John S Lewis

• Ph. D. in Geochemistry and Cosmochemistry, Univ. of California, San Diego
• Professor Emeritus at University of Arizona

The first asteroid simulants workshop was held in late 2015. These materials are needed for tests of technologies and mission operational concepts, for training astronauts , for medical studies, and a variety of other purposes. The new program is based on lessons learned from the earlier lunar simulants program. It aims to deliver families of simul...

Earth's global composition and its differentiation into core, mantle, and crust.

The most accessible bodies in the Solar System, namely those with propulsive energy requirements for accessing their surfaces that are less than that required for a round-trip to Earth's Moon, are members of the population of Near-Earth Asteroids (NEAs). The magnitude of the resources available for retrieval to Earth's surface or Low Earth Orbit is...

This paper describes the processes and challenges of producing high-fidelity asteroid simulants. DSI (in partnership with UCF) is producing four families of carbonaceous chondrite simulants: CI, CR, CM, and C2. Britt provided target mineralogies, recommendations for researcher safety considerations, and target physical characteristics of selected m...

Deep Space Industries is under contract to NASA to evaluate options for secondary spacecraft in support of the Asteroid Redirect Mission. One concept to enable broad participation by the scientific community is the Mothership of Asteroid CubeSats to deliver third-party experiments and sensors to a near Earth asteroid. The Mothership service include...

This paper provides a framework for evaluating trade-offs of science and prospecting instruments for asteroid flyby, orbital, and surface-contacting spacecraft.

This abstract reviews and seeks to apply concepts from terrestrial mineral exploration to NEA target identification and quantification of resource potential.

This report describes the results of a study sponsored by the Keck Institute for Space Studies (KISS) to investigate the feasibility of identifying, robotically capturing, and returning an entire Near-Earth Asteroid (NEA) to the vicinity of the Earth by the middle of the next decade. The KISS study was performed by people from Ames Research Cent...

This paper describes the results of a study into the feasibility of identifying, robotically capturing, and returning an entire Near-Earth Asteroid (NEA) to the vicinity of the Earth by the middle of the next decade. The feasibility of such an asteroid retrieval mission hinges on finding an overlap between the smallest NEAs that could be reasonably...

Chemical zoning of the Solar System, first noted by Harrison Brown in 1950, displays three major compositional classes distinguished by volatility, ranging from rocky material close to the Sun through ice-rock mixtures in more distant small bodies, to massive gas-giant planets rich in "permanent gases", notably hydrogen and helium. Spacecraft explo...

The use of mass drivers of adequate performance for planetary defense is discussed. Asteroids of 1 km in diameter or greater are focused because those rare impactors are responsible for the large majority of casualities and economic damage expected from NEO strikes. It is decided to baseline systems that were already off-the-shelf or in advanced de...

Space resources consist of all of the useful materials, energy sources, and energy found in space. For practical purposes, this article focuses on those resources that may be accessible within the next 25 years, and for which large‐scale demand is plausible. Therefore, the principal focus of this review is the bodies of nearby space: Earth's Moon,...

Stabilizing the carbon dioxide–induced component of climate change is an energy problem. Establishment of a course toward such stabilization will require the development within the coming decades of primary energy sources that do not emit carbon dioxide to the atmosphere, in addition to efforts to reduce end-use energy demand. Mid-century primary p...

Small Near-Earth Objects offer an opportunity for short-duration, low-Δv missions as the next logical step in human space activities beyond Earth orbit. Population characterization by groundbased observations using facilities including a Large Synoptic Survey Telescope is a critical precursor activity.

We are at a unique point in our exploration of the solar system in which missions to obtain samples from Near-Earth Asteroids (NEAs) are both required by the progress of asteroid and meteorite research and are technologically feasible. Recent successes with the Deep Space 1 and NEAR-Shoemaker missions have resolved many of the technical challenges...

Planetary science plays a unique role as the pathfinder for future human space activities beyond the International Space Station. It can also provide the rationale for the first human departure from LEO since the Apollo program. We are examining the potential for human missions to small near-Earth objects (typically tens of meters), passing close b...

A recent LPI workshop (summarized at the 32nd LPSC and AIAA Space 2001 meetings) addressed the scientific and engineering issues of NEA sample return. Participants of the workshop, and others, constitute the panel. The astronomical study of asteroids and the laboratory study of meteorites contribute considerably to the issues identified in the NASA...

The rate of discovery of new NEAs and the success of D-S 1 and NEAR-Shoemaker, suggest that sample return from NEAs is now technically feasible. Here we present a summary of a recent workshop on the topic.

