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On the moon, a spin launch or mass driver would be used for launching payloads to escape velocity. There is no point trying to put anything into orbit this way. The payloads are likely to be compressed slugs of regolith, contained within a bag of some kind. The target would be a receiver facility with some kind of bag at one of the Lagrangian points, probably L2 as TH indicated earlier. Ideally, the payload would be launched with just the right velocity to arrive at the L2 point within a circular error probability no greater than a few tens of metres, with as close to zero velocity as possible.
On Earth, I think the sensible use of any device of that kind is to boost a rocket projectile to a high enough speed to eliminate the need for a lower stage. The lower stage is much larger in mass than the upper stage and eliminating it should remove a substantial capital and operating cost, along with the need for recovery ships and refurbishment. For Starship, a linear accelerator, such as a rocket sled, imparting an initial velocity of 1-3km/s, may be sufficient to achieve this goal. The rocket sled could be propelled by a pressure fed rocket, a ramjet, maybe even compressed air. The track would have a high capital cost. For the investment to be worthwhile, the launch rate must be quite high. Assuming a exit velocity of 1km/s and a peak acceleration of 10g, track length would be 5km. For a 2km/s exit velocity, track length would be 20km. So capital cost is proportional to the square of takeoff speed.
Spin Launch may come into its own on the moon and other low Ve bodies, due to its relatively compact arrangement. Rocket sleds cannot use wheels because at speeds of kilometres per second, centrifugal force would fragment them. I suspect that spin launch from Earth will face the same problems.
Last edited by Calliban (2022-04-16 16:06:31)
"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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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.
I never said I intended to halt work. Our dispute happened when you insisted we contact manufacturers to fabricate parts. But we have no money, so we can't do that. Furthermore, the part you want fabricated is one of the parts that I said would be fabricated in space. We won't fabricate on Earth. Developing a prototype on Earth for the space-based operation is reasonable, but we can't just fabricate on Earth. And no, fabricating in space does not increase cost. The whole point of fabricating in space is to reduce cost.
Let's take a step back. One idea is a high-efficiency photovoltaic cell. That is the technical term for a solar cell. I read an article in the journal Science from year 2000, and the article includes work done at U.C. Berkeley materials lab which fabricated a prototype. It works. I want to mass-produce these for use on Earth. A house built with a roof that doesn't just have some solar panels attached, the roof *IS* the solar array. With integrated photovoltaic and solar thermal to pre-heat water for the hot water tank. One reason is to ensure photovoltaic cells do not overheat. That's how they fail. With solar roof, helical windmills in the back yard, geothermal heat pump, batteries in the basement, well insulated, and heat exchanger for home ventilation, the result is a house designed for southern Canada or northern US that is 100% energy independent during worst case weather. During the other 51 weeks per year, it produces excess electricity that it sells to the power grid. So the power utility never sends the homeowner a bill, instead a cheque very month. A larger cheque in summer, smaller in winter, medium in spring/fall. Of course it could be paid by direct deposit with emailed statement, so no snail-mail. These houses would be sized so starting with the first month a homeowner moves in, the total of mortgage plus utilities less cheque from the electric utility would be less than a traditional house: mortgage plus utilities. Purchase price would be a little higher, but as I just said, total monthly cost will be less, even if it's only $1 less. The trick to making this work is to ensure the municipality doesn't charge extra property tax. I believe these houses would be very profitable. The profits from these houses would subsidize our Large Ship project.
