The Cassini-Huygens Visit to Saturn: An Historic Mission to the Ringed Planet (Springer Praxis Books)

Cassini-Huygens was the most ambitious and successful space journey ever launched to the outer Solar System. This book examines all aspects of the journey: its conception and planning; the lengthy political processes needed to make it a reality; the engineering and development required to build the spacecraft; its 2.2-billion milejourney from Earth to the Ringed Planet and the amazing discoveriesfrom the mission.The author traces how the visions of a few brilliant scientists matured, gained popularity and eventually became a reality. Innovative technical leaps were necessary to assemble such a multifaceted spacecraft and reliably operate it while it orbited a planet so far from our own. The Cassini-Huygens spacecraft design evolved from other deep space efforts, most notably the Galileo mission to Jupiter, enabling the voluminous, paradigm-shifting scientific data collected by the spacecraft.Some of these discoveries are absolute gems. A small satellite that scientists once thought of as a dead piece of rock turned out to contain a warm underground sea that could conceivably harbor life. And we now know that hiding under the mist of Saturn s largest moon, Titan, is a world with lakes, fluvial channels, and dunes hauntingly reminiscent of those on our own planet, except that on Titan, it s not water that fills those lakes but hydrocarbons. These and other breakthroughs illustrate why the Cassini-Huygens mission will be remembered as one of greatest voyages of discovery ever made." WHO THIS BOOK IS WRITTEN FOR?......Page 6 EXAMPLES OF WHAT THE MISSION ACHIEVED......Page 7 Science returns and engineering achievements......Page 8 Technological benefits from the mission......Page 10 European contributions......Page 11 Issues of risk......Page 12 DATA SOURCES USED FOR THIS BOOK......Page 13 OVERVIEW OF THE BOOK’S PARTS AND CHAPTERS......Page 14 REFERENCES......Page 16 Contents......Page 20 Part I: Creating a new expedition to Saturn......Page 24 1: Conceiving and funding the mission......Page 25 1.1.1 Early work on outer planet missions......Page 26 1.1.1.3 The Saturn system conference......Page 27 1.1.2 The Voyager missions......Page 28 1.1.4 A special collaboration campaign for the Saturn mission......Page 29 1.1.5 The International Solar Polar Mission......Page 30 1.1.7 NASA’s reaction to an international Saturn mission concept......Page 31 1.1.9 Threats to U.S. leadership in space......Page 32 1.1.10 The Paine Commission report......Page 33 1.1.11 Sally Ride’s report......Page 34 1.1.12 The Cassini Phase A study......Page 36 1.1.13 What scientists hoped to learn from the Saturn mission......Page 38 1.2 PARTNERING WITH EUROPE......Page 39 1.3 CONGRESSIONAL NEGOTIATIONS......Page 41 1.3.3 The cost containment requirement......Page 42 REFERENCES......Page 43 2.1 NASA-ESA-ASI MISSION PLANNING ACTIVITIES......Page 49 2.1.1 The ESA memorandum of understanding......Page 50 2.1.2 The ASI memorandum of understanding......Page 51 2.2.1 The importance of the SRMU program......Page 52 2.2.2 Challenges to CRAF/Cassini......Page 53 2.2.3 The need for downscoping......Page 55 2.2.3.1 An omen of things to come?......Page 57 2.3 CHANGE OF ADMINISTRATOR: GOLDIN REPLACES TRULY......Page 58 2.3.1 Dan Goldin’s position on the Cassini-Huygens mission......Page 59 2.3.1.1 SSB/COMPLEX’s position......Page 62 2.3.1.2 Stable financial support......Page 63 REFERENCES......Page 64 Part II: Designing, fabricating, and integrating the Cassini-Huygens space vessel......Page 69 3: Constructing the Cassini