ROCKET PROPULSION SYSTEMS
This week I will be discussing space propulsion systems, our way of reaching the stars. I will try not to get too technical as to not lose interest. Today I will discuss the current technology and what we have used in the past. Back around the end of WWII, rockets were being developed by the Germans. Operation Paperclip allowed us to use that technology in developing jet engines, which changed the speed of flight as we know it. All current propulsion systems use biopropellents or solid fuel. Most satellites use simple, reliable chemical thrusts. They consist of a fuel tank, usually made of Titanium or Aluminum. The tank is then pressurized with Helium or Nitrogen. These engines are often small, and require occasional corrections t o compensate being in orbit a long time.
In space, the purpose of a propulsion system is to change velocity. The more massive a craft is, the harder it is to do this. The rate of velocity is called acceleration, and the rate of momentum is called force. The four major components of propulsion are:
This is also referred to a launch pad. The frame is what is used to launch the craft to its required trajectory.
This can be anything that is carried on a spacecraft, such as people, supplies, satellites or probes.
This is what operates the craft, and includes sophisticated sensors, on board computers, radars, and communication systems. The two main roles of the guidance system are stability and control.uel
The function of the propulsion is to provide thrust. I’m sure that we’ve all heard the third rule of Newton’s law: To every action there is a equal and opposite reaction. This simply means, that a spaceship needs enough thrust to negate the force which is putting upon it, which is gravity. The less gravity needed, the less thrust. We saw this on the moon with the LEM. There was not a lot of thrust needed to leave the moon because there is very little gravity, if any.
Rocket engines use fuel and an oxidizer, which are mixed and exploded in a combustion chamber. There are two types of rockets used today-liquid and solid fuel. In liquid rockets, the fuels are stored separately in individual chambers and combined in a combustion chamber, where the chemical reaction occurs and causes an explosion. In solid rockets, propellents are mixed together and packed into a solid cylinder. It is burned when a source of heat lights it, such as an igniter. Liquid fuels are able to be controlled by valves that can control the flow. Solid rockets don’t have this and must all be burned at once.
Rocket systems are slow and cumbersome in the world of space travel, but right now they’re all we have. Using a conventional rocket, it would take 500 days to reach Mars, and 10,000 yrs to reach the nearest star. The amount of fuel it would have to carry would make it virtually impossible to get there. The enormous size of the engines would dwarf anything that we have had in the past, and the astronauts would be subjected to long periods of solitude, inactivity, and exposed to lethal levels of radiation. NASA is currently working on ION propulsion systems,nuclear fusion, and nuclear fission , which will be tomorrow’s topic. Until then, here are today’s links:
NUCLEAR AND ION PROPULSION
Nuclear and ion propulsion systems are not new. Nuclear systems date back to the beginning of the twentieth century. Nuclear fission was first used in warships and submarines during and after WWII. Small nuclear reactors are used in a contained vessel. Several proposed nuclear rocket systems have been in the works since the 1950’s, but due to later nuclear treaties and concern about fallout, they were abandoned. There are several ideas NASA has come up with, but rockets would have to be built in space,, due to radiation concerns. One is using anti-matter catalyzed nuclear pulse propulsion, and another is external pulsed plasma propulsion, where there are small thrusts from plasma waves generated from a series of small super critical fission and fusion pulses behind the object in space. Biomodal nuclear thermal rockets are similar to the power plants in submarines.
Fusion rockets could provide efficient and long term acceleration in space without the need to carry a large fuel supply. The advantages of fusion power would be that the impulse would be very high, allowing less energy to initiate a thrust, and would also produce less radiation. The disadvantages are the large mass of the reactor, and the actual spacecraft would be much larger and more complex than anything currently developed. Although still a concept, if developed, it could propel a spacecraft to Mars is just 90 days, and the nearest star in forty years. Ram jet fusion allows the craft to gather energy from space itself and theoretically would never need refueling.
Ion propulsion is a form of electrical propulsion that creates thrust by accelerating ions by the use of plasma. Ions pass through an electromagnetic grid engine, and converts it to kinetic energy. This does not produce enough energy for escape velocity, however, and is only used in space, where only small thrust is needed. Orbiting satellites and space probes use this technology. As the thrusts are initiated, the spacecraft picks u p speed. This is the slowest form of space propulsion and is inefficient for long journeys. It would take months to even reach the moon using this method.
