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Wednesday October 18th 2017

‘Space Technology’

Asteroid Mining

Asteroid Itokawa
Near Earth Asteroid Itokawa. A likely candidate for future mining opportunities. Credit JAXA

Look back in history and you will see that the motivation behind huge investments in exploration and transportation has been the need for resources.  The American settlers headed west in their search of gold, oil and timber, and the Europeans headed east along the Silk Road and the spice trade routes.  Now, a company based in Seattle, Washington, plans to head away from Earth and into space in search of the precious resources to be found within the thousands of asteroids existing in orbits relatively close to our planet.

The company, Planetary Resources Inc, founded by Eric Anderson and Peter Diamandis, has attracted a group of investors and advisers including Eric Schmidt and Larry Page of Google, and film director James Cameron.  The ultimate goal is to exploit the valuable resources which asteroids can offer, and the biggest challenge is to achieve this within a budget which makes the whole project cost effective.

Why is asteroid mining such an exciting proposition

How an asteroid could be captured and moved into a more convenient orbit. Credit Planetary Resources

Asteroids contain an abundance of valuable resources including platinum, gold, iron, nickel, rare earth metals and water.  At present around 9,000 known asteroids travelling in an orbit close to Earth’s have been identified, with around 1,000 new ones being discovered each year, all of which as easy to reach as the moon.  And because they are much smaller than the moon the lower gravitational force will mean that landing and taking off will be less of a problem.  Unlike the Earth, heavier metals are distributed evenly throughout an asteroid’s mass rather than closer to the core, and as an added attraction the presence of these materials will often be found in much higher concentrations than on Earth.  For instance, it has been estimated that a one kilometer diameter asteroid could contain about 7,500 tons of platinum, worth more than $150 billion.

Rare Earth metals

Despite their name, rare earth metals are fairly common in the Earth’s crust, but the fact that they are so widely scattered makes them difficult to mine. So finding a viable means of harvesting them from space will potentially be a highly profitable business.  Added to this, around 95% of the world’s supply of rare earth metals presently comes from China, who have decided to cut back on their exports in order to accommodate their own rapidly expanding industrial needs.

Platinum group metals

Platinum group metals do not occur naturally in the Earth’s crust, but are present due to earlier meteorite impacts.  A meteorite is simply a piece of asteroid which has fallen to Earth, so the study of meteorites gives geologists a good idea of the most suitable types of asteroid to choose as candidates for mining.

Which are the most likely candidates?

An artist’s impression of the Asteroid Belt. Credit NASA

The vast majority of asteroids are located in the region of our Solar System between Mars and Jupiter called the Asteroid Belt, or Main Belt.  They range in size from around half a mile across to about 600 miles in diameter, and were created at the birth of the Solar System, 4.6 billion years ago.  To put it into perspective, the total mass of all known asteroids, more than half a million in all, is about 4% that of the moon.  Due to the gravitational influence of Jupiter some have orbits which carry them close to Earth, in which case they are called Near Earth Objects, or Near Earth Asteroids.  And these are the asteroids which Planetary Resources intend to study and ultimately exploit.

 

How are asteroids classified?

 In broad terms there are three classifications of asteroid based on their composition:

  • C-type, which are the most common, are carbonaceous, and consist of clay and silicate rocks.  They exist furthest from the Sun, and so have been least altered by heat, meaning that they are the most ancient. Due to the fact that some have never even reached temperatures above 50°C, it is estimated they can contain up to 22% water.
  • S-type or silaceous asteroids are made up primarily of stony materials and nickel-iron.  They inhabit the inner Asteroid Belt.
  • M-type, or metallic, are made up mostly of nickel-iron, and are found in the middle region of the Asteroid Belt.

 

2005-YU55, a C-type asteroid. Credit NASA

 

What are the challenges?

 The greatest challenge to Planetary Resources is to build commercially available robotic spacecraft which are at least an order of magnitude cheaper than those currently in use.  Unlike governments, failure can be accepted during the development process, and the goal is to build the crafts in an assembly line fashion in order to drive down costs.  The project will be carried out in stages, with the first phase already underway, and it is hoped that by the middle of next decade mankind will be reaping the benefits of the abundant resources that asteroids have to offer.

 The technology 

  • The Arkyd Series 100 – Leo Space Telescope.  Due for launch within the next two years, its job will be to analyse NEOs in order to determine the most likely candidates for future exploitation.  Techniques such as spectroscopy and radar technology will be used to determine properties such as the asteroid’s chemical composition, orbit, rotation, size, shape and metal concentration.  Due to its relatively low cost and its potential usefulness in a vast number of applications, the Leo will be of interest to the scientist and private citizen alike.  The sale of these crafts will therefore enable Planetary Resources to gain revenue in order to achieve its future objectives.
  • The Arkyd Series 200 – Interceptor.  The intention is for this craft to hitch a ride on a geostationary satellite in order to analyse asteroids at more close quarters.  Future advancements in micro-propulsion and imaging techniques will be utilised to enable the craft to get close enough to obtain high resolution data.  Two or more Interceptors working together will ensure that the data is collected as quickly and efficiently as possible.
  • The Arkyd Series 300 – Rendezvous Prospector.  This phase of the project will involve focusing on asteroids much deeper in space.  Laser communication technology will be used  to determine shape, rotation, density, and surface and sub-surface composition.  The Prospector’s capability as a low cost interplanetary spacecraft should also attract customers such as NASA and other scientific establishments.

