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A ratio of 30 seems to be where we are for the "axial compressor" atmospheric pressure on the Martian surface averages 600 pascals (0.087 psi) means 18,000 pascals (2.61 psi) so its got to be compressed more.
Nice touch to couple the Stirling shaft for rotation.
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4-21-21 NASA’s Perseverance Mars Rover Extracts First Oxygen from Red Planet
o burn its fuel, a rocket must have more oxygen by weight. Getting four astronauts off the Martian surface on a future mission would require approximately 15,000 pounds (7 metric tons) of rocket fuel and 55,000 pounds (25 metric tons) of oxygen. In contrast, astronauts living and working on Mars would require far less oxygen to breathe. “The astronauts who spend a year on the surface will maybe use one metric ton between them,” Hecht said.
Hauling 25 metric tons of oxygen from Earth to Mars would be an arduous task. Transporting a one-ton oxygen converter – a larger, more powerful descendant of MOXIE that could produce those 25 tons – would be far more economical and practical.
Mars’ atmosphere is 96% carbon dioxide. MOXIE works by separating oxygen atoms from carbon dioxide molecules, which are made up of one carbon atom and two oxygen atoms. A waste product, carbon monoxide, is emitted into the Martian atmosphere.
The conversion process requires high levels of heat to reach a temperature of approximately 1,470 degrees Fahrenheit (800 Celsius). To accommodate this, the MOXIE unit is made with heat-tolerant materials. These include 3D-printed nickel alloy parts, which heat and cool the gases flowing through it, and a lightweight aerogel that helps hold in the heat. A thin gold coating on the outside of MOXIE reflects infrared heat, keeping it from radiating outward and potentially damaging other parts of Perseverance.
In this first operation, MOXIE’s oxygen production was quite modest – about 5 grams, equivalent to about 10 minutes worth of breathable oxygen for an astronaut. MOXIE is designed to generate up to 10 grams of oxygen per hour.
seems that the design is way off if all that was made is 5.4 grams of oxygen in one hour and if that is roughly 10 minutes of breathable air for a human being. so we need 6 of these operating 24/7 to even break even for requirement for a person.
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The link below is for a commercial CO2 electrolysis unit, producing CO and O2.
https://www.topsoe.com/processes/carbon-monoxide
I was considering the possibility of using compressed CO/O2 as a bipropellant combination for a pressure fed rocket sled on Mars. If we can do this, we can manufacture interplanetary ships on Mars surface and launch them in a way that would never be possible on Earth. The thin atmosphere would allow bulky objects to be launched by rocket sled without too much problem from air resistance. The dV required to get from Mars surface to LMO is about 4km/s. If the rocket sled can accelerate the payload to 2-3km/s, then a minimal upper stage or the ships own propulsion system, can provide the remainder of dV needed to reach orbital velocity.
On Mars, we could feed a solid oxide electrolysis cell with liquid CO2 at a feed pressure of 200 bar. The CO/O2 gas stream emerging from the electrolysis unit would then have sufficient discharge pressure to feed the propellant tanks directly, without compression.
The propellant tanks would need high strength to weight ratio to make use of compressed gas fuels and still retain sufficiently high mass ratio at a burn out velocity of 2.5km/s. A basalt fibre wound carbon steel tank looks promising.
Last edited by Calliban (2022-04-20 06:09:02)
"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 Calliban re #53
In the context of Mars, good ideas in one specialization can be helpful in others.
Your description of a CO/O2 propulsion capability based upon an electrolysis unit matches up nicely with another topic in the forum. That one was (and is) dedicated to development of CO/O2 based tools and reciprocating engines for construction and manufacturing on Mars.
SearchTerm:CO/O2 infrastructure on Mars
This topic is presumably about a system to produce oxygen on Mars.
Since I have forgotten what the topic was about, here is a snippet from Google:
The Mars Oxygen In-Situ Resource Utilization Experiment (MOXIE) is a technology demonstration on the NASA Mars 2020 rover Perseverance investigating the production of oxygen on Mars. On April 20, 2021, MOXIE produced oxygen from carbon dioxide in the Martian atmosphere by using solid oxide electrolysis.
Mars Oxygen ISRU Experiment - Wikipedia
en.wikipedia.org › wiki › Mars_Oxygen_ISRU_Experiment
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So! The natural evolution of this discussion would be a comparison of the NASA experiment and the commercial system reported in Post #53
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yes co is an exhaust that after you have expended power should not be expelled back into the atmosphere only to require more power to recapture it for another purpose. This is where we get into complete process use so as to make a more encompassing use of the energy which if solar can not be wasted in any watt level.....
Yes there is a co/o2 fuel rocket topic.
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The triple point is a frost, and it takes quite a bit before the temperature and pressure will make it liquid.
The current device uses a scroll compressor that pushes the CO2 into the high temperature electrolysis plates with catalyst.
NASA made enough oxygen on Mars to last an astronaut for 100 minutes
worth of breathable oxygen in 2021...
