"Asteroid mining has been proposed as an approach to complement Earth-based supplies of rare earth metals and supplying resources in space, such as water. However, existing studies on the economic viability of asteroid mining have remained rather simplistic and do not provide much guidance on which technological improvements would be needed for increasing its economic viability."

"It is concluded that key technological drivers for asteroid mining missions are throughput rate, number of spacecraft per mission, and the rate in which successive missions are conducted."

"Regarding the supply of resources to Earth, only resources with a high value to mass ratio are interesting, due to the high cost of returning such material. Therefore, high-value metals such as rare earth metals and in particular the subgroup of platinum group metals have been the subject of mining studies."

"we specifically focus on economic viability compared to immediate alternatives, such as terrestrial mining and direct delivery of resources from Earth to space."

"probability that the elasticity is not lower than 0.25. This model has assumed that the quantity of platinum in the global market is the only factor affecting its price. However, platinum is a speculative asset as well as a useful rare earth and precious metal. Its price is subject not only to supply and demand, but to speculation."

"Craig et al. [32] provide a year-by-year cash flow analysis for a mining mission, using the M-type NEA 1986 DA as a case study. They conclude that a mining venture would currently be too risky to commercially succeed."

"It can be seen that the reduction of the throughput rate has a large effect on profitability and would render it not profitable."

"The value of 0.35 kg/s/kg seems very high. The spacecraft would need to be able to process the equivalent of its own mass within 3 seconds."

"it can be therefore seen that long-term prices of platinum would have a significant impact on asteroid platinum mining viability."

"The results indicate that asteroid water mining would have environmental benefits, as soon as the amount of water supplied via mining is larger than the mass of the spacecraft used for mining."

"For platinum mining, we find that by comparing the operations phase of terrestrial and space mining, space mining would have a lower environmental impact, if the spacecraft is able to return between 0.3 to 7% of its mass in platinum to Earth, assuming 100% primary platinum or 100% secondary platinum, respectively."

"Mines tend to go deeper and deeper, as resources in upper layers are depleted, which increases already high greenhouse gas emissions (currently ~40,000t CO2 per ton of platinum)."

"However, there are two major concerns regarding platinum group metals. First, current supplies of platinum group metals are dominated by only a few countries, namely, South Africa, Russia, and Canada, which introduces political uncertainties into the supply chain."

"Despite the potential environmental benefits of asteroid mining, either by reducing the number of launches into space or moving terrestrial industries into space, no dedicated studies for exploring these benefits has been conducted to the authors' knowledge. Existing research on asteroid mining has mainly looked into its economic viability."

"They refer to the benefits of asteroid mining for the environment and sustainability, but do not provide any analysis or quantitative backing."

"For future work, we propose a more detailed analysis, based on a more precise inventory and a larger system boundary, including the production of the launcher and spacecraft."

"A simple formalism is presented to assess how many asteroids contain ore, i.e. commercially profitable material, and not merely a high concentration of a resource."

"Ore is not simply a high concentration of some resource, but includes consideration of the cost of extraction of the resource and its price."

"Assuming for now that only Ni-Fe asteroids are of interest for PGMs, then 1% of NEOs are rich in PGMs. The dearth of ultra-low delta-v (<4.5 km s⁻¹) NEOs larger than 100 m diameter reduces the ore-bearing fraction to only ~1 in 2000 NEOs... the total population of PGM ore-bearing NEOs is roughly 10."

"I stress that this is a conservative and highly uncertain value. For example, an order of magnitude increase in PGM ore-bearing NEOs occurs if delta-v can be as large as 5.7 km s⁻¹."

"Water ore for utilization in space is likely to be found in ~1/1100 NEOs."

"NEOs as small as 18 m diameter can be water-ore-bodies because of the high richness of water (~20%) expected in ~25% of carbonaceous asteroids, bringing the number of water-ore-bearing NEOs to ~9000 out of the 10 million NEOs of this size."

"These estimates are at present highly imprecise and sensitive to small changes, especially in the maximum delta-v allowed. Nonetheless the low values found here mean that much improved determinations of each of the terms of the formalism are urgently needed."

"These meteorites, considered analogues of undifferentiated asteroids, preserve materials from the early solar system and provide a geochemical record of their parent bodies. Our results highlight the abundance and distribution of transition metals, siderophile elements, and rare earth elements across several chondrite groups."

"On the bulk Earth upper crust there is from 10 to 100 times more REEs than on CCs. Based on the results in Fig. 7, investing in mining to extract REE from CCs parent asteroids seems not worthy."

"We think that the asteroids can be a good supply for certain transition elements, which may be useful in future space missions."

"Data are presented for all six platinum group elements (PGE) plus gold."

