New Mars Forums

Human respiration primarily involves taking in oxygen and exhaling carbon dioxide and water vapor, but the air we breathe out is a mixture containing nitrogen, unused oxygen, and trace amounts of other waste gases like volatile organic compounds (VOCs), nitric oxide (NO), and ammonia (NH3). While carbon dioxide is the main waste product of cellular respiration, exhaled air still contains a significant amount of nitrogen (about 78%) and some oxygen (around 16%). 

Key Gases Given Off Carbon Dioxide (\(CO_{2}\)): The primary waste gas, produced when cells use oxygen to break down sugar for energy.Water Vapor (\(H_{2}O\)): A byproduct of cellular metabolism, released as humidified vapor.

Nitrogen (\(N_{2}\)): The most abundant gas in the air, most of which is exhaled unchanged, as humans don't use it.Oxygen (\(O_{2}\)): A portion of the oxygen we inhale isn't used and is exhaled, which is why rescue breaths in CPR can still provide oxygen.

Trace Gases: Small amounts of other substances, including:Volatile Organic Compounds (VOCs).Nitric Oxide (NO).Ammonia (NH3).Carbon Monoxide (CO).Alcohol (when consumed). 

The Process Inhalation: Air (21% Oxygen, 78% Nitrogen, ~0.04% Carbon Dioxide) enters the lungs.
Gas Exchange: In the alveoli (tiny air sacs in the lungs), oxygen moves into the blood, and carbon dioxide moves from the blood into the alveoli.
Exhalation: The diaphragm and chest muscles push air out, carrying the waste \(CO_{2}\) and water vapor, along with unused nitrogen and oxygen, out of the body

The U.S. primarily relies on imported bauxite (aluminum ore) for its aluminum production, though small amounts are mined domestically for non-metal uses like abrasives and proppants in oil/gas drilling. Arkansas has historically been the main U.S. source, but mining for metal ceased years ago, with the nation now depending on imports from countries like Jamaica, Guinea, and Brazil for its refineries, mainly in Louisiana.

Key Points:
Primary Ore: Bauxite, a rock rich in aluminum hydroxides (gibbsite, boehmite, diaspore).
Domestic Mining: Limited; primarily for non-metallurgical uses like refractories or hydraulic fracturing proppants, not primary aluminum.
Main Source: Imports, with significant quantities coming from Jamaica, Guyana, China, and Australia.
Refining: U.S. alumina refineries are in Louisiana, converting imported bauxite into alumina for smelting.
Energy Intensive: Aluminum production is energy-intensive, making electricity costs a major factor in U.S. smelter operations.

U.S. Bauxite Resources:
Arkansas: Historically the largest domestic producer, but mining for metal stopped in the 1980s.
Other States: Small deposits exist in Alabama, Georgia, and other areas, but aren't major suppliers for metal production.
In essence, while the U.S. consumes and produces aluminum, it relies heavily on foreign sources for the raw bauxite ore.

Yes, the U.S. has bauxite, primarily in Arkansas, Alabama, and Georgia, but production is small and mostly for non-metallurgical uses like chemicals, abrasives, and proppants for fracking; the nation imports the vast majority of its metallurgical-grade bauxite for aluminum production from other countries like Jamaica, Guinea, and Brazil.
Key Details:
Domestic Production: Small amounts are mined in the Southeastern U.S., with Arkansas being the leading domestic producer, though not for primary aluminum metal in recent decades.
Uses: U.S. bauxite is used for chemicals, abrasives, cements, and hydraulic fracturing proppants, not as much for aluminum metal as in the past.
Imports: The U.S. relies heavily on imports for aluminum, with significant quantities of metallurgical bauxite coming from global suppliers.
History: Major U.S. bauxite mining for aluminum happened in the past, especially in Arkansas, but stopped in the 1980s for metal production.

Suppose we did simply create an open pit "mine" of the kind shown by SpaceNut in Post #30.  The "Superdome" that Calliban want to build is merely a means to an end- pressurized living space, presumably appropriately "greened" using seeds brought from Earth.  Apart from holding in the pressure, I presume the most important secondary reason for piling on so much regolith over the structure is to block-out space-based radiation, primarily the highly penetrating and damaging (slowly but surely) Galactic Cosmic Rays (GCR).  All available literature from NASA indicates that using approximately 2m of regolith shielding is sufficient to absorb enough of the dose to remain below lifetime limits.  GCR is not like SPE / CME radiation, in that it consists of ionized nuclei, ranging in weight from Hydrogen to Iron, although it's over 90% Hydrogen in practice, traveling through space near the speed of light.  There's no practical passive shielding material for an interplanetary spacecraft due to shielding mass, but once the settlers arrive on Mars we're obligated to provide appropriate protective measures incorporated into the engineering of habitable spaces.

Here's a question I'd like the AI to answer for us:
By constructing Calliban's Superdome at the bottom of the open pit mine shown in Post #30, how much Solar Particle Event (SPE) / Coronal Mass Ejection (CME) / Galatic Cosmic Ray (GCR) radiation will the open pit mine block by erecting the dome at the bottom of the pit?