Over the course of seven hour-long production runs during that year, MOXIE was able to reliably produce roughly 15 minutes of oxygen per hour in a variety of harsh planetary conditions. That added up to a total of 50 grams of oxygen in total
7 hours is a very long period of time but then again that's with next to nothing for air pressure to get a breathable air pressure.
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Very important start and it might be good idea to have as many Oxygen sources as possible
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The device is meant to scale up in size but with that it's still will need testing to ensure that we get performance for power used.
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A new try has done, much better at the conversion...
NASA Is One Step Closer To Terraforming Mars
While Perserverance's Mars Oxygen In Situ Resource Utilization Experiment (MOXIE) has previously managed to harvest oxygen on the Red Planet, this time it went even further by doubling its production level. In a move that MOXIE's principal investigator, Michael Hecht called "the riskiest run" that the NASA team has ever pulled off, the rover raked in somewhere around 12 grams of oxygen from Mars in just 58 minutes. Pushing themselves and Perseverance to the limit, the scientists are thrilled that they challenged their original beliefs.
another note
News of NASA's latest win on Mars comes just days after it was revealed that the agency has found a way to recycle pee and other bodily fluids (i.e. sweat) into water. Another giant leap forward, this technology could elongate the time of missions in space, allowing astronauts to go farther than ever before. And don't worry – the water is totally safe to drink with one spokesperson even saying that it's cleaner than the water we have on Earth.
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NASA's completes Oxygen-Generating Experiment MOXIE
https://www.spacedaily.com/reports/NASA … E_999.html
Since Perseverance landed on Mars in 2021, MOXIE has generated a total of 122 grams of oxygen - about what a small dog breathes in 10 hours. At its most efficient, MOXIE was able to produce 12 grams of oxygen an hour - twice as much as NASA's original goals for the instrument - at 98% purity or better. On its 16th run, on Aug. 7, the instrument made 9.8 grams of oxygen. MOXIE successfully completed all of its technical requirements and was operated at a variety of conditions throughout a full Mars year, allowing the instrument's developers to learn a great deal about the technology.
"We're proud to have supported a breakthrough technology like MOXIE that could turn local resources into useful products for future exploration missions," said Trudy Kortes, director of technology demonstrations, Space Technology Mission Directorate (STMD) at NASA Headquarters in Washington, which funds the MOXIE demonstration. "By proving this technology in real-world conditions, we've come one step closer to a future in which astronauts 'live off the land' on the Red Planet."
MOXIE produces molecular oxygen through an electrochemical process that separates one oxygen atom from each molecule of carbon dioxide pumped in from Mars' thin atmosphere. As these gases flow through the system, they're analyzed to check the purity and quantity of the oxygen produced.
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It's sort of doing it with a process of super heat and catalyst materials sort of like electrolysis or a fuel cell in reverse.
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MOXIE demonstrated how to create breathable air on the Martian surface.
https://cosmicchroniclesnews.com/2023/1 … n-on-mars/
It successfully produced oxygen on Mars for the first time on April 20, 2021, and has since demonstrated its capability to generate oxygen from the carbon dioxide present in the Red Planet’s atmosphere. MOXIE has achieved multiple runs, generating oxygen at different rates to validate its functionality and performance in the challenging Martian environment. These successful oxygen production runs mark a significant milestone in the development of technologies necessary for future human survival.
Elon Musk Criticizes Stagnant Space Exploration, Stating: 'Humanity Should Have A Moon Base, Cities On Mars And Be Out There Among The Stars'
https://finance.yahoo.com/news/elon-mus … 38307.html
some backup ideas because you can never have too much air?
Chemistry? ISS Oxygten Candle and SCOGs are used in submarines, on Commercial aircraft provide emergency oxygen to passengers.
2 NaClO3 → 2 NaCl + 3 O2
LiClO4 → LiCl + 2 O2
discussion Chemistry - Chemists - Chemicals
https://newmars.com/forums/viewtopic.php?id=10415
Trees, Plants, Algae, Photosynthesis like aquatic plants, algae also produce oxygen via photosynthesis.
Current experiments on algea, lichen etc.?
https://newmars.com/forums/viewtopic.php?id=236
Productive walking Baba Yaga Robot Trees.
https://newmars.com/forums/viewtopic.php?id=9563
Mass About 37.7 pounds (17.1 kilograms) on Earth
https://mars.nasa.gov/mars2020/spacecra … nts/moxie/
Weight 37.7 pounds on Earth, 14.14 pounds on Mars
Power 300 watts
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Yes, it will be good to have backups in lots of different forms as you have indicated.
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Orion has for a crew of 4 they need for 21 days just 90 kg of oxygen in three tanks (= 270kg), 30 kg of nitrogen for near normal air
With space suits give another 144 hours.
At 300 watts to get about 6 g to 12 g which a far cry for an hour runtime when we need roughly 600 g for a days' worth of breathing per crewman.
Thanks to Void we have another to make use of in "Mars Direct 3 is a Mars mission architecture developed by Miguel Gurrea" topic.
https://www.marspapers.org/paper/Gurrea_2021.pdf
Plus Mars direct was a 40mT payload
https://www.marspapers.org/paper/Zubrin_1991.pdf
A reuseable craft requires the means to make the fuel of choice.
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