In-situ resource utilization
5333892
221331476
2008-06-24T01:41:12Z
24.127.11.71
/* The Moon */
[[Image:In-Situ Resource Utilization Testbed.gif||right|thumb|280px|ISRU Reverse Water Gas Shift Testbed (NASA KSC).]]
In [[space exploration]], '''In-Situ Resource Utilization''' (ISRU) describes the proposed use of resources found or manufactured on other planetary bodies (the Moon, Mars, etc.) or planetoids to further the goals of a space mission.
According to [[NASA]], "In-situ resource utilization will enable the affordable establishment of extraterrestrial exploration and operations by minimizing the materials carried from Earth."<ref>
{{cite web
| title = In-Situ Resource Utilization
| publisher = NASA Ames Research Center
| url = http://www.nasa.gov/centers/ames/research/technology-onepagers/in-situ_resource_Utiliza14.html
| format = html
| accessdate = 2007-01-14 }}
</ref>
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]] to harness the [[solar radiation]] found in-situ, and it is likely missions to planetary surfaces will also use [[solar power]]. 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.
==Locations==
===Mars===
ISRU research for Mars is focussed primarily on providing [[rocket propellant]] 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]] 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.<ref>{{citeweb|title=Mars Sample Return|url=http://www.esa.int/SPECIALS/Aurora/SEM1PM808BE_0.html|publisher=www.esa.int|accessdate=2008-02-05}}</ref>
A typical proposal for ISRU is the use of a [[Sabatier reaction]], CO<sub>2</sub> + 4H<sub>2</sub> → CH<sub>4</sub> + 2H<sub>2</sub>O, in order to produce methane on the Martian surface, to be used as a propellant. Oxygen is liberated from the water by [[Electrolysis of water|electrolysis]], 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.<ref>{{citeweb|title=Sizing of a Combined Sabatier Reaction and Water Electrolysis Plant for Use in In-Situ Resource Utilization on Mars|url=http://www.clas.ufl.edu/jur/200109/papers/paper_canton.html|publisher=www.clas.ufl.edu|accessdate=2008-02-05}}</ref>
A similar reaction proposed for Mars is the reverse [[water gas shift reaction]], CO<sub>2</sub> + H<sub>2</sub> → CO + H<sub>2</sub>O. This reaction takes place rapidly in the presence of an iron-chrome [[catalyst]] at 400 Celsius,<ref>
{{cite web
| title = The Reverse Water Gas Shift
| url = http://spot.colorado.edu/~meyertr/rwgs/rwgs.html
| format = html
| accessdate = 2007-01-14 }}
</ref> and has been implemented in an earth based testbed by NASA.<ref>
{{cite web
| title = Mars In Situ Resource Utilization (ISRU) Testbed
| url = http://rtreport.ksc.nasa.gov/techreports/2001report/100/103.html
| publisher = NASA
| format = html
| accessdate = 2007-01-14 }}
</ref> Again, oxygen is recycled from the water by [[Electrolysis of water|electrolysis]], 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, 2CO<sub>2</sub> (+ energy) → 2CO + O<sub>2</sub>l.
===The Moon===
[[Image:Footprint.gif|thumb|left|250px|Footprint in lunar [[regolith]].]]
On the [[moon]], the lunar highland material [[anorthite]] is similar to the earth mineral [[bauxite]], which is an [[aluminium]] [[ore]]. 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.<ref name = "mining">
{{cite web
| title = Mining and Manufacturing on the Moon
| publisher = NASA
| url = http://aerospacescholars.jsc.nasa.gov/HAS/cirr/em/6/6.cfm
| format = html
| accessdate = 2007-01-14 }}
</ref>
Over twenty different methods have been proposed for [[oxygen]] extraction on the Moon. Oxygen is often found in iron rich lunar minerals and glasses as [[iron oxide]]. 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 + H<sub>2</sub> → Fe + H<sub>2</sub>O. This process has recently been made much more practical by the discovery of significant amounts of [[hydrogen]]-containing [[regolith]] near the [[Moon#Presence of water|moon's poles]] by the [[Clementine spacecraft]].<ref>
{{cite web
| title = The Clementine Bistatic Radar Experiment
| publisher = Science Magazine
| url = http://www.sciencemag.org/cgi/content/full/274/5292/1495
| format = html
| accessdate = 2007-02-12 }}
</ref>
It has also been proposed to use lunar regolith as a general construction material,<ref>
{{cite web
| title = Indigenous lunar construction materials
| publisher = NASA
| url = http://ntrs.nasa.gov/search.jsp?R=696858&id=2&qs=N%3D4294819768
| format = html
| accessdate = 2007-01-14 }}
</ref> through processing techniques such as [[sintering]], hot-pressing, [[liquification]], and the [[cast basalt]] method. The cast basalt method 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]] ([[diamond]] is 10 Mohs) but is also susceptible to mechanical impact and [[thermal shock]]<ref>
{{cite web
| title = Cast Basalt
| publisher = Ultratech
| url = http://www.conforms.com/pdf/ultratech/UTD101.pdf
| format = html
| accessdate = 2007-01-14 }}
</ref> which could be a problem on the moon.
