Now as we are rapidly approaching the Millenium many people are getting the blues. This seems absurd because this offers all of us a perfect chance to start again. NASA is embracing this chance to grow and expand their departments. The phrase, Space, the final frontier, expresses the worlds obsession with space travel, that started centuries before it even became popular 30 years ago in Gene Roddenberrys TV series Star Trek. Science fiction has entertained our culture for years. Movies such as Star Wars and Planet of the Apes have helped fuel our desire to get off the planet earth, find new life forms, and conquer the stars. Science-fiction dreams of worlds beyond our solar system have taken on a more realistic aspect since astronomers discovered that the universe contains planets in surprisingly large numbers.
Studying those distant planets might show how special Earth really is and tell us more about our place in the universe (NASA homepage). Finding a planet that can support human life would revolutionize our society into the Jetsons. These ideas are soon to become our realities. NASA is currently experimenting with many methods to try to explore the outer edges of the galaxy. In order to understand NASAs excitement about star traveling, we will first fly through current projects concerning space travel, second explore three possible technologies being experimented with for the year 2000, finally take a trip into our future and experience how star traveling will change our lives as we approach the end of the second millenium.
NASAs goal of faster, better, cheaper has been the motivation for them to develop new mission concepts, and to validate never-before-used technologies in space. The new technologies, if proven to work, will revolutionize space exploration in the next century. According to NASAs New Millennium Program home page, last updated on September 16,1999, NASAs current project of Deep Space 1 demonstrates some of their most exotic technologies. One of the most impressive is the testing of an ion engine that is supposed to be 10 times more efficient than liquid or solid rocket engines. Deep Space 1 was launched on October 24, 1998. It is the first mission under NASAs New Millennium Program, which features flight testing of new technology, rather than science as its main focus (Rayman 4).
These new technologies will make spacecraft of the future smaller, more economical, reliable, and closer to the goal of efficient space travel. According to Dr. Marc Rayman, the deputy mission manager and chief mission engineer for Deep Space 1, there are 12 advanced technologies onboard the spacecraft and seven have completed testing (5). Despite some glitches, the great majority of the advanced technologies have worked extremely well. Rayman also said, Mission designers and scientists can now confidently use them on future missions(4).
All of this testing is now paving the way for star traveling. The great stumbling block in this road to the stars, however, is the sheer difficulty of getting anywhere in space. Merely achieving orbit is an expensive and risky proposition. Current space propulsion technologies make it a stretch to send probes to distant destinations within the solar system. Spacecrafts have to follow multiyear, indirect trajectories that loop around several planets in order to gain velocity from gravity assists. Then, the craft lacks the energy to come back. Fortunately, engineers have no shortage of inventive plans for new propulsion systems that might someday expand human presence beyond this planet. Anti-matter, compact nuclear rockets, and light sails are three ideas that engineers are experimenting with.
But these ideas are in their embryonic stages and it is already more than apparent that the task is as difficult as it could possibly be, but still remain possible. Robert Frisbee, a researcher at NASAs Jet Propulsion Lab said, right now, based on our current level of ignorance, all three energy sources are equally impossible or possible (DiChristina 2). Some of these ideas are just radical refinements of current rocket or jet technologies. Others harness nuclear energies or ride on powerful laser beams. Even the equivalents of space elevators used for hoisting cargoes into orbit are on the drawing boards.
Out of all the ideas that have been brought up, NASA is seriously exploring three. One of the first possibilities but the hardest to obtain is anti-matter. When antimatter comes into contact with regular matter they annihilate and the mass is converted into energy. Stephanie Leifer of the Jet Propulsion Lab stated in the June 1999 issue of Popular Science Magazine that, The antimatter-matter reaction has the highest energy density we know of(55). The reaction releases charged particles that could be directed out the back of the spacecraft for thrust using magnetic nozzles. A small problem is that engineers dont know how to make the nozzle big enough for antimatter engine. Then add another problem of making thousands of tons of antimatter when only mere a nanogram of antimatter is made at special laboratories like Fermilab and CERN. The largest problem to add on to this is antimatter cannot make contact with matter. Currently it has been extremely difficult to store more than a tiny amount of antimatter in magnetic traps. These magnetic traps keep charged particles from hitting the matter containment walls and annihilating. To solve the problem physicist Gerald Smith and his team at Penn State decided to tackle the problem on several fronts. They were able to trap shoebox-size antimatter and hold 100 million antiprotons (Beardsley 5). But until scientist can contain over a ton the antimatter-matter reaction will be put away.
A second energy source is nuclear fission, also called compact nuclear rockets. These rockets can impart a maximum velocity increment of up to about 22 kilometers a second even, though it is not even close to the amount of energy the anti-matter reaction can create. Hydrogen, the key element in fission, is much easier to obtain and engineers are closer to building a rocket motor that can be powered with nuclear fission. According to the Scientific American web page last updated on September 12, 1999, James Powell and his colleagues have designed a compact nuclear rocket engine that they call Mitee (4). In reality this rocket can be built in six years and would cost about 600 million dollars, which is modest in context of past space launches. Another key attraction to nuclear propulsion is that its propellanthydrogenis widely available in gaseous forms on the giant planets of the outer solar system and in the water and ice of distant moons and planets.
