First Ring System Around Asteroid

Observations at many sites in South America, including ESO’s La Silla Observatory, have made the surprise discovery that the remote asteroid Chariklo is surrounded by two dense and narrow rings. This is the smallest object by far found to have rings and only the fifth body in the Solar System — after the much larger planets Jupiter, Saturn, Uranus and Neptune — to have this feature. 

How to Mine Asteroids: Learn From NASA's OSIRIS-REx Asteroid Mission

This is an artist's concept of NASA's OSIRIS-REx spacecraft preparing to take a sample from asteroid Bennu.

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 asteroid 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 rocket fuel, 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.

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 launch 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.
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Related:
Astronomers discover comets in asteroid belt that can revive after millions of years

Reflecting on an Asteroid’s Really Close Encounter with Earth (Closer than Some Satellites)

Amid all the progress on this planet — declining losses from terrible diseases and war, rising literacy and the rest — there remain plenty of planet-scale risks requiring serious focus, from pandemic flu to centuries of locked-in climate change to, yes, collisions with space rocks.

This week provides another reminder of the reality of that threat, not that Earth’s history doesn’t already provide plenty of warnings. Bill Marsh, an illustrator at The Times, created the illuminating chart above (the image is a detail; click for the full graphic) to show just how close the asteroid known as 2012 DA14 will come on 15 februari 2013. It will pass not only far inside the orbit of the Moon, but even closer than the 22,300-mile distance where geosynchronous satellites orbit.

I was fortunate to participate in a 2010 workshop assessing what kinds of protocols should be developed to coordinate international responses when astronomers finally identify an object that will hit Earth. A report from that meeting, “Responding to the Threat of Potentially-Hazardous Near Earth Objects,” provides a primer on both the risk and possible responses. Here’s the introduction:

The record of history, as written in the many impact craters on Earth and the moon, demonstrate that it is just a matter of time before astronomers discover a near Earth object (NEO) headed toward a collision with Earth. As the 1908 Tunguska event, which leveled trees across an area of Siberia some 30 km in diameter demonstrated, even relatively small objects (30-50 m diameter) are capable of inflicting enormous damage. When such an event is imminent, how should we respond? Who should respond?

I encourage you to explore the group’s proposals for answering those questions.

To track this asteroid and related issues, there’s no better starting point than the @Asteroidwatch Twitter feed from NASA’s Jet Propulsion Laboratory, which has close to a million followers and demonstrates how 140 characters can matter.  

In a ranking of near-term “fatal discontinuities” in his 2008 book, “Global Catastrophes and Trends: The Next Fifty Years", Vaclav Smil puts asteroid collisions far below the persistent risk of large-scale war (particularly because so many nuclear weapons are still arrayed around the world), great earthquakes and tsunamis and pandemics, but above global warming (because of its gradual slope). (Here are reviews by Martin Lewis and Michael Shellenberger.)

On longer time scales, of course, the inevitability of discovering an asteroid on a collision course is clear — which makes figuring out strategies for dealing with that eventuality not simply fodder for screenwriters and novelists.

There’s plenty more on “Close Encounters of the Rocky Kind” on Dot Earth. 

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Interesting:
Earth-like Planets Are Right Next Door
More evidence emerges that our universe is a grand simulation created by an intelligent designer
The Earth’s Magnetic Poles Are Shifting
Colossal cosmic structure discovered
Mini Solar System Entering Our’s, Says Astrophysicist Jim McCanney