New NASA mission to help us learn how to mine asteroids

Aug 08, 2013
These photos show the relative size of three asteroids that have been imaged at close range by spacecraft. Mathilde (37 x 29 miles) (left) was taken by the NEAR spacecraft on June 27, 1997. Images of the asteroids Gaspra (middle) and Ida (right) were taken by the Galileo spacecraft in 1991 and 1993, respectively. Credit: NASA/JPL/NEAR and Galileo missions

Over the last hundred years, the human population has exploded from about 1.5 billion to more than seven billion, driving an ever-increasing demand for resources. To satisfy civilization's appetite, communities have expanded recycling efforts while mine operators must explore forbidding frontiers to seek out new deposits, opening mines miles underground or even at the bottom of the ocean.

Asteroids could one day be a vast new source of scarce material if the financial and technological obstacles can be overcome. Asteroids are lumps of metals, rock and dust, sometimes laced with ices and tar, which are the cosmic "leftovers" from the solar system's formation about 4.5 billion years ago. There are hundreds of thousands of them, ranging in size from a few yards to hundreds of miles across. Small asteroids are much more numerous than large ones, but even a little, house-sized should contain metals possibly worth millions of dollars.

There are different kinds of asteroids, and they are grouped into three classes from their spectral type – a classification based on an analysis of the light reflected off of their surfaces. Dark, carbon-rich, "C-type" asteroids have high abundances of water bound up as hydrated clay minerals. Although these asteroids currently have little economic value since water is so abundant on Earth, they will be extremely important if we decide we want to expand the human presence throughout the solar system.

"Water is a critical life-support item for a spacefaring civilization, and it takes a lot of energy to launch it into space," says Dante Lauretta of the University of Arizona, Tucson, principal investigator for NASA's OSIRIS-REx asteroid sample return mission. "With launch costs currently thousands of dollars per pound, you want to use water already available in space to reduce mission costs. The other thing you can do with water is break it apart into its constituent hydrogen and oxygen, and that becomes , so you could have fuel depots out there where you're mining these asteroids. The other thing C-type asteroids have is organic material – they have a lot of organic carbon, phosphorous and other key elements for fertilizer to grow your food," said Lauretta.

This video is not supported by your browser at this time.
OSIRIS-REx will visit a Near Earth asteroid called Bennu and return with samples that may hold clues to the origins of the solar system and perhaps life itself. It will also investigate the asteroid's chance of impacting Earth in 2182. For the mission, NASA has selected the team led by Principal Investigator Dr. Dante Lauretta from the University of Arizona. NASA GSFC will manage the mission and Lockheed Martin Space Systems will build the spacecraft. Arizona State University will supply the OTES instrument; NASA GSFC will supply the OVIRS instrument; the Canadian Space Agency will supply the OLA instrument; the University of Arizona will supply the OCAMS camera suite; Harvard/MIT will supply the REXIS instrument; and Flight Dynamics will supply the KinetX instrument. Credit: NASA

Somewhat brighter asteroids have a stony composition. These "S-type" asteroids have very little water but are currently more economically relevant since they contain a significant fraction of metal, mostly iron, nickel and cobalt.

"However, there are a fair amount of trace elements that are economically valuable like gold, platinum and rhodium," said Lauretta. "A small, 10-meter (yard) S-type asteroid contains about 1,433,000 pounds (650,000 kg) of metal, with about 110 pounds (50 kg) in the form of rare metals like platinum and gold," said Lauretta.

There are rare asteroids with about ten times more metal in them, the metallic or "M-class" asteroids, according to Lauretta.

However, it currently costs hundreds of millions to billions of dollars to build and launch a space mission, so innovations that would make these costs fall dramatically are needed before it is profitable to mine asteroids for the value of their metals alone.

Another obstacle is simply our lack of experience with mapping and analyzing the resources in asteroids to extract material from them. This critical experience will be gained with NASA's asteroid sample return mission, OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security and Regolith Explorer).

The spacecraft, scheduled for in September 2016, will arrive at the asteroid Bennu in October 2018 and study it in detail before returning with a sample of material from its surface. Its primary purpose is scientific—since asteroids are relics from our solar system's formation, analysis of the sample is expected to give insights into how the planets formed and life originated. Also, the spacecraft will accurately measure how the tiny push from sunlight alters the orbit of Bennu, helping astronomers better predict this influence on the path of any asteroid that presents an impact risk to Earth.

"However, the mission will develop important technologies for asteroid exploration that will benefit anyone interested in exploring or mining asteroids, whether it's NASA or a private company," said Lauretta.

