|
Showing 1 - 8 of
8 matches in All Departments
October 1995 marked the fiftieth anniversary of Arthur C. Clarke's
famous article in Wireless World proposing the use of satellites
placed in geosynchronous orbit for worldwide communications relay.
The article proved prophetic, for it heralded the modern era of
telecommunications. Beginning in the early 1960s, several series of
satellites were launched into Earth's orbit; collectively they
transformed the latter twentieth century, creating a global village
of instantaneous communications. Previously, the ionosphere had
defined the limits of radio communication; today, by going beyond
the ionosphere, broadband telecommunication has entered a new age.
This book describes the first attempts to go beyond the ionosphere,
including both the earliest uses of the Moon as a passive, natural
relay satellite and Project Echo, the massive inflated satellite
off which Earth stations bounced radio signals, as well as
contemporary communications via active-repeater artificial moons in
orbit about the Earth. It analyzes both American and foreign
satellite communications, the histories of several satellite
communications companies, the roles of government agencies, and the
contribution of research laboratories. The book is a collection of
papers originally presented during an international symposium held
in Washington, D.C., at the time of the fiftieth anniversary of
Clarke's 1945 article. Contributions from historians and other
scholars from throughout the world present a stimulating analysis
of one of the most important global technologies at work today-and
how it originated and evolved.
This is the story behind NASA's successful exploration of the solar
system. For a half century, NASA has sent one probe after another
into space, achieving scientific and technological successes along
the way and adding to humanity's knowledge of the solar system.
NASA has reaped these great rewards thanks to a small investment in
deep-space navigation. With rare exceptions, navigation's great
achievements-and scientific accomplishments-have gone unobserved.
The failures of the Mars Climate Orbiter and Mars Polar Lander shed
navigation (wrongly) in a negative light. Yet, the indispensable
role of navigators behind NASA's many successes over the past half
century has not come to light-until now. The institutional home of
deep-space navigation is the NASA's Jet Propulsion Laboratory. JPL
navigation originated long before it became part of NASA, when the
lab developed and tested missiles for the nation's military space
effort. From the start, deep-space navigation was an endeavor built
on science and mathematics and dependent on the Deep Space Network
for tracking spacecraft and on digital computers and software for
processing data. Navigation is multidisciplinary. It involves
astronomy and radio astronomy, geodesy and geophysics, cartography
and meteorology, ionospheric physics and radio science. Navigators
interact with a panoply of institutions, whether the Bureau
International de l'Heure, the International Polar Motion Service,
the International Union of Geodesy and Geophysics, and the
International Astronomical Union. JPL navigation started as a
consumer of Naval Observatory data, practices, and ephemerides, but
in the 1970s became the source of ephemerides, constants, models,
and ephemerides for the world's almanac offices. Navigators have
been project scientists on many NASA missions, performing
experiments in celestial mechanics and gravitational fields,
undertaking radio occultations, and testing Einstein's General
Theory of Relativity. They also have made a number of memorable
scientific discoveries: mascons on the Moon and Mars, volcanism on
Io, and over a dozen satellites of the outer planets. The nature of
deep-space navigation began to change with the introduction of
optical navigation, which uses a probes science camera and
telemetry to determine its position relative to a planet, moon, or
asteroid. Deep-space navigation began-and remains-an activity
carried out entirely on Earth. Radio signals from the Deep Space
Network constituted the only information processed. Optical
navigation began to move some of the process-and equipment-to
spacecraft. At first, image processing was a labor-intensive and
computer-intensive effort. Software improvements and advances in
spacecraft computers paved the way for autonomous navigation, which
transferred many basic navigation processes to the onboard
computer: estimating trajectories, planning and executing imaging,
and analyzing pictures. The most recent evolutionary stage has been
the merger of this autonomous software with spacecraft guidance and
control functions.
The past 50 years have brought forward a unique capability to
research and expand scientific knowledge of the Solar System
through the use of radar to conduct planetary astronomy. This
technology involves the aiming of a carefully controlled radio
signal at a planet (or some other Solar System target, such as a
planetary satellite, an asteroid, or a ring system), detecting its
echo, and analyzing the information that the echo carries. This
capability has contributed to the scientific knowledge of the Solar
System in two fundamental ways. Most directly, planetary radars can
produce images of target surfaces otherwise hidden from sight and
can furnish other kinds of information about target surface
features. Radar also can provide highly accurate measurements of a
target's rotational and orbital motions. Such measurements are
obviously invaluable for the navigation of Solar System exploratory
spacecraft, a principal activity of NASA since its inception in
1958. Andrew J. Butrica has written a comprehensive and
illuminating history of this little-understood but surprisingly
significant scientific activity. Quite rigorous and systematic in
its methodology, To See the Unseen explores the development of the
radar astronomy specialty in the larger community of scientists.
More than just discussing the development of this field, however,
Butrica uses planetary radar astronomy as a vehicle for
understanding larger issues relative to the planning and execution
of "big science" by the Federal government. His application of the
"social construction of science" and Kuhnian paradigms to planetary
radar astronomy is a most welcome and sophisticated means of making
sense of the field's historical development.
The story of Air Products and Chemicals, Inc., is exciting--full
of struggle, determination, crisis, and heroic endeavor. Air
Products grew out of the vision and drive of one individual,
Leonard Pool. In the course of fifty years, Pool's precarious
project has become a major, multinational corporation. Words like
entrepreneurship, sales, finance, engineering, and technology are
central to the history of Air Products. So too are concepts like
being a late entrant to an established business, struggling to find
market niches, moving into fields of endeavor, developing human
resources, and breaking through to the level where economies of
scale and scope would allow a secure future as a major player on a
global scale. The story is one of success; plain luck at some
points. But it also contains its share of hard knocks,
disappointments, and mistaken strategies.
The enduring style of Air Products--its customer-focus and its
emphasis on sales and growth--emerged from the interactions of
Leonard Pool's personality, the engineering skills of his
colleagues, and the opportunities offered by the industrial gas
supplier in the world. It is also a major chemical company and a
pioneer in the emerging field of environmental and energy systems.
Multinational, technology-based firms like Air Products are an
important part of American society and of the emerging global
economy. The history of Air Products will be of value to everyone
interested in the industrial gas and chemical industries, business
history, entrepreneurial history, and American studies.
|
|