    Arkyd Series100 - LEO Space Telescope. Credit Planetary Resources

 

Mining

After all the prospecting has taken place, the most exciting phase of the project can then be carried out, the actual mining of the precious resources.  Initially the most important resource available in space will be water.  Apart from being essential to sustain life, it can also be split into hydrogen and oxygen to create fuel to enable spacecraft to travel further into space.  This would allow us to build refuelling stations in order to reach more distant asteroids and aid future manned exploration of the solar system.  For this reason the first targeted asteroids will most likely be C-type.

What methods will be used?

Could this be the future of asteroid mining? Credit Kevin Hand for Popular Science, 2012

The technology needed to carry out the mining process has not yet been developed, but possible methods have been suggested.  A device similar to a snow blower, anchored to the surface, could be used to collect loose rubble by using a spinning blade to fling the material through a chute and into a high-strength bag.  Many of the mining methods will be similar to those used on Earth, and will consist of drilling, blasting, cutting and crushing.  Extraction of individual materials, depending upon their properties, will be achieved by either chemical or physical means.  Water can be extracted by heating the solid material, capturing the vapour and then distilling it; electrolysis of molten silicates would produce oxygen, iron and other alloys; and a method called the Mond process could be used to extract nickel.  As well as being used for creating industrial wealth on Earth, these raw materials could also be used to actually build structures in space.  Dozens of other processes are being considered, and meteorites are the perfect objects to experiment with on Earth.

 

Within reach!

The idea of landing a robotic craft onto an asteroid in order to extract its precious materials may at first seem the stuff of science fiction.  But the more scientists get to grips with the technology necessary to achieve it, the more likely it is that science fiction will soon become science fact.

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Voyager Explores Stagnation Region

Voyager Spacecraft
Voyager Spaceraft, Image credit : NASA

 NASA’s Voyager 1 has entered a new region between our solar system and interstellar space, which scientists are calling the stagnation region. The inner edge of this region is located about 113 astronomical units (10.5 billion miles or 16.9 billion kilometers) from the sun. Voyager 1 is currently about 119 astronomical units (11 billion miles or 17.8 billion kilometers) from the sun. The exact distance to the outer edge is unknown.

Voyager 1 spacecraft has entered the stagnation region.
Artist's concept of Voyager 1 spacecraft has entered the stagnation region. Image credit: NASA/JPL-Caltech

The stagnation region is considered to be a kind of cosmic purgatory according to data obtained from the spacecraft during the last year. In it, the wind of charged particles streaming out from our sun has calmed, but our solar system’s magnetic field has piled up, and higher-energy particles from inside our solar system appear to be leaking out into interstellar space. At the same time, Voyager has detected a 100-fold increase in the intensity of high-energy electrons from elsewhere in the galaxy diffusing into our solar system from outside, which is another indication of the approaching boundary

There is not much time left to find out what the space between stars is. The spacecraft has passed through the heliosheath, the outer shell of the sun’s sphere of influence and is still within the heliosphere, the bubble of charged particles the sun blows around itself. Interstellar space begins at the heliopause, and scientists estimate Voyager 1 will cross this frontier around 2015. 

Interstellar Flow
Stream of interstellar charged particles, Image credit: NASA

 Voyager’s magnetometer detected a doubling in the intensity of the magnetic field in the stagnation region which shows that inward pressure from interstellar space is compacting it. “We are evidently traveling in completely new territory. Scientists had suggested previously that there might be a stagnation layer, but we weren’t sure it existed until now.,” said Rob Decker, a Voyager Low-Energy Charged Particle Instrument co-investigator at the Johns Hopkins University Applied Physics Laboratory in Laurel, MD.

Voyager - The Sounds of Earth - Golden Record
Voyager Golden Record, Image credit: NASA

Launched in 1977, Voyager 1 is about 18 billion kilometers from the sun. A signal from the ground, traveling at the speed of light, takes about 16 hours one way to reach the spacecraft. Voyager carries aboard recorded messages from Earth on golden phonograph record – 12-inch, gold-plated copper disk that contains images and natural sounds, spoken greetings in 55 languages and musical selections from different cultures and eras.