Because the nuclear fuel would be relatively long lasting, a nuclear-powered craft could in theory tour the outer solar system for 10 or 15 years, thus replenishing its hydrogen propellant as necessary (7). Its reactor would start up well away from Earth. A nuclear-powered spacecraft could actually be made safer than some deep-space probes that are powered by chemical thrusters. In the near term, only nuclear rockets could give us the kind of power, reliability, and flexibility that we would need to dramatically improve our understanding of the still largely mysterious worlds at the far edges of our solar system.
The last chief option is to leave the engine at home and power the spacecraft with solar sails most commonly called light sails. Light sails may be initially more promising than anti-matter or fission. According to the previous mentioned issue of Popular Science, Robert Forward, a retired Hughes physicist who now consults for NASA, concluded that, in terms of the closest and cleanest development program light sails may be the first step(3). The sail literally allows the shuttle to be pushed through space by photons from a laser or the sun. When the photon collides with the sail, it will either simply be absorbed by the sail material or will reflect off the photon. Both processes impart acceleration, but reflection imparts twice as much as absorption. Thus, the most efficient sail is a reflective one. Like other propulsion methods light sails are limited in their performance by the thermal properties and the strength of materials, as well as by our limited ability to design anything that consists of a polished, thin metal film.
However, a good deal of work relevant to light sails has already been done. The Department of Defense has developed high-powered lasers and precision-pointing capability as part of its research into ballistic-missile defenses and possible anti-satellite weaponry. Closer to home the US National Oceanic and Atmospheric Administration announced its planning to launch within four years a spacecraft powered by a light sail. NASA is now evaluating plans to develop laser light sails as a possible low-cost alternative to conventional rockets. We see in light sails a possible glimpse of the future, an inexpensive access to the remote solar system and beyond. In time they could make travel to distant stars a reality.
Now that we have seen how close to star traveling we really are, lets get aboard the perfect spacecraft and let our imagination become reality. Every one loads the new and improved star traveling vehicle. Buckle up it is going to be a bumpy ride. We travel for about two light years which seems like an extremely quick trip. Our craft lands on a neighboring planet to our solar system. As a team we start to explore and record the data we are finding on this new planet. After our explorations, we head back to Earth. When we return, we find that every one has gotten several years older and technology has just exploded to mind boggling heights. Another space race has begun but this time it is to colonize planets. Our knowledge and understanding of who we are would be forever altered. The next step would be to start exploring possibilities for intersolar travel. Going back and forth between Jupiter, Pluto, and the Moon to retrieve energy sources or visit a friend that is now a Lunar citizen.
Jupiter is converted into a large gas station were the spacecrafts could stop and refuel with the indefinite supply of Hydrogen gas that makes up this large planet. Our planet could start to mine the Asteroid belt for old energy sources and find new ones. The biggest change for our world would be social standards. How will we treat people when they introduce themselves as a citizen of Pluto? Picture all of the new art forms and sporting events that could take shape in zero gravity conditions. Would our society expand and have states on distant moons of Jupiter? Students in school on Venus could look out their windows when they are tired of reading Antigone and see the outline of the Earth instead of a boring playground.
When the technology is ready, our world as we know it will be completely turned upside down thinking about colonizing planets and other solar systems dozens of light years away. Space enthusiasts look to the day when ordinary people, as well as professional astronauts and members of Congress, can leave Earth behind and head for a space resort, or maybe a base on the moon or Mars. The Space Transportation Association, an industry lobbying group, recently created a division devoted to promoting space tourism on their web page which was last updated on August 12, 1999. They see space travel as a viable way to spur economic development beyond Earth.
Just imagine, someday we may be able to leave Earth and head to a planet that can support human life and have new energy sources for faster and more efficient way of doing simple task in life. Our imaginary trip will soon become a reality for future generations, even though this is still a science fiction goal to us. Serious investigators continue to look for ways to turn each of these concepts into a reality. If one of the energy sources work, it will change our ideas about the universe radically. Then possibly space would no longer be the final frontier. Instead of getting the Millenium blues, everyone should take a look at NASAs enthusiasm and jump on the new space race bandwagon.
Beardsley, Tim. The Way to Go in Space. Scientific American August 1999: 1-10.
DiChristina, Mariette. Star Travelers. Popular Science June 1999: 54-59. Harris, Henry M. Light Sails. Scientific American August 1999: 56-60.
Morehead, Albert and Loy. The New American Webster Handy College Dictionary. 3rd
ed. New York: Signet, 1995.
Powell, James R. Compact Nuclear Rockets. Scientific American July 1999: 34-43.
Rayman, Dr. Marc. Understanding the Space Popular Science March 1999: 3-9.
Stern, David P. Far-out Pathways to Space: Solar Sails. NASA Homepage updated 3
April 1999. www.istp.gsfc,nasangov/stargaze/Solsail.htm.
The New Millennium Program. NASA Homepage updated 12 August 1999.