Table Of ContentMission
Jupiter
Daniel Fischer
Mission
Jupiter
The Spectacular Journey
of the Calileo Spacecraft
c
COPERNICUS BOOKS
An Imprint of Springer-Verlag
Originally published as Mission Jupiter: Die spektakulare Reise der Raumsonde Galileo,
© 1998 by Birkhauser Verlag, Basel, Switzerland.
© 2001 Springer Science+Business Media New York
Originally published by Springer-Verlag New York, Inc. in 2001
Softcover reprint of the hardcover I st edition 2001
All rights reserved. No part of this publication may be reproduced, stored in a
retrieval system, or transmitted, in any form or by any means, electronic,
mechanical, photocopying, recording, or otherwise, without the prior written
permission of the publisher.
Copernicus Books
www.copernicusbooks.com
Library of Congress Cataloging-in-Publication Data
Fischer, Daniel.
Mission Jupiter / Daniel Fischer; translated by Don Reneau.
p. em.
Includes bibliographical references and index.
ISBN 978-1-4419-3158-0 ISBN 978-1-4757-4141-4 (eBook)
DOI 10.1007/978-1-4757-4141-4
1. Galileo Project. 2. Jupiter (Planet)-Exploration. I. Title.
QB661.F57 1999
629.43'545-dc21 99-31342
Manufactured in the United States of America.
Printed on acid-free paper.
Text designed by Irmgard Lochner.
Translated by Don Reneau.
9 8 7 6 5 432 1
ISBN 978-1-4419-3158-0 SPIN 10711962
Foreword to the Original
Edition
When Galileo Galelei discovered the four major moons of Jupiter in
161O-the Galilean moons, as we call them-he could hardly have
dreamed that scarcely 400 years later a spacecraft named after him
would be traveling there to give us a first-hand look at the gas giant
and its satellites. Still, the Galileo project has to be regarded as one of
the most spectacular undertakings in the history of unmanned space
flight. Capturing such an enterprise in all its aspects between the cov
ers of a book would seem an impossible task. It necessarily covers
a quarter century of planetary research, along with the largest and
most expensive interplanetary probe of its epoch making the longest
v
vi Foreword to the Original Edition
journey to the biggest and most complicated planet in the Solar Sys
tem-as well as the many discoveries it made on the way. Certain fun
damentals have to be introduced, and interpretations of the data must
be conveyed in detail, even while some of them have been understood
by only a handful of experts. The project has had an eventful history,
often experiencing fewer highs than lows, and in addition to telling
that story, the very best images must be selected and explained from
among a multitude of available photographs. Writing the book is in
evitably accompanied by a nagging sense that most of the mass of in
formation and analysis collected loses its place to something else even
more important.
I have received assistance from a variety of quarters, illuminating
some of the specialized aspects of this enormous scientific undertak
ing, even while others remained in the dark. The excitement of wit
nessing raw images arriving in fragments from jupiter, shared with the
public during the Voyager mission, this time was withheld. My hope,
nevertheless, is that I have allowed myself to be influenced more by
the relevance of particular details than by disorganization in the source
base.
This book covers essentially three complex areas of subject matter,
presenting them in five chapters. The first concerns the lengthy chain
of events leading up to the Galileo project, which is tightly interwoven
with the stories of its two predecessors, the Pioneer and Voyager
probes. These early adventures in the jovian system lie over two
decades in the past now, making it more than appropriate to recall in
some detail their path-breaking careers in space flight. Doing so sup
plies an occasion for presenting the basics about jupiter and the sys
tem surrounding it, the same facts underlying the scientific conception
of the Galileo project. The result is a survey of the lengthy develop
ment of the Galileo mission, from its now-forgotten beginnings to its
repeatedly delayed launch date. From there we move through a long
Foreword to the Original Edition vii
list of difficulties-and an equal number of triumphs-over the course
of a six-year journey to the giant planet. Arrival day is presented, along
with the major discoveries made by Galileo's atmospheric probe. Even
now, two years after the probe's brief and intense encounter with the
gas giant, scientists are still at work analyzing the complex data.
Galileo spent 1996 and 1997 observing whatever came in range of
its sensors, based, of course, on an orbital trajectory calculated with
the utmost precision. The nature of the chronology changes at this
point, when we turn to the book's central focus on all of Galileo's dis
coveries during its two-year primary mission through the Jovian sys
tem. Among them are discoveries aboutjupiter's four major and many
minor moons, about Jupiter itself, its ring and powerful magneto
sphere. The last part of the book ventures an overall view of the Jovian
system, which like all scientific statements is necessarily provisional.
With a parting look at the extension of the Galileo project through
1999, at the quite comparable Cassini mission to Saturn, and ideas for
future Jupiter missions, the book comes to an end.
