bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nuclear Rockets and Ramjets
Authors: Finger Harold B. 
Published: October 2003

AbstractThe objective of this article is to describe the design concepts of and the programs to develop our nuclear rocket propulsion capability for spaceflight and the nuclear ramjet systems intended for missile delivery and to describe the mission capabilities they could provide. In both systems, the nuclear reactor replaces the combustion chamber as the source of high‐temperature energy used to provide the thrust in place of their chemical alternatives. The nuclear rocket was, and still is, considered for deep space missions, including missions, such as human flight to Mars, whereas the stimulus for the nuclear ramjet was its potential performance as a high‐speed, almost limitless range, low‐altitude and, therefore, almost undetectable missile delivery system. In the early phases of research on the nuclear rocket, it too had been considered as a possible missile system.The hardware weight of the entire system must be limited so that the various mission benefits resulting from the nuclear energy source are not counterbalanced by that total weight. Major design and development requirements include selecting materials that have high‐temperature strength and are compatible with hydrogen propellant in the rocket and air in the ramjet, appropriate neutronic characteristics, controlled and stable start‐up and operation, component design and reliability, and are safe. All of these matters must be and were comprehensively researched and developed to provide systems that could achieve the desired performance. These were all high priority tasks in both the nuclear rocket and nuclear ramjet programs, and they are discussed in this article, as are the important management organizations and technical capabilities established to carry them out.Though significant progress was made in these programs, neither the nuclear rocket nor the nuclear ramjet program was carried to actual application in its proposed and anticipated missions. In the nuclear rocket case, the space program has not yet committed to mission objectives that require the high payload and deep space capability of that system. However, nuclear rocket propulsion continues to be recognized as necessary for large, deep space missions. In the nuclear ramjet case, existing chemical rocket systems provide all of the military missile requirements that are foreseen. Similar to the nuclear ramjet development, the extensive work that had been done on nuclear‐powered turbojet engines, that is mentioned here, was also discontinued because chemically fueled turbojets provide all of the capability that was required.
Planetary Exploration Spacecraft Design
Authors: Jones Ross M. 
Published: October 2003

AbstractHaving only begun in the early 1960s, planetary‐exploration spacecraft design is a fairly new art. Between 1962 and 1973, NASA designed, built, and launched 10 spacecraft named Mariner to explore Venus, Mars, and Mercury for the first time. In 1962, the Jet Propulsion Laboratory (JPL) launched the Mariner 2 spacecraft to explore Venus. In 1965, Mariner 4 flew by Mars and captured the first close‐up photos of another planet.Each year since 1962, NASA, the USSR, Japan, or the European Space Agency has launched at least one planetary‐exploration spacecraft. Two of the best known are NASA's Voyagers, which were launched in 1977, two years after NASA's Viking mission sent landers and orbiters to Mars. Today, 24 years after launch, Voyager 2 has completed a tour of Jupiter, Saturn, Uranus, and Neptune, and still returns data from a distance of 64 AU. NASA spacecraft have visited every planet in the solar system except Pluto, and orbited Venus, Mars, and Jupiter. In 1975, the USSR's Venera 9 and 10 spacecraft sent the first photos from the surface of another planet (Venus); in 1986, the European Space Agency's Giotto spacecraft captured the first detailed photos of a comet's nucleus (Halley's). The NASA/JPL Cassini spacecraft is due to enter Saturn orbit in 2004. The NASA/APL MESSENGER spacecraft is due to orbit Mercury in 2009. MESSENGER is being built by the Johns Hopkins Applied Physics Laboratory (APL), which also built the Near Earth Asteroid Rendezvous 10 (NEAR) spacecraft that orbited and touched down on the asteroid Eros in February 2001.This article addresses the important elements of planetary‐exploration spacecraft (PES) design. The scope of this article includes those spacecraft that fly by, orbit, or land on other planets, asteroids, or comets. Planetary‐exploration spacecraft are truly fascinating machines, and their missions are some of humankind's most audacious endeavors. Spacecraft elements are described in some detail, and the principal focus is on the system design and the technical subsystems. Ground stations, launch vehicles, science, and navigational elements are not addressed.
Pluto and Charon
Authors: Young Eliot , Young Leslie 
Published: October 2003

Abstract
Pluto is a small, cold planet on the outskirts of the known solar system. Pluto's diameter (∼2370 km) is roughly equivalent to the distance from New York to Las Vegas, or about two‐thirds the size of our Moon. Pluto has one known moon of its own, Charon, whose diameter (∼1250 km) is slightly more than half of Pluto's. Unlike seven of the other eight planets (Uranus is the exception), Pluto rotates on its side, as does Charon in its orbit around Pluto. Charon's distance from Pluto is 19,636 km, compared to the Earth–Moon distance of 384,400 km.