In my book, Jeff Walker’s race, the Martians use these methods of travel, but have not yet left their own star system. One day we will achieve this travel, and it may be our key to finding out how to colonize Mars and other moons around planets within our own back yards. Tomorrow, we will discuss propulsion straight out of science fiction-Antimatter and Warp drives, which allows travel up to and beyond the speed of light. Until then, here are the links for today:
ANTI-MATTER & WAR DRIVES
When I was a kid, a fantastic and unbelievable show came out called Star Trek. It was based on ideas that were far out and outlandish to say the least, but nonetheless, I was captivated by the show. Even at a young age, its ideas and method of travel fascinated me. It seemed that they could go anywhere in the galaxy in a matter of days, weeks, or months. Although it was science fiction then, Gene Roddenberry based his ideas for the show on real theories developed by Albert Einstein. The ship’s engines used a combined propulsion system based on antimatter and warp drive. But are these ideas even feasible?
The answer theoretically is yes. In an antimatter drive engine, the electrical charges of antimatter particles are reversed, and form a positive charge instead of a negative charge. When the two particles meet, they create an explosion that produces pure energy, electromagnetic radiation that spreads outward at the speed of light. This energy produces 10 million times the energy produced by conventional chemical rockets, 1000 times the energy produced in an atomic bomb, and 300 times the energy than a nuclear fusion engine. The problem of antimatter rocket is that it would take tons of antimatter, which doesn’t exist here. One solution to this problem is to mine it from space, where it does exist in the form of cosmic rays. Another potential problem would be the lethal amount of radiation and gamma rays exposed to the vessel. The crew, payload area and engine would have to be shielded against radiation and extensive heat. Unfortunately, these type of ships would only travel 70% the speed of light, and would still take at least 7 years to reach the nearest star.
Warp drives are similar, but instead of trying to achieve the speed of light, it bends the space time around the vessel, allowing the speed of light or faster. The vessel doesn’t move, only the space in front and behind it. The theoretical solution for warp drive is called the Alcubierre drive, formulated by physicist Miguel Alcubierre in 1994. The model requires massive amounts of negative mass or exotic matter, which we know exists theoretically, but there is currently no proof. The amount of energy needed would be equal to the mass of Jupiter. The gravitational fields produced would rip a ship to shreds, unless we developed a system that could work. The other problem is that if we could create a bubble around the ship to produce the field, how could we turn it on and off without affecting the ship itself?
So far now, Star Trek is just fantasy. It is nice to believe that we could someday visit other worlds and get around in a matter of days, but it won’t be possible for at least 500-1000 yrs. But who knows, years ago, we said we would never fly either. Tomorrow, we will really go in full throttle-into the wormhole with Plank technology. Until then, here are today’s links:
PLANCK TECHNOLOGY & WORMHOLES
Max Planck was a German scientist and the first real physicist to formulate a quantum theory in 1900, and the first explain why black bodies absorb all light that hits it. At the time, it couldn’t be explained with normal physics. He developed an equation to explain this, using (E)energy=(N)integer(h)constant(f)frequency, In determining this equation, Planck came up with the constant, now known as Planck’s constant. His discovery led to the belief that energy, which appears to be emitted in wavelengths, is actually discharged in small packets, or quanta, and led the way to Einstein’s theory of relativity.
I’m sure everyone has heard of these theoretical passages through space and time. They are staples of science fiction, my novel included. In my novel, a wormhole is created, and Jeff Walker is dragged into it by his nemesis, the Tolarions. He ends up in another universe where this type of travel is commonplace. But what are wormholes, and are we able to actually ever travel through them to other places in the universe, or even another universe?
Wormholes, or Einstein-Rosen bridges, are named after two men whose work in the early 20th century led to the first theories involving the warping of space and time. They are four dimensional tunnels through space and time. Although there is conjecture about how they are created, there is a possibly they exist in space, but are extremely small. The major problem that most physicists agree on is their instability. If someone or something enters it, the disruption of energy forces it to collapse, and if it were a spaceship, it would crushed instantly.
