In-Situ Resource Utilization - AbsoluteAstronomy.com

Space exploration

Space exploration is the use of space technology to explore outer space. Physical exploration of space is conducted both by human spaceflights and by robotic spacecraft....

, in-situ resource utilization (ISRU) describes the proposed use of resources found or manufactured on other astronomical objects (the Moon, Mars, Asteroids, etc.) to further the goals of a space mission.

According to NASA

NASA

The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

, "In-situ resource utilization will enable the affordable establishment of extraterrestrial exploration and operations by minimizing the materials carried from Earth."

ISRU can provide materials for life support, propellants, construction materials, and energy to a science payload or a crew deployed on a planet, moon, or asteroid.

It is now very common for spacecraft

Spacecraft

A spacecraft or spaceship is a craft or machine designed for spaceflight. Spacecraft are used for a variety of purposes, including communications, earth observation, meteorology, navigation, planetary exploration and transportation of humans and cargo....

to harness the solar radiation found in-situ, and it is likely missions to planetary surfaces will also use solar power

Solar power

Solar energy, radiant light and heat from the sun, has been harnessed by humans since ancient times using a range of ever-evolving technologies. Solar radiation, along with secondary solar-powered resources such as wind and wave power, hydroelectricity and biomass, account for most of the available...

. Beyond that, ISRU has not yet received any practical application, but it is seen by exploration proponents as a way to drastically reduce the amount of payload that must be launched from Earth in order to explore a given planetary body.

Proposals have been made for "mining" atmospheric gases for rocket propulsion, using what is called a Propulsive Fluid Accumulator

Propulsive Fluid Accumulator

A Propulsive Fluid Accumulator is an artificial Earth satellite which collects and stores oxygen and other atmospheric gases for in-situ refuelling of high-thrust rockets. This eliminates the need to lift oxidizer to orbit and therefore brings significant cost benefits.- Propulsive Fluid...

Solar cell production

It has long been suggested that solar cell

Solar cell

A solar cell is a solid state electrical device that converts the energy of light directly into electricity by the photovoltaic effect....

s could be produced from the materials present on the lunar surface. In its original form, known as the solar power satellite, the proposal was intended as an alternate power source for Earth. Solar cells would be shipped to Earth orbit and assembled, the power being transmitted to Earth via microwave beams. Despite much work on the cost of such a venture, the uncertainty lay in the cost and complexity of fabrication procedures on the lunar surface. A more modest reincarnation of this dream is for it to create solar cells to power future lunar bases. One particular proposal is to simplify the process by using fluorine

Fluorine

Fluorine is the chemical element with atomic number 9, represented by the symbol F. It is the lightest element of the halogen column of the periodic table and has a single stable isotope, fluorine-19. At standard pressure and temperature, fluorine is a pale yellow gas composed of diatomic...

brought from Earth as potassium fluoride

Potassium fluoride

Potassium fluoride is the chemical compound with the formula KF. After hydrogen fluoride, KF is the primary source of the fluoride ion for applications in manufacturing and in chemistry. It is an alkali metal halide and occurs naturally as the rare mineral carobbiite...

to separate the raw materials from the lunar rocks.

Rocket propellant

Rocket propellant from water ice has also been proposed for the moon, mainly from ice that has been found at the poles. The likely difficulties include working at extremely low temperatures and simply digging the material. Most schemes electrolyse the water

Electrolysis of water

Electrolysis of water is the decomposition of water into oxygen and hydrogen gas due to an electric current being passed through the water.-Principle:...

and form hydrogen and oxygen, liquify and cryogenically store them, which requires large amounts of equipment and power to achieve. Alternatively it is possible to simply heat the water in a nuclear or solar thermal rocket

Thermal rocket

A thermal rocket is a rocket engine that uses a propellant that is externally heated before being passed through a nozzle, as opposed to undergoing a chemical reaction as in a chemical rocket.Thermal rockets can give high performance....

, which seems to give very much more mass delivered to LEO

Low Earth orbit

A low Earth orbit is generally defined as an orbit within the locus extending from the Earth’s surface up to an altitude of 2,000 km...

in spite of the much lower specific impulse, for a given amount of equipment.

Aluminium

Aluminium

Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....

as well as other metals have been proposed for use as rocket propellant made using lunar resources, and proposals include reacting the aluminium with water.

