On Thursday, October 20, 2022 at 1:45:26 PM UTC-5, pete...@gmail.com wrote:
> On Thursday, October 20, 2022 at 2:25:16 PM UTC-4, Lynn McGuire wrote:
> > On 10/19/2022 10:31 PM, peterw...@hotmail.com wrote:
> > > On Wednesday, October 19, 2022 at 1:03:04 AM UTC-5, peterw...@hotmail..com wrote:
> > >> On Tuesday, October 18, 2022 at 9:08:29 PM UTC-5, Lynn McGuire wrote:
> > >>> On 10/18/2022 2:52 PM, Lynn McGuire wrote:
> > >>>> "Artemis: A Novel" by Andy Weir
> > >>>> https://www.amazon.com/Artemis-Novel-Andy-Weir/dp/0553448145/
> > >>>>
> > >>>> A standalone science fiction book, no sequel or prequel that I know of.
> > >>>> I read the well printed and well bound trade paperback published by
> > >>>> Ballantine Books in 2018 that I bought new on Amazon. Hopefully there
> > >>>> will be a sequel some day.
> > >>>>
> > >>>> If you are looking for a hard science book, your book is here. The only
> > >>>> thing that I had a problem with is the low pressure 100% pure oxygen
> > >>>> atmosphere of the 2,000 person lunar colony, Artemis. I have a problem
> > >>>> with that but getting it to work might be doable, I just don't know.
> > >>>> Andy Weir actually wrote an article about the economics of a lunar
> > >>>> colony: "'The Martian' author Andy Weir solved moon economics to make
> > >>>> his new book 'Artemis' believable"
> > >>>>
> > >>>> https://www.businessinsider.com/andy-weir-artemis-moon-city-economics-the-martian-2017-11
> > >>>>
> > >>>> Jasmine Bashara moved to Artemis with her father from Saudi Arabia when
> > >>>> she was six years old, the legal minimum age. She grew up in Artemis
> > >>>> and is constantly on the edge of being evicted. She has a good heart
> > >>>> but is always looking for the easy way to get things accomplished. So
> > >>>> she lives on the shady side of Artemis and smuggles things in to make
> > >>>> extra cash. And her customers know that she can get almost anything for
> > >>>> them.
> > >>>>
> > >>>> The book is solid, I stayed up until 4 am last night reading it. I do
> > >>>> not understand why so many people do not like the book on Amazon. And
> > >>>> it makes me more than ever want to take a two week or four week trip to
> > >>>> the Moon. Once, a colony is established.
> > >>>>
> > >>>> My rating: 5 out of 5 stars
> > >>>> Amazon rating: 4.2 out of 5 stars (13,729 reviews)
> > >>>>
> > >>>> Lynn
> > >>> From a friend of mine: "Nitrogen is in short supply on the moon, and
> > >>> any recovered through mining would be reserved for growing plants. There
> > >>> are three nitrogen-free gas mixtures used for deep sea diving that do
> > >>> not contain nitrogen, but rely on helium, helium/hydrogen, or hydrogen
> > >>> to dilute the oxygen. I’,m not sure if any research has been done on use
> > >>> at sub-atmospheric pressures."
> > >>>
> > >>> "Helium and hydrogen have booth been found in lunar soils, but helium
> > >>> would be a poor candidate due to it’s ability to exfiltrate through the
> > >>> tiniest hole and through many materials. Hydrogen sounds like something
> > >>> the Soviets would have tried."
> > >>>
> > >>> So, 5 psia of pure O2 for a lunar colony is reasonable as a general
> > >>> atmosphere. I would have never thought so. The author does talk
> > >>> extensively about limiting usage of fire causing materials and many fire
> > >>> resistant / air blowout cubbyholes throughout the five domes.
> > >>> Incidentally, the lunar domes are half buried aluminum spheres many
> > >>> hundreds of meters in diameter with a double wall of six cm of aluminum
> > >>> each.
> > >>>
> > >> According to this NASA history, the Apollo spacecraft used a 5 psi oxygen
> > >> atmosphere in flight, so there is a good deal of practical experience with it:
> > >>
> > >> https://history.nasa.gov/SP-350/toc.html
> > >>
> > >> Quoting from an article from the National Air and Space Museum website,
> > >> written by senior curator Michael Neufeld, about the Gemini VI mission,
> > >> "To save weight, Mercury, Gemini, and Apollo spacecraft were designed to
> > >> operate at a cabin pressure of 5.5 lbs. per square inch of pure oxygen in space."
