April 30, 2019

Asteroid Mining: Getting the first mission off the ground

A fully-contained near-Earth asteroid retrieved to cislunar space can be used as a Research and Development destination for resource extraction and engineering tests as space-native material, unaltered by a radical change in environment, in industrial quantity, and in an accessible orbit.

As a geologist and data manager working in petroleum exploration, I'm not qualified to analyze an all-encompassing view of asteroid mining…but maybe I'm qualified to share what I see from my perspective.  Rather than looking at all the reasons why asteroid mining is not currently happening, I'd like to dive deep into how changing decision-making perspectives may make a mission possible.  

As human activity and accessibility to do business in space broadens, potential demand for resources delivered to space will also increase.  Now is the time to start looking at alternative sources of materials to fuel this expansion. Rather than launching everything from Earth, some materials could be sourced from near-Earth asteroids that are energetically easier to reach than our Moon.  While mining asteroids for bulk materials like water might be theoretically profitable compared to launch from Earth, the upfront costs so far have been prohibitive.  We've already seen the first wave of asteroid mining startups come and go.  The high cost of technology development and long timescales for return-on-investment have kept commercial asteroid mining missions grounded.

As proposed in a previous Asteroid Analytics post, asteroid mining is (not) dead.  Many others working on this problem share the sentiment[1].  It may be difficult but not impossible.

I believe the most cost-effective mission is one that reduces complexity, shortens timelines, and offers the greatest tonnage of material back to cislunar space.

With so many grand scales of space futurism portrayed in fiction, it's easy to imagine the eventual scale of such ventures without realizing the incremental first steps necessary to get there.  It's too expensive to get started, and nobody is willing to front the cost.  We can envision what a multi-trillion dollar space economy may look like...but maybe not the first mission.

Tycho Station from The Expanse. Artwork by Tim Warnock

We've watched over the past few years as companies like SpaceX have taken incremental steps to develop and test the Falcon 9 launch system (and now Starship).  Reliability, reusibility, and cost-competitiveness are key design components.  SpaceX has been successful because they are developing the technology of tomorrow while serving the customers of today.  This all is possible because NASA invested in this vision, paying for the technology development and becoming a customer of launch services via the Commerical Resupply Services program.  NASA and its international partners have also spent upwards of $150 billion over many decades to design, construct, and operate the International Space Station.  Without that sustained investment in infrastructure, there would be no destination to deliver commercial cargo services.

The Story of SpaceX's Falcon 9 Rocket by Kinematic

The first asteroid mining mission may not be performed until a government agency either funds the research and development of the technology, performs the mission themselves to demonstrate the technology, becomes the customer by agreeing to buy some certain refined material, or all of the above.  But perhaps most critically, it will require minimizing the upfront expenses, reducing complexity, reducing risk, reducing timelines, and reducing overall costs.

Goal: Get the first asteroid mining mission off the ground.

How does the first asteroid mining mission get off the ground?

First, we must define the goal of asteroid mining.  In its simplest form, the idea is to use robotic spacecraft to obtain material from asteroids and turn it into something useful that a customer might buy for use in cislunar space.  Ideally this would be a profitable endeavor to enable further activities and innovation in the future.

Planetary scientist Dr. Phil Metzger on what he thinks is one of the least appreciated aspects of space mining.

C-type asteroids have organic compounds and water that can be refined and used as rocket propellant.  S-type asteroids are abundant in silicates, which can be used to manufacture solar panels and electronics.  M-type asteroids have high metal concentrations, which are useful to manufacture structural components of large space facilities.  Nearly any material found on Earth can also be found in asteroids, and eventually every type of asteroid could be mined for some space-based use.  However, the infrastructure necessary to support that level of industry will require long-term maturation of the market.

Water makes sense as the primary first-order product.  Compared to other materials, it can be identified remotely (via the 3-micron absorption band[2]), requires minimal energy to extract and refine, and is useful for a variety of space activities.  Water is a high-performance, storable rocket propellant and perhaps the most versatile resource in these early days of humanity expanding into the Solar System.

