How many ore-bearing asteroids?

Abstract

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. I apply this formalism to two resource cases: platinum group metals (PGMs) and water. 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. As 100 m diameter NEOs are needed to have a value ≥US$1 B and the population of near--Earth objects (NEOs) larger than 100 m diameter is 20,000 (Mainzer et al. 2011) 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 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 small NEOs are, however, hard to find with present surveys. There will be 18 water--ore--bearing NEOs >100 m diameter. 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. If better estimates still find small numbers of ore--bearing NEOs then thorough surveys for NEA discovery and, especially, characterization are needed. Strategies for the two classes are likely to be different.

A trio of horseshoes: past, present and future dynamical evolution of Earth co-orbital asteroids 2015 XX 169 $\mbox{XX}_{169}$ , 2015 YA and 2015 YQ 1 $\mbox{YQ}_{1}$

“…5 Both are horseshoe li- brators like the NEAs discussed here. Other NEAs experiencing horseshoe behaviour are 54509 YORP (2000 PH 5 ) Margot & Nicholson 2003), 2001 GO 2 Margot & Nicholson 2003;Brasser et al 2004), 2002 AA 29 Brasser et al 2004), 2003YN 107 (Brasser et al 2004Connors et al 2004) Elvis 2012Elvis , 2014García Yárnoz et al 2013;Harris & Drube 2014). The three objects studied here and several other Earth co-orbitals are included in the NHATS list of potentially accessible targets that compiles attractive objects of interest for, e.g., future robotic missions.…”

What can space resources do for astronomy and planetary science?

“…Both plan to mine water from near-Earth asteroids as their first "ore", and both expect to send out their first small experimental interplanetary spacecraft to asteroids within 5 years. Water ore bodies among the asteroids may be relatively hard to find [14] requiring large numbers of probes, each one of which must then be cheap in order to close the business case.…”

How Many Hydrated NEOs Are There?

“…Sanchez and McInnes () made an estimate of the liters of water available for mining in the NEO population but were focused on dynamical and engineering topics and did not consider the number of objects this water would be contained in. Elvis () also addressed this question from a somewhat more engineering‐ and economics‐based angle than we use, quantifying the number of ore‐bearing asteroids ( N ore ) as where P ore is the probability the object is ore bearing and M min is the minimum profitable mass .…”