If the protection provided is still insufficient for humans, is it enough for the plants to survive all or most SPE / CME / GCR?

Maybe the humans will still need to temporarily seek more substantial shelter during a SPE / CME, presumably by evacuating to tunnels carved into the rock underneath the dome or into the walls of the pit.  I'm thinking of the open pit mine as being somewhat akin to "castle walls", used to protect the people inside from powerful space-based radiation rather than invaders, but a castle nonetheless.  The Superdome at the bottom is the castle's "keep"- for keeping the people inside warm / fed / clothed.

Erecting a giant dome is supposed to be a significant quality of life improvement for the settlers, so if it still gets sufficient sunlight to grow plants using fiber optics and/or mirrors arrayed around the pit, then perhaps the effort to dig the pit and erect the Superdome at the bottom of the pit still represents an acceptable energy trade for the long term security and psychological support of a miniature Earth-like environment.

Russia’s Roscosmos is taking an unconventional route to its new space station, by recycling old modules from the International Space Station (ISS). With the ISS slated for retirement, Roscosmos has announced plans to repurpose several modules from the Russian segment of the station, marking a significant shift in the country’s space station strategy.

The new Russian Orbital Station (ROS) will incorporate modules like Zarya, Zvezda, Poisk, Rassvet, Nauka, and Pricha. These aging structures, which have been orbiting Earth for nearly 30 years, will be separated from the ISS once the program concludes, forming the heart of the new station. It’s a move that raises questions about the long-term durability of these modules and the scientific viability of the station as a whole.

A Shifting Vision for Russia’s Space Future

For years, Roscosmos has been toying with the idea of an independent space station. Initially, the Russian Orbital Service Station (ROSS), a successor to the Orbital Piloted Assembly and Experiment Complex (OPSEK) project, was supposed to be entirely new, free of the ISS’s aging modules. But by 2021, the plan shifted to an even bolder vision: creating a new space station using some of the hardware that has already been in orbit for decades.

According to the report published inUniverse Today, the re-use of ISS modules marks a significant departure from Roscosmos’ previous plans, and according to a recent statement from Oleg Orlov, director of the Institute of Biomedical Problems at the Russian Academy of Sciences (RAS), the decision reflects the growing financial constraints and geopolitical shifts the country has faced in recent years.

With many of the ISS modules showing their age, particularly the Russian ones, it may seem like a cost-effective move, but some experts are skeptical of just how feasible it is to recycle these old, often problematic pieces of hardware.

Aging Modules and Serious Concerns
While the idea of recycling ISS modules may seem like a quick fix, there are significant concerns about the condition of the modules Roscosmos plans to repurpose. As Maria Sokolova of New Izvestia pointed out, some of the Russian modules are well over 25 years old and have suffered considerable wear and tear. The Zarya module, for instance, is 27 years old, and Zvezda, which is another key module for the new station, is not far behind.

These modules were designed for a much shorter operational lifespan, and the harsh conditions of space, including extreme temperature fluctuations and radiation, have taken their toll. Still, with Roscosmos under financial strain and facing limited options, recycling the modules could be seen as the only realistic path forward.

Acoustic signals have been important markers during NASA's Mars missions. Measurements of sound can provide information both about Mars itself—such as turbulence in its atmosphere, changes in its temperature, and its surface conditions—and about the movement of the Mars rovers.

Using these sound measurements to the best extent possible requires an accurate understanding of how sound propagates on Mars. Charlie Zheng, a professor of mechanical and aerospace engineering at Utah State University, and his doctoral student Hayden Baird, presented their work simulating sound propagation on Mars at the Sixth Joint Meeting of the Acoustical Society of America and Acoustical Society of Japan, running Dec. 1–5 in Honolulu, Hawaii.

"We expect that the study will provide deeper insight into weather and terrain effects on acoustic propagation in environments that are not easily measured," said Zheng. "The Martian environment is obviously one of them."

Baird and Zheng's work uses NASA's measurements of the atmospheric conditions and terrain on Mars, most of which have been previously modeled at meter-scale resolutions. They also had access to decades of data about the red planet's atmospheric composition and properties, as well as seismic studies that measure the ground porosity—all factors that play into how sound propagates.

"The setup of the simulation model used in this study relies heavily on previous results from multiple scientific disciplines," said Baird.

Focusing on the Jezero crater, the 2021 landing and exploration site of NASA's Perseverance rover and its attached Ingenuity helicopter, the researchers simulated how sound moves through and scatters off the region's complex terrains, whether it comes from a moving or stationary source. This will help them understand how other atmospheres compare to our own.

The researchers hope their model will help identify signals and patterns that indicate specific Martian atmospheric events. In the longer term, it may even help with sensor designs for future missions to other planets or moons to study atmospheric conditions.

"This study is a beginning to dive into many potential areas of planetary research," said Zheng.

Provided by Acoustical Society of America

This story was originally published on Phys.org.