This is an artist's concept of NASA's OSIRIS-REx spacecraft preparing to take a sample from asteroid Bennu. Credit: NASA/Goddard/Chris Meaney

The mission is designed to have triple redundancy for its sample acquisition – if the first attempt fails, the team can try two more times to get at least 60 grams (about two ounces) of sample, and up to 2,000 grams (about 4.4 pounds). To make the most of these opportunities, the spacecraft is equipped with instruments that map the asteroid's composition from orbit, allowing the team to select the best sample sites well in advance of the first attempt.

A good way to determine an asteroid's composition from a distance is to analyze its light. All materials reflect, emit, and absorb light at specific colors or frequencies depending on the properties of the material. The make-up of a material can be identified using special instruments called spectrometers which measure the intensity of light at different frequencies.

Materials emit and absorb light over an extremely wide range of frequencies, well beyond what our eyes can see, so OSIRIS-REx has three spectrometers that together cover this range in the X-ray, visible and infrared.

The OSIRIS-REx Visible and Infrared Spectrometer (OVIRS) detects visible and near-infrared light. Infrared light is invisible to the human eye, but we can feel it as heat. This spectrometer will be able to detect organic compounds in addition to a variety of minerals and other chemicals. Organic compounds contain carbon and are of interest because some are used by life. The team hopes to sample a site rich in organic molecules for clues to the organic chemistry in the early solar system that led to the emergence of life on Earth. "OVIRS will help map the distribution of organic molecules on the asteroid and guide sample site selection based on that information," said Lauretta.

The OSIRIS-REx Thermal Emission Spectrometer (OTES) goes deeper into the infrared range and will detect minerals on the surface of Bennu and measure the temperature of the asteroid. In particular, found by OTES will provide a map of the water-rich material on the asteroid. Just as beach sand heats up quickly in the sun and cools off rapidly at night while the pavement stays hot long after sunset, the rate at which the surface warms in the day and cools at night will be used to measure the surface properties.

The Regolith X-ray Imaging Spectrometer will look at the faint X-ray glow of the sunlit surface to map the distribution and abundance of elements, such as iron, silicon, sulfur, and magnesium.

OVIRS and OTES also will work together to determine the influence of sunlight on Bennu's orbit. This influence, called the Yarkovsky effect, happens when the surface of an asteroid absorbs sunlight and later radiates it as heat while the asteroid rotates, giving the asteroid a tiny push, which adds up over time to significantly change its trajectory.

OVIRS will reveal how much sunlight is reflected from Bennu. Since what's not reflected must be absorbed, the team can use this measurement to calculate how much sunlight is being stored by the asteroid to be later radiated as heat. OTES will measure this heat and provide a map to show which areas on Bennu radiate the most, giving the direction of the Yarkovsky push.

The light detected by the spectrometers doesn't penetrate far, so these instruments can identify composition only in a thin layer near the surface, not more than about one-half of a millimeter deep (about a hundredth of an inch). It's likely that Bennu's composition changes deeper in its interior. The mission's sampling mechanism will go deeper by blowing nitrogen gas to agitate material near the surface, forcing it to flow into a collection chamber.

"We'll get down five or six centimeters (around two inches) with this technique," says Lauretta. Although still relatively shallow, it is about 200 times deeper than with spectrometry alone.

"Also, the spectroscopists will tell us that they know the composition of this material, but at the end of the day, we get to test that," adds Lauretta. "We'll bring a sample back to the lab and say, alright you guys said it was made out of this, we found it was made out of that, did you get it right or not?"

Other instruments will help refine the composition maps from the spectrometers. The smallest features in the OVIRS chemistry maps will be about 20 meters (yards) across, while the OTES mineralogy features are even bigger, at about 40 meters across. Color maps from the cameras will have much higher resolution, less than a meter, so any variations in color over a feature in the chemistry and mineralogy maps from the spectrometers gives a clue that perhaps the composition changes a bit in those areas, according to Lauretta.

Similar to radar, the laser altimeter instrument will bounce laser light off the surface of Bennu to build a three-dimensional map of its shape and surface features. Measuring how brightly the surface reflects the laser light can give a clue to the type of material present; for example, a really bright reflection could indicate they hit a metallic spot, according to Lauretta.

Although developed for science, the instruments on OSIRIS-REx are similar to those necessary for an asteroid mining mission.

"The mission will be a proof-of-concept – can you go to an asteroid, get material, and bring it back to Earth," said Lauretta. "Next, people will have to industrialize it so that the economy works out, so for the recoverable value in any given asteroid, you're spending half that to bring it back."

"The only thing you might want to add is the ability to do a quick chemical analysis of material on board the spacecraft, so you can say, 'The platinum concentration is X,' for example," says Lauretta. "We couldn't afford it – that's a pretty sporty option. Other than that, for anyone who's thinking about an asteroid mission, this is the set of instruments that you want to fly."

