Passage to a Ringed World - NASA's History Office

More documents

Recommendations

Info

Voyager 1 captured this striking image of Saturn and its rings, with the rings cutting a dark shadow across the planet. This false-color image of Saturn’s outer Aring was constructed from green, violet and ultraviolet frames. Voyager 2 captured the image on August 23, 1981. THOSE MAGNIFICENT RINGS 43
44 PASSAGE TO A RINGED WORLD crystallized centuries of Saturn observations, almost instantly sorting observational fact from fiction — just as the Mariner flybys shattered the myths of Martian canals and civilizations. Ring Structure Large-Scale Features. Viewing Saturn and its rings through a modest telescope easily allows us to see that the ring system is divided into several visually different radial zones. The outer zone (visible to an Earth observer) is known as the A-ring, while the brighter, inner zone is known as the B-ring. Between these two zones we can sometimes see the gap SATURN’S FLYING SNOWBALLS Saturn’s rings have intrigued scientists on Earth for nearly four centuries. Seen up close, the rings may be even more astonishing than they appear at a distance. Although the rings stretch over 40,000 kilometers in width, they may be as little as 100 meters in thickness. The ring particles — from a few micrometers (one micrometer = one millionth of a meter) to a few meters in size — have been described as ice-covered rocks or icy snowballs. Scientists are continuing in their attempts to known as the Cassini division; on an exceptional viewing night, we may see an inner, semitransparent ring, the C or Crepe ring. This view of the rings, while modest, nevertheless introduces us to the system’s unexplained features. Why are there several morphologically distinct rings? Beyond the A, B, C and E-rings, which can be seen or imaged from Earth-bound telescopes, Saturn has several other distinct rings — the D, F and G-rings — detected in the images from Pioneer and Voyager. The mysteries of Saturn’s rings lie at an even more fundamental level: analyze ring composition, hoping that the Cassini–Huygens mission will bring them clearer clues to the icy puzzle. THE RINGS OF SATURN Distance, Width, Ring kilometers* kilometers D 66,970 7,500 C 74,500 17,500 B 92,000 25,400 A 122,170 14,610 F 140,180 50 G 170,180 8,000 E 180,000 300,000 * Distance from Saturn to closest edge of ring. Why are the rings there at all? How did the rings form? How stable is the ring system? How does the system maintain itself? So far, we have only bits and pieces of answers and much speculation about these questions. Smaller-Scale Features. As Pioneer and Voyager moved closer to Saturn, the spacecraft captured images that made clear the features glimpsed over the centuries, as well as many previously unseen features. Pioneer found a new ring feature (the F-ring) outside the A-ring, which became an object of major interest when Voyager later arrived. The fields and particles sensors on Pioneer 11 showed the possible presence of satellites in the vicinity of the new F-ring. This ring proved to be particularly interesting — it is a narrow ring, and the satellites that (as we now know) maintain the ring in position were the first proof of a theory put forth in 1979 to explain the narrow rings of Uranus.
Page 1: Passage to a Ringed World The Cassi
Page 4 and 5: On the Cover: A collage of images s
Page 6 and 7: FOREWORD This book is for you. You
Page 8 and 9: ACKNOWLEDGMENTS This book would not
Page 10 and 11: Three separate images, taken by Voy
Page 12 and 13: descent to the surface. The Huygens
Page 14 and 15: address the challenges of the missi
Page 16 and 17: Participant Nations* * First flag i
Page 18 and 19: PROBING A MOON OF MYSTERY Huygens
Page 20 and 21: TOUR T18-3 TARGETED SATELLITE FLYBY
Page 22 and 23: SATURN CASSINI-HUYGENS MISSION SCIE
