JUNO: sopravvivere alle radiazioni Alberto Adriani INAF Istituto di Fisica dello Spazio Interplanetario Roma
Science Goals are aimed at understanding both our own solar system and extra-solar planetary systems The Formation of Jupiter Jupiter is our archetype for extrasolar giant planet formation and evolution theory. The abundances of oxygen and nitrogen are key to understanding how giant planets formed. Competing theories on the formation of Jupiter do not agree on temperature, birthplace, composition, and proportion of icy planetesimals that led to Jupiter s formation. Theories also have different predictions for core sizes and total amount of heavy elements in present day Jupiter. The Evolution of Jupiter Improving our understanding of Jupiter evolution will allow more accurate determination of the composition of extra-solar planets with direct consequences for formation theories of planetary systems. Current evolution models are very uncertain due to a lack of data on the possible presence of a radiative zone, the amount of heavy elements present in Jupiter, and the structure of its molecular envelope. Models of Jupiter s interior lack observational constraints to pinpoint the planets central core mass and global composition.
Key Questions o o o o o How did the giant planets form? Does Jupiter have a rock-ice core, and if so how large is it? How different is the composition of Jupiter from the original solar nebula, and if it's different, what is the cause? How deep into the atmosphere do the Great Red Spot and other atmospheric features reach? How does the dynamo on Jupiter work?
JUNO Measurement Objectives Summary (1/2) X and Ka band doppler radio measurements High order gravity zonal harmonics Integrated radio science/telecomm (gravimeter) Scalar and vector measurements of magnetic field Magnetic field spherical harmonics and maps Magnetometer Radio brightness temperatures between 1 and 100 cm at all latitudes, infrared emission, and solar reflection Global water and ammonia abundances Radiometer, Image Spectrometer Zone/belt variability at pressures up to 1000 bars Radiometer
JUNO Measurement Objectives Summary (2/2) Particles, waves and field measurements in polar magnetosphere (fluxes, pitch angle, composition, wave power). Sources of aurora, exploration of Jovian polar magnetosphere Particle acceleration mechanisms associated with aurora and Io footprint. Energetic Particle Spectrometer, plasma sensor, plasma wave detector Remote sensing of aurora and Jovian atmosphere in UV & IR. Time variability and morphology of Jovian aurora IR image spectrometer, UV spectrometer
Mission Description (1) Launch: August 2011 32 Jupiter orbits, 11 days per orbit X and Ka band (up and down) telecom/ gravity science subsystem 2 rpm spin High inclination (80º-90º), low perijove (1.06 R J ), 11 day Jupiter orbit (~39 R J apojove) Dual mode (bi-prop) propulsion subsystem (1700 m/s direct, 2000 m/s V-EGA) Magnetically clean orbiter Design to 375 krad (behind 100 mils Aluminum), RDM of 2 (750 krads)
Mission Description (2)
The Italian Contribution to JUNO JIRAM, the Jovian InfraRed Auroral Mapper Mirror Heritage: Cassini-VIMS, Rosetta- VIRTIS, VEX-VIRTIS, Dawn-VIR. New Challenges: Spinning Spacecraft Passive Cooling Harsh Environment New Detection Concept New In-Flight Calibration Very High Vibrations Limited Mass Allowance Limited Power Allowance Limited Data Volume Limited Developing Time
SCIENTIFIC OBJECTIVE 1: Auroral Region H3+ emissions measured by Cassini-VIMS H3+ emissions
SCIENTIFIC OBJECTIVE 2: Hot Spots Hot spots seen by Galileo-NIMS Simulations for JIRAM H 2 O NH 3
SCIENTIFIC OBJECTIVE 3: Troposphere Sounding Credit: Imke de Pater, Michael Wong (UC Berkeley); Al Conrad (Keck), and Chris Go (Cebu, Philippines) by Cassini VIMS Jupiter by Cassini VIMS Saturn Atreya et al., 2005
Conclusions JIRAM is the missing ring of the Juno mission