Despite the title, this is not a physics textbook, and it will tell you
only part of the fascinating story of satellite communications. However,
we have tried to tell this story in a rather special way. Part I
explains why we are so interested in communicating by means of man-made
satellites, describes the important events in the progress of satellite
communications (with special emphasis on Project Telstar), and points
out some of the very knotty problems that had to be solved. Then, in
Part II, we pick out six typical satellite communications problems and
go into them more deeply.
These case histories are examples of the things scientists and engineers
are constantly faced with. To narrate them we have called on six
experts—Bell Telephone Laboratories engineers and scientists who
actually have been working on the problems. The second half of our book
is taken up by their accounts of their own personal experiences. We hope
that reading them will give you an insight into what it is really like
to be a scientist or engineer working in a laboratory on an important
new venture into the future. We hope you will see that what they do is
not all excitement and glamour. It involves hard work, ingenious
thinking, and plugging away at tough problems. But this is what
scientists and engineers enjoy—along with the excitement and glamour, of
course.
Only a part of what our authors talk about can strictly be called
“physics”—it is also engineering, chemistry, mathematics, and even
psychology. But almost all their work _is_ based—when you get down to
fundamentals—on basic principles of classical physics taught in high
school.
Now, a word of caution. In Part I, in talking about satellite
communications in general, we have kept things at a level that should be
understandable to almost everyone—even those who have never taken a high
school science course. But we warn you this isn’t true of Part II. Our
authors have tried to tell their stories as carefully and as logically
as possible, but some readers may have trouble in following all they
say. This we expect. We haven’t tried to sugar-coat or gloss over any
essential details of the problems or their solutions. We don’t want you
to think that solving them was any easier than it actually was. And,
since this is not intended as a textbook, we may sometimes omit
elementary material and go right to the heart of the matter.
When this book was written satellite communications was still a
technological infant. It is growing and changing so swiftly that much of
what we say may soon be out of date. That can’t be helped, of course,
and we ask you—who may be reading it long afterward—to be tolerant. Our
problems may well be forgotten when new, more sophisticated ones appear.
But we are dealing here in methods, not in history; the ways in which
these problems were attacked are just as lasting and important as the
problems themselves.
part 1
Satellite Communications
[Illustration: Title image]
“_Our intensive research and development in the field of
communications satellites have brought us to the point where we are
now certain of the technical feasibility of transmitting messages to
any part of the world by directing them to satellites.... The actual
operation of such a system would provide a dramatic demonstration of
our leadership in this area of space activity.... The direct
benefits—economic, educational, and political—of this improved
world-wide communication will be invaluable_.”
—JOHN F. KENNEDY
Why Do We Bother With Satellite Communications?
That’s a good question to begin with. Why should we get involved in a
vast, complicated program such as communication by means of man-made
satellites? Is the end result really worth all the trouble that is
involved? As you go further, you will see that nothing to do with
satellite communications is as simple as it first seems. Even some of
the easier questions have been answered only after long hours of
perceptive thinking, ingenious experimenting, and shrewd deduction. They
have required a lot of hard work, led to many frustrating difficulties,
and cost quite a bit of money. But the answer still is yes. Despite all
the difficulties, it is clear that the creation of a successful
satellite communicating system is worth it.
There is a double reason for this. On the one hand, it is a
technological target that is now clearly within our range. We must
either reach it or let progress pass us by. Satellite communications is
one field in which, as far as we know, American engineering and science
have been well in the lead—so we have an even greater incentive to press
on in this direction as hard and as fast as we can.
But perhaps more important than the prestige it would give our country
is a second reason for our great interest in satellite communications:
We need it. The world today is going through one of its great periods of
change. This has caused many complications, and one of the most
important is the need for much better communications between nations and
peoples. By “communications” we mean all the various ways of sending
information from one place to another: mail, telephone calls, business
data, radio, television. The demand for these services—especially when
we look ahead to the 1970’s and 1980’s—will be tremendous. Our
international communications channels will be completely swamped unless
some major improvements are made.
Fortunately, modern technology—given a boost by the world’s interest in
rockets, missiles, and the exploration of space—has shown us one answer
to this problem: the communications satellite. The conventional pathways
for long-distance communication have led along the earth’s surface,
under the oceans, and through the lower atmosphere. No one of these
routes has yet provided all the capacity, speed, or quality we need.
Present underseas cables have a limited capacity; surface travel by ship
is too slow for anything but routine mail; short-wave radio is subject
to distortion and noise, and the available frequencies are rapidly being
used up. Although jet planes can span the oceans in a few hours with
mail and such things as taped television shows, the big need will be to
send information instantaneously. And the communications satellite
offers us a very promising way to do this.