Orbiter......Page 70 3.1 FROM GALILEO TO CASSINI-HUYGENS......Page 71 3.2.1 The Ulysses, Giotto and Galileo designs considered......Page 72 3.2.2 Use a spare Galileo spacecraft for Saturn, or develop a new design?......Page 73 3.2.3 The Mark II space platform......Page 75 3.2.3.1.1 Hemispherical resonator gyros......Page 76 3.2.3.3 Ground support system......Page 77 3.3 FINAL DESIGN OF THE CASSINI ORBITER......Page 78 3.3.1 The high-gain antenna......Page 80 3.3.2 Power for the spacecraft......Page 81 3.3.5 Radiation hardening of spacecraft electronics......Page 82 3.3.5.1 Cumulative versus single event effects......Page 83 3.3.5.4 Material selection......Page 84 3.3.6 Attitude and Articulation Control Subsystem......Page 85 3.3.6.1 Determining spacecraft attitude......Page 86 3.3.7 Thermal control system......Page 87 3.3.9 Power system......Page 88 3.4 SPACECRAFT PERFORMANCE PREDICTIONS......Page 89 3.4.4 Contamination......Page 90 3.5.2 Switches......Page 91 3.5.4 Hemispherical resonator gyro......Page 92 3.6 THE SCIENCE INSTRUMENT SELECTION PROCESS......Page 93 3.7.1 Composite Infrared Spectrometer......Page 95 3.7.2 Imaging Science Subsystem......Page 96 3.7.3 Ultraviolet Imaging Spectrograph: Seeing in the butterfly range......Page 99 3.7.4 Visual and Infrared Mapping Spectrometer......Page 101 3.8.1 Cassini Plasma Spectrometer......Page 102 3.8.2 Cosmic Dust Analyzer......Page 104 3.8.3 Ion and Neutral Mass Spectrometer......Page 106 3.8.4.1 Saturn’s rotation rate......Page 107 3.8.4.4 Preventing interference from other spacecraft instruments......Page 108 3.8.5 Magnetospheric Imaging Instrument......Page 109 3.8.6 Radio and Plasma Wave Science......Page 110 3.9.1 RADAR......Page 112 3.9.2 Radio Science Subsystem......Page 113 3.10 BUILDING FLIGHT INSTRUMENTS AT JPL: INAPPROPRIATE COMPETITION WITH OUTSIDE ORGANIZATIONS?......Page 114 3.11.1 PI instruments......Page 115 3.11.2 Facility instruments......Page 116 3.12 THE SPACECRAFT: OUR EYES, HANDS, LEGS, AND BRAINS AT SATURN......Page 117 REFERENCES......Page 118 4.1 PHASES OF THE HUYGENS PROBE MISSION......Page 128 4.2 HUYGENS PROBE DEVELOPMENT......Page 130 4.2.1 ESA’s juste retour policy for dispersing development contracts......Page 131 4.2.3.1 Separation system......Page 132 4.2.3.2.2 Aft cover......Page 135 4.2.3.3.1 Parachutes......Page 136 4.2.3.3.2 Estimating descent times......Page 137 4.2.3.4.1 Thermal control......Page 138 4.2.3.4.2 Electrical power......Page 139 4.3 SELECTION PROCEDURES FOR THE PROBE’S SCIENCE PACKAGE......Page 140 4.4 THE HUYGENS PROBE’S SUITE OF INSTRUMENTS......Page 141 4.4.1 Aerosol Collector and Pyrolyzer......Page 142 4.4.2 Descent Imager/Spectral Radiometer......Page 143 4.4.3 Doppler Wind Experiment......Page 144 4.4.4 Gas Chromatograph/Mass Spectrometer......Page 145 4.4.5 Huygens Atmosphere Structure Instrument......Page 146 4.4.6 Surface Science Package......Page 147 4.4.6.1 The SSP principal investigator......Page 150 4.5.1 Drop test......Page 151 4.5.2 Lightning susceptibility testing......Page 152 REFERENCES......Page 153 5.1 ORBITER INTEGRATION......Page 159 5.2 PROBE INTEGRATION......Page 161 5.4 ENVIRONMENTAL TESTING......Page 162 5.4.1 Electromagnetic interference testing......Page 163 5.4.2 Dynamic environmental test......Page 164 5.4.3 Solar/thermal/vacuum test......Page 165 5.5 RISK ISSUES IN SHIPPING THE SPACECRAFT TO KENNEDY SPACE CENTER......Page 166 5.5.3 Arrival of the rest of the Cassini Orbiter......Page 167 5.6.2 RTG temporary installation and test......Page 168 5.7 THE LAUNCH VEHICLE......Page 169 5.7.1 The Centaur stage......Page 170 5.8.2 Discovery of an air