Transmat World: space mirror

Showing posts with label space mirror. Show all posts

Wednesday, May 15, 2019

How a Space Mirror Could Deal With Orbital Debris and the Threat of an Asteroid Strike

On August 20, 2075, in Kalispell, Wyoming, a young amateur astronomer is drinking ice tea to cool his thoughts about the 103 degrees F. outside his window at 9:30 in the evening. Climate change is relentless. Harold thinks this is fairly normal weather. It’s been nearly this hot most of his adult life.

Checking the laptop hooked to the homemade telescope in the plastic bubble on top of the house, he inputs values into a program and runs it. He runs it again. And again. He shows the results to several astronomer friends by email. They check it and verify the output. Soon thereafter, the world goes crazy.

Something happened to asteroid 2005 YU55. It was supposed to come within 237,000 miles of Earth on November 8, 2075. Now it is on a collision course. Some other asteroid came close to or bumped 2005 YU55 and slightly changed its direction. NASA has known for weeks but not released the information for fear of mass panic. The amateur astronomers have forced the issue, and NASA holds a press conference.

The head of NASA explains the situation is not as dire as it would have been just five years ago because of Project Drogon. Everybody knows about the large, focusing mirror in orbit because it has been efficiently vaporizing space debris cluttering orbital lanes near Earth for several years. Few gave thought to its second purpose until now. It’s shiny discs have been re-focused on 2005 YU55, and it is currently engraving an ablation trench in a spiral pattern as the asteroid sedately rotates every nineteen hours. The mirror is in an orbit that keeps it in sunlight 24 hours a day.

Not meant to cut the asteroid in pieces, the focused power of the mirror explosively evaporates the surface material it comes in contact with. This creates, in effect, a thruster on one side of 2005 YU55, gradually changing its course. The Earth is saved, and the young astronomer is made the new head of NASA. Well … yes, the story does kind of break down there. That would not normally happen in real life, but the description of a focusing mirror is not so hard to believe. We have the technology.

Imagine a mirror array with six circular pads in a circular array and one in the middle. Each pad is about 27 feet in diameter, made up of 120 flat panels per pad. Each panel is 2.25 feet square. Each panel is driven by a precision servomotor. With a total of 4,200 square feet, the mirror could concentrate 530,670 watts of power onto an area 2.25 feet by 2.25 feet. This is enough to vaporize most forms of matter. Note: Sun’s energy in space is 126.35 watts per square foot.

Drawing by Glen Hendrix in AutoCad. Click to enlarge.

The entire mirror is aligned with its target using a system similar to that of the Hubble telescope. Six gyroscopes and four reaction wheels can target the mirror to within .007 arcseconds. Let’s use 2005 YU55 as an example to show what that means. Let’s say we start beaming concentrated sunlight to 2005 YU55 when it is a hundred million miles from Earth, 400 times further than the Moon, about 38 days away. This accuracy guarantees the beam will hit within 40 feet of where it’s pointed. Since 2005 YU55 is about 1300 feet in diameter, it is a pretty sure thing it will be hit. The space mirror’s software will automatically track the asteroid on its path through space.

Drawing by Glen Hendrix in AutoCad. Click to enlarge.

To aim at objects beyond the orbit of Earth will require a reflector mirror about the size of the focusing mirror. It is much simpler, being a large, flat mirror that reflects the sun’s rays back to the focusing mirror when it’s pointed away from the Sun so that it can do its job. It will also need gyroscopes and reaction wheels as well as a suite of thrusters to position it. The whole thing could be lifted into orbit on a couple of Big Falcon Rocket trips with some assembly required, batteries included.

Drawing by Glen Hendrix in AutoCad. Click to enlarge.

The space mirror may be particularly adept at getting rid of that modern day scourge—space debris. The modularity of this design would allow a killing field to be set up for approaching debris, an invisible tunnel of dense solar energy. The idea would be to completely vaporize debris, turning it into a spreading gas cloud without the inertia to be harmful.

Astronauts working on reaction wheels of Hubble. Courtesy NASA.

Another application could be the smelting of ores in space. Nickel and iron from asteroids can be turned to steel. Ore from the Moon can be processed into aluminum. Off-world mining and other heat intense manufacturing processes will not be able to advance without this type of ancillary tool.

