Interplanetary Travel: How Feasible Is It - Coursework Example

Interplanetary Travel The need to explore is strong. This urge is the result of a deep-seated inherenttrait originating from survival skills learned by our earliest nomadic human-like ancestors. Exploration expands knowledge which greatly enhances chances for survival. The concept of reaching beyond the known helped to make us what we are and will determine what or if we are in the future. The question is not whether or not mankind will lose the desire to explore but how far can it reasonably expect to travel, just what are the limits? The Universe is known to be incomprehensibly large, so how far is too far for either present or near-future technology to reach? This discussion addresses the feasibility of interplanetary travel. The challenge of traveling extremely long distances can be overcome if technology advances well beyond the space shuttle but this barrier can be broken only to a point. Following the successful landings on the Moon four decades ago, many thought that space travel may someday be limitless. Man could possibly fly through the galaxy making selected stops at colonized planets much as an airplane on a three-stop flight from New York to Los Angeles. The Moon was widely thought beyond man’s reach until Neil Armstrong made his small step. This giant leap for mankind took the reins off people’s imaginations. The sky was no longer the limit and the stars were the new destination for humans who must continue beyond the known, but this was hardly a reasonable assumption. It was then and remains now just a dream. The stars will likely never be reached by humans other than when they visit the movie theater. The immenseness of the home galaxy, the Milky Way, is alone difficult to grasp, never mind the entire universe. Yet some still speculate about the eventuality of manned spacecraft landing on planets orbiting the nearest star. The following illustration attempts to put the problem of distance into perspective. If the universe could be viewed on a five billion-to-one scale map, the sun, conveniently enough for this illustration would be the size of a regulation basketball. Mercury, the smallest and closest planet to the sun, would be a small one millimeter across dot located about 35 feet or so away. Venus is two-and-a- half times larger and twice the distance from the basketball, Earth that same size and 25 feet from Venus, Mars about 50 feet from Earth. Jupiter is huge by comparison, a one inch ball almost 500 feet from the ‘sun,’ the golf ball-sized Saturn another 400 feet away and Uranus 1000 feet more. The former planet Pluto is a tiny fleck of ice more than half a mile from the basketball (Frybarger, 2007). The entire galaxy is contained in an area about a mile in diameter. If this scaled down galaxy was located on one square block in downtown Los Angeles, the nearest star would be located somewhere east of Greenland and west of Iceland. So far, astronauts have only ventured about three inches from Earth. If manned spacecraft could travel 250,000 miles per hour, people could theoretically eat breakfast on Earth, fly to and land on the moon then be back home by lunch. It would be a shorter flight than from New York to Philadelphia in a commercial jet. At that speed, the nearest star would take an amazing 10,000 years to reach (Milan, 1999). Reasonable discussion of space travel regarding either the near or far future must be limited to reachable goals, even the optimistic of which remain contained well within that downtown city mile. “Some proponents of future space travel pin their hopes on methods of travel that ‘cheat’ physical distances, such as space warps, faster-than-light travel, etc. These sorts of devices are staples of science fiction, but in the real world there is absolutely no evidence that any such thing can be built” (Milan, 1999). The next celestial conquest according to the Bush administration and therefore NASA appears to be Mars. Technically speaking, the first interplanetary excursion to Mars would be a much greater leap for mankind than was the moon voyage. At its closest, Mars is 38 million miles away from Earth, 150 times that of the moon, but only comes that close every year and a half. At its greatest distance in its elliptical orbit around the sun, Mars is 250 millions miles from Earth. It’s the difference between going for an afternoon trip to the beach and moving to the other side of the world for a couple of years on a much larger scale. The greater distance presents immense challenges and relies on technology as yet to be created. The first challenge is financing the cost of this venture. “Designing a shuttle, and more importantly a launch vehicle, that could carry all of the fuel, oxygen, water, food, and equipment needed for such a journey would cost $450 billion dollars and would require significant technological advances” (Zubrin & Wagner, 1996). The second challenge in the proposed mission to Mars is the answering psychological and physical health concerns for the astronauts. The trip to Mars would take six months at the current rate of spacecraft speed as opposed to the three day trip to the moon. In addition, the length of the stay is restrictive. “Because both legs of the trip must be carefully timed due to the changing separation of the Earth and Mars, the time spent at the planet itself is restricted to either 30 days or 550 days” (Zubrin & Wagner, 1996).  