There are a couple of problems arising from making interstellar space voyages. Two main problems are time and fuel energy required. Scientists still do not consider that space travel beyond Solar System is a physical possibility even by using powerful propulsion systems like fission rockets. In addition there is Einstein’s theory of relativity and concept of relative time.
The former says that to attain the speed of light, the highest speed limit in nature, the mass has to increase to infinity – thus making the energy needed for this acceleration also to be infinite. While the concept of relative time states that if one travels faster, time travels slower, and theoretically when an object attains the speed of light the time stops completely. With the existence of these problems, the space travel to far away galaxies still seems a sci-fi concept (Ratliff, Kimball & Heraty n.d.)
Propulsion Theories –Antimatter propulsion
Theoretically every particle has its corresponding antiparticle, identical in nature but opposed in charge. When these oppositely charged particles combine they are converted into combination energy and other particle, the process is known as annihilation. Scientists are currently doing experiments to use this energy as a power source for spacecrafts.
There are several methods to do this. One of them follows the principles of fission reactor and a steam engine. This method would provide twice of the present impulse to spacecrafts. A more complicated method used magnetic coils to direct the by-products of annihilation to provide the thrust, which would give an impulse of 10,000,000 million seconds but the thrust would be lower (Ratliff, Kimball & Heraty n.d.)
While the method is very efficient, the main limitation of using the antimatter in the propulsion system is its price – one mg of antimatter may cost nearly one hundred billion dollars to produce. This is the major difficulty in the implementation of antimatter propulsion technology. (Ratliff, Kimball & Heraty n.d.)
Research and Experiments
Many experiments have been going on for making the propulsion scheme using Antimatter, to be more specific antiprotons, feasible in near future.
Antimatter is generated in a handful of laboratories around the world. The laboratories in America include facilities such as Brookhaven National Laboratory in New York and Fermi National Accelerator Laboratory in Illinois. These laboratories produce antimatter by accelerating subatomic particles like protons near the speed of lights and then hit them against other target particles. The most famous of these laboratories is at CERN in Geneva. In fact the first antimatter particle was produced by a scientist names Carl Anderson in the year 1932 (Forward Blase 1997)
The Antimatter particles are difficult to produce because of their inherent nature. The process of annihilation consists of making a contact between particles of antimatter with particles of matter. When this happens both are annihilated and energy is created. However, the synthesized antiatoms have lasted only 40 billionths of a second before their annihilation.
The simplest antimatter atom to produce was Antihydrogen. This too took billion of dollars and decades of research. Even CERN, considered to be the most advanced laboratory, where this experiment was performed, agrees that the present method is far too expensive and that newer, faster and cheaper methods need to be researched or increasing the production of antimatter (Book Rags)
The current worldwide, annual production of antimatter is only two billionths of a gram. Unless this number is increased multifold to the order of milligrams; the use of antimatter in space propulsion is not a viable option. This is because “at least several milligrams of antimatter is needed to fuel a beam core antimatter engine in local operations and several kilograms for interstellar travel to Alpha Centuri” (Persson 2007).
NASA has made an approximation that “the requirements for antimatter are on the scale of 1 to 100 micrograms per mission, which with the current infrastructure equates to an antiproton cost of $60 million to $6 billion.” (Schmidt Gerrish Martin n.d). However they also speculate that with the many research projects focused on the reduction of costs, the cost per mission could drop to $60 million per mission, or even lesser possibly less. At this rate the antimatter propulsion might become a feasible option for the future space voyages.
Book Rags, “Antimatter Propulsion”,
Forward R L, Blasé WP, “Advanced Space Propulsion Study – Antiproton and Beamed
Power Propulsion”, 1997, http://www.transorbital.net/Library/D001_S01.html
Leonard D, “Looking to Lasers, Microwaves and Antimatter for Space travel”, 26th
November 2003, Tech Wednesday, http://www.space.com/businesstechnology/technology/fof_physics_031126-1.html
Persson J, “Antimatter Propulsion-Future Space Propulsion Systems”, 2007,
Ratliff S, Kimball K, Heraty G, “The Speed of light: How faster can we go”,
Schmidt G R, Gerrish HP, Martin JJ, Smith GA, Meyer K J, “Antimatter Production for
Near-term Propulsion Applications”, NASA