Despite their proximity, Pluto and Charon are covered by bright frosts of differing compositions: H
2
O ice covers Charon, whereas Pluto's surface is predominantly N
2
frost that has traces of methane and carbon monoxide ices. Both objects have densities near 2 gm/cm
3
, implying a roughly even mixture of rock and H
2
O ice for their bulk compositions.

The Pluto/Charon system has a highly elliptical orbit around the Sun. A Pluto recedes from the Sun, much of its thin N
2
atmosphere will condense as frost on the surface. This periodic redeposition of fresh frost takes place every Pluto year (248 Earth‐years) and is the reason that Pluto's surface has one of the highest albedos in the solar system.

The Pluto/Charon system currently represents one of the wide open frontiers in the solar system. No spacecraft has visited Pluto/Charon (although NASA has plans for an upcoming Pluto–Kuiper Belt mission). The angular diameter of Pluto is only a tenth of an arcsecond at best, which is just about the resolving limit of the Hubble Space Telescope (HST) and ground‐based observatories that have adaptive optics capabilities. Consequently much of what is known about the Pluto/Charon system has been pieced together from indirect clues or observations taken during unique observing geometries.
Much has been determined by infrared spectroscopy. A rare opportunity to study Pluto's atmosphere takes place when Pluto passes directly between Earth and a star (stellar occulations). The 1988 occulation provided the most detailed and direct information about Pluto’s atmosphere.
Rocket Propulsion Theory
Authors: Hawk Clark W. 
Published: October 2003

AbstractA rocket is defined as an “engine or motor that develops thrust by ejecting a stream of matter rearward, or the missile or vehicle powered by such an engine.” Since the reaction principle involved assumes a self‐contained source of energy, a rocket can operate in any medium including space outside the earth's atmosphere, where there is no oxygen to support combustion. This article gives the history of the use of rockets. The laws governing these operations are discussed. The rocket is an energy conversion device that converts potential energy to thermal energy. The energy source can be chemical, electrical, beamed (solar or laser), or nuclear. Nozzle theory is described.
Saturn System
Authors: Fink Uwe 
Published: October 2003

Abstract

Saturn has intrigued human beings ever since they noticed that it belongs to the group of objects called
planets
, which move relative to the “fixed stars” in the sky. Saturn is the slowest moving of the ancient planets. It takes fully 29.46 years to return to the same position in the sky. Two orbits of Saturn are thus very close to an integral number of 59 Earth years, so that the phenomena of Saturn repeat on roughly the same yearly date after an interval of 59 years. This was recognized by the ancient Babylonians and Greeks. Thus, Saturn was associated with the measurement of time being it was named
Cronos
(time) in Greek legend and served as the father of the lord of planets Jupiter (Zeus). The Romans celebrated the winter feast
Saturnalia
in his honor, and the name Saturn today is fixed in our language in the word
Saturday
.

The physical models used to determine the bulk composition and interior are discussed. Atmospheric composition appearance and colors rotational rate and circulation are also discussed.
Which all of the major planets have faint ring systems, rings of Saturn are so bright and extensive that Saturn is undoubtedly the most spectacular telescopic object in the sky. When viewed with a good telescope, Saturn seems to float mysteriously and serenely in the vast reaches of space. When the rings of Saturn are opened to their maximum, they provide 1.3 times as much light as the ball of the planet. Thirty satellites are presently known. Features of the principal satellites are detailed. Physical details of Titan (the largest moon) are discussed. Voyager spacecraft has returned data on the atmosphere of Titan.
Sun
Authors: Chupp Edward L. 
Published: October 2003

AbstractThe Sun is only one of several billion stars in our galaxy, but as a special example, it is important to understand how it compares to other stars. Following the development of stellar spectroscopy, techniques became available to classify stars by their locations on the Hertzsprung–Russell (HR) diagram, which is a plot of stellar luminosity as a function of spectral type. To place a star on the HR diagram, the star's distance must be known, so its absolute luminosity can be determined from the measured luminous flux using the inverse square law. The star's spectral type is determined by measuring the star's “color” and characterizing its spectrum. The sun is a “G” class star. Stars that have higher surface temperatures, for example, are “O” class, and “M” class stars have lower surface temperatures. All normal stars span a temperature range from ∼40,000 K to ∼4000 K. Actually a star's spectral class is determined by comparing its spectrum with the spectra of a set of standard stars. Some physical properties of the Sun and the way the properties are determined are given here.From direct measurement of isotope ratios, we know that the Sun's age is ∼4.5 billion years, and from the theory of stellar evolution, that it may live at least another 5 billion years. When its current internal energy source is depleted, it will expand and become a red giant and eventually a dwarf star similar to those on the HR diagram. However the goal here is to describe the present Sun in some detail.The current understanding of the Sun draws on advances in both ground‐based observing techniques and sophisticated space instrumentation, as well as in theoretical computer models using the observations as input. This article first briefly describes some important ground‐based observations and identifies several space missions whose main purpose has been to advance knowledge of Earth’s nearest star. Next, the structure of the Sun and its atmosphere is described in more detail, beginning at the center of the Sun and emphasizing current understanding in appropriate detail. A major goal of this work is to give an up‐to‐date summary of our knowledge of solar activity. The new science of helioseismology is discussed, and space weather, as it affects Earth, is also covered briefly later. For each topic, a brief history will be given with a summary of current knowledge followed by identification of important unsolved problems. References for further study will be given for each topic discussed.
Space Radiation
Authors: Dicello J.F. , Cucinotta F.A. 
Published: October 2003

