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#1 2022-01-02 08:29:59

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 16,760

Off Earth Habitat Atmosphere Prescription: 431 Rule of Thumb

For SpaceNut ... we had no topic for "atmosphere" and "habitat"

The purpose of this new topic is to provide a home for the work of GW Johnson on the optimum specification of atmosphere for Large Ship, Mars habitats, or any off-Earth location where humans may venture.

The Rule of Thumb that came out of the most recent work by GW Johnson is "431".

I hope that GW Johnson will post additional information in posts after this one.

My goal is to find an easy-to-remember set of numbers that every child can learn when preparing for EVA, or for management of the habitat.

Numerous other mnemonics were evaluated, but this one has the advantage of:

Adequate oxygen for humans including mothers and children
Ability to support transfer to EVA suit without pre-breathing
Ability to support optimum EVA suit pressure for mobility and leak tolerance
Ability to prevent excessive fire danger due to optimum presence of inert gas in the mix

There are other advantages as well, and hopefully they will be included in subsequent posts to this topic.

This ** should ** become a standard associated with the Mars Society going forward.

(th)

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#2 2022-01-02 09:32:18

Mars_B4_Moon
Member
Registered: 2006-03-23
Posts: 8,903

Re: Off Earth Habitat Atmosphere Prescription: 431 Rule of Thumb

Maybe Kids if they go to Mars should be taught math, language, physics and chemistry from a young age

I think chemical cration of Atmosphere would be used as back up in case power fails or a break down rescue team would have chemicals on stand by. Submarine Air Modification and Atmosphere Monitoring & Air Purification is an interesting read, there is also the option to produce Oxygen by Chemical fires when Electrolysis fails, the self-sustaining chemical reaction burning a Candle that creates Oxygen so to speak like they have done on MIR and the ISS. On a sub constant monitoring or ventilation is important as toxins can build up in an area where people are sleeping or bunked together, a guy can have a full time job as an air monitor on a sub, other equipment on a ship or sub might leak gasses. The chemicals Potassium and lithium chlorate, and sodium, potassium and lithium perchlorates can be used in oxygen candles on a space colony. During a watch it might be seen that Oxygen is Low, a Can is Opened a Chemical Candle Put inside a safe fire proof area, Delta Class self oxidize combustible metal fires with phosphorus chlorate, releases oxygen by a very hot chemical reaction through a controlled chemical oxygen generator, Iron and Sodium Chlorate can be used and Potassium superoxide has been used by Russians or was used on early manned missions of the Soviet space program.  In cleaning pressurized CO2 gets scrubbed in a self sustaining cycle of pre-heated Monoethanolamine (MEA) the CO2 is taken out, fresh air comes out, there is rich fizzy amine and flat amine, inside a sealed system lean MEA is sprayed to take more CO2 out of the air,the chemical is boiled and compressed to the pressure needed to pump the gas outside. The model of Vika oxygen generator which has been used on spacecraft with lithium perchlorate releases 60% of its weight as oxygen LiClO4 → LiCl + 2 O2. https://chemiday.com/en/reaction/3-1-0-7088 also  , https://chemicalequationbalance.com/equ … O4/O2+LiCl it has also been used in under sea emergency for firefighters, and for mine rescue...these are also extreme 'fire hazzards' with very high levels of heat. We do not know the Pressure Deep inside a Lake of Titan or Deep inside the Moon of Europa but the Marianas Trench Challenger Deep sea pressure is 108.6 MPa, over one thousand times the standard atmospheric pressure at sea level. In the 90s NASA's Galileo mission revealed that Europa has a thin atmosphere composed mostly of molecular oxygen (O2) with surface pressure of Europa's atmosphere is 0.1 micro Pascals, or 10 ^ -minus12 times that of the Earth, there is a tenuous ionosphere an upper-atmospheric layer of charged particles.  NASA says that Europa's Deep Ocean under the ice ocean may contain twice as much water as all of Earth’s oceans combined https://solarsystem.nasa.gov/moons/jupi … /in-depth/

There has also been a discussion on more scifi fringe topics for Underwater cities on Europa or Titan or floating towns on Venus or some Venusian balloon ship concept. http://newmars.com/forums/viewtopic.php?id=7165 , http://newmars.com/forums/viewtopic.php?id=5729 ,  , http://newmars.com/forums/viewtopic.php?id=3662 , http://newmars.com/forums/viewtopic.php?id=5962 , http://newmars.com/forums/viewtopic.php?id=5962 , http://newmars.com/forums/viewtopic.php?id=5963 , http://newmars.com/forums/viewtopic.php?id=1870 , http://newmars.com/forums/viewtopic.php?id=7426 , http://newmars.com/forums/viewtopic.php?id=358 , http://newmars.com/forums/viewtopic.php?id=7423 Giant solar powered airship blimps is a thing.