Materials extracted from Near-Earth Asteroids may find use in future space-based activities as propellants, life-support fluids, or structures. The utility of any space resource is governed by several factors, including energetic accessibility from Low Earth Orbit (LEO), resource concentration, availability of appropriate microgravity extraction an...

Why does researchgate routinely identify books as "articles"?

We have started a systematic collection and analysis of meteoritic materials from Meteor Crater, Arizona. Since our earlier report (Kargel, J.S., Kraft, M.D., Roddy, D.J., Wittke, J.H., and Lewis, J.S., 1995, Eos, v. 76, p. F337), we have found 47 small fragments of the Canyon Diablo iron meteorite. We also have collected impactite lapilli; oxidize...

A weighted average composition is suggestd as the "Best Bulk Silicate Earth" (BBSE). BBSE, thought to represent Earth's primitive mantle (modern mantle + crust), is a concept based on analyses of oceanic theoleiites and continental flood basalts, oceanic and continental alkali basalts, ultramafic ophiolites, Archean komatiites, and spinel- and garn...

K/T-Mass extinctions: some astronomical constraints; the dynamical properties of near-earth objects; predicting close earth approaches of asteroids and comets; Australiasian Near-Earth Object programs; the cosmic impact hazard; large body impacts and mass extinction events: evidence from the cretaceous/tertiary boundary and a possible general relat...

Parts of the solar system that are most accessible from Earth - the Moon, near-Earth asteroids, Mars and its moons - are rich in materials of great potential value to humanity. The book, comprising over 30 separately authored contributions, explores the possibility of utilizing these materials to produce propellants, structural materials, refractor...

The meteorites that fall on Earth are necessarily samples of the near-Earth population of small solar system bodies, and hence are a very useful guide to the nature of the materials available in near-Earth space. The authors review the compositions of the most abundant classes of noncarbonaceous meteorites that fall on Earth for the purpose of iden...

A preliminary survey of Magellan imagery reveals more than 200 newly discovered relic channel and valley landform complexes. For purposes of discussion the channels can be classed as simple, complex, and compound. Integrated valleys also occur. Simple channels include: (1) sinuous rilles that closely resemble their lunar counterparts and (2) a newl...

This report concerns several research tasks related to the origin and evolution of planetary atmospheres and the large-scale distribution of volatile elements in the Solar System. These tasks and their present status are as follows: (1) we have conducted an analysis of the volatility and condensation behavior of compounds of iron, aluminum, and pho...

There are three types of possible asteroidal materials that appear to be attractive for exploitation: (1) volatiles, (2) free metals, and (3) bulk dirt. Because some of the near-Earth asteroids are energetically more accessible than the Moon (require a round-trip total change in velocity less than 9 km/sec, though the trip time would be measured in...

The status of research on the importation of energy and nonterrestrial materials is reviewed, and certain specific directions for new research are proposed. New technologies which are to be developed include aerobraking, in situ propellant production, mining and beneficiation of extraterresrrial minerals, nuclear power systems, electromagnetic laun...

An overview is presented of near-earth asteroids, whose orbits cross those of the inner solar system planets including earth. It is suggested that a mission to an asteroid that comes close to earth may provide a significant technological challenge to advance the search for a base on Mars, reveal the answers to current problems regarding the nature...

Hydrated magnesium sulfate constitutes up to 1/6 of the mass of carbonaceous chondrites, and probably is important in many icy asteroids and satellites. It occurs naturally in meteorites mostly as epsomite. MgSO4, considered anhydrously, comprises nearly 3/4 of the highly soluble fraction of C1 chondrites. Thus, MgSO4 is probably an important solut...

The laboratory-measured viscosities of liquid mixtures representative of the variety of cryovolcanic substances of the icy satellites are presently noted to be much greater than could be expected on the assumption that end-member molecules are noninteractive; this observation is supported by others concerning molar volumes and vapor pressure relati...

The highly reduced nature of the enstatite meteorites (chondrites and achondrites) differs from that of all other types of stony meteorites. The silicates in the enstatite meteorites contain almost no FeO. In addition, many normally lithophile elements such as Na, Ca, Mg, Cr, and Ti display chalcophilic behavior. A study of the chemistry and minera...

Because of a change in the NASA funding cycle, the present reporting period covers only the six months from March to September 1991. Nevertheless, remarkable progress was made in a number of areas, some of the most noteworthy of which are: (1) Engineering operation of a breadboard CO2 yields O2 demonstration plant that produced over 10 grams of oxy...