AbstractThe most critical biomedical risks of space habitation are (1) carcinogenesis caused by radiation, (2) loss of bone mass or density, (3) poor psychosocial adaptation, and (4) clinical manifestations of trauma or acute medical problems. Because of the unique problems and the potential long‐term consequences, radiation is frequently considered the most serious of these for long‐duration space missions, and cancer is the major risk followed by damage to the central nervous system. Radiative hazards in space have been discussed in depth by a Task Group of the National Research Council along with overall research strategies.The term radiation in the present context refers specifically to directly and indirectly ionizing radiation, including X rays, gamma rays, neutrons, ions, and other somewhat esoteric particles such as muons and pions. Radiation is a natural part of our environment on the surface of Earth. Biological organisms in general, and humans in particular, have adapted to the normal radiative environment at Earth's surface and certainly have even benefited from the radiation. At the same time, those radiations also initiate biological damage ranging from sunburn to cancer. Earth's atmosphere and its magnetic field act as excellent radiative shields by reducing the levels of radiation. As one goes farther away from Earth's surface into orbit or toward outer space, the radiative level generally increases in intensity and changes in the types and energies of the radiation. It is known that the radiative dose rates for personnel in space are significantly higher than on Earth's surface. There has been little experience with regard to the biological consequences of healthy people exposed to these types of radiation for protracted periods of time. Best estimates indicate, however, that the additional exposure to higher energy radiation beyond that on Earth's surface or above the present allowable limits for radiation workers could result in significant risks of cancer or other serious diseases.Because of higher level of exposures and the potential for long‐term negative consequences, radiation has been categorized as the worst biomedical risk of long‐duration space missions. At the same time, using an appropriate programmatic strategy and focused research, the risks of radiation in space should be reduced to levels comparable to or less than those of other hazards.
Interplanetary Medium
Authors: Manweiler Jerry W. 
Published: October 2003

Abstract
In the commonness of life on Earth, most would expect that the composition of space beyond our atmosphere might be planets, comets, asteroids, and an occasional meteor. In reality, the space between the planets and other larger objects of our solar system is richly composed of a variety of complex phenomena, which on Earth drive weather, affect communications, and provide beautiful displays with the aurora.
Long considered an empty void, the vast space between the planets and our Sun is actually filled with a tenuous gas comprised of neutral and ionized particles along with small dust grains. The source of the ionized particles comprising this gas is mostly outflows and outbursts of the Sun. Some of this gas is due to outflow of particles from planets, comets, and asteroids. Finally, some of this gas comes from the infall of particles of gas and dust from the surrounding interstellar space. In this article, the boundaries, composition, sources, and dynamics of the particles filling the interplanetary medium are explored.
Electromagnetic Propulsion
Authors: McNab Ian R. 
Published: October 2003

AbstractSporadic attempts have been made for more than 150 years to use electrical energy to launch projectiles at high velocities. Throughout the world during the last 20 years, most of the funding invested in electromagnetic (EM) launcher development has been for military applications. In most cases, the perceived advantage has been attaining higher velocities than can be achieved with propellant guns, leading to enhanced lethality. The elimination of gun propellants would also reduce vulnerability as well as allowing an increased number of stored rounds and enabling extended missions. The EM rail gun has been the preferred choice for this application because it has already repeatedly demonstrated muzzle velocities well above those of conventional guns—typically 2500 m/s versus 1750 m/s. The military challenge is to fit the electric pulsed power equipment into a battleworthy vehicle, especially if it needs to be compact. The main potential applications are direct fire tank guns, long‐range artillery, and air and missile defense.Several electrical or electromagnetic (EM) concepts have been suggested, as described here, but their potential for space applications is, as yet, limited. However, the technological bases are now being created on which future EM launch systems for space exploration could be based in the twenty‐first century. Such systems could include launch to space from the surface of Earth, the Moon or asteroids, Maglev launch assist for large rocket systems and, possibly, EM thrusters for space transportation. Electrical ion engines have been used in space, and the Hall plasma thruster is under development for NASA.The interest in electric launchers for military applications has led to improved understanding and advances in many technical areas. Most military applications for EM launchers require gigawatt power levels for pulse lengths of a few milliseconds to accelerate a useful projectile in a launcher of acceptable length. Coupled with the need for compact and robust equipment, this is a challenging goal for the pulsed power system. The desire to achieve muzzle velocities significantly greater than those of conventional guns—from 2–3 km/s—also requires developing the launcher and projectile. Recent progress in these areas could be the basis for future space applications.
Russian Space Stations
Authors: Semyonov Yuri P. , Gorshkov L. 
Published: October 2003