> > >> Any of these spacecraft would ascend through the perceptible atmosphere in
> > >> minutes, so the cabin pressure was rapidly bled down to maintain a 5 psi
> > >> pressure differential between inside and outside. If the crew were breathing
> > >> normal air at launch the drop in pressure could have caused decompression
> > >> sickness (commonly called the bends) as nitrogen gas came out of solution
> > >> in their blood and tissues. To prevent this, throughout the Mercury and Gemini
> > >> programs, at launch the cabin atmosphere was 100 percent oxygen, and the
> > >> crew were breathing pure oxygen long enough (several hours) to purge all
> > >> dissolved nitrogen from their bodies.
> > >>
> > >> After the Apollo One fire which killed three astronauts during a training
> > >> exercise this procedure was modified in a compromise between dangers..
> > >> Preflight atmosphere was changed to 60 percent oxygen and forty percent
> > >> nitrogen. The astronauts would breath 100 percent oxygen in their space
> > >> suits, sealed off from the cabin atmosphere, and would not remove their
> > >> helmets until cabin pressure was down to 5 psi. 60 percent oxygen was
> > >> much less of a fire risk than 100 percent oxygen, and was the lowest
> > >> percentage that would ensure that the cabin atmosphere would always
> > >> have a partial pressure of oxygen high enough to support human
> > >> consciousness. Astronauts would purge nitrogen as before.
> > >>
> > >> From Wikipedia:
> > >>
> > >> "The cabin atmosphere at launch was adjusted to 60% oxygen and
> > >> 40% nitrogen at sea-level pressure: 14.7 psi (101 kPa). During ascent
> > >> the cabin rapidly vented down to 5 psi (34 kPa), releasing approximately
> > >> 2/3 of the gas originally present at launch. The vent then closed and the
> > >> environmental control system maintained a nominal cabin pressure of
> > >> 5 psi (34 kPa) as the spacecraft continued into vacuum. The cabin was
> > >> then very slowly purged (vented to space and simultaneously replaced
> > >> with 100% oxygen), so the nitrogen concentration gradually fell off to zero
> > >> over the next day. Although the new cabin launch atmosphere was
> > >> significantly safer than 100% oxygen, it still contained almost three times
> > >> the amount of oxygen present in ordinary sea level air (20.9% oxygen).
> > >> This was necessary to ensure a sufficient partial pressure of oxygen
> > >> when the astronauts removed their helmets after reaching orbit.
> > >> (60% of five psi is three psi, compared to 60% of 14.7 psi (101 kPa)
> > >> which is 8.8 psi (61 kPa) at launch, and 20.9% of 14.7 psi (101 kPa)
> > >> which is 3.07 psi (21.2 kPa) in sea-level air.)[64]
> > >>
> > > Skylab was the first American space station, launched in 1973 using a
> > > Saturn 5 rocket left over from the Apollo program. The first two stages
> > > of the Saturn 5 could achieve low Earth orbit with a sufficiently small
> > > payload. In this case the payload was the essentially empty Saturn third
> > > stage with a pressurized crew compartment built into the hydrogen tank,
> > > a large solar cell array, a solar observatory, and other equipment.
> > >
> > > Skylab was pressurized to 5 psi with 70 percent oxygen and 30 percent
> > > nitrogen, for an oxygen partial pressure of 3.5 psi, similar to sea level
> > > on Earth. I have not heard of any problems resulting from this choice..
> > >
> > > Peter Wezeman
> > > anti-social Darwinist
> > It does seem to me that would be safer but, if there is ZERO nitrogen
> > available on the moon, would not be a good choice.
> >
> > And I still like that they do not have to prebreathe to go on a space
> > walk with pure O2.
> I'll just throw in that breathing 100% oxygen at sea level pressures will
> cause serious medical problems after 12 hours or so, and can be deadly
> in a day or two.
>
Looking at Mayo Clinic and other on line information on hyperbaric oxygen
therapy I see that sessions are limited to no more than three atmospheres
oxygen pressure for no more than two hours duration. Under these conditions
oxygen toxicity is a rare complication, one in 2,000 to 3,000 treatments.

Peter Wezeman
anti-social Darwinist