"The AMS data suggest a variation in overall precious-metal abundances of a factor of 16 between the most-enriched (Negrillos, ΣPGE + Au = 270 ppm) and the least-enriched (Welland, 16–19 ppm)."

"We have measured the abundances of seven precious metals in Ni-Fe phases (kamacite and plessite) in six iron meteorites. These in-situ analyses, obtained by accelerator mass spectrometry (AMS) on small polished samples previously characterized by electron microprobe techniques, constrain the distribution of the rare siderophile elements."

"A clear illustration of the use of AMS data for provenance studies of meteoritic iron is presented for the Welland IIIA iron, an 1888 find from Ontario. Few published data are available for Welland: comparison of a type sample with a smaller piece of unknown metal, with respect to chondrite-normalized PGE patterns, major-element chemistry and textures of the metals, strongly support a suggestion that the latter is a fragment of the same iron."

"Recent discoveries of near-Earth asteroids (NEAs) and chemical analyses of fragments of asteroids (meteorites) suggest that there may be a gold mine, literally, in near-Earth space."

"Judged from meteorite analyses, two types of asteroids offer particularly bright prospects for recovery of large quantities of precious metals (defined as Au, Pt, Ir, Os, Pd, Rh, and Ru), the ordinary LL chondrites, which contain 1.2–5.3% Fe-Ni metal containing 50–220 ppm of precious metals, and metallic asteroids, which consist almost wholly of Fe-Ni phases and contain variable amounts of precious metals up to several hundred ppm."

"The pulverized regolith of LL chondrite asteroids could be electromagnetically raked to separate the metallic grains. Suitable metallic asteroids could be processed in their entirety. Statistically, there should be approximately six metallic NEAs larger than 1 km in diameter that contain over 100 ppm of precious metals."

"It was thought to be the exposed core of a protoplanet, but observations reported in 2020 have cast doubt on that hypothesis."

"However, most recent estimates have begun to converge on values near (2.29±0.14)×1019 kg. Assuming the mean volume of (5.75±0.19)×106 km3, this equates to a bulk density of 3.977±0.253 g/cm3, which is considerably higher than most small Solar System bodies."

"The bulk density of Psyche (3.9±0.3 g/cm3) places constraints on its overall composition. The iron-nickel found in most iron meteorites has a bulk density of 7.9 g/cm3. If Psyche were the remnant core of an early planetesimal, it would have an overall porosity of 50%. Given Psyche's size, this is considered improbable."

"However, this idea has fallen out of recent favor as mass and density estimates are inconsistent with a remnant core."

"A second hypothesis is that Psyche was disrupted and gravitationally re-accreted into a mix of metal and silicate. In this case, it may be a candidate for the parent body of the mesosiderites, a class of stony–iron meteorites."

"No spacecraft has visited Psyche, but a mission to Psyche was proposed to NASA in 2014. A team led by Lindy Elkins-Tanton, the director of the School for Earth and Space Exploration at Arizona State University, presented a concept for a robotic Psyche orbiter. This team argued that 16 Psyche would be a valuable object for study because it is the only metallic core-like body discovered so far."

"The bulk density of Psyche is too low for it to be a predominantly metallic body. With the meteoric Fe-Ni mineral kamacite having a 1 atm density of 7,870 kg/m³, a bulk porosity of ∼50% would be required if Psyche consists mostly of this metal (Elkins-Tanton et al., 2020)."

"Carry (2012) found that most asteroids more than 200 km in diameter have a bulk porosity of <10%."

"Asteroid 16 Psyche's surface appears to be highly metallic, but its bulk density suggests a silicate-rich interior. Ferrovolcanism has been suggested to explain how a silicate-rich body could develop a metallic surface."

"The considered endmember meteorite building blocks of Psyche are an ordinary chondrite, an enstatite chondrite and a mesosiderite, with the used bulk compositions presented in Jorritsma and van Westrenen (2025)."

"Core size, light element partitioning between mantle and core, and silicate mass loss are calculated for three meteoritic bulk compositional models (H-chondrite, EH-chondrite and mesosiderite) based on mantle density and mantle porosity combinations."

"These bulk density estimates indicate that Psyche either has considerable porosity, considerable non-metallic constituents, or a combination of both."

"Asteroid (16) Psyche (henceforth referred to as Psyche), the largest M-type (metallic) Main Belt Asteroid (MBA), is the subject of a forthcoming National Aeronautics and Space Administration (NASA) discovery mission."

"Asteroid 16 Psyche is the largest metallic Main Belt Asteroid and is the subject of a forthcoming NASA mission. The composition of Psyche is still unknown and subject of recent debate."