A few other projects:
kit to convert used cars to battery electric. Specifically target models of car used as host for a body kit. Customers willing to install a body kit will be willing to do other work, such as install our kit.
hearing aid that uses direct nerve induction to allow the completely nerve deaf to hear
thermal depolymerization plant that converts used plastic into oil & natural gas, but do not sell that as fuel, instead convert to new plastic. Sell bulk plastic as nurdles.
recycling carbon anode for aluminum smelting. Only emission is pure O2, no carbon emission. Eliminates coke and pitch that smelters must currently purchase, so saves them money. O2 can be sold as medical gas, so a byproduct to generate a little additional revenue. (Originally developed for Mars, but can be used on Earth.)
mining asteroid for steel, but byproduct is precious metals. Export precious metals to Earth for sale to raise money. Gold/silver alloy can be refined on Earth, but better use would be to sell as "asteroid gold" (10 to 18 carat) for designer jewellery.
aluminum oxynitride manufactured and sold on Earth as storefront windows. Designed to withstand a half-brick or baseball-size chunk of concrete, or baseball-size river stone thrown as hard as a man can throw it. Designed to prevent broken windows from break-and-enter or riots. Expect price to be 3 times that of the best tempered glass storefront windows. Patent on aluminum oxynitride expired more than a decade ago.
Can you think of other ways of earning money?
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This evening's US/Canada/Mexico Zoom will be hosted by kbd512.
The starting time is Midnight UTC.
If anyone who does not already have the access codes would like to attend, please put a request in this topic.
GW Johnson has prepared a document for discussion.
http://newmars.com/forums/viewtopic.php … 77#p193777
This is a preliminary study, not intended for publication.
The subject is sourcing of propellant from the Moon, for flights by Large Ship to and from Mars.
I understand the energy economics are compared to Earth sourcing and to Mars sourcing.
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Today is Zoom day for NewMars forum.
No one reserved for the European Zoom, (tentatively) scheduled for 19:00 London time. However, the entire week ahead is available to put in a reservation for next Sunday.
The US/Canada/Mexico Zoom is scheduled for Midnight UTC, with host kbd512.
I'm looking forward to joining at 1 AM Monday UTC.
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Discussing large ship funding if anyone else besides Keith wishes to join.
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For kbd512 re Zoom
Thanks (again) for hosting the US/Canada/Mexico Zoom at Midnight UTC
I am delighted that a member of the North Houston chapter of NSS joined the Zoom, and i am hoping he will be successful in persuading more chapter members to join one or two of the weekly meetings. The chapter has a fairly high energy level, with a number of activities under way. I'm hoping we can catch a wave with Large Ship and Space Tug as our opening gambits.
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Today is Zoom day for NewMars.
kbd512 is hosting the US/Canada/Mexico session starting at Midnight UTC.
I'm planning to join at 1 AM UTC as usual.
Last week a member of the North Houston chapter of the National Space Society joined to discuss a possibility of preparing a presentation on financing a large project, such as Large Ship or Space Tug.
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Today is Zoom Day for NewMars
kbd512 is hosting the US/Canada/Mexico session starting at Midnight UTC.
I'm planning to join at 1 AM UTC as usual.
***
We offer a Zoom time for European members. If anyone is interested in taking advantage of the offer, it is help to make a request in this topic prior to Sunday. A request that comes in today (Sunday) will be scheduled for next week.
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tahanson43206,
There's probably not much point in having Zoom calls if we're going to be the only ones in the calls.
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The Night Owl Zoom is in session .... the starting topic is Electric Drive agriculture
(th)
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Meeting was ended by host, apparently, so James had to use the Zoom.
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Hi! Yes, I lost track of time! Enjoyed the discussion ...
Will check the link you suggested.
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For SpaceNut .... let's talk about Zoom ...
Zoom sessions were not your idea, but you have been supportive.
We seem to have run through a cycle of enthusiasm followed by a lull ...
The Midnight UTC session seems to have run out of steam.
kbd512 has been kind enough to keep it going, even without participants, but it is unfair to expect any volunteer to keep a service going if no one participates.
We have the rest of this week to think about what (if anything) we might want to do.
I would observe that while we have offered the "European" Zoom for our European members, none have chosen to take us up on the offer.
My schedule is such that I can keep attending at 1 AM UTC, and the session yesterday shows that even when only two participants are in a Zoom, the time can be used productively.