"What we can do with asteroid water" - CNN interview with Chris Lewicki

The dynamic orbits of near-Earth asteroids also plays a huge role in filtering down the options for the earliest asteroid mining targets[3].  It's difficult to compare an asteroid mining mission with any of the asteroid science missions that have been conducted or are being planned because those missions are geared towards scientific return, technology development, and characterizing impact hazards.  Shifting the primary focus from scientific goals to industrial goals tends to change the calculus of how such a mission should be designed and executed.

Asteroids and the "Mass Payback Ratio"

There are many asteroids for whom the energy expenditure required to reach them is less than that required to rendezvous with the Moon.  Any mining hardware that is sent to an asteroid must be launched from Earth first, and this is where the "mass payback ratio"[4] comes in.  Assuming low-Earth orbit (LEO) is your staging point, the mass payback ratio is the amount of material that you can return to LEO given a particular mass that is first launched to LEO.  The staging point could be in Lunar orbit or some other orbit, and the principle would still apply.  Sending 10 tons of mining hardware from LEO to a near-Earth asteroid and returning 50 tons of useful material back to LEO yields a mass payback ratio of 5.  Maximizing the mass payback ratio increases the economic case for sourcing materials from near-Earth asteroids, regardless of launch costs.

Most of the proposed asteroid mining mission architectures tend to follow the same basic operational workflow:

  • Find many potential targets.
  • Filter down to low delta-v targets with short round-trip mission times.
  • Perform follow-up remote sensing observations.
  • Filter down targets again based on favorability results.
  • Plan and conduct reconaissance missions to one or more of the top targets to survey the asteroid's shape, size, spin rate, gravity, and composition with the possibility of sample return or in-situ sample analysis.
  • Filter down targets again based on favorability results.
  • Plan and conduct large-scale asteroid mining mission.
  • Extract and refine asteroid materials on-site.
  • Return only the finished product back to LEO or cislunar space for sale to customer.

This mirrors the way that terrestrial operations are structured for metal mining and petroleum extraction (which I am professionally familiar with).  Using this architecture involves a roughly 10-15 year timeline and at least single-digit billions of dollars of investment before the first drop of water or propellant is delivered to a customer.  For a mature industry, this makes a lot of sense, and indeed, asteroid mining is a long-term play[5].  Sending smaller reconaissance missions to many asteroids (and larger asteroids) helps to build a portfolio of profitable targets with scaled-up extraction operations.  But this is not reflective of the current situation regarding a fledgling space resource industry.

Challenges postponing the first asteroid mining mission:

The first mission will not be profitable

Due to the amount of technology development and upfront capital expenditure, it's unrealistic for companies or investors to expect a quick return-on-investment.  We're better off embracing that reality rather than willfully ignoring it.  Even so, designing the mission with long-term profitability and multiple branches of resource extraction would go a long way towards convincing a government agency or billionaire investor to finance it.  This will help to secure a future where the second/third/fourth missions are profitable and economically sustainable going forward.


On-site extraction is complex with many "unknown unknowns"

Nearly all concepts for asteroid mining involve sending the processing facility to the asteroid target and refining a certain resource on-site.  This is the best in terms of minimizing return payloads for use in cislunar space and setting up infrastructure for long-term operations. Manufacturing your own fuel for the return trip also helps get more mass back.  That is, assuming you find it in the expected concentration and the materials processing hardware doesn't fail due to an unforeseen issue.

However, this introduces a disproportionate amount of operational risk.  On one hand, there may be problems of structural integrity and dust environment, which you might not discover until you began to excavate large amounts of material.  On another hand, the issue of grappling or anchoring any smaller-than-asteroid spacecraft to perform such extraction would require very extensive engineering R&D which very likely could not be thoroughly tested in an operational environment prior to use.  Doing this autonomously adds an additional layer of complexity between software and hardware systems.

Sending reconnaisance spacecraft extends timelines

To develop this level of sophisticated and autonomous mining technology for a single high-stakes mission with reasonable expectations of success, you would almost certainly need to pare down this risk by sending reconnaissance spacecraft to perform an in-situ assessment.