The total time of the trip to Mars and back would be two-and-a-half years because astronauts would be expected to spend 550 days, 30 days of research does not justify the expense of the trip. On a trip of this length, spacecraft could hypothetically be constructed to withstand the massive amounts of radiation bombarding the craft but people can not be similarly redesigned. Astronauts who journeyed to Mars would certainly suffer greater instances of cancer, eye cataracts, infertility and their children more susceptible to contracting birth defects according to the FAA (U.S. Federal Aviation Administration). “Cosmic rays, which come from outer space and solar flares, are now regarded as a potential limiting factor for space travel. I do not see how the problem of this hostile radiation environment can be easily overcome in the future” said Northern Arizona University space physicist Keran O’Brien (cited in Edwards, 2005). The most advanced space ship ever created, the Space Shuttle, could not accomplish such a mission nor will be a prototype of one that could. O’Brien believes that man will never be able to travel past Venus or Mars because of health concerns even if the most advanced spacecraft imaginable to scientists is created. At present, technology isn’t close to addressing the complex issues presented by a Mars mission. “Clearly, a new manner of space travel has to be created if the possibility of a manned mission to Mars is not to be abandoned or passed on to a future generation” (Zubrin & Wagner, 1996). Whatever the construction the spacecraft of the future, it will likely require nuclear power to sustain such long voyages. It will also require propulsion units that can be turned off and on throughout the trip and not simply discarded into the sea. Propulsion technology is not yet a reality but the nuclear know-how exists. Many scientists believe nuclear power is the only viable answer to long-term space travel. “So the choice is either we quit, or we develop the means for exploring space and that is nuclear power. It’s a very clear situation. There is no ambiguity. It’s either one or the other” (Halvorson, 2003). Using current nuclear technology, the costs of deploying a manned rocket safely to Mars would drop from an estimated $450 billion to less than $50 billion. If the cost was spread out over 20 years, it would entail only about ten percent of NASA’s annual budget. By comparison, in 1969 the year of the first moon landing, space exploration represented nearly six percent of the federal budget whereas today, it is allocated less than one percent (NASA, 2007). In other words, the mission to Mars would cost less than the moon landing if the spacecraft were nuclear powered. If the future spacecraft are not designed to operate on nuclear power “we might as well just quit” according to Franklin Chang-Diaz, Director of the Advanced Propulsion Laboratory at the Johnson Space Center. “It has to be very clear and transparent to the people of our planet that without nuclear power, we simply are not going to go (to Mars). We just cannot go” (Halvorson, 2003). Nuclear powered spacecraft may have already been in production and possibly deployed if not for the nuclear accidents at Three Mile Island and Chernobyl. The term ‘nuclear’ is not generally associated with ‘safe,’ more usually with ‘catastrophic.’ The idea of launching a nuclear reactor into space frightens many Americans as least to the degree that it alarms both allied and hostile nations. The fear among other nations is directed toward the technology itself, that the new developments in science would be used more for military rather than merely exploration purposes. “They say the U.S. military would adapt systems developed by NASA for space-based weapons” (Halvorson, 2003). Using nuclear powered spacecraft may also violate international treaties that prohibit nuclear, chemical or biological substances from being launched into space. Environmentalists point to the dangers posed by the inevitable accident. “During the past 15 years alone, launches of plutonium-powered probes to the sun and the outer planets have sparked protests by anti-nuclear activists. They fear that launch explosions or inadvertent atmospheric re-entries could result in fallout that would contaminate the environment and spawn an increase in global cancer cases” (Halvorson, 2003). While nuclear power may be the only feasible answer for future planetary exploration, it is not yet the political answer and of course politicians fund the space program based on the projects they approve. Other methods of sustained and reliable power have been suggested intended to bypass the nuclear controversy and continue unabated with the Mars ambition. Great sails of solar collectors mounted on an unconventional looking craft and propulsion via chemicals have piqued the imagination but have yet to prove worthy of serious consideration. According to Chang-Diaz, “When it comes to interplanetary travel conventional chemical propulsion and solar electric systems won’t cut it” (Halvorson, 2003). The great distance between the Earth and Mars or Venus and certainly all other planets is at present too time-consuming to cross without serious health consequences for the astronauts. This is the problem for any future interplanetary aspirations. It is, however, the way not the will that is keeping mankind from taking the next step in its never ending quest to discover what is yet to be known. Environmentalists are correct to be concerned with the use of nuclear power but if the technology to dispose of nuclear wastes can be developed, it may be both to the explorers and Earths advantage. Nuclear power does not emit greenhouse gasses at near the same rate as coal powered electric producing plants and may in fact ultimately help instead of harm the planet. The use of ‘nukes’ may also allow mankind to continue exploring. References Edwards, Rob. (August 1, 2005). “Cosmic Rays May Prevent Long-Haul Space Travel.” NewScientist.com. Available July 27, 2007 from Frybarger, Duane. (2007). “The Stars, Our Galaxy and the Universe.” Virtual Colony. Available July 27, 2007 from Halvorson, Todd. (November 16, 2003). “Nuclear Power Key to Future Spaceships.” Florida Today. Available July 27, 2007 from Milan, Wil. (November 16, 1999). “Exploring Space by Not Going There.” Space.com. Available July 27, 2007 from NASA. (2007).  FY 2008 Budget. Available July 27, 2007 from Zubrin, R. & Wagner, R.  (1996). The Case For Mars. New York: Touchstone. Read More