A possible outcome of last Sunday's Zoom ** may ** be a vision of a Concentrated Solar Power plant to make diesel fuel.
There is a ** lot ** to like about this proposal...
First and foremost, it puts kbd512 in the driver's seat making diesel fuel, which is far and away his favorite "fossil" fuel.
Second and Vital, it puts the anti-nuclear forces in Texas on the back foot. Those forces appear to be strong in Texas, hard as that might be to believe.
Third and ** really significant **, everything kbd512 discussed last night is literally "ancient" technology...
The challenge before this forum is how to create social momentum to achieve the realization of this quite sensible vision.
SpaceNut ... your instinct is to pour cold water on any new idea, and then to see if it survives the mushing.
You might as well take this opportunity to flood the idea early, before it sprouts and becomes a weed.
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This week we have a meeting of the North Houston chapter of the NSS on Saturday.
Because attendance of the Midnight UTC Zoom session has fallen off in recent weeks, I'd like to suggest asking the NSS chapter leadership to promote the NewMars Zoom as a convenient place to work on projects.
The ** really ** big project we've already introduced is the Large Ship.
The ** next ** big project we introduced was the Space Tug, and all the infrastructure that goes with it
Today, we have an opportunity to introduce a "decent sized" project to make diesel fuel from CO2 and hydrogen using sunlight.
Tomorrow's Zoom session would be (could be) a convenient meeting place to advance those or other projects.
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Today is Zoom day at NewMars....
Attendance at the Midnight UTC Zoom is down.
I'm planning to join at 1 AM as usual.
If any of our European members would like to set up a Zoom next Sunday, please post a request in this topic.
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tahanson43206,
I don't have "favorites". Diesel fuel provides energy for most industrial application engines, such as cargo ships, trains, trucks of every description, construction equipment, agricultural equipment, and backup generators. There are no like-kind replacements ready to take over, and nearly all existing infrastructure that uses diesel powered machinery cannot be easily substituted or replaced by new technology. I don't view gasoline for personal transportation as any less important to our modern lifestyles and economies, I merely note that without diesel powered machines to supply the vast quantities of food and consumer products that we enjoy today, large numbers of people starve to death.
What I want to do is to come to a practical compromise between environmentalists and economists, until such time as "electric everything" is truly ready for prime time. It took 100+ years to create our modern world using fossil fuel powered machines. It's unreasonable to think it will take less than 100 years to replace all of that with electrically powered machines.
It is reasonable to think that we can gradually reduce but not entirely eliminate our CO2 emissions over the next 100 years using the same power sources that created the problem in the first place, because the basic math of resource availability and energy consumption happens to work out. I'm not asking for something that requires very specific natural resources (Lithium, Copper, rare Earth metals) that don't exist in the required quantities, technology that doesn't exist (drastically more efficient photovoltaics or batteries that store equivalent energy as fossil fuels on a per unit weight and volume basis), or efficiency improvements (gravimetric battery energy density or photovoltaic photon conversion efficiency) that are nowhere to be found.
The difference between this power source and extraction is that we are now in the business of recycling ocean and atmospheric CO2. We dumped enough of the stuff into the environment to be able to economically recycle it without invoking technology that doesn't exist.
We're running a combination of concentrators, chemical reactors, and reverse fuel cells that supply liquid hyrocarbon fuels, which is most of what we use, in a matter that draws down atmospheric CO2 over time, at the same pace it was added to the atmosphere.
I understand the wisdom of the following statement (from Neuro-Linguistic Programming):
The problem is not the solution, and the solution is not the answer.
What does that actually mean in this context?
1. The problem is excess CO2 warming up the planet, however gradually.
2. The solution we're presented with is "just stop emitting CO2".
3. The issue with the proposed solution is that we don't have a replacement technology that can actually eliminate CO2 emissions.
