Passage to a Ringed World - NASA's History Office

More documents

Recommendations

Info

• Study the erosional and electromagnetic processes responsible for E-ring structure. • Search for ring particles beyond the known E-ring. • Study the effect of Titan on the Saturn dust complex. • Study the chemical composition of icy satellites from studies of ejecta particles. • Determine the role of icy satellites as a source of ring particles. • Determine the role of dust as a charged-particle source or sink in the magnetosphere. The CDA measures the flux, velocity, charge, mass and composition of dust and ice particles in the mass range from 10 –16 to 10 –6 gram. It has two types of sensors, high-rate detectors and a dust analyzer. The two high-rate detectors, intended primarily for measurements in Saturn’s rings, count impacts up to 10,000 per second, giving the integral flux of dust particles above the mass threshold of each detector. The threshold varies with impact velocity, but since ring particle orbits are nearly circular, their velocity at a given point does not vary much. The dust analyzer determines the electric charge carried by dust particles, the flight direction and impact speed and the mass and chemical composition, at rates up to one particle per second, and for speeds of 1–100 kilometers per second. Some dust particles strike a separate chemical analyzer in the dust analyzer and also produce impact ionization. A grid accelerates positive ions; ions reaching the grid signal the start time for the time-of-flight mass spectrometer. Other dust particles pass through into the spectrometer and eventually reach the ion collector and electron multiplier. Their time of flight is an inverse function of the ion mass. The distribution of ion masses (atomic weights) gives the chemical composition of the dust particle. The mass resolution of the ion spectrum is approximately 50. An articulation mechanism allows the entire CDA instrument to be rotated or repositioned, relative to the Cassini Orbiter body. Dual Technique Magnetometer. The Dual Technique Magnetometer (MAG) will determine planetary magnetic fields and study dynamic interactions in the planetary environment. The MAG science objectives include the following: • Determine the internal magnetic field of Saturn. • Develop a three-dimensional model of Saturn’s magnetosphere. • Determine the magnetic state of Titan and its atmosphere. • Derive an empirical model of Titan’s electromagnetic environment. • Investigate the interactions of Titan with the magnetosphere, magnetosheath and solar wind. • Survey ring and dust interactions with the electromagnetic environment. • Study the interactions of the icy satellites with Saturn’s magnetosphere. • Investigate the structure of the magnetotail and the dynamic processes therein. The MAG consists of direct-sensing instruments that detect and measure the strength of magnetic fields in the vicinity of the spacecraft. The MAG comprises both a flux gate magnetometer and a vector/scalar helium magnetometer. The flux gate magnetometer is used to make vector field measurements. The vector/scalar helium magnetometer is used to make vector (magnitude and direction) and scalar (magnitude only) measurements of magnetic fields. Since magnetometers are sensitive to electric currents and ferrous components, they are generally placed on an extended boom, as far from the spacecraft as possible. On Cassini, the flux gate magnetometer is located The Dual Technique Magnetometer (MAG) comprises the flux gate magnetometer (above) and the vector/scalar helium magnetometer (left). TOOLS OF DISCOVERY 111
Optical Remote Sensing Composite Infrared Spectrometer – CIRS Imaging Science Subsystem – ISS Ultraviolet Imaging Spectrograph – UVIS Visible and Infrared Mapping Spectrometer – VIMS Radio Remote Sensing Cassini Radar – RADAR Radio Science Instrument – RSS Magnetospheric Imaging Instrument – MIMI Cassini Plasma Spectrometer – CAPS Cosmic Dust Analyzer – CDA Dual Technique Magnetometer – MAG Ion and Neutral Mass Spectrometer – INMS Radio and Plasma Wave Science – RPWS 112 PASSAGE TO A RINGED WORLD Measurements Particle Remote Sensing & In Situ Measurement In Situ Measurement CASSINI ORBITER INSTRUMENTS High-resolution spectra, 7–1000 μm Photometric images through filters, 0.2–1.1 μm Spectral images, 0.055–0.190 μm; occultation photometry, 2 ms; H and D spectroscopy, 0.0002-μm resolution Spectral images, 0.35–1.05 μm (0.073-μm resolution); 0.85– 5.1 μm (0.166-μm resolution); occultation photometry K u -band RADAR images (13.8 GHz); radiometry resolution less than 5 K K a -, S- and X-bands; frequency, phase, timing and amplitude Image energetic neutrals and ions at less than 10 keV to 8 MeV per nucleon; composition, 10–265 keV/e; charge state; directional flux; mass spec: 20 keV to 130 MeV ions; 15 keV to greater than 11 MeV electrons, directional flux Particle energy/charge, 0.7– 30,000 eV/e; 1–50,000 eV/e Directional flux and mass of dust particles in the range 10 –16 –10 –6 g B DC to 4 Hz up to 256 nT; scalar field DC to 20 Hz up to 44,000 nT Fluxes of +ions and neutrals in mass range 1–66 amu E, 10 Hz–2MHz; B, 1 Hz–20 kHz; plasma density Techniques Spectroscopy using 3 interferometric spectrometers Imaging with CCD detectors; 1 wideangle camera (61.2 mr FOV); 1 narrow-angle camera (6.1 mr FOV) Imaging spectroscopy, 2 spectrometers; hydrogen–deuterium absorption cell Imaging spectroscopy, 2 spectrometers Synthetic aperture radar; radiometry with a microwave receiver X- and Ka-band transmissions to Cassini Orbiter; K a -, S- and X-band transmissions to Earth Particle detection and imaging; ionneutral camera (time-of-flight, total energy detector); charge energy mass spectrometer; solid-state detectors with magnetic focusing telescope and aperture-controlled ~45° FOV Particle detection and spectroscopy; electron spectrometer; ion-mass spectrometer; ion-beam spectrometer Impact-induced currents Magnetic field measurement; flux gate magnetometer; vector–scalar magnetometer Mass spectrometry Radio frequency receivers; 3 electric dipole antennas; 3 magnetic search coils; Langmuir probe current Partner Nations US, France, Germany, Italy, UK US, France, Germany, UK US, France, Germany US, France, Germany, Italy US, France, Italy, UK US, Italy US, France, Germany US, Finland, France, Hungary, Norway, UK Germany, Czech Republic, France, The Netherlands, Norway, UK, US UK, Germany, US US, Germany US, Austria, France, The Netherlands, Sweden, UK
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 52 and 53:
Voyager 1 captured this striking im
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 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

Create successful ePaper yourself

Delete template?

Save as template?