Mirrors in space might come in very handy for diverting asteroids, mining asteroids, smelting metals, terraforming Mars, vaporizing space debris, and paving small areas of the Moon with glass. Putting large mirrors in space, however, may have adverse political consequences for whatever nation or corporation that tries it. The main fear will come from those that don’t have a similar device in orbit worried that it could be used as a weapon. It would be possible to burn a hole in some other country’s spy satellite, start multiple fires in forests and brush lands, heat gas and oil lines until they rupture and burn, put a hole in a ship’s hull in the middle of the ocean, and on and on. Concerned parties would be looking at ways to guarantee the safe use of such tools, and they would have a legal basis for protest. One of the guiding principles of the Outer Space Treaty is “States shall not place nuclear weapons or other weapons of mass destruction in orbit or on celestial bodies or station them in outer space in any other manner; ....”

Perhaps the United Nations will evolve to have its own space force, like Trump has proposed for the United States. Trained members of this elite task force will go into space along with worker astronauts to check out the control software of space-based mirrors, their focusing capabilities, their accuracy in aiming and maintaining that target, and all the other things that could turn such a dangerous machine into a weapon. Space Marshall U.N.! It will make a great TV series. Maybe the fiction has to come before the fact as it has with so many such ideas in the past.

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Thursday, August 2, 2018

The Military Values High Ground - Space Is the Highest

Moon being bombed by asteroids - courtesy NASA

The energy of the Sun near Earth is about 1368 watts/meter squared. The Falcon Heavy will be able to lift a directional mirror into space with a variable focus length of about 50 feet to thousands of miles. Its 332 square meters could focus 455,000 watts onto a spot the size of a baseball, vaporizing whatever has the poor fortune to be there at the time.

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Why would someone want such a machine? To mine asteroids. To mine the moon. To melt lunar regolith and asteroid material into shapes to build habitats in space or on the Moon. To power crucibles making steel and aluminum and other metals in space. To vaporize space debris that has become a hazard. Such power is handy in space, but there is a dark side.

Asteroid being mined with solar mirror - courtesy Dan Brown on flickr

What if someone wanted to use such a mirror to do damage to a particular country or city for military purposes? One could set fire to or melt just about anything on the Earth or Moon with such a machine - cities, missile silos, air fields, ships, cities, individual buildings. No satellite in orbit would be safe. It could destroy the International Space Station. Keep the keys to the space mirror in a safe place.

There is a lot of money invested in the idea of moving an asteroid near to the Earth and mining it for metals and minerals. The acceptable location for such a huge mass of metal would be one of the lunar Lagrange points L4 or L5 where it would rest in a stable orbit about the Earth. Getting it there is the trick. It would require a robotic space tug.

It costs $4000 to recycle ton of plastic bags worth $500 on open market.

What if someone deliberately sabotaged the space tug’s guidance system and sent a kilometer diameter chunk of iron hurtling toward the Earth? The damage could be incalculable. From treasure trove for the future of mankind to the fall of civilization for some poor region of Earth, perhaps the whole planet. Or someone could attach such a tug to a smaller asteroid and program it to come fast out of the sun. Undetectable until it is too late.

Asteroid being moved by space tug - courtesy Korite on flickr

These examples are besides what may be already in orbit or planned to go into orbit. This includes EMP (electromagnetic pulse) bombs and “rods of god”. Since 1967 it has been illegal to park atomic weapons in orbit, but that may not stop the likes of North Korea. To get around the orbital nuclear bomb ban, the U.S. has come up with a simple rod of tungsten dropped from orbit. The one foot diameter by twenty feet long cylinder of metal reaches ten times the speed of sound by the time it hits and mimics a small nuclear device in its devastation. It penetrates hundreds of feet into the ground, destroying underground bunkers and silos - something a nuclear weapon cannot do.

That is not the only kinetic weapon available. Combine several NASA HiPEP ion thrusters with a TOPAZ style nuclear reactor, a guidance system, and a few tons of xenon (all properly armored against cosmic radiation); and you have a weapon that travels for light years and builds up a velocity that is an appreciable fraction of the speed of light. Besides targeting other planets for destruction, the truly paranoid might put such a device, perhaps several, in a long elliptical orbit around Earth, coming close to Earth on a periodic basis. In a form of mutually assured destruction, a country under attack could threaten to have one of these hit the Earth instead of continue its normal orbit. The affect would be similar to a super volcano eruption. Actual destruction might cover a continent. The weather effects could destroy the rest of civilization over the next few years.

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Another thing about having control of weapons in space is that it would allow an interdiction of anyone else coming into space for commercial or exploratory purposes. The entity in control of such weapons would be the arbiter of who comes and goes in space, who gets the benefits, who prospers and who doesn't. This is a very powerful position. This is the kind of lopsided power that starts wars.