The spacecraft could use the propellant itself or supply a propellant depot

Propellant depot

An orbital propellant depot is a cache of propellant that is placed on an orbit about the Earth or another body to allow spacecraft to be fuelled in space. Launching a spacecraft separately from some of its propellant enables missions with more massive payloads...

Oxygen to breathe and water to drink

Water ice could replenish a space ship's water tanks. Water is needed for hygiene and obviously to drink, but may also be used for radiation protection in deep space (living quarters inside a double-walled cylindrical water tank). Splitting water allows the creation of rocket propellant, but also liberates oxygen that could be used to replenish the atmosphere in a closed-loop recycling system.

Metals for construction or return to Earth

Asteroid mining

Asteroid mining refers to the possibility of exploiting raw materials from asteroids and planetoids in space, including near-Earth objects. Minerals and volatiles could be mined from an asteroid or spent comet to provide space construction material , to extract water and oxygen to sustain the lives...

could also involve extraction of metals for construction material in space, which may be more cost-effective than bringing such material up out of Earth

Earth

Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...

's deep gravity well, or that of any other large body like the Moon

Moon

The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...

or Mars

Mars

Mars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...

. Metallic asteroids contain huge amounts of siderophilic metals, including precious metal

Precious metal

A precious metal is a rare, naturally occurring metallic chemical element of high economic value.Chemically, the precious metals are less reactive than most elements, have high lustre, are softer or more ductile, and have higher melting points than other metals...

Mars

ISRU research for Mars is focused primarily on providing rocket propellant

Rocket propellant

Rocket propellant is mass that is stored in some form of propellant tank, prior to being used as the propulsive mass that is ejected from a rocket engine in the form of a fluid jet to produce thrust. A fuel propellant is often burned with an oxidizer propellant to produce large volumes of very hot...

for a return trip to Earth — either for a manned or a sample return mission — or for use as fuel on Mars. Many of the proposed techniques utilize the well-characterised atmosphere of Mars

Atmosphere of Mars

The atmosphere of Mars is relatively thin and is composed mostly of carbon dioxide . There has been interest in studying its composition since the detection of trace amounts of methane, which may indicate the presence of life on Mars, but may also be produced by a geochemical process, volcanic or...

as feedstock. Since this can be easily simulated on Earth, these proposals are relatively simple to implement, though it is by no means certain that NASA or the ESA will favour this approach over a more conventional direct mission.

A typical proposal for ISRU is the use of a Sabatier reaction

Sabatier reaction

The Sabatier reaction or Sabatier process involves the reaction of hydrogen with carbon dioxide at elevated temperatures and pressures in the presence of a nickel catalyst to produce methane and water. Optionally ruthenium on alumina makes a more efficient catalyst...

, CO₂ + 4H₂ → CH₄ + 2H₂O, in order to produce methane on the Martian surface, to be used as a propellant. Oxygen is liberated from the water by electrolysis

Electrolysis of water

Electrolysis of water is the decomposition of water into oxygen and hydrogen gas due to an electric current being passed through the water.-Principle:...

, and the hydrogen recycled back into the Sabatier reaction. The usefulness of this reaction is that only the hydrogen (which is light) need be brought from Earth.

A similar reaction proposed for Mars is the reverse water gas shift reaction

Water gas shift reaction

The water-gas shift reaction is a chemical reaction in which carbon monoxide reacts with water vapor to form carbon dioxide and hydrogen:The water-gas shift reaction is an important industrial reaction. It is often used in conjunction with steam reforming of methane or other hydrocarbons, which is...

, CO₂ + H₂ → CO + H₂O. This reaction takes place rapidly in the presence of an iron-chrome catalyst at 400 Celsius, and has been implemented in an Earth-based testbed by NASA. Again, oxygen is recycled from the water by electrolysis

Electrolysis of water

Electrolysis of water is the decomposition of water into oxygen and hydrogen gas due to an electric current being passed through the water.-Principle:...

, and only a small amount of hydrogen is needed from Earth. The net result of this reaction is the production of oxygen, to be used as the oxidizer component of rocket fuel.

Another reaction proposed for production of oxygen is electrolysis of the atmosphere, 2CO₂ (+ energy) → 2CO + O₂.