"In particular, how much porosity is within Psyche, along with how much of Psyche consists of non-metallic versus metallic materials, are central questions to the issue of Psyche’s composition."

"If Psyche is indeed predominantly composed of metallic materials, it would need to have considerable porosity (∼ 30–50%) for a composition consistent with its expected bulk density (∼ 3.7–4.1 g/cm3)."

"Recent estimates for bulk densities within the median range have called into question that Psyche is an intact metal (iron) core remnant. These bulk density estimates indicate that Psyche either has considerable porosity, considerable non-metallic constituents, or a combination of both."

"The degree of porosity and amount of non-metallic materials comprising Psyche is one of the most pressing questions regarding Psyche's composition."

"Through 3D computational models of Psyche's deepest impact structure, we show that Psyche's composition is unlikely to contain only pseudo-microporosity. Rather, rubble pile structures, which include macroscopic voids, are shown to match the crater's measured aspect ratio better than simulations of structures that included only pseudo-microporosity."

"Through 3D hydrocode simulations, we conclude that Psyche likely contains density variations at a variety of spatial scales."

"Our best matches to current crater dimensions resulted from simulations of Psyche as a rubble pile."

"it is reasonable to consider the possibility of several different types of porosity within Psyche's structure, such as uniform pseudo-microporosity, layered pseudo-microporosity (with lower pseudo-porosity values in the interior and a less dense regolith at the surface), and macroscopic voids or rubble-like structures."

"Ultimately, it is likely that Psyche includes porosity across a wide range of length scales."

"The Psyche mission is a journey to a unique metal-rich asteroid orbiting the Sun between Mars and Jupiter."

"What makes the asteroid Psyche unique is that it appears to be the exposed nickel-iron core of an early planet, one of the building blocks of our solar system."

"Deep within rocky, terrestrial planets - including Earth - scientists infer the presence of metallic cores, but these lie unreachably far below the planets' rocky mantles and crusts. Because we cannot see or measure Earth's core directly, Psyche offers a unique window into the violent history of collisions and accretion that created terrestrial planets."

"Determine whether Psyche is a core, or if it is unmelted material."

"Although widely assumed to be metal-rich (the reason for use of "M" in the classification), the evidence for a high metal content in the M-type asteroids is only indirect, though highly plausible."

"High resolution spectra of the M-type have sometimes shown subtle features longward of 0.75 μm and shortward of 0.55 μm. The presence of silicates is evident in many, and a significant fraction show evidence of absorption features at 3 μm, attributed to hydrated silicates. The presence of silicates, and especially hydrated silicates, is at odds with the traditional interpretation of M-types as remnant iron cores."

"None of the M-type asteroids have bulk densities consistent with a pure iron-nickel core."

"We estimate that the cost of delivering this propellant from an asteroid to low-Earth orbit (LEO), $2–3000 per kilogram, could be comparable to the estimated costs of delivering propellant to LEO using a Falcon Heavy."

"Deprived of the market in LEO, we estimate the cost of delivering asteroid-derived propellant to lunar orbit is at least $3600 per kilogram."

"The economic viability of asteroid resources for space missions is driven by three major factors: the cost of the asteroid mining and in-space processing infrastructure; the total demand for the in-space resources over which the infrastructure cost is spread; and the competing cost of launching those same resources from Earth."

"water for on-orbit propellant is the only asteroid-derived resource that may become economical in our period of interest."

"We estimate that demand for LOX/LH2 propellant in space over this 20-year period is about 6000–10,000 metric tons."

"As of 2026, sending a payload to low Earth orbit costs about $3,000 per kilogram on a reused SpaceX Falcon 9 — down from roughly $54,000/kg on the Space Shuttle, a drop of more than 90% in two decades."

"Starship targets under $100–200/kg once fully reusable."

"It depends on the vehicle. Falcon 9 lists near $69.75M (~$3,000/kg at max payload, ~$2,700/kg reused). Rocket Lab Electron is ~$7.5M for 300 kg (~$25,000/kg). Rideshare slots start near $6,000/kg with a ~50 kg minimum. Starship targets under $100–200/kg once fully reusable."

"Asteroid 162173 Ryugu (1999 JU3) is a member of the Apollo group and has a delta-v of 4.646 km s⁻¹. This asteroid is the target body of the Hayabusa2 mission."

"The albedo and rotational period of this asteroid have been estimated to be 0.05 and 7.6311 hr, respectively (Müller et al. 2017)."

"The primary target body of Hayabusa2 was asteroid 162173 Ryugu; however, it was also necessary to gather physical information for backup target selection. Therefore, we examined five asteroids spectroscopically, 43 asteroids spectrophotometrically, and 41 asteroids through periodic analysis. Hence, the physical properties of 74 near-Earth asteroids were obtained, which helped the Hayabusa2 backup target search, and also furthered understanding of the physical properties of individual asteroids and their origins."

"Following the success of the Itokawa rendezvous performed by the Hayabusa spacecraft, a subsequent asteroid exploration project, 'Hayabusa2,' was planned (Tsuda et al. 2013). The objective of the Hayabusa mission was demonstration of sample return technology; thus, the target body was an object reachable by the Mu-5 launch vehicle."

"Sample return from the near-Earth asteroid known as 25143 Itokawa was conducted as part of the Hayabusa mission, with a large number of scientific findings being derived from the returned samples. Following the Hayabusa mission, Hayabusa2 was planned, targeting sample return from a primitive asteroid."

"The key issue is that the availability of water in NEOs remains uncertain. Elvis (2014) asserted that 'water ore for utilization in space is likely to be found in 1/1100 NEOs' but we will argue that this estimate is too pessimistic and is not supported by evidence on the taxonomic classification of smaller, minable NEOs."

"The fraction of near-Earth asteroids containing water-bearing minerals appears to increase for smaller asteroids."

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

"The use of ISRU for material production has not yet been implemented in a space mission, though several field tests in the late 2000s demonstrated various lunar ISRU techniques in a relevant environment."

"On April 20, 2021, MOXIE produced oxygen from carbon dioxide in the Martian atmosphere by using solid oxide electrolysis. This was the first experimental extraction of a natural resource from another planet for human use."

"it was projected, for example, in a mission of four astronauts on the Martian surface for a year, only about 1 metric ton of oxygen would be used for life support for the entire year, compared to about 25 metric tons of oxygen needed for propulsion off the surface of Mars for the return mission."

"The successful delivery of 4.3 ounces (122 grams) of material from near-Earth asteroid Bennu marked a pivotal moment in space exploration."

"We measured the mineralogy and bulk chemical and isotopic compositions of Ryugu samples. The samples are mainly composed of materials similar to those of carbonaceous chondrite meteorites, particularly the CI (Ivuna-type) group."

"As of 2024, no commercial asteroid mining efforts have been successful, although several government-led missions have successfully returned asteroid samples."

"Odin launched on 27 February 2025 as a rideshare of the IM-2 lunar mission; it failed due to ground station and communication issues."

"Although there have been a number of robotic missions that have returned asteroid material to Earth (JAXA's Hayabusa and Hayabusa2 probes along with NASA's Osiris-REx probe), the process has yet to be commercialized, or completed on an M-type asteroid given that the past research targets of JAXA and NASA were C-type asteroids."

"AstroForge is not interested in this concept due to the lack of a current market for interplanetary fuel depots."

"Following financial troubles caused by 'delayed investment', it was announced on 31 October 2018, that the company's human assets were purchased by the blockchain software technology company ConsenSys, Inc."

"In May 2020, ConsenSys made all Planetary Resources intellectual property available to the public domain, and in June 2020, all the remaining hardware assets were auctioned off."

"The Commercial Space Launch Competitiveness Act, sometimes referred to as the Spurring Private Aerospace Competitiveness and Entrepreneurship (SPACE) Act of 2015, is an update of the United States Government of its commercial space use, legislated in 2015. The update to US law explicitly allows US citizens and industries to 'engage in the commercial exploration and exploitation of space resources' including water and minerals."

"The law was passed on May 21, 2015 to allow US industries to 'engage in the commercial exploration and exploitation of space resources', but it asserts that 'the United States does not [by this Act] assert sovereignty, or sovereign or exclusive rights or jurisdiction over, or the ownership of, any celestial body.'"

"Some scholars argue that the United States recognizing ownership of space resources is an act of sovereignty, and that the act violates the Outer Space Treaty."

"The first is in-situ resource utilization (ISRU), in which resources are extracted from a celestial body to be used for other in-space activities. The second is the extraction of resources from a celestial body and the transport of those resources to Earth to be used for commercial purposes."

"More recent density measurements also suggest Psyche may not be as metal-rich as once thought. Rather than being a solid iron-nickel body, the asteroid likely has a porous, sponge-like interior with empty spaces and a mixture of metals and silicate rock. Psyche's density is estimated to be around 3.9 grams per cubic centimeter, about half of what would be expected for solid iron-nickel."

"While sensational estimates of Psyche's trillion-dollar value are unrealistic and misleading, this metal world still holds immense scientific and potential economic importance."

"However, Elkins-Tanton notes this estimate is essentially meaningless, as there is currently no technology available to mine and transport Psyche’s resources back to Earth. Additionally, introducing such a large supply of precious metals would completely disrupt the global economy and commodities markets, rendering the metals nearly worthless."