On June 18, 2018, President Trump directed the Pentagon to create a new division of the military - the Space Force. “My administration is reclaiming America’s heritage as the world’s greatest space-faring nation. The essence of the American character is to explore new horizons and to tame new frontiers. But our destiny, beyond the Earth, is not only a matter of national identity, but a matter of national security,” he announced. “[I]t is not enough to merely have an American presence in space. We must have American dominance in space.”

It seems the President may have been ill-informed about the advisability of a new branch of the military devoted only to space. The reason is that dominance of space means true dominance of the Earth. Other countries know this. The military has always valued high ground and space is the highest. That makes the President’s statement, “We must have American dominance in space,” one of the most nakedly aggressive of any leader of a nation on Earth regarding the frontiers of space. If any other large nations are taking him seriously, they will be making plans to counter aggressive actions taken in the last frontier.

With all of this death and destruction possible from outer space, it should be obvious that the exploration and exploitation of space should be done in joint ventures with as many countries participating as possible. This will cut down on paranoia about what any one country may be up to in space and prevent physical confrontations on Earth surrounding this subject and possibly prevent the use of space as the ultimate militarily strategic high ground.

Wednesday, August 1, 2018

Very Large Scale 3D Printing In Space

Bryan Versteeg / Spacehabs.com

In 2011 German designer Markus Kayser built a machine called a Solar Sinter. It concentrates sunlight via a 3 foot by 5 foot fresnel lens onto a box containing sand. The box moves a layer of sand in programmed patterns, allowing the 1600 degree Celsius beam to melt the sand in a controlled design. Once that pattern, or layer, is complete, another layer of sand is added and the process is repeated until a 3D object is created from fused sand.

A very similar machine could 3D print objects in orbit around the Earth or Moon or anywhere in space sufficient sunlight can be collected to melt stuff. It would have to be highly modified over Mr. Kayser’s design. For one thing, you don’t have the convenience of gravity holding down your bed of sand. Another thing … you don’t have sand.

Plastic grocery bags prefer this as their second career.

The fresnel lens will have to be replaced with mirrors simply because mirrors are cheaper, more rugged, and more flexible. The bed of the printer will have to be inside a centrifuge affair producing artificial gravity. Envision a large cylinder 80 feet in diameter and 300 feet long. It spins around its long axis. The printer head can travel the length of the cylinder or in a circular path inside the cylinder, or a flat path on a chord of some arc of the cylinder that is still far enough from the central axis of the cylinder to have enough “gravity” for the system to work. Flexible light pipes will take the sunlight collected by the mirrors at the center of one end of the cylinder and feed it to the printer head. A lens at the printer head will further control the acuity of the beam that hits the medium to be melted.

Ideally, the centrifuge portion would be attached to an asteroid placed in orbit at one of the Lagrange points L4 or L5 in the Earth-Moon gravity system. That would simplify spinning it without the worry of compensating for precession like a top or anything else that spins. It would be attached to the relatively massive asteroid with brackets that extend to the ends of the cylinder where bearings and electric motors provide smooth, stable rotation with a minimum of fuss and bother. The asteroid is acting like a good work bench, providing stabilizing mass to carry out projects in space.

If a suitable mass isn't available, the cylinder would simply be set spinning by tangential thrusters with any precession also controlled by swiveling thrusters at each end of the cylinder.

Centrifugal 3D printer attached to asteroid. Drawing by Glen Hendrix.
Click to Enlarge

If we’re not talking about sand as a printing medium, what are we talking about? There are really only two practical sources for meltable medium to be used in our 3D printer. One is lunar regolith and the other is ground up asteroid. The asteroid option is cheaper if you discount the getting it there part. Lunar regolith would have to be transported from the Moon’s surface. Asteroid material is already in orbit. So far, two good reasons asteroid mining will complement our travel to space and our ability to stay there for any length of time.

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The disadvantages of using asteroid material are that it has to be excavated from the asteroid, sorted by material, and milled into a powder. This will call for the invention of robotic excavators that drill into the asteroid much as tunnel borers do their job on Earth. One of the first jobs to be done in mining an asteroid will be to make safe, comfortable housing for personnel during the project. The asteroid excavator can hollow out tunnels which will be outfitted for habitation safe from any stray cosmic rays.

Asteroid mining - courtesy NASA

The Moon’s regolith, on the other hand, is already a fine powder. So fine, it was a problem on the lunar landing missions. It is also fairly uniform in composition. Although it would have to be transported from the surface of the Moon, the one sixth Earth gravity should make that a cheaper solution than bringing material from Earth, especially if water can be found on the Moon in sufficient quantity for use as fuel. A lot of regolith can be hauled into orbit for the cost of moving an asteroid.