The University of Arizona, Tucson, is the principal investigator institution which leads the mission. NASA's Goddard Space Flight Center, Greenbelt, Md., provides overall mission management, systems engineering, and safety and mission assurance. Lockheed Martin Space Systems is building the spacecraft. OSIRIS-REx is the third mission in NASA's New Frontiers Program.

Explore further: New Horizons sights tiny Pluto moon as spacecraft races toward dwarf planet

Related Stories

Bennu: NASA spacecraft will visit asteroid with new name

May 01, 2013

(Phys.org) —An asteroid that will be explored by a NASA spacecraft has a new name, thanks to a third-grade student in North Carolina. NASA's Origins-Spectral Interpretation-Resource Identification-Security-Regolith ...

NASA wants your help in finding asteroids

Apr 20, 2012

If you are an amateur astronomer who likes a challenge, NASA has a new project and is looking for a little help from their amateur astronomers friends. Called called “Target Asteroids!” the project ...

Recommended for you

Image: Rainbow aurora captured from space station

12 minutes ago

Auroras occur when particle radiation from the Sun hits Earth's upper atmosphere, making it glow in a greenish blue light. ESA astronaut Alexander Gerst has one of our planet's best views of this phenomenon, ...

Experts: Mystery fireball was Russian satellite

3 hours ago

People from New Mexico to Montana saw the bright object break apart as it moved slowly northward across the night sky. Witnesses described it as three "rocks" with glowing red and orange streaks.

User comments : 13

Adjust slider to filter visible comments by rank

Display comments: newest first

Egleton
2.7 / 5 (7) Aug 09, 2013
Over the last hundred years, the human population has exploded from about 1.5 billion to more than seven billion

That there is the most important statement. A doubling time of 35 years.

This is very important work, but not for the purposes that are stated in the article. I dont get too excited about someone else getting rich.
It is important because unless we want to enjoy the Limits to Growth predictions we have to attack their assumptions.
Their assumptions are that we will be forever bound to the surface of this rock. 2 dimensional creatures.
At our present technological level that is our fate. But before the next doubling of the population our present technology will no longer be state of the art.
Even with our present bag of tricks we can do it. We can leave.
But we will not, because of a failure of the Will.
Desperation will cure that.
antialias_physorg
3.3 / 5 (4) Aug 09, 2013
Their assumptions are that we will be forever bound to the surface of this rock

Another assumption is that we won't - ever - be able to reuse stuff by breaking it apart and separating it cleanly by atomic element. If we manage to do that, and I don't think it's THAT much of a SciFi-idea, then the whole issue of needing to mine resources (on Earth or off world) will become moot.

3D printing and deconstruction at the atomic level. The end of the need for resources (and economy in general) as we know it.
Surly
2.3 / 5 (3) Aug 09, 2013
@antialias: separating elements is certainly doable; that's what chemistry's all about. Changing one element into another is also possible, with certain constraints; look up nuclear transmutation.

But we still need to mine resources, because mining is vastly easier, faster, and energetically cheaper than trying to make everything from other materials.

It's entirely possible to filter gold out of seawater, and even to turn lead into gold with a particle accelerator. (http://chemistry....601a.htm ). But it's way more cost-effective to just mine it.
JohnGee
2.5 / 5 (8) Aug 09, 2013
Wouldn't it be crazy if we had such a surplus of energy someday that it made more sense to shoot particles at lead than to mine gold? It's kind of like the saying that Bill Gates would lose money taking the time to pick a $100 bill off the street, but on a species level.
antialias_physorg
3 / 5 (4) Aug 09, 2013
Changing one element into another is also possible, with certain constraints; look up nuclear transmutation.

That takes TONS of energy - and isn't worth it when compared to simple separation of already availabel materials. There's plenty of everything in any handful of dirt if you can separate it out. There's no need to rely on concentrated ores.
because mining is vastly easier, faster, and energetically cheaper than trying to make everything from other materials.

I'm not so sure. All you need is energy. And when energy is available to everyone in sufficient quantity then that means materials are free. No form of mining can be cheaper than for free. And speed is not all its cracked up to be.
GSwift7
2.6 / 5 (5) Aug 09, 2013
Wouldn't it be crazy if we had such a surplus of energy someday that it made more sense to shoot particles at lead than to mine gold?


wow, that's one of the best points I've seen anyone make in a long time. That's really rather profound, and given a long enough time frame, entirely likely.

I would also predict that population growth will slow, as more third world countries become developed and their population growth rates level off.

I like Antialias' point about molecular mining and manufacturing also.

Combine abundant energy with molecular assembly, and access to space is much easier, since you can adapt and live in much more harsh conditions and still be self-sufficient.

It's also strange how those things don't really seem like comic book fantasy as much as they did 40 years ago.