Every asteroid science mission has yielded new questions regarding the science and understanding of asteroids.  The two asteroid sample return missions currently underway are having to problem-solve through unexpected hazards.  Asteroid Ryugu's surface is devoid of regolith and littered with boulders, while asteroid Bennu is mysteriously ejecting particles.

Each reconaissance mission costs money and time, reducing the profitability of the full-scale operation and further lengthening the financing timeline for return-on-investment.  It's difficult to play such a waiting game with someone else's money.

Reconaissance would theoretically be able to confirm the particle size distribution, homogeneity, and chemical composition of the surface and subsurface.  It may be able to rule out the physical dangers and risks of proximity spacecraft operations, but the economic concerns are much more nuanced.  Due to the complex nature of asteroid formation and reworking, such robotic rendezvous probe may still not sufficiently answer all the necessary questions to inform proper development of a full-scale mission to process the asteroid target for some prize material in economic quantities.

Put another way, the main reason for sending the reconaissance mission to conduct in-situ analysis is to lower the risk of failure for the large-scale mining mission.  The risk of failure can be drawn into two categories: operational risk and economic risk.

Operational risks - things that can kill your spacecraft

There may be unforeseen issue that would cause the entire mining mission to fail or would prompt a go/no go decision.  Maybe this asteroid is spinning too fast or is a weird shape, making it difficult to model and perform safe proximity operations with a spacecraft.  Maybe it's slightly too big for the capture enclosure or begins to shed materials in a dust cloud or tail.

Asteroid Bennu ejecting particles. Credit: NASA/Goddard/University of Arizona/Lockheed Martin

While these examples are real risks and possible scenarios, enough (but not all) operational risks can be pared down by a rigorous ground-based observing program prior to launch.  There are no technical show-stoppers which would require the extra expenditure and timeline of conducting a reconaissance mission[6]…at least for the first mining mission.

Economic risks - things that can kill your bottom line

As part of this rigorous ground-based observation, spectra of the asteroid should confirm the presence of hydrated minerals via the 3-micron band[2].  This doesn't necessarily rule out the possibility that the target asteroid might be "drier" than expected.  A reconaissance mission that observes the surface up close will likely clear up that ambiguity, but at what cost?  If it's assumed that the first mission will not be profitable, the risk of a delayed timeline is more critical to the overall life cycle of the mission (and potential for getting canceled) than the risk of bringing back a "less than optimal" ore body.  While in-situ measurements and "ground truth" are always good practice, the cost of a reconaissance probe is extremely high for what amounts to diminishing returns on the economic bottom-line.

Perhaps, this mission architecture is being over-engineered.  Complexity can easily snowball into more complexity.  To achieve a "Faster, Better, Cheaper"[7] outcome, a certain level of risk must be acceptable.

Viable solution:

Tackle the problem in manageable chunks.  Separate the capture/transport operations from extraction/refining.

As stated before, I believe the most cost-effective mission is one that reduces complexity, shortens timelines, and offers the greatest tonnage of material back to cislunar space.  If it is also sold as a mission that unlocks capability for multiple domains of space technology applications, then it would be more likely to get funded by government, private entities, or a public-private partnership.

There is strong rationale for performing fully-contained bulk transport of an asteroid back to cislunar space.  Not only would such a mission offer a fully intact asteroid for scientific study and multiple paths of resource utilization for commercial development, it could also successfully test technology for multi-purpose applications for impact deflection and military deterrence.

Asteroid mining rebranded as a bulk transport operation

One part of the solution is to remove the need for reconaissance missions by front-loading remote observations, which can be done relatively cheaply and on a more condensed time scale.  Target a small asteroid that can be fully captured inside an enclosure.  Narrow the scope of guided-autonomous robotics to only the rendezvous, capture, and de-spin operations.  Bring the entire asteroid back to cislunar space, and then send up additional extraction hardware to it.  These considerations are somewhat similar to NASA's now-defunded Asteroid Redirect Mission.  However, a bulk asteroid transport operation like this does not involve a human crew and can be performed at a fraction of the timeline and budget.