The Moon

On the moon

Moon

, the lunar highland material anorthite

Anorthite

Anorthite is the calcium endmember of plagioclase feldspar. Plagioclase is an abundant mineral in the Earth's crust. The formula of pure anorthite is CaAl2Si2O8.-Mineralogy :...

is similar to the earth mineral bauxite

Bauxite

Bauxite is an aluminium ore and is the main source of aluminium. This form of rock consists mostly of the minerals gibbsite Al3, boehmite γ-AlO, and diaspore α-AlO, in a mixture with the two iron oxides goethite and hematite, the clay mineral kaolinite, and small amounts of anatase TiO2...

, which is an aluminium

Aluminium

Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....

ore

Ore

An ore is a type of rock that contains minerals with important elements including metals. The ores are extracted through mining; these are then refined to extract the valuable element....

. Smelters can produce pure aluminum, calcium metal, oxygen and silica glass from anorthite. Raw anorthite is also good for making fiberglass and other glass and ceramic products.

Over twenty different methods have been proposed for oxygen

Oxygen

Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...

extraction on the moon. Oxygen is often found in iron rich lunar minerals and glasses as iron oxide

Iron oxide

Iron oxides are chemical compounds composed of iron and oxygen. All together, there are sixteen known iron oxides and oxyhydroxides.Iron oxides and oxide-hydroxides are widespread in nature, play an important role in many geological and biological processes, and are widely utilized by humans, e.g.,...

. The oxygen can be extracted by heating the material to temperatures above 900 °C and exposing it to hydrogen gas. The basic equation is: FeO + H₂ → Fe + H₂O. This process has recently been made much more practical by the discovery of significant amounts of hydrogen

Hydrogen

Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...

-containing regolith

Regolith

Regolith is a layer of loose, heterogeneous material covering solid rock. It includes dust, soil, broken rock, and other related materials and is present on Earth, the Moon, some asteroids, and other terrestrial planets and moons.-Etymology:...

near the moon's poles by the Clementine spacecraft.

Lunar materials may also be valuable for other uses. It has also been proposed to use lunar regolith as a general construction material, through processing techniques such as sintering

Sintering

Sintering is a method used to create objects from powders. It is based on atomic diffusion. Diffusion occurs in any material above absolute zero, but it occurs much faster at higher temperatures. In most sintering processes, the powdered material is held in a mold and then heated to a temperature...

, hot-pressing, liquification

Liquification

In physics, to liquefy means to turn something into the liquid state.-In Geology:In geology, liquefaction refers to the process by which saturated, unconsolidated sediments are transformed into a substance that acts like a liquid.Earthquakes can cause soil liquefaction where loosely packed,...

, and the cast basalt

Basalt

Basalt is a common extrusive volcanic rock. It is usually grey to black and fine-grained due to rapid cooling of lava at the surface of a planet. It may be porphyritic containing larger crystals in a fine matrix, or vesicular, or frothy scoria. Unweathered basalt is black or grey...

method. Cast basalt is used on Earth for construction of, for example, pipes where a high resistance to abrasion is required. Cast basalt has a very high hardness of 8 Mohs

Mohs scale of mineral hardness

The Mohs scale of mineral hardness characterizes the scratch resistance of various minerals through the ability of a harder material to scratch a softer material. It was created in 1812 by the German geologist and mineralogist Friedrich Mohs and is one of several definitions of hardness in...

(diamond

Diamond

In mineralogy, diamond is an allotrope of carbon, where the carbon atoms are arranged in a variation of the face-centered cubic crystal structure called a diamond lattice. Diamond is less stable than graphite, but the conversion rate from diamond to graphite is negligible at ambient conditions...

is 10 Mohs) but is also susceptible to mechanical impact and thermal shock

Thermal shock

Thermal shock is the name given to cracking as a result of rapid temperature change. Glass and ceramic objects are particularly vulnerable to this form of failure, due to their low toughness, low thermal conductivity, and high thermal expansion coefficients...

which could be a problem on the moon.

Glass

Glass

Glass is an amorphous solid material. Glasses are typically brittle and optically transparent.The most familiar type of glass, used for centuries in windows and drinking vessels, is soda-lime glass, composed of about 75% silica plus Na2O, CaO, and several minor additives...

and glass fibre are straightforward to process on the moon and Mars, and it has been argued that the glass is optically superior to that made on the Earth because it can be made anhydrous

Anhydrous

As a general term, a substance is said to be anhydrous if it contains no water. The way of achieving the anhydrous form differs from one substance to another...

