32

The Urine Processor in the Regenerative Environmental Control and Life Support System uses hexavalent chromium as a pretreatment solution for the urine.


25

note: protests in comments have led me to add the following sentence. Arsenic is a toxic metal and arsenic is used on the ISS, but the arsenic used on the ISS as discussed below is not a toxic metal per se, instead it's a nasty, extremely toxic semiconductor. GaAs is soluble in HCl which means if you eat it you are eating soluble arsenic. So don't eat it. ...


21

The bearings on the CMG (Control Moment Gyro) rotors use beryllium, which is pretty toxic when you machine it.


11

From the NASA web site for Juno: While other materials exist that make good radiation blockers, engineers chose titanium because lead is too soft to withstand the vibrations of launch, and some other materials were too difficult to work with. There are harder and softer lead alloys, but nothing begins to approach titanium. Later on the same page: ...


9

The satellite The most expensive thing is usually the satellite(s) source ranging in the hundreds of millions USD. Rockets costs usually in the single hundreds of millions range. The engines The second most expensive thing is the engine(s). That's why plans have been made to recover them instead of the whole rocket source


8

The in-development Prime launcher from Orbex has an uncommon arrangement: One key aspect of propane is that it remains liquid at cryogenic temperatures. That enabled a “coaxial tank” design for Prime where a central tube of propane is surrounded by an outer tank of liquid oxygen, creating structural mass savings in the rocket. (From Space News ) Others ...


6

Googled and found that the alloys mentioned below are available for purchase in Russia.... For example "Steel 12Х18НЮТ" - 195 000 rubles ($3036) per ton The main recommendations for the selection of structural materials in the production of chamber-liquid jet engines are presented below: Steel 12Х18НЮТ is used for the inner shells of the cylindrical ...


6

First things first: A titanium [dentist's patient] apron would weigh about 6.6 times a lead apron. This is true in their specific example, because the mass attenuation coefficient of lead is about 6.6 times higher than titanium for 60 keV x-rays. Crank the x-ray source up to 10 MeV and lead is more like 1.82x more effective than titanium, and ...


6

The heating system has ammonia in one of its loops, which is very irritating to human eyes, nose, throat, and lungs. On Earth, you can just leave spilled ammonia for a few hours, and it will waft away into the atmosphere until it's at a low enough concentration to be tolerable. In a space habitat, it would be terrible. You might be able to get everyone ...


5

As Wikipedia says... The material is believed to be a type of intumescent material and products with roughly similar properties are commercially available. ...intumescents produce a light char, which is a poor conductor of heat, thus retarding heat transfer. Seems it has been replicated, or since we don't know what it was something with similar ...


5

Iron, while abundant in weight percents only accounts for 2% iron in martian soil samples. This is not sufficient concentrations for a strong naturally occurring exothermic reaction. And if you are interested in "local" sources of aluminum on the surface, it's about 10% but already in an oxidized form. Source also see Inspecting Soils Across Mars


5

Actually, it's Kapton (polyimide), not Mylar (polyethylene terephthalate) or multi-layer insulation. Kapton and Mylar are both DuPont trademarks for polymer films, so perhaps it is easy to get them confused. According to the Apollo Experience Report: Thermal Protection Subsystem, The thermal control requirements for the spacecraft in outer space ...


5

Carbon-carbon (CC) grids were used on the mu10 microwave discharge ion thrusters on the 'Hayabusa' asteroid sample return mission. They are being used at this very moment on the Hayabusa2 spacecraft. I believe CC grids are planned to be used on the NEXIS engine for the NASA Jupiter mission and the Cross Enterprise Technology Development Program (CETDP). CC ...


5

Titanium is too ambitious for a first project. It's difficult to machine and weld. It's also overkill: even many orbital rockets use aluminium hulls. Amateur rockets generally use plastic bodies. To get a good start in amateur rocketry, join an amateur rocket group. Start by launching a few Estes rockets, and scale up from there.


5

There was a proposed 'escape capsule' to be used to return from low Earth orbit called MOOSE (Man Out Of Space Easiest). It had an ablative heatshield backed up with an expanded polyurethane foam substrate. The foam was expanded prior to use, so that the 'escape capsule' didn't take up too much volume when stowed. Never built or flown, but some tests were ...


4

The shuttle SRBs didn't have refractory material as such; they were lined with an impregnated rubber insulation. The insulation was made of chrysotile-filled rubber: chrysotile being the most-common mineral form of asbestos. source: https://www.nasaspaceflight.com/2014/09/atk-making-progress-srb-propellant-void-issue/ (Asbestos by itself would be ...


4

The third test of the Low-Density Supersonic Decelerator (LDSD) never occurred, the program was cut as part of a budget shortfall in 2016. However the paper "Reconstructed Parachute System Performance During the Second LDSD Supersonic Flight Dynamics Test" provides an in-depth analysis of the parachute system during the test including some great graphics ...


4

For your goal, molten metal is not suitable, or at least, has no benefits. Metals are generally good conductors of heat. So all that heat from the Sun will be distributed quickly throughout the metal blob, until all sides are at equilibrium temperature. That will be a bit lower than the temperature from direct insolation (the sphere will radiate heat in ...


3

On the Merlin Vacuum engine, the nozzle extension uses a Niobium alloy. The nozzle is cooled via film cooling: The exhaust from the turbopump is injected just above the nozzle extension and helps shield it from the engine exhaust.


3

Paint the side facing the sun black and insulate everywhere else. To a first approximation it doesn't matter what material if you assume the following characteristics. You will have to do some homework. Heat is lost by radiation is P = (epsilon1 + epsilon2) x (Area/2) * sigma * T^4. Heat is gained from the Sun is P = Area(projected) * S * alpha. Solve ...


3

Absent specific details about the printing filament, it's impossible to say anything in particular about this application. Some general points of knowledge though: The primary sources of polymer degradation in orbit are UV radiation, atomic oxygen (AO) erosion, outgassing, and thermal degradation. These all present challenges regarding material selection, ...


3

Difficult to know for sure, as with all things Musk, but likely it's similar to the shuttle Fibrous Refractory Composite Insulation (FRCI) tiles. The FRCI tiles are a high strength tile derived by adding AB312 (alumina-borosilicate fiber), called Nextel, to the pure silica tile slurry. These tiles are developed by the 3M Company of St. Paul, Minn....


2

It depends on how much pressure the aluminum alloy is exposed to. Explosion pressure can range from 1MPa to 52.82GPa for the most powerful experimental explosives. Aluminum alloys are usually ductile and can undergo significant plastic deformations before they rupture, therefore extremely high pressures will be required to turn them into powder. This is ...


2

Your question is underspecified, but you might find something like TransHab (or other inflatable spacecraft designs) to fit the bill. There's already one such module attached to the ISS, so the principle appears to be entirely sound and practical. From this older NASA page on TransHab, you can see that the membranes are made from layers of nextel ceramic ...


1

I would say the turbopumps are the most expensive. They cost 3 million+ each, and are extremely vital in rocket engines. Falcon heavy uses 28 turbopumps. That is a whopping 84 million+ dollars, and falcon heavy launches cost 90 million+. So you can see why they want those rockets to be reusable to keep launch costs down. 1 turbopump is lost on every launch, ...


1

First, I am skeptical whether it's actually true true that stainless steel is actually never used in modern rocket engines (as some commments have asked). Stainless steels in general are not necessarily high performance materials when heated to high temperatures, in either practical strength (including vulnerability to various undesirable heat treatments, ...


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