In regard to the mission, I wish they were planning a core sample in stead of or in addition to that surface scrape. THAT's what I'd want if I were going to mine it, but she didn't say that
GSwift7
2 / 5 (4) Aug 09, 2013
That takes TONS of energy - and isn't worth it when compared to simple separation of already availabel materials


That is assuming that the only way to do it is by brute force, and we won't ever find a more nuanced method to synthesize elements. If we can assemble molecules one atom at a time with a 3d printer, then why can't we start with a bottle of quarks and gluons and such and print atoms too? :)
antialias_physorg
5 / 5 (1) Aug 09, 2013
For one gluons and quarks aren't available in a naked state. So you have to create them. And the only way to create them is via vastly energy consuming processes (you have to rip apart nucleons which don't really give up their constituent parts easily)

Transmutation - especially from lighter to heavier elements beyond iron takes shitloads of energy (it takes entire supernovae to make significant amounts of that stuff). The other way around you have to rely on fission (which has its own problematics. Either the elements are so stable that fission doesn't happen without massive input. Or they're so unstable that you get radioactive stuff)

The transmutations we're capable of use huge accelerators and create single atom changes. If you look how many atoms are in even a microgram of matter you quickly find that the amount of energy that would be required would quickly outstrip all the energy that impacts the Earth from the sun for quite some time.

antialias_physorg
5 / 5 (1) Aug 09, 2013
(cont.)

But we DO know how to isolate elements which are bound up in molecules (you can go to any chemistry lab and they'll have vials of most elements in rather pure form and in significant quantities) . That is a chemical process and takes comparatively little energy (orders of magnitude less). Currently we do this via other chemicals (mostly), but also via just pumping very little energy into it (e.g. electrolysis to get pure hydrogen). So it is doable with very (comparatively to transmutation) little apparatus. I see no real advantage of building atoms from scratch when you can get the same atoms much more cheaply by taking the ones that are already there.
TheGhostofOtto1923
2.7 / 5 (7) Aug 10, 2013
I'm not so sure. All you need is energy. And when energy is available to everyone in sufficient quantity then that means materials are free. No form of mining can be cheaper than for free. And speed is not all its cracked up to be
Again I am confused. Are you saying that 'when energy is free', then it will somehow take less of it to transmute materials than to mine them?

I think it will always take less energy to mine commonly-used materials than to somehow create them in equivalent amounts by transmutation; whether this be by mining them here on earth or somewhere else in the solar system.

One must consider all the entropy created by generating this energy here on the surface, and all the energy required to counter that entropy, as well as all the waste heat created by generating all that energy, and all the additional energy needed to mitigate the effects of that waste heat.

Even if this energy is indeed, free.
TheGhostofOtto1923
2.3 / 5 (6) Aug 10, 2013
I see no real advantage of building atoms from scratch when you can get the same atoms much more cheaply by taking the ones that are already there
Already there... already where? This parent material still needs to be mined.

Lets see you posted this at about midnight last night. Perhaps you were tired and were not thinking clearly as a result.
wow, that's one of the best points I've seen anyone make in a long time. That's really rather profound, and given a long enough time frame, entirely likely
Profound?? You would still need to mine and process the lead, and this energy expenditure in addition to what you use in transmuting it, would far exceed what you would expend in simply mining the gold to begin with.

I think you both need to get a little sleep.
Ober
1 / 5 (3) Aug 10, 2013
I think what people might really be suggesting, is the ultimate in recycling. Being able to break down a discarded product, and build a new item from it. Having plentiful energy will revolutionise recycling. The alternative is that we keep growing in population, keep mining materials from Earth and other celestial bodies, and keep discarding. That will lead to us having to travel further and further away from Earth in order to maintain this wasteful lifestyle.
But being able to atomically dissociate a discarded object and build a new object would be the ultimate in my opinion (and others as the posts have suggested). I still believe that one day energy will not be our limiting factor. But plentiful energy presents its own problems.
GSwift7
1 / 5 (4) Aug 12, 2013
to Antialias and Otto:

You are both making rational and common sense comments, and I agree 100%. However, we're talking about future stuff. You cannot rule anything out simply because it isn't thus right now.

You could make very practical, rational arguments against many of the technologies we have today, from the point of view of someone in a previous century.

I say again that you are 'assuming we are bound to the rules' which you claim prevent assembly of atoms. As long as mass and energy are conserved in the final product, who are you to say that the process is energy prohibitive. Maybe atoms assemble themselves under the 'right' conditions. How do you KNOW that starting out with 1kg of hydrogen and turning it into 1kg of iron isn't as simple as shuffling a deck of cards? Mass is mass, right? E=MC^2 doesn't care whether it's hydrogen or iron, so if you take the hydrogen apart without losing the energy, then you should be able to put it back together any way you want.