Studies of the system architectures for acquisition, processing, and transportation of key nonterrestrial materials (structural metals, propellants, and radiation shielding) to near-earth space suggest that the ideal target orbit for retrieval of materials from the moon, nearby asteroids, and the Martian moons is highly eccentric earth orbit of alm...

The possibility of using the lunar regolith and the atmosphere of Uranus as a source of He-3 for fusion power on earth is examined. The energetic costs of acquiring, isolating and transporting He-3 to earth from the moon and from Uranus are compared. It is shown that the total energy expended per ton of He-3 retrieved from the atmosphere of Uranus...

The solar system is believed to have formed from a primordial gas and dust cloud, i.e., the primitive solar nebula (PSN). Constraints on the chemical composition and structure of the PSN are provided by ovserved densities and compositions of the planets, the asteroids and meteorites together with theoretical modelling. Many of these properties can...

We present results of an extensive laboratory and telescopic investigation of H2O distribution among the low-albedo, outer belt asteroids (2.5–5.2 AU). The water distribution was determined by surveying asteroids in that region for the 3-ωm reflectance absorption of molecular H2O and structural OH ions; the 3-ωm band is the spectral signature of me...

The NASA/University of Arizona Space Engineering Research Center is dedicated to research on the discovery, characterization, mapping, beneficiation, extraction, processing, and fabrication of useful products from extraterrestrial material. Schemes for the automated production of low-technology products that are likely to be desired in large quanti...

Several lines of evidence concerning the vertical abundance profile of water in the atmosphere of Venus lead to strikingly unusual distributions (the water vapor abundance decreases sharply in the immediately vicinity of the surface) or to serious conflicts in the profiles (different infrared bands suggest water abundances that are discrepant by a...

Modeling of physical and chemical processes in solar nebula environments is applied to the present data base on the composition of gases in Halley's comet to infer the conditions under which that comet formed. Key molecular ratios—CH4 to CO, CO2 to CO, and NH3 to N2—are compared to predictions of solar nebula models. Nebular thermochemistry is quan...

Various theories on the nature and formation of the solar system are described. Particular attention is given to two models: a model involving the accretion of asteroid-sized bodies from which the planets ultimately accumulate, and a model involving the detachment of unstable rings of material from the contracting nebula's outer edge. Possible futu...

The abundances of the elments and their chemical compounds in the atmospheres of Solar System bodies (planets and major satellites) are reviewed with the purpose of deriving information about the relationships between planetary volatiles and pre‐planetary material of galactic origin. In general, the processes affecting the compositions of the atmos...

Extraterrestrial materials, processes, and products were identified which are associated with the production of propellants in space, including the most complete possible conversion of the feedstocks for propellant production into useful products with the minimum feasible expenditure of energy. Laboratory research was identified and begun on severa...

The possible processes involved in making planets from initially volatile ingredients are discussed, with consideration given to the process of equilibrium condensation, the transport of volatiles, and the chemical kinetics of the nebula. Particular attention is given to the question of the nature of mass accretion, i.e., a homogeneous accretion vs...

The short lifetime of water on Venus suggests that the water abundance is in a near steady-state balance between loss by escape and replenishment by infall. In addition, the observed deuterium-to-hydrogen ratio on Venus is consistent with a steady state and does not necessarily imply a past water excess. We present results of a model incorporating...

The predictions of the expected range of composition of Mercury at the time of its formation made on the basis of a suite of condensation-accretion models of Mercury spanning a range of condensation temperature and accretion sampling functions appropriate to Mercury are examined. It is concluded that these compositonal models can, if modified to ta...

The origin and early history of Mars and the relationship between Mars and the other planets are reviewed. The solar system formation and planetary differentiation are examined using data from planetary missions. Different views of Mars are presented, showing how ideas about the planet have changed as the amount of available observational data has...

It is suggested that the Mond process for carbonyl extraction of metals from ore may be used as an efficient, low-energy scheme for producing high-purity Fe, Ni, Cr, Mn, and Co from lunar or asteroidal feedstocks. It is proposed that scenarios for obtaining oxygen from the lunar relogith can be enhanced by carbonyl processing of the metallic alloy...

Bombardment of Titan by Uranus-Neptune planetesimals and/or fragments of a disrupted Hyperion progenitor supplied more than enough energy to drive vigorous atmospheric shock chemistry. Chemical equilibrium modeling of the shock products in simulated atmospheres indicates that impact energy has produced large amounts of N2 and organic compounds over...

The refractory inclusions in carbonaceous chondrites were the subject of considerable interest since their discovery. These inclusions contain minerals that are predicted to be some of the earliest condensates from the solar nebula, and contain a plethora of isotopic anomalies of unknown origin. Of particular interest are those coarse-grained inclu...