How stations work Environmental Control and Life Support  http://science.howstuffworks.com/space-station2.htm Breathing Air Science https://science.nasa.gov/science-news/s … st13nov_1/. ESA closed loop system https://www.esa.int/Science_Exploration … oop_System NASA and Russian system Vozdukh  report 30 pages   https://web.archive.org/web/20110627061 … 216126.pdf solid lithium perchlorate https://web.archive.org/web/20111120223 … pport.html
NASA lesson
http://llis.nasa.gov/lesson/1143

There were very interesting discussion on Titan, Venus and Europa

Although the challenges of these Moons and Planets are different to what an Astronaut would face in trying to live on Mars.

Last edited by Mars_B4_Moon (2022-01-02 10:16:13)

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#3 2022-01-02 10:03:07

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 28,750

Re: Off Earth Habitat Atmosphere Prescription: 431 Rule of Thumb

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#4 2022-01-02 12:12:42

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 3,352

Re: Off Earth Habitat Atmosphere Prescription: 431 Rule of Thumb

Being able to EVA without pre-breathing is a huge logistical advantage.  Especially if we can develop an MCP suit that is quick and easy to put on and takeoff, with a pure O2 gas system.  It gets almost as easy as donning your boots and coat when going outside here on Earth.  You sit down for the evening and realise you left some vegetables outside.  The Martian night will obliterate them.  You want a suit that you can put on in 30 seconds and be back indoors within a few minutes.  That is the sort of flexibility that we want.  It makes living on Mars much easier if you can switch between habitat pressure and suit pressure quickly and easily.

Last edited by Calliban (2022-01-02 12:17:41)


"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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#5 2022-01-02 12:20:30

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 16,760

Re: Off Earth Habitat Atmosphere Prescription: 431 Rule of Thumb

I'd like to follow up on the post of Calliban (#4) by encouraging our newest member daGeck0, to continue working on an EVA suit.

For those readers who may not be familiar with the work of daGeck0, he set out to try to make a safety apparatus to keep the Covid virus at bay.  In the process, he found himself venturing into the arena of space flight.

The initial design for a breathing apparatus features a fish-bowl design.  There are those in the forum who prefer a helmet that flts closely to the head, for a variety of reasons.

However, a helmet is something that must be fitted to each wearer, and is NOT interchangeable.

A fishbowl helmet, on the other hand, is universal in accessibility.

I have seen (and can appreciate) the objection that a fishbowl helmet might crack if the wearer were to fall and allow the helmet to strike rocks or other hard objects.

My recommendation to the wearer of such a suit is to avoid falls, or to fall in such a way that the helmet is protected.

In any case, I would like to try to encourage daGeck0 to continue working on his concept, and to share his progress with the forum as time permits.

(th)

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#6 2022-01-04 12:05:16

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 16,760

Re: Off Earth Habitat Atmosphere Prescription: 431 Rule of Thumb

The quote below is from a tech newsletter that shows up here periodically ... I am posting in Atmosphere Prescription because sensors are going to be critical for life support for humans and all their living companions when they are away from Earth.

Learn how to choose a pressure sensor
<name of> Corporation

MEMS technology has helped create a wider range of pressure sensor style and performance options. With so many available pressure sensor models, it can get overwhelming trying to decide which features are needed to best meet your application requirements. <Corporation's> Pressure Sensor Selection Guide helps you evaluate your options by exploring key considerations to keep in mind when selecting a pressure sensor. Some of these factors include:

• Calibration — amplified or unamplified
• Accuracy requirements
• Resolution and response time

If anyone is interested in seeing the source material including links, just ask.

A detail I have not investigated is measurement of partial pressure.

GW Johnson has recommended a configuration of gases he remembers by the Rule of 431.

I do not know what that rule might be, but I ** do ** remember RobertDyck's formula 3-5-8 (3 PSI O2, 5 PSI inert, 8 PSI total).

If GW Johnson can provide a mnemonic suitable for a first grader, based upon the Rule of 431, I'll attempt to remember it.

In the mean time, it is my understanding that 3-5-8 is "good enough" for a youngster to use to set the controls for the family habitat when the folks are away.

(th)

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