Most of the broad knowledge regarding asteroid populations has been gained due to near-Earth observation projects designed to discover potential impact threats.  There are some very powerful telescopes like the Large Synoptic Survey Telescope (LSST) coming online within the next few years which will vastly improve near-Earth asteroid discovery rates[8].  But where discovery ends, characterization must begin.  With many new potential targets, supporting this sort of mission architecture would require a broad set of facilities dedicated to follow-up observations close to the time of asteroid discovery, when these objects are nearest to Earth.  A previous Asteroid Analytics post using the example of near-Earth asteroid 2017 OM1 highlights a few of the challenges for follow-up observations.  Some facilities would need to be built or repurposed to characterize potential asteroid mining targets.

The major advantage is that all the critical go/no go decisions are made in the data gathering phase prior to launching any hardware to space.  Simplifying the payload on the rendezvous craft allows for more propellant to be carried, which maximizes the tonnage returned to cislunar space.  The mass payback ratio is key to asteroid operations, since the "return" trip is the maneuver requiring the least energy expenditure of the mission.

The asteroid 2016 BQ is a small, recently-discovered asteroid in a favorable orbit that can be observed within the next few years ahead of a mission launch in 5 years.  While chances are low that 2016 BQ is a good mining target, asteroids in similar orbits are good candidates for follow-up observations to obtain more accurate measurements of diameter, shape, and spectra.

NHATS info on 2016 BQ

If extraction is done after transport to cislunar, it opens up opportunities to utilize resources and techniques that may not be expected or are developed after the transport mission is complete.  Near real-time telerobotic operations are much less complex than autonomous systems and allow for troubleshooting and improvisation when encountering unforeseen issues.

Skipping reconaissance missions does come at the cost of potentially accepting the retrieval of a suboptimal ore body.  This trade-off is an intentional design decision for the first mission in order to minimize the overall "final return" timeline and decrease operational overhead costs to ensure that it results in something usable.  At the end of the mission, there's a physical asset ready for extraction, sale, or study rather than just data.  This is crucial because the mission provides material that both scientists and commercial entities will want to study, in addition to the proof-of-concept that this scale of asteroid retrieval is possible.  It's a sample return...but at wholesale price in bulk rather than single serve from a boutique brand.

A fully-contained near-Earth asteroid retrieved to cislunar space can be used as a Research and Development destination for resource extraction and engineering tests as space-native material, unaltered by a radical change in environment, in industrial quantity, and in an accessible orbit.

In the nominal "return only the asteroid's water back to cislunar" architecture, there's no possibility of using or testing extraction methods for additional resources like metals or silicates out of the leftover material.  Returning a whole asteroid in bulk can bootstrap future resource extraction.  Even if water is the "money-maker", selling the other bulk mass as a by-product for additional extraction or to manufacturing companies could kickstart many branches of resource supply chains in space.

First mission profile: Send a robotic mission to capture an entire small (5-10 m) hydrated (Ch or Cgh) asteroid on a low delta-v (4-6 km/s) trajectory with a short round-trip time (<1 year) in order to bring back material (water + rest of asteroid) for use in space (cislunar).

A mission like this paves the way for humanity's expansion into the Solar System.  We start by looking at reliable, low tech solutions and grow from there.  We have to walk before we can run.  Once someone fronts the cost for mining technology and infrastructure, the economics take over with massively transformative effects toward the progression of human civilization throughout the remainder of the 21st century and beyond.  If we aren't intentionally pushing against these barriers with thoughtful and rational approaches, then we will be ill-equipped to respond to their effects.

Discussion & Additional Considerations

With respect to remote sensing, determining the mass is one of the most difficult measurements to make.  If the asteroid has a moon (less likely with smaller targets), the radial velocity method can be used to determine the mass.  Radar astronomy is preferred, but there are very few high-powered planetary radar facilities available.  This method is also limited to when asteroids pass close to Earth, resulting in a high signal-to-noise ratio.  If you've also measured spin, taken spectra, and can determine shape from lightcurve data (or ideally radar), something can be said about the asteroid's composition and internal structure.  Without that crucial mass measurement, though, sending a spacecraft with a gravitometer is the only way to solve that variable.