3D printed Lunar base - courtesy European Space Agency

Let’s say we use another, more traditional method of 3D printing whereby a small, sticky glob of substance is deposited out of a nozzle and the nozzle moves on. Mixing our asteroid or lunar powder with water and some other adhering substance to hold everything together gives us a paste to use similar to what concrete printers use now, perhaps thicker to cut down on explosive evaporation of the paste as it comes out of the printer nozzle.

Imagine a large steel plate as the print bed. It could be a light gauge steel sheet with stiffeners on the bottom. Without gravity and its attendant forces, the print bed is just a place holder and starting point. The printing side is coated with Teflon for easy removal of the printed object. The edges of the plate are rounded to fit pulleys. Four pulleys with bearings, two on each side of the print bed and aligned with each other, roll continuously along the edges of the printer bed in the plus or minus “x” direction. From the centers of these pulleys extend upwards four shafts in the “y” axis direction. These shafts go through a stabilizer frame that holds everything together. This whole stabilizer frame moves in the plus or minus “y” direction. Mounted through this stabilizer frame is another shaft with the printer head and motor to drive that head in the plus or minus “z” direction. A large tank for mixing, storage, and pumping floats around, making sure there is no binding or interference with the umbilical delivering print medium to the printer head.

Free-floating 3D printer. Printing volume about 300' x 60' x 15'. Drawing by Glen Hendrix
Click to Enlarge.

This type of printer might be good for producing parts for habitats in orbit or insulating cladding for equipment or personnel tunnels in an asteroid. The cold of space will seep into the deepest parts of an asteroid and must be dealt with.

Whether we bring an asteroid into Earth’s orbit or not, I predict 3D printing of large objects in space will become a reality. It may or may not look and work like what I’ve described here, but they will be an integral part of a robotic fabrication milieu in outer space. Human workers will be at a premium. Machines will have to fill the gap.

The human race is on a course of infinite growth in a finite environment. The push into an infinite environment with infinite space, materials, and energy is inevitable and desirable if a global catastrophe is to be avoided. The sooner we start, the better chance we have of surviving our immature macro-societal tendencies.

Other articles you may enjoy:

Oumuamua: Alien Probe or Asteroid? It Could Be Both

Cryptocurrency Is Going Into Space

Going Back To the Moon Is Not Just for Governments Anymore

Why It Is a Certainty We Will Become a Space-Based Civilization

Asteroid Mining - How to Pick the Right Asteroid

Recycling Asteroids For Fun and Profit

Taking the 06-03-25 Asteroid Shuttle to Mars - An Alternative to Planned Mars Missions

A Heavy Metal, Cannibalistic Asteroid Propulsion System

Sticking the Landing On Your Billion Dollar Asteroid

Artificial Intelligence and Asteroid Mining Will Be a (Necessary) Match Made In the Heavens

The Weapon of Mass Destruction Nobody Is Talking About

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What Will Be the Most Common Currency In a Future Space-Based Society?

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Tuesday, July 31, 2018

Energy and Space; Tweedle Dee and Tweedle Dum

courtesy NASA

by Glen Hendrix

There is a substantial cadre of people and organizations that are very interested in the space industry. The whole industry is currently worth about $350 billion dollars, but Bank of America predicts 30 years will see an increase to nearly $3 trillion dollars.

While mostly concerned with Earth-orbiting satellites, a small portion of the industry is seriously considering the mining of asteroids on the assumption of a tremendous payback from the presence of metals and minerals in these floating mountains.

NASA has missions scheduled in 2021 and 2023 to explore 16 Psyche, an asteroid that contains a lot of resources. It is a 130 mile diameter nickel and iron asteroid thought to once be part of the core of a planet.

The material of this asteroid is similar to that at the center of the Earth, mostly iron with some nickel and traces of other metals. It’s the other metals I would be interested in, but the iron alone is, according to the article, worth $10,000 quadrillion.

Let’s think about that. If you did manage to bring this space mountain into Earth orbit, nobody on Earth would buy a pound of it. It is iron, but it still needs to be melted down and turned into useable shapes, so it is essentially high grade ore. Iron ore is going for $70 per ton but this has been pre-smelted by the fiery center of a now-defunct planet so let’s give it a round figure of $100 per ton.

Plastic grocery bags prefer this as their second career.

There is about 1,150,000 cubic miles of iron. A cubic mile of iron weighs about 36 billion tons and is worth $3.6 trillion dollars. So the whole caboodle is worth only $4,000 quadrillion, not $10,000 quadrillion. Hah! Caught ya! Who cares. It’s a lot.