Abstract
The Soviet and Russian long duration orbital space stations, Salyut and Mir, were operated from 1971 to 2001. During this period, eight stations were placed into orbit. This article discusses the history and goals of these stations. While the stations were in operation, a variety of improvements were made to extend their operational lifetimes and improve their performance. Experience in on‐orbit operations enabled the Energia Rocket and Space Corporation (Energia RSC) to develop a Russian space‐station concept. This concept was most fully embodied by the Mir space station and the Russian segment of the International Space Station.
The basic principles behind the Energia RSC concept, as actually developed and implemented, are discussed.
The major goals of space‐station use are as follows: research on the behavior of the human body, space research, remote sensing of Earth's surface and atmosphere, basic research in materials science and the production of materials and biological substances under microgravity conditions and research and development of proposed materials and techniques for future projects.
Space Life Sciences
Authors: Grigoriev Anatoly I. , Malashenkov Dmitry C. 
Published: October 2003

AbstractThe term space life sciences refers to the set of sciences that study the biology of living things under conditions of spaceflight. The synonymous term, space biology, coined in 1920 by K. Tsiolkovsky, is more common in Russia (USSR) and will be used in this article. The origin and development of space life sciences as a discipline are the result of certain advancements in modern science and technology and are associated with the development of jet propelled flight vehicles that can overcome the force of gravity to ascend beyond the bounds of Earth's atmosphere.Space Biology arose at the intersection of many scientific disciplines. It is indissolubly bound up with cosmonautics and space medicine.Space medicine is the area of general medicine that studies what happens to human physiological processes under the unique conditions of space flight to develop means and methods for maintaining the health and performance capacity of crews of spacecraft and space station pre‐, in‐ and postflight. As one of the branches of occupational medicine, space medicine attempts to provide the answers to a number of questions confronting humanity as a result of scientific and technological progress. These answers are derived from a very large medical knowledge base relating to various areas of theoretical and clinical medicine such as space physiology and psychophysiology, space hygiene, space radiobiology, and medical expertise.Major phases in the evolution of space life sciences are discussed. Understanding how living things react to extreme environments and tolerance to the extremes is key to developing an artificial closed system for space exploration. The main results of scientific studies conducted are provided.
U.S.
Manned Space Flight: Mercury to the Shuttle
Authors: Faget Maxime A. , Silveira Milton A. 
Published: October 2003

Abstract
There are many publications relating to Mercury, Gemini, Apollo, Skylab, Apollo‐Soyuz Test Project, and the Space Shuttle. This article presents an objective review of some of the technical considerations of the design, development, and operation of these spacecraft. Although there were many triumphs, a number of surprises, and not a few setbacks during the 39‐year period covered, such incidents will be mentioned only in the context of technical significance. A little more than 19 years elapsed between 20 February 1962, when John Glenn first rode Mercury into orbit, and 12 April 1981, when John Young and Robert Crippen inaugurated orbital flight for the Space Transportation System, or the Space Shuttle as it is commonly called. A comparison of the Mercury capsule and the spaceship Columbia reviews the extent of progress made during these first years of manned flight.
During the early 1920s after approximately 19 years of development, the aviation industry was also entering the transportation phase. But there is a significant difference between the development of airplanes and the development of manned spacecraft. Early airplanes were relatively cheap and easy to build. A great number of airplanes was built and flown. This led to a rapid evolutionary process for both the design and the operation of aircraft, and a number of accidents and fatalities provided a strong cooperative influence on any misdirection. The philosophical basis for the design and operation of spacecraft has had to progress without this impartial and unerring guidance of “survival of the fittest.” As a substitute, we have had to rely on intensive analysis, extensive testing, imperfect simulations, and the judgment and experience of the hundreds of key people working on these programs.
American manned spacecraft by type together with a number of weights, dimensions, and features that characterize them are listed. Mercury was a first of a kind design, and the Gemini and Apollo command and service module (CSM) followed in an evolutionary trend. The Apollo lunar module (LM) and the Space Shuttle, on the other hand, represent new and distinctive designs and have unique features for which no prior art existed.