DOCSLIB.ORG

A Look Inside the Juno Mission to Jupiter12 Richard S

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
A Look Inside the Juno Mission to Jupiter12 Richard S A Look Inside the Juno Mission to Jupiter12 Richard S. Grammier Jet Propulsion Laboratory, California Institute of Technology 4800 Oak Grove Drive, M/S 301-320 Pasadena, CA 91109 818-354-0596 [email protected] Abstract—Juno, the second mission within the New deep-space maneuvers approximately one year after launch, Frontiers Program, is a Jupiter polar orbiter mission perform an Earth-gravity assist approximately 26 months designed to return high-priority science data that spans after launch, and achieve Jupiter orbit insertion in 2016 after across multiple divisions within NASA’s Science Mission a five-year journey. Juno will investigate the gas giant for Directorate. Juno’s science objectives, coupled with the one year, operating a suite of eight instruments to meet its natural constraints of a cost-capped, PI-led mission and the scientific objectives. After completing one year of orbital harsh environment of Jupiter, have led to a very unique science, the spacecraft will de-orbit into Jupiter for the mission and spacecraft design. purpose of planetary protection. The mission and spacecraft design accommodates the required payload suite of instruments in a way that maximizes science data collection and return, maintains a simplified orbital operations approach, and meets the many challenges associated with operating a spin-stabilized, solar- powered spacecraft in Jupiter’s high radiation and magnetic environment. The project’s efforts during the preliminary design phase have resulted in an integrated design and operations approach that meets all science objectives, retains significant technical, schedule and cost margins, and has retired key risks and challenges. As a result, Juno has been authorized to proceed with the detailed design phase and work toward an August 2011 launch. TABLE OF CONTENTS 1. INTRODUCTION .................................................................1 2. HISTORY ...........................................................................2 3. PRIMARY SCIENCE OBJECTIVES .....................................2 4. INSTRUMENT PAYLOAD ...................................................3 5. FIELDS AND PARTICLES INSTRUMENTS ...........................3 6. SPACECRAFT OVERVIEW .................................................4 7. MISSION AND OPERATIONS DESIGN ................................4 7. SPACECRAFT DESIGN SOLUTIONS ...................................8 8. SOLAR ARRAYS ................................................................8 9. VAULT DESIGN .................................................................8 10. STELLAR REFERENCE UNIT (SRU) ...............................9 11. OTHER SPACECRAFT DESIGN CHARACTERISTICS ........9 12. CONCLUSION ................................................................10 ACKNOWLEDGEMENT ........................................................10 Figure 1 – The Juno Spacecraft in Orbit about Jupiter BIOGRAPHY ........................................................................10 This paper will describe the primary science objectives of the Juno mission and how these objectives have been translated into the instrument suite and mission and 1. INTRODUCTION spacecraft designs. This will include a discussion of key The Juno mission to Jupiter is expected to significantly requirements and how these requirements have been realized advance current theories of the Solar System’s origin and in the current design, as well as an examination of the evolution. Juno will launch in August 2011, perform two associated technical challenges and design solutions. 1 1978-1-4244-2622-5/09/$25.00 ©2009 IEEE. 2 IEEEAC paper #1582, Version 6, Updated December 16, 2008 1 A brief history on the mission will be provided, followed by b. Determine depths of cloud and atmospheric a description of Juno’s primary science objectives. Next, the features such as zones, belts, spots, and map scientific payload will be introduced with a brief description dynamical variations in ammonia and water. of each instrument and associated science objectives/requirements. A brief overview of the spacecraft c. Characterize microwave opacity of the polar will then be followed by a more detailed treatment of the atmosphere region. mission design that primarily focuses upon the orbital operations and how the design has evolved to satisfy key (3) Magnetic Field — Juno investigates the fine structure science and operational requirements. Finally, a more in- of Jupiter’s magnetic field, providing information on depth look at the spacecraft will be conducted to describe its internal structure and the nature of the dynamo. how its design has been influenced by the science and a. Map the magnetic field of Jupiter, globally, by mission requirements, as well as the associated technical direct measurement of the field at close-in radial challenges. distances. b. Determine the magnetic spectrum of the field, 2. HISTORY providing information on the dynamo core radius. Juno was selected in May 2005 as the second mission in the c. Investigate secular variations (long-term time New Frontiers Program within NASA’s Science Mission variability) of the magnetic field. Directorate (SMD). Juno was originally scheduled for a 2009 launch opportunity, but was subsequently slipped to a (4) Gravity Field — Gravity sounding by Juno explores 2010 launch and, ultimately, a 2011 launch (within the first the distribution of mass inside the planet. year following