Even with this "incomplete data" problem, ground-based methods are prefered from a cost standpoint, since they allow for fundamentally faster development iteration. There's lots of overlap with underlying technologies that are driven by economics unrelated to astronomy (CCDs, tracking algorithms, etc.), providing a forcing function for improvement.  This would cost less and require fewer personnel than a single reconaissance mission, with the ability to support multiple missions and begin to gather data on the entire near-Earth asteroid population rather than just a few individual asteroids.

Discovering, characterizing, and targeting a small (5-10m) asteroid is very difficult.  If you can carry, operate, and deploy a larger enclosure and can return a greater mass back to cislunar using available propulsion technology, then a larger asteroid would be favorable by all metrics.  The major consideration is to have reasonable diameter margins to avoid the embarrassment of pulling up to an asteroid that's just a bit too large for your enclosure.

Plucking a small boulder from a larger asteroid could also be an alternative.  This adds risk in the form of requirements for automated robotic grappling systems and additional complexity to the science payload to characterize which boulder is best.  There are also considerations of boulder integrity and dust environment.  This method would incur more development costs, but may lower the overall level of operational risk.

Artist's concept of NASA's Asteroid Redirect Robotic Mission capturing an asteroid boulder before redirecting it to a astronaut-accessible orbit around Earth's moon. Image Credit: NASA/JPL

If a mission targets an asteroid that had already been visited by a science probe, then this would pare down an immense amount of operational and economic risk across the board.  However, this may come at the expense of public backlash or navigating additional geopolitical, regulatory, and legal hurdles.  According to a common reading of the Outer Space Treaty of 1967, nobody can "claim" a celestial body.  However, the Commercial Space Launch Competitiveness Act (United States law) and the Law on the Exploration and Use of Space Resources (Luxembourg law) grant ownership rights to private companies for space resources that they extract.

NASA is currrently operating the ongoing OSIRIS-REx mission at the asteroid Bennu, but it can't "claim" Bennu for exclusive ownership.  If NASA enters a public-private partnership with an asteroid mining company to retrieve a piece of Bennu for NASA's scientific study and the company's economic development, could an unrelated third party (private or government) also do the same?

The considerations for asteroid mining are numerous and complex.  These are just a few of many routes that are worth pursuing.  I would love to hear feedback (info@asteroidanalytics.com) on ways this mission design breaks down or can be done better.  And while nobody has yet been able to execute the "right" answer, the expansion of humanity as a spacefaring and multi-planet species is reason enough to continue working the problem.  As we look ahead, we must always be mindful the cost of turning back too soon.

1. "Asteroid Mining is Dead... Long Live Asteroid Mining!" [2019]
JL Galache
2. "Hydrated Minerals on Asteroids: The Astronomical Record" [2002]
AS Rivkin, ES Howell, F Vilas, LA Lebofsky
Asteroids III 1, 235-253
3. "Availability and delta-v requirements for delivering water extracted from near-Earth objects to cis-lunar space" [2019]
R Jedicke, J Sercel, J Gillis-Davis, K Morenz, L Gertsch
4. "What Space Resources Will Let Us Do" [1987]
JS Lewis, R Lewis
Space Resources: Breaking the Bonds of Earth 333
5. "Mining off-Earth minerals: a long-term play?" [2014]
GA Craig, S Saydam, AG Dempster
6. "ASIME 2016 White Paper: In-Space Utilisation of Asteroids: "Answers to Questions from the Asteroid Miners"" [2016]
A Graps + 30 co-authors
7. "Faster, Better, Cheaper: A maligned era of NASA's history" [2019]
E Frank
8. "Modeling the Performance of the LSST in Surveying the Near-Earth Object Population" [2016]
T Grav, A Mainzer, T Spahr