conditioning problem......Page 171 5.8.3 Back to the launch pad......Page 173 REFERENCES......Page 174 6.1 WHY NASA USES RADIOISOTOPE THERMOELECTRIC GENERATORS (RTG) FOR SHIPBOARD POWER......Page 177 6.2 WHY DIDN’T NASA USE SOLAR POWER ON CASSINI-HUYGENS?......Page 178 6.3 RADIOISOTOPE HEATER UNITS (RHU): A SECOND PLUTONIUM APPLICATION......Page 179 6.4 THE POLITICS OF OBTAINING PLUTONIUM 238......Page 180 6.5 DANGERS AND SAFETY FEATURES OF RTGS......Page 182 6.6 PUBLIC OPPOSITION TO THE USE OF PLUTONIUM......Page 184 6.7 ATTEMPTS TO STOP THE LAUNCH......Page 187 6.9 TWENTY-FIRST CENTURY RTG ISSUES......Page 189 REFERENCES......Page 193 Part III: From Earth to Saturn......Page 198 7.1 THE JOURNEY BEGINS......Page 199 7.2.1 What the team had to expect after launch......Page 200 7.2.3.1 TCM-1: Fine tuning the spacecraft path after launch......Page 201 7.2.3.3 TCM-2: Adjusting the first Venus flyby......Page 203 7.2.4.1 The search for lightning......Page 204 7.2.5.1 TCM-5: Maximizing the second gravity assist......Page 205 7.2.5.3 TCM-6: Fine tuning the second gravity assist......Page 206 7.2.6 The second Venus flyby (Venus-2)......Page 207 7.2.8 Solar wind interaction......Page 208 7.2.9 Surface and atmospheric structures and processes......Page 210 7.3.3 Orbiter calibration operations and scientific measurements at Earth......Page 211 7.3.3.2 Science observations and instrument performance evaluations......Page 212 7.4 HUYGENS PROBE ACTIVITIES DURING THE CRUISE......Page 213 7.4.2 Preparing for the Jupiter flyby......Page 214 7.5.1 Imaging science......Page 215 7.5.3 Radio emissions and aurorae......Page 216 7.5.5 Satellite analyses......Page 217 7.5.10 Gravity assist summary......Page 218 7.6.2 Solar conjunctions......Page 219 7.6.3 The Phoebe flyby......Page 220 7.7 ARRIVAL AT SATURN......Page 221 REFERENCES......Page 224 8.1 THE PROBE-ORBITER TRANSMITTER LINK......Page 231 8.3 ENQUIRIES INTO THE DOPPLER PROBLEM......Page 234 8.3.1 Issues of trust, economics, and geography......Page 235 8.4 SAVING THE MISSION......Page 236 REFERENCES......Page 237 9: The Titan Huygens Probe mission......Page 239 9.1.2 Separation phase......Page 240 9.1.3 Coast phase......Page 241 9.3.2 Descent phase through the atmosphere......Page 242 9.4 WHAT DID THE HUYGENS PROBE TELL US ABOUT TITAN?......Page 244 9.4.2 The DWE problem......Page 245 9.4.3 Titan’s weather: Haze, aerosols, clouds, and rain......Page 247 9.4.5 Temperature, pressure, and density......Page 248 9.4.6.1 A slowly oscillating tool for seeing below Titan’s surface......Page 249 9.4.7 Titan’s surface......Page 250 9.4.7.2 Methane sources......Page 251 9.4.7.3 Surface Science Package observations......Page 252 REFERENCES......Page 254 10.1 CHOOSING TRAJECTORIES AND ASSIGNING TIME ON THE SPACECRAFT......Page 258 10.1.1 The art of tour design......Page 259 10.1.2 A valuable commodity: Pointing time on the Orbiter......Page 261 10.1.3 Planning activities on Galileo versus Cassini-Huygens......Page 262 10.2 USING TITAN AS THE “TOUR ENGINE” FOR CHANGING SPACECRAFT ORBITS......Page 263 10.3 THE CASSINI-HUYGENS PRIME MISSION TOUR......Page 265 10.3.1 The unusual numbering system of Prime Mission orbits......Page 266 10.3.3 The magnetometer issue......Page 267 10.4 THE CASSINI EQUINOX MISSION......Page 268 10.4.1 A major management change......Page 269 10.4.2 An aging spacecraft: Trouble with the Orbiter’s thrusters......Page 270 10.5 THE SOLSTICE MISSION......Page 271 10.5.1.2 Proximal orbit phase......Page 272 10.5.1.3 Planetary protection phase......Page 273 REFERENCES......Page 274 Part IV: A great natural laboratory......Page 277 