. Successful tests have been performed on earth using two lunar regolith simulant

Lunar regolith simulant

A Lunar regolith simulant is a terrestrial material synthesized in order to approximate the chemical, mechanical, and engineering properties of, and the mineralogy and particle size distributions of, lunar regolith. Lunar regolith simulants are used by researchers who wish to research the...

s MLS-1 and MLS-2. Basalt fibre has also been made from lunar regolith simulators.

In August 2005, NASA contracted for the production of 16 metric tons of simulated lunar soil,
or "Lunar Regolith Simulant Material

Lunar regolith simulant

."
This material, called JSC-1a, is now commercially available for research on how lunar soil could be utilized in-situ.

Martian Moons, Ceres, asteroids

Other proposals are based on Phobos

Phobos (moon)

Phobos is the larger and closer of the two natural satellites of Mars. Both moons were discovered in 1877. With a mean radius of , Phobos is 7.24 times as massive as Deimos...

and Deimos

Deimos (moon)

Deimos is the smaller and outer of Mars's two moons . It is named after Deimos, a figure representing dread in Greek Mythology. Its systematic designation is '.-Discovery:Deimos was discovered by Asaph Hall, Sr...

. These moons are in reasonably high orbits above Mars, have very low escape velocities, and unlike Mars have return delta-v

Delta-v budget

In the astrodynamics and aerospace industry, a delta-v budget is the estimated delta-v requirements for the various propulsive tasks and orbital maneuvers over one or more phases of a space mission.Sample delta-v budget will enumerate various classes of maneuvers, delta-v per maneuver, number of...

's from their surfaces to LEO

Low Earth orbit

A low Earth orbit is generally defined as an orbit within the locus extending from the Earth’s surface up to an altitude of 2,000 km...

which are less than the return from the Moon.

Ceres is further out than Mars, with a higher delta-v, but launch windows and travel times are better, and the surface gravity is just 0.028 g, with a very low escape velocity of 510 m/s. Researchers have speculated that the interior configuration of Ceres includes a water-ice-rich mantle over a rocky core.

Near Earth Asteroids and bodies in the asteroid

Asteroid

Asteroids are a class of small Solar System bodies in orbit around the Sun. They have also been called planetoids, especially the larger ones...

belt could also be sources of raw materials for ISRU.

Low Orbit

Gasses like oxygen and argon

Argon

Argon is a chemical element represented by the symbol Ar. Argon has atomic number 18 and is the third element in group 18 of the periodic table . Argon is the third most common gas in the Earth's atmosphere, at 0.93%, making it more common than carbon dioxide...

can be extracted from the atmospheres of planets like the Earth and Mars by Propulsive Fluid Accumulator

Propulsive Fluid Accumulator

satellites in low orbit.

ISRU classification

In October 2004, NASA’s Advanced Planning and Integration Office commissioned an ISRU capability roadmap team.
The team's report, along with those of 14 other capability roadmap teams, were published May 22, 2005.
The report identifies seven ISRU capabilities:
(i) resource extraction, (ii) material handling and transport, (iii) resource processing, (iv) surface manufacturing with in-situ resources, (v) surface construction, (vi) surface ISRU product and consumable storage and distribution, and (vii) ISRU unique development and certification capabilities.

External links

Homesteading the Planets with Local Materials
The Space Resources Roundtable
UW AA Dept. ISRU Research Lab
ISRU solar cell manufacture
ISRU on the Moon
Moon Ice For LEO to GEO Transfers Orders of magnitude lower cost for rocket propellant if lunar ice
Lunar ice
Lunar water is water that is present on the Moon. Liquid water cannot persist at the Moon's surface, and water vapour is quickly decomposed by sunlight and lost to outer space...

is present
Homesteading the Planets with Local Materials
From Importing to Exporting : The Impact of Moon ISRU on Space Logistic, AIAA Space 2011

The source of this article is wikipedia, the free encyclopedia. The text of this article is licensed under the GFDL.

Solar cell production

Rocket propellant

Oxygen to breathe and water to drink

Metals for construction or return to Earth

Mars

The Moon

Martian Moons, Ceres, asteroids

Low Orbit

ISRU classification

See also

Further reading

External links