Credit: NASA/JPL-Caltech
Source URL: http://www.nasa.gov/mission_pages/voyager/index.html

 

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Mars Express – Scientific Highlights

Mars Express - Credit: ESA/Medialab
Mars Express - Credit: ESA/Medialab

The following DLR article talks about measurements and scientific experiments performed by Mars Express mission.

By: DLR

This success story began eight years ago, with the launch of a Soyuz carrier rocket from the Baikonur Cosmodrome in Kazakhstan that sent the Mars Express spacecraft on its journey to our planetary neighbour. Since then, a wealth of information about Mars, its surface, subsurface and atmosphere has led to a completely new view of the Red Planet.

The Infrared Mineralogical Mapping Spectrometer (OMEGA) has identified phyllosilicates (sheet silicates) on the surface of Mars. Such minerals are rich in iron and aluminium and arise as a result of the prolonged effect of water on volcanic rock. This discovery has led to a new view of the history of Mars; in its early days, at least, vast amounts of liquid water shaped its surface.

Water ice in the northern polar region of Mars - perspective colour view. Credit: ESA/DLR/FU Berlin (G. Neukum).
Water ice in the northern polar region of Mars – perspective colour view. Credit: ESA/DLR/FU Berlin (G. Neukum).

Using images from the High Resolution Stereo Camera (HRSC) operated by DLR, the HRSC team has determined that volcanism on Mars lasted for a long period of time, until the most recent geological past. Consequently the youngest lava concretions in the summit caldera of Olympus Mons are just 100 million years old. In fact, there may still be residual activity here and at a few volcanoes near the North Pole. Data obtained with the Planetary Fourier Spectrometer (PFS) also indicates that short-lived methane gas has been discovered and its concentrations mapped in the Martian atmosphere above volcanic regions. This leads to the assumption that Mars may still be geologically active today, as the methane might be generated and introduced into the atmosphere by volcanic activity present underneath the surface of Mars.

On HRSC images of areas at low to mid-latitudes – close to the equator – surface features that can only have occurred as a result of the action of glacial ice are recognisable. Evidence indicates three episodes of activity in the last 300 million years, the most recent of which may have taken place just four million years ago. An ice age at mid-latitudes is impossible in today’s climatic conditions. Hence scientists presume that dramatic climatic changes must have occurred on Mars, since the inclination of Mars’ rotational axis has undergone major fluctuations. This means that different climatic conditions might have been predominant at the equator and in other regions of Mars at other times.

Mars: A dry, rocky river bed, in the shape of a narrow channel, lying in a larger valley in the Libya Montes highland region. The elevation is exaggerated by a factor of three (view looking northeast).
Mars: A dry, rocky river bed. Credit: SA/DLR/FU Berlin (G. Neukum).

Data from the MARSIS (Mars Advanced Radar for Subsurface and Ionosphere Sounding) radar sounder shows that layered sediments at the Martian North Pole consist of almost pure water ice. Meanwhile the OMEGA spectrometer has produced maps of water and methane ice deposits. Observations by Mars Express have proven that much more water exists beneath the surface of Mars in the form of ice, as was anticipated ten years ago.

The data obtained with ASPERA (Energetic Neutral Atoms Analyser) show that the solar wind penetrates deeper into the Martian atmosphere than was previously assumed (down to 250 kilometres). The loss of energetic ions as a result of this is relatively low. The loss of atmospheric constituents occurs in episodic ‘outbursts’, the cause of which is not yet understood. In the absence of a magnetic field, protons and helium ions in the solar wind penetrate the Martian ionosphere to a depth of 270 kilometres and cause planetary oxygen ions to be accelerated by the energy-rich particles and flow outwards. This occurs at lower altitudes and also with greater efficiency than was previously thought.

For the first time, clouds of methane ice have been discovered, investigated and imaged in the Martian mesosphere using the HRSC, OMEGA, PFS (Planetary Fourier Spectrometer) and SPICAM (Ultraviolet and Infrared Atmospheric Spectrometer) instruments.

The mission has also yielded a wealth of research results; particularly concerning the Martian moon Phobos. These results include the most accurate determination of its mass, its exact path and its volume and density, as well as the discovery of backscattered solar wind protons by the ASPERA instrument. Furthermore, the sharpest images to date of this moon have been captured, with a resolution of 4 metres per pixel. Among other things, these seem to confirm that Phobos is orbiting Mars faster and faster and is slowly getting closer to the planet, before it potentially breaks up as a result of tidal forces in 10-20 million years, colliding with Mars.

Credit: SA/DLR/FU Berlin (G. Neukum).
Source URL: http://www.dlr.de/dlr/en/desktopdefault.aspx/tabid-10463/701_read-882/

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Helio Now

Solar Dynamics Observatory

Solar Dynamics Observatory 2017-10-18T12:45:50Z
Observatory: SDO
Instrument: AIA
Detector: AIA
Measurement: 171

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