Therefore, the solution will not be so simple as "just stop burning things that produce CO2".
We need a pragmatic "bridge solution" that both provides the energy we require and removes excess CO2 at the same time.
How do we do that?
By using the efficiency of solar thermal power to produce liquid hydrocarbon fuels before we run out, and then have no energy to continue our path towards electrification and no energy to merely feed everyone. We need a step-wise approach to solving the global warming problem we created.
The first step is to drastically reduce extraction and absurd over-consumption in the name of "transformational new technology" that is only transforming our civilization into a state of energy poverty. We cannot do that by switching to using technologies that require even more over-consumption and ever-greater energy inputs, which can only occur over time using surpluses not already required for other purposes. Drastic expansions of the electric grid are not sustainable at the present time, using existing Aluminum / Copper / rare Earth metal extraction rates.
The second step is to start recycling CO2 into new fuels and new structural fabrication materials. CO2 surpluses will not be dumped into the ground at fantastic energy cost. They will be transformed into Carbon Fiber or CNT or other Carbon-based products like plastics and rubbers, which are exceptionally useful and required no matter what kind of energy source is ultimately used.
The third step is to gradually replace more consumptive combustion engines with fuel cells, which begins the transition to electrification in a way that we can actually sustain. Over time, as we accumulate the required materials, we will fully transition over to using batteries for energy storage, but there's no sense trying to do that at an unsustainable rate that quickly depletes the existing Lithium natural resource stocks with no successor or complimentary technologies ready to make up for the shortage, or no new supply of Lithium so that we can continue using Lithium-ion.
Although nuclear technologies at least have the potential to make this endeavor easier to accomplish, I'm unwilling to continue fighting with the people who oppose nuclear, because staving off mass starvation and death is higher on my agenda than absolutely minimizing material consumption as compared to solar thermal solutions. Apart from steel / concrete / glass consumption, solar thermal has all the other benefits of nuclear thermal when thermal power storage is taken into account, with none of the long term waste storage drawbacks.
Last edited by kbd512 (2022-05-15 14:40:02)
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All liquid synthetic fuels start with hydrogen in one way or another. Turning CO2 into methanol requures 3 mols H2 for every mol of CO2. Ammonia requires 3 mols of H2 for every 2 mols of ammonia produced. If you want to produce synthetic liquid fuels from coal, tar sands or kerogen, then you need hydrogen to crack those long carbon chains into shorter carbon chains. If you want synthetic fuels that are as cheap as diesel was back in the good ol bad ol days, before 2007, then cheap hydrogen is the key.
But producing synthetic diesel cheaply enough to lift everyone out of poverty is a tall order. This link shows historical retail diesel prices in the US.
https://fred.stlouisfed.org/series/GASDESM
Diesel prices rose above $1.5/gallon back in 2004 and have never been so cheap ever since. It was rising energy prices that drove inflation leading up to 2007. It was that and the interest rate rises that were intended to combat inflation that caused the great financial crisis. Over indebted people suddenly found themselves squeezed from both ends. So we can set $1.5/gallon as a very approximate threshold beyond which economic growth becomes difficult. That is about 40 cents per litre.
One litre of diesel contains about 10kWh of chemical energy. So it implies a cost no greater than 4 cents to produce each kWh of diesel. That includes the energy needed to make the hydrogen and the capital and maintenance cost of all the infrastructure. This is why it makes sense to begin with some form of fixed carbon rather than pure CO2. If you begin with some form of biomass, then the energy cost of producing a litre of diesel is reduced by a factor of 3 compared to having to reduce CO2. Even so, it is a tall order being able to produce synthetic fuels as cheaply as diesel. Even $5/gallon would be a challenge.
The production of synthetic diesel shouod be combined with investments to improve the economic value extracted from each unit of diesel. This means extending rail and water based transportation wherever possible and implimenting fuel efficiency measures. The further we can go with improving fuel efficiency, the higher the sustainable price of diesel can be without crashing the economy.
Last edited by Calliban (2022-05-15 16:24:52)
"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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Calliban,
The US Federal Government has blown mad money on all manner of idiotic and wasteful endeavors. If necessary, we will force them to do everyone a solid by underwriting the expenses for this project, and then run it the same way we run our government arsenals. Even the Derpistanis we presently have in power can be convinced if you threaten to remove them from power.
We're going to apply enough horsepower in the form of photons to solve this problem, because it needs to be solved. If there are ways to finesse the energy requirements to lower values, then so long as that doesn't represent another huge energy / technology / capital sink, we'll do it. Otherwise, we'll use brute force, because we can.
Everyone else is hoping for a miracle breakthrough or dithering while the problem continues to worsen. We don't need miracles, and no miracles appear to be forthcoming anyhow. Simple engineering principles, applied at the appropriate scale and using resources we have rather than resources we wished we had, will solve this problem, even though the overall solution is still fantastically complex.
I've already looked at every manner of biomass solution. They all fall woefully short of the output side unless deployed at scales that become unmanageable, and they're still dependent upon factors outside of our control.
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For kbd512 and Calliban....
This post is NOT criticism ... far from it! Your two posts are important reading from several points of view....
However, they belong somewhere else ... The Zoom Collaboration is ** exclusively ** for the purpose of encouraging and facilitating Zoom meetings, and specifically, for the purpose of accomplishing something in the Real Universe.
Learned posts (which these most certainly ARE) are best placed in some more appropriate topic!
There is no need to remove the posts ... they add substance.
However, as you continue the conversation, please find a more suitable topic.
In the case of the post by kbd512, #316, I ** think ** I am reading a forward to a book about how to save the world.
The Zoom Collaboration topic is offered to encourage individual human beings to find it worth their while to join one (or hopefully more) Zoom events, to make decisions for the near term future, and to receive feedback and encouragement as they progress with a course of action.
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This evening's Zoom meeting was productive (from my point of view, for sure!)...
The focus was on the technologies needed to make gasoline or diesel from CO2 and Hydrogen, in the context of a business that would serve one large gas burning power plant by accepting the discharge from the plant as input to the downstream enterprise.
I will attempt to edit my notes in the near future, so they can be reviewed by kbd512 (and whoever else may wish to comment).
For SpaceNut ... do we have a topic set up to plan activity that makes gasoline / diesel from CO2 and Hydrogen?
We have so many topics at this point, I'm not sure which is best?
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Today is Zoom day for NewMars.
kbd512 is host for the Midnight UTC session.
I'll be joining for the Night Owl at 1 AM UTC.
Our European members are welcome to request a session at 19:00 UTC, next week.
Anyone interested in the early Zoom has a full week to post a request here.
I am interested in seeing solid progress happen during Zoom sessions.
We have multiple initiatives floating in the conceptual space over NewMars.
Any one of these could make the transition from discussion to action.
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Today is Zoom day for NewMars ...
We have no requests for the European Zoom.
We have no requests for the Midnight UTC Zoom hosted by kbd512.
I'm planning to join kbd512 for the NightOwl Zoom at 1 AM UTC.
If anyone not already familiar with these Zoom sessions would like to participate, please add a post here.
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Since we seem to have no takers for our weekly meeting, I'm going to join at 1AM UTC as well.
If someone wants to join earlier, please post something in this thread and I'll start the Zoom session.
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tahanson43206,
If you read these articles, then you should be able to determine that I am not "speculating" about how higher partial pressures of Oxygen in a higher or lower total pressure environment will eventually become "toxic" in various ways to the human body:
From the article:
The earliest measurements of pulmonary function in space flight date back to the early 1970s during the Skylab series of flights. The principal measurement was that of vital capacity. Data from an 84-day period in zero gravity on Skylab 4 showed about 10% reduction in vital capacity compared with before and after flight in the three crew members.11 However, because of the physical structure of the Skylab space station (it was built in the fuel tank of a rocket upper stage), the absolute cabin pressure was only 258 mmHg, and in order to avoid severe hypoxia, the fraction of inspired oxygen (Fio2) was 0.70 (70%). Ground chamber tests with a comparable atmosphere also showed a similar reduction in vital capacity, likely through the development of some atelectasis.