I had been planning a book on Jupiter for a long time, but 1998
seems to have been the right time to get started on it. The primary mis
sion is now history, even though the two-year extension of the mission
has since gotten under way. The steady stream of new images has let
up, and it is time to strike a balance, which, incidentally, is what scien
tists are doing as well. By now the first in-depth examinations of the
central questions have already come out in scientific journals, and in
any case the thought of waiting for all the data to be analyzed is as
utopian as ever. Twenty years follOwing the Pioneer and Voyager visits
to Jupiter, new analyses of those data are still being published.
The beginnings of the Galileo project lie so far in the past by now
that it was often hard to locate either documents about or witnesses to
the events in question. Particularly useful in reconstructing the history
of the project were contemporaneous articles written by Wolfgang
viii Foreword to the Original Edition
Engelhardt. My chronology of the mission from 1986 to 1997 is based
on countless publications in the technical journals of both the natural
sciences and the space flight industry, as well as on status reports and
press releases from mission managers. The latter sources, fortunately, I
had already processed into a series of articles for Sterne und Weltraum
and Skyweek-otherwise, it might have taken me years to subdue the
mountain of documentary material. Also part of the story are scientific
publications on the various discoveries of planetary objects along
Galileo's way, the sometimes up-to-the-minute reports of findings at
the international conferences of planetary scientists in 1992, 1996,
and 1997, and the Baltimore conference on the crash of the comet
Shoemaker-Levy 9 in 1995. Invaluable firsthand information came, as
always, from the press conferences on Galileo's discoveries held by
NASA, which I was able to follow either live via NASA's special televi
sion channel or through reports by third parties.
For their assistance I would especially like to thank Ms. Susanne
Huttemeister (at the time, of Cambridge, Massachusetts) as well as the
friendly staff at the European Space Agency's headquarters in Paris,
who made it possible for me to follow developments either by record
ing NASA television via ISDN or even, the night Galileo arrived at
Jupiter, allowing me to experience the events in real time. Many inter
esting tangents to my primary material came from this source, and but
for my encounters there, they would not have found their way into the
printed literature. For a depiction of the personal dramas that are also
part of the history of the Galileo project, there was simply not enough
room. When the narrative turns to the failure of critical systems-the
main antenna and the onboard tape recorder, for example-and to des
perate efforts of scientists and engineers to save the mission, I hope
readers will be able to put themselves in the place of a Galileo "tiger
team" and feel the special drama of these weeks. The same, of course,
also applies to the steadily increasing number of triumphs.
Foreword to the Original Edition ix
Thanks are due to many people who contributed individual details
to this overall depiction of the Galileo mission, in the case of some
during the final days the manuscript was being prepared. Deserving of
special mention are Fritz Neubauer of the University of Cologne, Ger
many, who made himself available for an interview in the midst of an
important conference, the dust researchers working with Eberhard
Grun, who steered much valuable material my way, and the Washing
ton editorial staff of Nature, who faxed parts of the latest publications
the day before the book went to press. Very special thanks, finally, to
the book's editor and publisher for sensibly allowing what was ideal
for the contents of the book to determine the publication schedule.
Daniel Fischer
Konigswinter, March 1998
Foreword to the English
Edition
Published almost three years after the German edition, the English
version has been updated in numerous places in the "Looping from
Moon to Moon" and "What the Future Holds" sections-the latter
with the help ofJim Erickson, project manager until early 2001. New
scientific inSights were added that had become available from recent
publications and through picture and press releases, and about 25
interesting black and white images were included, without sacrificing
earlier material. The very latest developments of 1999,2000, and early
2001 are being presented as progress reports at the end of several sub
chapters. While few of the earlier conclusions have been overturned
xi
xii For e W 0 r d tot h e Eng lis h E d i t ion
completely by the continuing analysis so far, some mysteries have
deepened. At the same time, other aspects of the Jovian system have
become surprisingly clear. Since the middle of 2000, for example, the
existence of an ocean of a salty liquid under the icy crust of the moon
Europa can be considered proven, thanks to Galileo's magnetometer.
As this edition goes to press in the year 2001, Galileo is still alive and
well and has just completed yet another mission milestone: joint ob
servations of Jupiter's vast magnetosphere, together with that other
outer planets explorer Cassini, which is on its way to Saturn. And if no
major electronic failure kills the spacecraft, its mission will continue
well into 2003, to be ended in a controlled fashion by sending Galileo
right into jupiter's atmosphere. Yet more discoveries can be expected
when the orbiter makes some more close flybys of the moons Callisto,
10, and perhaps Amalthea during its final orbits, as its epic journey
draws to a close. Galileo has already changed mankind's view of the
largest planet of the Solar System and its companions forever. Enjoy
the trip!
Daniel Fischer
Kbnigswinter, March 2001