selection) due to factors not specifically related to Juno itself. This resulted in an extended Phase B a. Determine the gravity field to provide constraints period (almost three years). The extended Phase B allowed on the mass of the core. the project to dedicate much more effort to requirements and preliminary design maturation, as well as to focus on key b. Determine the gravity field to detect the centrifugal risk-reduction activities. As a result, Juno had a very response of the planet to its own differential successful Preliminary Design Review (PDR) and obtained rotation (winds) at depths of kilo-bars and greater. authorization from NASA Headquarters to proceed into Phase C effective September 1, 2008. c. Investigate the response to tides raised by the Jovian satellites. (5) Polar Magnetosphere — Juno explores Jupiter’s three- 3. PRIMARY SCIENCE OBJECTIVES dimensional polar magnetosphere and aurorae. The overall goal of the Juno Mission is to improve our understanding of the solar system by understanding the a. Investigate the primary auroral processes origin and evolution of Jupiter. The science objectives for responsible for particle acceleration. the Juno investigation are: b. Characterize the field-aligned currents that transfer (1) Atmospheric Composition — Juno investigates the angular momentum from Jupiter to its formation and origin of Jupiter’s atmosphere and the magnetosphere. potential migration of planets through the measurement c. Identify and characterize auroral radio and plasma of Jupiter’s global abundance of oxygen (water) and wave emissions associated with particle nitrogen (ammonia). acceleration. a. Measure the global O/H ratio (water abundance) in d. Characterize the nature, location and spatial scale Jupiter’s atmosphere. of auroral features. b. Measure the global N/H ratio (ammonia) in Jupiter’s atmosphere. (2) Atmospheric Structure — Juno investigates variations in Jupiter’s deep atmosphere related to meteorology, composition, temperature profiles, cloud opacity, and atmospheric dynamics. a. Determine microwave opacity as a function of latitude and altitude (pressure). 2 Table 1 – Instrument Mapping to Science Objectives Instrument Description Science Investigation Associated Objective Gravity Science X- & Ka-band uplink and downlink Interior Structure 4 Magnetometer (MAG) Vector fluxgates (FGM) Interior Structure & Magnetic 3 Dynamo Microwave Radiometer (MWR) 6 wavelengths (1.3-50 cm) Deep atm. sounding & 1, 2 composition Juno Energetic particle TOF vs. energy, ion & electron Auroral distributions, ion 5 Detector Instrument (JEDI) sensors composition Jovian Auroral Distributions Ion mass spec. & electron analyzers Auroral distributions, ion 5 Experiment (JADE) composition Waves 4-m. elec. dipole and search coil Radio & Plasma waves 5 Ultraviolet Spectrometer (UVS) FUV spectral imager Spatial & temporal auroral 5 structure Juno Infra-Red Auroral Mapper IR imager and IR spectrometer Auroral structure, troposphere 2, 5 (JIRAM) structure, atmospheric sounding 4. INSTRUMENT PAYLOAD waves, and radio emissions) and charged particles (ions and electrons) and obtains ultraviolet images of the auroral To satisfy the science objectives described previously, Juno emissions to provide context for the in-situ observations. carries a complement of eight scientific instruments. Refer to Table 1 for a mapping of the scientific objectives to each The Jovian Auroral Distribution Experiment (JADE) instrument. instrument provided by the Southwest Research Institute (SwRI) measures the pitch angle and energy distributions of The Microwave Radiometer (MWR) is a Jet Propulsion electrons as well as the time variable, pitch angle, energy, Laboratory (JPL) delivered instrument that consists of six and composition distribution of ions over both polar regions. peripherally mounted antennas, radiometers, and JADE consists of three electron analyzers and one ion mass control/calibration electronics for six frequencies between spectrometer. 600 MHz and 22 GHz. The MWR is used for deep atmospheric sounding and composition. The Jupiter Energetic-particle Detector
Load more

Recommended publications
  • Lessons Learned from the Juno Project
    Lessons Learned from the Juno Project Presented by: William McAlpine Insoo Jun EJSM Instrument Workshop January 18‐20, 2010 © 2010 All rights reserved. Pre‐decisional, For Planning and Discussion Purposes Only Y‐1 Topics Covered • Radiation environment • Radiation control program • Radiation control program lessons learned Pre‐decisional, For Planning and Discussion Purposes Only Y‐2 Juno Radiation Environments Pre‐decisional, For Planning and Discussion Purposes Only Y‐3 Radiation Environment Comparison • Juno TID environment is about a factor of 5 less than JEO • Juno peak flux rate is about a factor of 3 above JEO Pre‐decisional, For Planning and Discussion Purposes Only Y‐4 Approach for Mitigating Radiation (1) • Assign a radiation control manager to act as a focal point for radiation related activities and issues across the Project early in the lifecycle – Requirements, EEE parts, materials, environments, and verification • Establish a radiation advisory board to address challenging radiation control issues • Hold external reviews for challenging radiation control issues • Establish a radiation control process that defines environments, defines requirements, and radiation requirements verification documentation • Design the mission trajectory to minimize the radiation exposure Pre‐decisional, For Planning and Discussion Purposes Only Y‐5 Approach for Mitigating Radiation (2) • Optimize shielding design to accommodate cumulative total ionizing dose and displacement damage dose and instantaneous charged particle fluxes near Perijove
