Planetary Exploration

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Planetary Exploration

The exploration of space has been of interest to people since Nicholas Copernicus (1473-1543) and Galileo Galilei (1564-1642) discovered and described the true nature of the solar system. About 100 years ago, Russian Konstantin Tsiolkovsky (1857-1935) was the first scientist to describe the modern concepts of rocket engines and space travel. Tsiolkovsky, who wrote books about space travel, stated: "Earth is the cradle of humanity, but one cannot remain in the cradle forever."

In 1957 the Soviet Union surprised everyone by launching the world's first satellite, Sputnik. Only four years later, American amateur radio operators (hams) built and launched the world's first volunteer-and citizen-built satellite, Oscar I. Oscar I weighed about 3.7 kilograms (10 pounds) and transmitted the word "Hi" in Morse code as it orbited Earth.

Government-Backed Exploration

In the beginning, national space programs were exclusively military. While Robert H. Goddard (1882-1945) was experimenting with small and unsuccessful rockets in the United States, the German Nazi war effort progressed to the point where the Nazis were able to bomb downtown London with their V-2 rockets. When the Nazis were defeated, the armed forces of the Soviet Union and the United States raced to obtain valuable German engineers to gain their knowledge of advanced rocketry. After World War II (1939-1945), the programs of both countries were based on former German rocket scientists, such as Wernher von Braun (1912-1977), who was brought to the United States.

The National Aeronautics and Space Administration (NASA) was formed in 1958 at the urging of President Dwight D. Eisenhower (1890-1969). President Eisenhower wanted a civilian and not a military agency to challenge the Soviet Union in the race to space. NASA's first challenge was to beat the Soviet Union to the Moon, which it successfully accomplished with the Apollo 11 mission in 1969.

Moving Beyond Government-Sponsored Space Programs

The excitement generated by humans walking on the surface of another planetary body resulted in many nongovernment people dreaming and working toward the private exploration and development of space. A leader during the 1970s was Gerard O'Neill of Princeton University, who imagined and described the possibility of people working, living, and playing in space. Much research was done on his concepts of space colonies orbiting Earth, but because his designs depended on large amounts of materials being launched to Earth orbit, and because of the very high cost of government technology and launches, such space colonies never materialized.

In 1965, Comsat launched the first commercial communications satellite. Today, college students design, build, and launch smaller, more powerful satellites. These "nano-sats" and other small microsatellites are usually launched as "hitchhikers" on large expensive rockets. Many space entrepreneurs today believe that a revolution may be happening with the introduction of smaller, more modern technology into space products. With college students building 1-pound satellites, and with the introduction of the concept of formation-flying dozens or hundreds of nano-satellites in orbits close to each other, it is possible to think of small satellites being like the personal computers linked together in local area networks that replaced the big expensive mainframe computers.

Also during the mid-1990s, a number of companies were started with the hope of designing and producing dramatically less expensive launch vehicles. Each company began with the hope that it had some kind of breakthrough technology that would revolutionize launch vehicles and reduce the cost of orbiting material from $22,000 per kilogram ($10,000 per pound) to as little as $220 per kilogram ($100 per pound). Because of the expense and risk involved in developing new technologies, these companies have not yet made much progress.

While many people are beginning to understand that space is a place and not a government program, there are many hurdles to overcome in making space happen for large numbers of nongovernment people—workers, tourists, and others wanting to experience space. Those interested in seeing space blossom feel that there are two primary paths. The first involves more government spending on large programs, such as an Apollo-like human mission to Mars. It appears, however, that taxpayers are not willing to fund such an expensive program. The other commercial and entrepreneurial paths to space may be encompassed in the slogan: "If we want to go to space to stay, space has to pay."

Difficult and expensive ventures often need to start with baby steps: learning to crawl and then walk before being able to run. Space may be like that. Many companies are starting with the goal of finding ways to make space pay in order to generate profits that can be used to conduct increasingly bolder and larger space ventures, without government intervention or taxpayer subsidies. Sources of revenue include planetary science data, returned samples, delivery of science instruments to planetary destinations, use of the abundant natural resources in space, delivery of television and Internet content in the form of photos and videos, manufacture of materials in space, and space tourism. All of these can be done commercially.

Robert A. Heinlein (1907-1988), an American writer and scientist, said that getting to Earth orbit is halfway to anywhere in the solar system. He meant that the energy required to lift off the ground and get up enough speed to achieve Earth orbit is about the same amount of energy required to leave Earth orbit and head for any other destination in the solar system. In other words, when we reach Earth orbit today, we are running on empty, our tanks are empty, and about the best we can do is go around in circles, as with the shuttle. Even with more expensive, larger rockets, we can just manage enough energy to break away from Earth's gravity. Our deep-space missions then coast, on empty, to their destination whether it is Venus, Mars, Jupiter, or the boundaries of the solar system itself.

What some believe is needed for serious exploration of space are filling stations in Earth orbit where a spacecraft could refill its tanks and could then power its way through space and not just coast for years. Earth-bound society is dependent on concentrated, portable energy such as gasoline, petroleum (black gold), natural gas, and coal. Space is no different: concentrated, portable energy is needed to explore space. Water is the most abundant substance in the universe and in the solar system. Scientists know that Earth travels in a cloud of inner belt asteroids called near-Earth objects. Many planetary scientists, such as John S. Lewis of the University of Arizona in Tucson, believe that 20 percent or more of these objects may be dormant comets . These space icebergs, then, might be considered "white gold."

With the cost of lifting anything into space at about $22,000 per kilogram ($10,000 per pound), it can be understood that anything already in space is already worth $10,000 per pound. If private exploration companies were to find water in near-Earth asteroids, the water could be extracted and converted to its constituent parts—oxygen and hydrogen—with simple electrolysis. Like Earth, space is filled with diffused energy: solar energy. This energy could be captured by satellite solar arrays and converted into electricity to power spacecraft, and could also be used to generate rocket fuel: specifically, hydrogen and oxygen, which, for example, are used in the main engines of the space shuttle.

By 2000 the international space sector of the global economy exceeded $100 billion per year with about one launch per week somewhere in the world. Since about 1998 over half of that space activity has been commercial and not military or governmental. With smaller modern technology and entrepreneurial space companies starting, we may be on the verge of the real space age.

see also Apollo (volume 3); Data Purchase (volume 1); Earth—Why Leave? (volume 4); Exploration Programs (volume 2); Planetary Exploration, Future of (volume 2); Satellite Industry (volume 1).

James W. Benson