REFERENCES......Page 278 11: The mother planet and its magnetosphere......Page 279 11.1.1 Composition......Page 280 11.1.4 Horizontal cloud bands......Page 281 11.2 WIND AND STORM CHARACTERISTICS......Page 283 11.2.1 The eye of a Saturn cyclone......Page 284 11.2.2 A hexagonal cyclone-related structure at the north pole......Page 285 11.3 LIGHTNING DISCHARGES......Page 286 11.4 ORIGIN AND STRUCTURE OF SATURN’S LIQUID AND SOLID REGIONS......Page 288 11.5 INTERNAL AND EXTERNAL ROTATIONAL CHARACTERISTICS......Page 289 11.6 THE MAGNETOSPHERE......Page 291 11.6.2 Auroral phenomena......Page 292 11.6.4 Plasma waves......Page 293 11.6.5 Interactions with satellites and rings......Page 294 11.8 LOOKING BEYOND SATURN: STUDIES OF THE HELIOSPHERE......Page 295 REFERENCES......Page 296 12: The ring system......Page 301 12.1 MODERN RING SCIENTISTS......Page 302 12.2 CHARACTERISTICS OF THE RING SYSTEM......Page 304 12.2.3 Ring system formation models......Page 306 12.2.4 The main and faint ring systems......Page 307 12.2.5 The A ring......Page 308 12.2.5.1 Ringlets......Page 310 12.2.5.2 Self-gravity wakes......Page 311 12.2.5.3 Propellers......Page 312 12.2.6 The B ring......Page 314 12.2.6.1 Spokes of the B ring......Page 315 12.2.8 The D ring......Page 316 12.2.9 The F ring......Page 317 12.2.9.1 Shepherd moons: When gravity repels......Page 318 12.2.10 The G ring......Page 321 12.2.11 The E ring......Page 322 12.2.11.1 E ring particle properties and the characteristics of Enceladus......Page 323 12.2.12 The new supersize Phoebe ring......Page 324 12.2.14 Satellites sculpting and filling Saturn’s rings......Page 325 12.2.14.1 Mimas resonances and the Cassini Division......Page 326 12.2.14.2 Other ring-moon interactions......Page 327 12.2.15.2 Connection with the A ring......Page 328 12.3 SATURN’S EQUINOX: VIEWING RINGS EDGE-ON......Page 329 REFERENCES......Page 331 13: The icy moons......Page 337 13.2 TWO-FACED IAPETUS......Page 338 13.2.1 Orbital and rotational characteristics......Page 341 13.2.2 The equatorial ridge......Page 342 13.3 TETHYS: SIGNS OF A TUMULTUOUS PAST......Page 343 13.4 ENCELADUS: WATER JETS AND A POSSIBLE OCEAN......Page 345 13.4.1 Key flybys......Page 347 13.4.2 Enceladus and the E ring......Page 348 13.4.3 Enceladean eruptions......Page 350 13.4.5 Why is Enceladus more active than Mimas?......Page 351 13.4.7 The effects of tidal forces......Page 352 13.5 HYPERION: SPONGY AND SMALL......Page 353 13.6 MIMAS: THE BULL’S-EYE MOON......Page 355 13.6.1 The Pac-Man temperature map......Page 356 13.7 RHEA......Page 357 13.8 DIONE......Page 358 13.8.1 Helene: Dione’s Trojan moon......Page 359 13.8.2 The 2010 doubleheader flyby......Page 360 13.9 SUMMARY OF MOONS DISCOVERED TO DATE......Page 361 REFERENCES......Page 368 14.1 THE VOYAGER LEGACY......Page 372 14.2.1 Titan’s haze......Page 373 14.2.2 Benzene, PAHs, and smog......Page 375 14.2.4 The north polar wind vortex and hood......Page 376 14.2.5 Atmospheric super-rotation......Page 377 14.2.7 Titan’s methane cycle and rainfall......Page 378 14.3 EXPLORING TITAN’S SURFACE FROM ORBIT......Page 379 14.3.2 The RADAR instrument......Page 380 14.3.4 VIMS and ISS: Other instruments that imaged the surface......Page 381 14.3.5 Pre-Huygens RADAR, VIMS, and ISS data from Titan’s surface......Page 382 14.3.6 The search for hydrocarbon lakes......Page 383 14.3.7 Why are the lakes distributed unevenly between Titan’s northern and southern polar regions?......Page 385 14.3.9 Can terrestrial models of fluvial erosion be applied to Titan?......Page 386 14.3.10 The case for cryovolcanism......Page 388 14.3.11 The dunes of Titan......Page 391 