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1. Nuclear and Plasma Space Propulsion - Chapter 1 NUCLEAR...

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Chapter 1 NUCLEAR AND PLASMA SPACE PROPULSION © M. Ragheb 2/22/2009 1.1 INTRODUCTION In their role as stewards of life on Earth and perhaps in the whole known universe, humans have a duty to preserve and spread life. With their acquired intelligence, science and technology, it is their sacred destiny to preserve life with the equivalent of Noah’s Arks on both the Moon and Mars. Life can be subject to extinction on Earth either from within through volcanic eruptions or viral epidemics or from asteroid or comets impacts from space, as we know may have happened in the past. It is urgent to keep backup copies of life, like we keep for files on computers, on the moon and Mars protected from the possible unexpected calamities that could extinguish life on Earth. Fig. 1: The power requirements versus the length of mission stay times for space missions.
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Large amounts of chemical energy must be used in space travel to propel the space vehicle, especially out of the main pull of the Earth's gravity. The first stage of the Saturn V rocket used in the Moon missions Apollo program generated as much energy as 1 million automobile engines. The rocket engine as well as the propellant fuel must also be compact and lightweight, before the space vehicle can carry them. Fig. 2: Apollo 11 boot print on the moon, July 20, 1969. NASA Photograph. The power requirements versus the length of mission stay times away from Earth favor solar and nuclear energy means. As shown in Fig. 1, for large power needs, nuclear propulsion becomes the only alternative, particularly in the deep reaches of space where solar energy is not even available. 1.2 HUMAN DESTINY AND SPACE TRAVEL The American astronomer Frank Drake, an originator of the Search for Extra Terrestrial Intelligence (SETI) Project, suggested in 1960 an equation considering the probabilities of existence of intelligent life in the universe and estimating the possible number N of planets with Earth-like life with a technological civilization in the known universe as: N = R * .P p .n e .P l .P i .P c .L (1)
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where: R* is the number of stars systems, P p is the probability of occurrence of stars with planets, n e is the fraction of planets with habitable environments, P l is the probability that life has originated on a given planet, P i is the probability of life evolving into intelligence on a given planet, P c is the probability that the evolved creatures have the technology to send signals, L is the Longevity factor. Other factors could be added to this equation. For instance a factor possibly designated as the moon effect, P m , can be added for the probability that a planet would possess an Earth- moon balance relationship like the existing one. It is suggested that the Earth was initially at half the size of the present planet, when a celestial object, collided with the Earth forming a double planet. A smaller body separated and orbited the larger one initially, then moved away with a decreasing orbital velocity forming the present-day moon. Maybe the Earth and Mars collided in
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