When you go to sell it, though, no one on Earth wants it. It currently costs $10,000 dollars per pound to get something into orbit and, therefore, $10,000 per pound to get something back to Earth. Your ton of high grade ore jumped to $20,000,100 per ton on the open market because of transportation cost. Buyers on Earth would rather pay the $70 per ton. I don’t blame them. You grifter!

There are only two options; sell it to someone that is going to use it for construction in space or figure out a cheaper means for getting it down to the Earth’s surface. Discussion of the latter will be the subject of another article.

No one is building enormous structures in orbit … yet. Your asteroid is like that 1000 acres the family owns outside of Phoenix. You know that someday it will be worth a lot when developers are ready for it. You need money now, though, to pay the bills. It doesn’t help that it cost nearly half a trillion dollars to get it back to Earth and it is really your great grandchildren who will reap the benefits because it would take so long to move that much mass.

To give you a financial break let’s say the asteroid is not 16 Psych but 162173 Ryugu. This is a rock that comes within 6,000,000 miles of Earth (very close) in December of 2020. It is a more manageable size (1km diameter) and contains not just nickel and iron but cobalt, water, nitrogen, hydrogen, and ammonia as well. Here is a great site for picking out your asteroid. That’s where I found 16217 Ryugu.

A Falcon Heavy delivers your 30,000 pound asteroid retrieval robot spaceship named More In That Vein from Cape Canaveral into a high Earth orbit. More In That Vein unfolds its solar arrays and begins the electrolysis of water, burning the hydrogen and oxygen in thrusters.

It arrives at Ryugu six months later. The apparent rotational velocity of the surface of the asteroid is only one quarter mile per hour, no problem for the agile More In That Vein to match up to. The spaceship’s interface adaptor frame comes into contact with the surface at a pre-screened, structurally sound spot and sixteen explosive bolts penetrate the surface and expand slightly to provide a solid connection between the ship and the asteroid.

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Robotic crawlers explore the asteroid for water and methane. Finding a major deposit of ice, it mines this to top the tanks off for the trip home and sets up an automated refill schedule. Meanwhile, More In That Vein has de-spun the asteroid to zero rotation and plotted the quickest journey back to Earth orbit. Its swivel-mounted engine swings to the calculated coordinates and fires up gently so as not to disturb some slight structural faults uncovered by prospector bots and heads back to Earth with its treasure.

The artificial intelligence of More In That Vein constantly adjusts the course of the asteroid, micromanaging it into place at the L5 Lagrange point of the Earth-Moon gravitational system. This is a stable point 239,000 miles from both the Earth and the Moon.

Yeah! But you still can’t sell anything. It is too expensive … wait … my phone. Let me get this. It’s for you. The Chinese want one million tons of shaped steel for a facility orbiting the Moon and a ten year option on three more million. Lucky you. Someone on Earth has just announced a breakthrough in fusion technology making it commercially feasible. The Chinese are going to build a Moon base and space elevator to extract hydrogen-3 (tritium) from the Moon’s surface and sell it on Earth to make those new fusion reactors purr like kittens.

courtesy NASA

Obviously, no one is going to retrieve an asteroid on speculation. The initial investment is too much to leave to chance. There will be a lot of wheeling and dealing. If you hear of a robot asteroid miner being launched you will soon hear of a major orbital space project being planned for the Earth or the Moon.

Energy and asteroid mining are intertwined. Whether its mining the Moon for hydrogen-3; or building giant mirrors to gather solar energy, convert it to microwaves, and send it back to Earth; or finding water to split into hydrogen and oxygen to burn for rocket fuel; the basic economic reason we will go into space will be for energy. There is simply so much of it, and it is so cheap there will be no way for the uber rich to funnel all of that energy wealth into their pockets. Their pants would catch on fire. Energy needs to be available in vast, non-polluting, inexpensive quantities for the lifestyles we are accustomed to on this fine blue marble to be maintained without detriment to the environment. The resources we extract from asteroids are an important part of that equation.

Other articles you may enjoy:

Oumuamua: Alien Probe or Asteroid? It Could Be Both

Cryptocurrency Is Going Into Space

Going Back To the Moon Is Not Just for Governments Anymore

Why It Is a Certainty We Will Become a Space-Based Civilization

Asteroid Mining - How to Pick the Right Asteroid

Recycling Asteroids For Fun and Profit

Taking the 06-03-25 Asteroid Shuttle to Mars - An Alternative to Planned Mars Missions

A Heavy Metal, Cannibalistic Asteroid Propulsion System

Sticking the Landing On Your Billion Dollar Asteroid

Artificial Intelligence and Asteroid Mining Will Be a (Necessary) Match Made In the Heavens

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