14.3.12 Could Titan’s methane indicate life?......Page 392 14.3.14 A subsurface ocean?......Page 393 REFERENCES......Page 395 15: Conclusions......Page 401 15.1 THEMES RUNNING THROUGH THE BOOK......Page 402 15.1.1.3 Failure modes......Page 403 15.1.3 Adaptability to unforeseen problems......Page 404 15.2 THE REMAINING YEARS OF THE MISSION......Page 405 REFERENCES......Page 407 3.1 NASA costs......Page 408 REFERENCES......Page 409 About the author......Page 410 Image credits......Page 411 Index......Page 414 Cassini-huygens Was The Most Ambitious And Successful Space Journey Ever Launched To The Outer Solar System. This Book Examines All Aspects Of The Journey: Its Conception And Planning; The Lengthy Political Processes Needed To Make It A Reality; The Engineering And Development Required To Build The Spacecraft; Its 2.2-billion Mile journey From Earth To The Ringed Planet; And The Amazing Discoveries from The Mission. the Author Traces How The Visions Of A Few Brilliant Scientists Matured, Gained Popularity, And Eventually Became A Reality. Innovative Technical Leaps Were Necessary To Assemble Such A Multifaceted Spacecraft And Reliably Operate It While It Orbited A Planet So Far From Our Own. The Cassini-huygens Spacecraft Design Evolved From Other Deep Space Efforts, Most Notably The Galileo Mission To Jupiter, enabling The Voluminous, Paradigm-shifting Scientific Data Collected By The Spacecraft. some Of These Discoveries Are Absolute Gems. A Small Satellite That Scientists Once Thought Of As A Dead Piece Of Rock Turned Out To Contain A Warm Underground Sea That Could Conceivably Harbor Life. And We Now Know That Hiding Under The Mist Of Saturn’s Largest Moon, Titan, Is A World With Lakes, Fluvial Channels, And Dunes Hauntingly Reminiscent Of Those On Our Own Planet, Except That On Titan, It’s Not Water That Fills Those Lakes But Hydrocarbons. These And Other Breakthroughs Illustrate Why The Cassini-huygens Mission Will Be Remembered As One Of Greatest Voyages Of Discovery Ever Made. Part I: Creating A New Expedition To Saturn -- Conceiving And Funding The Mission -- Building An International Partnership And Preventing Mission Cancellation -- Part Ii: Designing, Fabricating, And Integrating The Cassini-huygens Space Vessel -- Constructing The Cassini Orbiter -- The Titan Huygens Probe -- Integrating The Cassini Orbiter, Huygens Probe, And Titan/centaur Launch Vehicle -- Using Plutonium To Run A Spacecraft -- Part Iii: From Earth To Saturn -- The Interplanetary Journey -- How A Few People Can Make A Big Difference: The Doppler Shift Problem That Nearly Ended The Huygens Mission -- The Huygens Titan Probe Mission -- The Saturn Tour: Decision-making Processes, Trajectory Design, And Changes Of Management -- Part Iv: A Great Natural Laboratory -- The Mother Planet And Its Magnetosphere -- The Ring System -- The Icy Moons -- Titan Observations By The Cassini Orbiter -- Conclusions -- Appendix: Breakdown Of Mission Costs. By Michael Meltzer. Conceiving and funding the mission Building an international partnership and preventing mission cancellation Constructing the Cassini Orbiter The Titan Huygens Probe Integrating the Cassini Orbiter, Huygens Probe, and Titan/Centaur launch vehicle Using plutonium to run a spacecraft The interplanetary journey How a few people can make a big difference: The Doppler shift problem that nearly ended the Huygens mission The Titan Huygens Probe mission The Saturn tour: Decision-making processes, trajectory design, and changes of management The mother planet and its magnetosphere The ring system The icy moons Titan observations by the Cassini Orbiter.