[[Glass]] 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]].<ref name = "mining"> empty </ref> Successful tests have been performed on earth using two lunar regolith simulants [[MLS-1]] and [[MLS-2]].<ref>http://science.nasa.gov/newhome/headlines/space98pdf/fiber.pdf</ref>
In August 2005, NASA contracted for the production of 16 metric tons of simulated lunar soil,
or "Lunar Regolith Simulant Material."<ref>
{{cite web
| title = NASA Science & Mission Systems Office
| url = http://isru.msfc.nasa.gov/index.html
| format = html
| accessdate = 2007-01-14 }}
</ref>
This material, called [http://science.nasa.gov/headlines/y2006/28dec_truefake.htm JSC-1a], is now commercially available for research on how lunar soil could be utilized in-situ.<ref>
{{cite web
| title = bringing commercialization to maturity
| publisher = PLANET LLC
| url = http://www.planet-llc.com/simulant.htm
| format = html
| accessdate = 2007-01-14 }}
</ref>
====Solar cell production====
It has long been suggested that [[solar cell]]s could be produced from the materials present on the lunar surface. In its original form the proposal was intended as an alternate power source for Earth, the power being transmitted to Earth via microwave beams.<ref>
{{cite web
| title = Lunar Solar Power System for Energy Prosperity Within the 21st Century
| publisher = World Energy Council
| url = http://www.worldenergy.org/wec-geis/publications/default/tech_papers/17th_congress/4_1_33.asp
| format = html
| accessdate = 2007-03-26}}
</ref> However 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 brought from Earth as potassium fluoride to separate the raw materials from the lunar rocks.<ref>
{{cite web
| last=Landis
| first=Geoffrey
| title = Refining Lunar Materials for Solar Array Production on the Moon
| publisher = NASA
| url = http://gltrs.grc.nasa.gov/reports/2005/TM-2005-214014.pdf | format = html
| accessdate = 2007-03-26}}
</ref>
===Martian Moons===
Other proposals{{Fact|date=December 2007}} are based on [[Phobos (moon)|Phobos]] and [[Deimos (moon)|Deimos]]. These moons are in reasonably high orbits above Mars, have very low escape velocities, and unlike Mars have return [[delta-v budget|delta-v]]'s from their surfaces to [[Low Earth Orbit|LEO]] which are less than the return from the Moon.
===Ceres===
[[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.<ref name="Thomas2005">
{{cite journal | first=P.C | last=Thomas | coauthors=Parker J.Wm.; McFadden, L.A.; et.al. | title=Differentiation of the asteroid Ceres as revealed by its shape | year=2005 | journal=Nature | volume=437 | pages=224–226 | doi=10.1038/nature03938 | url=http://adsabs.harvard.edu/abs/2005Natur.437..224T}}</ref>
==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.<ref>
{{cite web
| title = NASA Capability Roadmaps Executive Summary
| publisher = NASA
| url = http://ntrs.nasa.gov/details.jsp?R=205136 }}
</ref>
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.
==See also==
*[[Asteroid mining]]
*[[David Criswell]]
*[[Design reference mission 3.0]]
*[[Gerard O'Neill]]
*[[Lunar Architecture (NASA)]]
*[[Lunar ice]]
*[[Lunar outpost (NASA)]]
*[[Mars Direct]]
*[[Paul Spudis]]
*[[Planetary surface construction]]
*[[Space colonization]]
== References ==
{{reflist|2}}
==External links==
*[http://science.nasa.gov/newhome/headlines/msad28apr98_1a.htm Homesteading the Planets with Local Materials]
*[http://www.isruinfo.com/ The Space Resources Roundtable]
*[http://www.aa.washington.edu/research/ISRU/ UW AA Dept. ISRU Research Lab]
*[http://www.newmars.com/wiki/index.php/ISRU_solar_cells ISRU solar cell manufacture]
*[http://www.lpi.usra.edu/lunar_knowledge/LTaylor.pdf ISRU on the Moon]
*[http://www.neofuel.com/mirf/ Moon Ice For LEO to GEO Transfers] Orders of magnitude lower cost for rocket propellant if [[lunar ice]] is present
[[Category:Mars missions]]
[[Category:Space colonization]]
[[Category:Space exploration]]
[[Category:Exploration of the Moon]]