New instrument could help make asteroid mining a reality

The development of a new generation of gamma-ray spectroscope could bring asteroid mining one step closer to fruition, as it appears to be capable of easily detecting veins of gold, platinum and other precious metals hidden in space rocks, moons, and other floating objects.

The new spectroscope was developed by a team of scientists from Vanderbilt University, along with colleagues from Fisk University, NASA’s Jet Propulsion Laboratory in California and the Planetary Science Institute in Arizona, and was detailed in a paper published last month in SPIE Newsroom, the publication of the International Society for Optics and Photonics.

Planetary gamma-ray spectroscopy is based on the notion that every object in the solar system is constantly pelted by deep-space, high-energy particles called cosmic rays. When these rays hit an object’s surface at relativistic velocities, it produces a shower of neutrons that collide with atoms in the material, producing a type of electromagnetic radiation known as gamma rays.

The new device measures the intensity and the wavelengths of these powerful gamma rays, and the data can be analyzed to determine how much of key, rock-forming elements such as oxygen, magnesium, silicon, and iron are present in an object, as well as the amount of gold and diamonds each contains, the researchers explained in a statement.

More compact and energy efficient than comparable devices

“Space missions to the Moon, Mars, Mercury and the asteroid Vesta among others have included low-resolution spectrometers, but it has taken months of observation time and great expense to map their elemental surface compositions from orbit,” explained Vanderbilt astronomy professor and study co-author Keivan Stassun.

“With our proposed system it should be possible to measure sub-surface elemental abundances accurately, and to do it much more cheaply because our sensors weigh less and require less power to operate,” he added. “That is good news for commercial ventures where cost, power and launch weight are all at a premium.”

What makes the new spectrometer so valuable is its use of a recently discovered material called europium-doped strontium iodide (SrI2), which is a transparent crystal that can efficiently detect gamma rays by giving off flashes of light in the presence of these high-energy particles. While it isn’t as good as high purity germanium (HPGe) detector, the researchers noted that the SrI2 unit is far less bulky, consumes less energy and performs nearly as well as its counterpart.

While it could take several decades for the asteroid mining industry to begin thriving, experts believe that the first commercial mission in what is expected to be a multi-billion dollar market could launch within the next five years. Until then, the new spectroscope will be used to provide scientists with new details about the chemical compositions of asteroids, moons, minor planets and comets, which could enhance our knowledge of the early solar system.

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