Page 24 and 25: Cassini-Huygens designed to determi
Page 26 and 27: In this diagram from his book, Syst
Page 28 and 29: This Voyager 1 image shows Saturn
Page 30 and 31: An Extended Atmosphere From Liquid
Page 32 and 33: Haze layers are also observed above
Page 34 and 35: IN THE EYE OF THE BEHOLDER Taken fr
Page 36 and 37: This spectacular view of the edge o
Page 38 and 39: the interaction was described as a
Page 40 and 41: have a signature of a tone decreasi
Page 42 and 43: CONSTITUENTS OF THE TITAN ATMOSPHER
Page 44 and 45: The processes of plate tectonics an
Page 46 and 47: tan was accreting, it is possible t
Page 48 and 49: Surface Science. The highest resolu
Page 50 and 51: This enhanced Voyager 2 image shows
Page 54 and 55: Prometheus and Pandora, two tiny sa
Page 56 and 57: In the stellar occultation experime
Page 58 and 59: scattering than are larger particle
Page 60 and 61: In fact, Saturn’s rings — as we
Page 62 and 63: The satellites of Saturn comprise a
Page 64 and 65: Before the advent of spacecraft exp
Page 66 and 67: The bright surface of Saturn’s mo
Page 68 and 69: Galilean satellites. Most of what i
Page 70 and 71: duced that one hemisphere is compos
Page 72 and 73: patches on the surface. Although it
Page 74 and 75: Artist’s conception of Ithaca Cha
Page 76 and 77: An artist’s rendition of Saturn
Page 78 and 79: The MAPS Instruments Coordinated ob
Page 80 and 81: field reverses direction across the
Page 82 and 83: SATURN’S MAGNETIC FIELD Saturn’
Page 84 and 85: Solar Wind Magnetosheath Titan neut
Page 86 and 87: per atmosphere. Energetic particles
Page 88 and 89: and plasma wave emissions from narr
Page 90 and 91: CHAPTER 7 Space mission design aims
Page 92 and 93: (SOI) propulsive maneuver to initia
Page 94 and 95: the tour cannot continue. Of course
Page 96 and 97: crease inclination to this value. T
Page 98 and 99: This illustration shows the main de
Page 100 and 101: discussed earlier) and data handlin
Page 102 and 103:
of the spacecraft! Below the oxidiz
Page 104 and 105:
• Opening or shutting thermal lou
Page 106 and 107:
management subsystem and the Probe
Page 108 and 109:
falls below its storage temperature
Page 110 and 111:
The Cassini-Huygens spacecraft stan
Page 112 and 113:
The Imaging Science Subsystem (ISS)
Page 114 and 115:
• Map the composition and thermal
Page 116 and 117:
cise distance between the surface f
Page 118 and 119:
• Study the interaction of the ma
Page 120 and 121:
• Study the erosional and electro
Page 122 and 123:
midway out on the magnetometer boom
Page 124 and 125:
The RPWS instrument will be used to
Page 126 and 127:
altitudes down to 40 kilometers abo
Page 128 and 129:
dex. A group of platinum resistance
Page 130 and 131:
CHAPTER 10 Mission operations are t
Page 132 and 133:
PLANETARY MISSION OPERATIONS Functi
Page 134 and 135:
two low-gain antennas 1 and will pr
Page 136 and 137:
During much of Cassini’s orbital
Page 138 and 139:
articulation control subsystem’s
Page 140 and 141:
AFTERWORD It has been said that in
Page 142 and 143:
Developments tied to the Cassini-Hu
Page 144 and 145:
APPENDIX A Command. A data transact
Page 146 and 147:
APPENDIX A 138 PASSAGE TO A RINGED
Page 148 and 149:
APPENDIX A Plasma wave. A wave char
Page 150 and 151:
APPENDIX A 142 PASSAGE TO A RINGED
Page 152 and 153:
APPENDIX B H O 2 + Water molecule w
Page 154 and 155:
APPENDIX C 146 PASSAGE TO A RINGED
Page 156 and 157:
APPENDIX D 148 PASSAGE TO A RINGED
Page 158 and 159:
APPENDIX D 150 PASSAGE TO A RINGED
Page 160 and 161:
APPENDIX F 152 PASSAGE TO A RINGED
Page 162 and 163:
APPENDIX F 154 PASSAGE TO A RINGED
Page 164 and 165:
APPENDIX F Peralta, F. and S. Flana
Page 168:
National Aeronautics and Space Admi
show all

Passage to a Ringed World - NASA's History Office

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?