There are two types of wormholes, Einstein-Rosen bridges, also known as Schwarzschild wormholes, and traversable wormholes. Bridges are formed with the use of a black hole. Astromoners didn’t have proof of their existence until recently, within the last ten years. It is believed that there is a massive black hole at the center of our own galaxy. Without its existence, we wouldn’t be where we are today. They are givers of life and death in our galaxy. Black holes absorb all light, energy, and matter. The singularity is the point of a black hole where the mass of a star is packed into a tiny point at its center. The super collapsed matter is the remnant of a dead star; many massive stars go through this process, but it takes billions of years. There is a massive black hole at the center of every galaxy in the universe. It is surmised that black holes cannot be used as wormhole passages because they lead to dead ends. The only possible solution to this problem is to use dark energy to spin the wormhole faster than the speed of light to keep it open for passage. It is believed, however, that the mass of a black hole would be too great to pass through it, and it is not known if a spaceship would even find an end to it. Not all black holes would work, only Kerr Newman black holes, where a massive electric charge and a high spin rate are used to achieve the passage.
There is another solution. Traversable wormholes are theoretical in nature, and are small if they do exist. Exotic energy is used to pry open the existing wormhole using the mass equivalent to a star. While the hole is open, the exotic energy keeps the hole open, allowing passage. Although physicists believe this might be possible, they are eons away from making it happen. Stories like mine, and the popular Interstellar are strictly science fiction, and are at least 10,000 yrs away, if possible at all. Maybe some advanced civilization somewhere in the universe has solved this problem. Human beings only use 3% of their brain capacity, so who knows what smarter civilizations can accomplish.
Tomorrow, I will discuss how wormholes, warp drives, and fusion engines can change space travel for mankind. Until then, here are today’s links:
THE FUTURE OF INTERPLANETARY SPACE TRAVEL ON MANKIND
How will space travel affect mankind, and why should we even go there in the first place? First of all, if we want to survive as a species, we will have to go there. Our Earth has limited resources, and unless we learn how to renew them naturally, we will die as a species. It may not be right away, but it will eventually happen. That is the number one reason space is a good idea. There are many others reasons as well; such as finding a world similar to our own to colonize, finding renewable sources of energy not found here, and expansion of the human race.
There are several missions planned in NASA’s agenda. One is the New Horizons mission, in which is currently near Pluto. Within the next few weeks, we will be within 10,000 miles of the dwarf planet, Pluto, closer to any external planet than ever before. This probe will continue to explore the Kuiper belt and the Oort cloud. It will also explore the nature of the Interstellar medium and its influence on the solar system, and nearby solar systems. The Kepler Probe is similar, searching for Earth-like worlds like our own.
In order for us to achieve Interstellar travel, we first we have to tackle the the many and nearly impossible problems we will face in space. The speed of light is 186,000 miles per second, or 670,616,629 miles per hour. One light year is 5,88 trillion miles. Even one of our fastest probes, the Helios II probe, would take 19,000 years to reach Proxima Centauri, our nearest stars. Traveling at the speed of light, we could leave our system within 11 hours. The distances are too great for conventional rockets, and we have learned that other forms of travel have yet to be achieved. Even if we were too achieve FTL travel, or even fusion powered systems, which could get us to the nearest star during a lifetime, there are surmountable obstacles we must overcome first.
First of all, and most important is the effect it would have on humans. The extended exposure to 0 gravity, the cosmic radiation, lack of reference to surroundings, muscular degeneration, sense of solitude, just to name a few. Then there is the fact that there is no rescues billions of miles from home; as from a quote in a familiar movie-In space, no one can hear you scream. Even if we were to solve all of these problems, such as using suspended animation to combat long periods in space, we will still have the major problem of how to get there in a reasonable amount of time. And even with a fusion-based system, there is the problem of protecting against cosmic rays, power sources, and obstacles in space, such as charged particles, asteroids, cosmic dust, and spurious hot gasses. There is no solar energy available in between stars, and no celestial bodies from which to mine and extract fuel, oxygen or water. We no very little about what’s in between stars, even though we have found exoplanets that seem to orbit no stars at all. Dark matter and dark energy are concepts we are only beginning to understand, and currently there is no theory to explain everything in quantum physics.
So for now, Interstellar travel is just a dream of science fiction. It is reality, however, to assume the possibility of other forms of life in our universe, and even our galaxy. We just haven’t found them yet. The universe is too vast, and our solar system is no longer thought to be unique. Kepler is on the verge of discovering these worlds, and within 10-20 years, the verdict will be in. Are we ready? Monday, we will investigate this prospect-what will happen when we finally land on a far away world, in a whole series titled, Distant Worlds. Until then, here are today’s links: