PERIAPSIS ALTITUDE EQUAL TO ZERO!
Your apoapsis speed and altitude depend upon what precisely your zero-altitude launch speed tangent to the surface actually was. Simple as that. But this DOES NOT AFFECT your periapsis speed and altitude!
If your periapsis altitude is ZERO, you WILL smack the surface at periapsis speed, precisely one orbital period after launch! There is NO WAY AROUND that outcome, other than an apoapsis "burn" of some kind, to raise your periapsis altitude! That's just basic orbital mechanics.
Most of these odd concepts for spin launch, or light gas gun launch, or mass drivers, or pretty much anything but a simple rocket, require the payload to endure 100's, to 1000's, to 10,000's of gees. That puts VERY severe limits on what will survive the launch, with which to make that apoapsis "burn" that keeps you from smacking the surface again, in only one elliptical orbit period.
For solid propellants, I do know of some designs capable of surviving 1000's to 10,000's of launch gees, but these notions are quite restricted in what you can really do. I know of NOTHING in the liquid propellants that can survive that kind of abuse.
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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