Just because some people never did the required reading, or were never curious enough to know to begin with, doesn't mean that's applicable to everyone.
Nobody has used the exact atmospheric composition that RobertDyck has proposed using, but that doesn't mean we can't draw useful inferences from our Skylab missions and NASA's ground hyperbaric chamber testing that preceded the Skylab missions.
Here's what I think will happen, and what most likely will happen over time:
Over a significantly longer period of time, those living at 8psi with a 40% ppO2 will also develop atelectasis. The onset and severity of the symptoms (reduction in pulmonary capacity) will not be as fast or severe, but it will still happen.
Why do I think that?
1. Prior testing done for the Skylab missions, on the ground and at 1g
2. The actual mission data which mirrored ground testing, completed in micro-gravity
3. What we know about the human body's tolerance for abnormal life support conditions (there's no hard line between what's tolerable and what's intolerable, similar to poisoning and radiation doses- all we really know is that "more" of certain things is not equal to "better", much less equal to "desirable")
I'm willing to take that risk, because the risk of aerobullosis is even greater for people doing frequent EVA activities, and aerobullosis (aka, "the bends") can be immediately fatal.
Everything is a trade-off in engineering. Lower pressure environments are another form of trade-off. In return, we gain zero pre-breathe EVA capabilities that present little to no risk of "the bends" (which is an exceptionally serious and possibly immediately fatal medical condition). Gradual onset of atelectasis is a less serious medical condition, but over time it will become a problem.
I will repeat myself one final time here:
Human beings are best adapted to operate at 1g (9.81m/s^2) and 14.7psi of atmospheric pressure, with about 21% O2 and about 78% N2.
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For kbd512 re RobertDyck's Atmosphere prescription...
Thank you for your detailed follow up on your (quite surprising to me) revelation that you have serious doubts about the long term sufficiency of the atmosphere prescription recommended by RobertDyck.
Your example of experience on Skylab is instructive, to show what NOT to do.
In a quick search of the internet (with the assistance of Google) I confirmed that people have lived on Earth for extended periods at 500 Mg. And ** that ** is at normal oxygen for that altitude. One citation gave forty years as the time period for a mining village in Peru.
The experience of that set of people would surely be instructive, just as the experience of Skylab was instructive on what NOT to do.
In any case, your NOW PUBLIC caution is available for everyone to study.
It is clearly indicated for someone to set up a Mars Simulation at the Peru mining village, and to supply the RobertDyck atmosphere prescription for an extended period. The cost would be modest, compared to flights to Mars, and the scientific study should be valuable.
Your concession that the atmosphere prescription offered by RobertDyck might be useful for preventing bends after EVA is encouraging but not conclusive.
The gentleman you spoke to might not be aware the atmosphere he is publishing for his space station is too high.
It is entirely possible that if the reasons for the RobertDyck atmosphere prescription are offered to him, he might appreciate the savings that will result by the reduced pressure on the interior walls of his space station, and the distinct advantage that his customer/guests can go for space walks conveniently and safely.
What is more, if the budget available is sufficient, this gent might be willing to secure funding for an experimental scientific station in Peru (or a comparable site in the US if there is one). Having searched previously, I am pretty sure the US has no mountains tall enough to deliver 500 Mb as the base pressure.
Your concern about possible negative impact of 500 Mb pressure on human beings over long periods deserves to be given the attention it deserves.
Thanks again for taking the time to explain your concern in the first place, and then to follow up with a detailed explanation of recorded experience of what NOT to do.
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