    [Show full text]
  • Ganymede–Induced Decametric Radio Emission: In-Situ
    manuscript submitted to Geophysical Research Letters 1 Ganymede{induced decametric radio emission: in-situ 2 observations and measurements by Juno 1 1 2;3 4 5 3 C. K. Louis , P. Louarn , F. Allegrini , W. S. Kurth , J. R. Szalay 1 4 IRAP, Universit´ede Toulouse, CNRS, CNES, UPS, (Toulouse), France 2 5 Southwest Research Institute, San Antonio, Texas, USA 3 6 Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, Texas, USA 4 7 Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa, USA 5 8 Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey, USA 9 Key Points: 10 • First detailed wave/particle investigation of a Ganymede-induced decametric ra- 11 dio source using Juno/Waves and Juno/JADE instruments 12 • Confirmation that the emission is produced by a loss-cone-driven Cyclotron Maser 13 Instability 14 • Ganymede-induced radio emission is produced by electrons of ∼ 4-15 keV, at a ◦ ◦ 15 beaming angle [76 -83 ], and a frequency 1:005 − 1:021 × fce Corresponding author: C. K. Louis, [email protected] {1{ manuscript submitted to Geophysical Research Letters 16 Abstract 17 At Jupiter, part of the auroral radio emissions are induced by the Galilean moons 18 Io, Europa and Ganymede. Until now, they have been remotely detected, using ground- 19 based radio-telescopes or electric antennas aboard spacecraft. The polar trajectory of 20 the Juno orbiter allows the spacecraft to cross the magnetic flux tubes connected to these 21 moons, or their tail, and gives a direct measure of the characteristics of these decamet- 22 ric moon{induced radio emissions.
    [Show full text]
  • Juno Spacecraft Description
    Juno Spacecraft Description By Bill Kurth 2012-06-01 Juno Spacecraft (ID=JNO) Description The majority of the text in this file was extracted from the Juno Mission Plan Document, S. Stephens, 29 March 2012. [JPL D-35556] Overview For most Juno experiments, data were collected by instruments on the spacecraft then relayed via the orbiter telemetry system to stations of the NASA Deep Space Network (DSN). Radio Science required the DSN for its data acquisition on the ground. The following sections provide an overview, first of the orbiter, then the science instruments, and finally the DSN ground system. Juno launched on 5 August 2011. The spacecraft uses a deltaV-EGA trajectory consisting of a two-part deep space maneuver on 30 August and 14 September 2012 followed by an Earth gravity assist on 9 October 2013 at an altitude of 559 km. Jupiter arrival is on 5 July 2016 using two 53.5-day capture orbits prior to commencing operations for a 1.3-(Earth) year-long prime mission comprising 32 high inclination, high eccentricity orbits of Jupiter. The orbit is polar (90 degree inclination) with a periapsis altitude of 4200-8000 km and a semi-major axis of 23.4 RJ (Jovian radius) giving an orbital period of 13.965 days. The primary science is acquired for approximately 6 hours centered on each periapsis although fields and particles data are acquired at low rates for the remaining apoapsis portion of each orbit. Juno is a spin-stabilized spacecraft equipped for 8 diverse science investigations plus a camera included for education and public outreach.
    [Show full text]
  • Juno Magnetometer (MAG) Standard Product Data Record and Archive Volume Software Interface Specification
    Juno Magnetometer Juno Magnetometer (MAG) Standard Product Data Record and Archive Volume Software Interface Specification Preliminary March 6, 2018 Prepared by: Jack Connerney and Patricia Lawton Juno Magnetometer MAG Standard Product Data Record and Archive Volume Software Interface Specification Preliminary March 6, 2018 Approved: John E. P. Connerney Date MAG Principal Investigator Raymond J. Walker Date PDS PPI Node Manager Concurrence: Patricia J. Lawton Date MAG Ground Data System Staff 2 Table of Contents 1 Introduction ............................................................................................................................. 1 1.1 Distribution list ................................................................................................................... 1 1.2 Document change log ......................................................................................................... 2 1.3 TBD items ........................................................................................................................... 3 1.4 Abbreviations ...................................................................................................................... 4 1.5 Glossary .............................................................................................................................. 6 1.6 Juno Mission Overview ...................................................................................................... 7 1.7 Software Interface Specification Content Overview .........................................................
    [Show full text]
  • Planetary Science
    Mission Directorate: Science Theme: Planetary Science Theme Overview Planetary Science is a grand human enterprise that seeks to discover the nature and origin of the celestial bodies among which we live, and to explore whether life exists beyond Earth. The scientific imperative for Planetary Science, the quest to understand our origins, is universal. How did we get here? Are we alone? What does the future hold? These overarching questions lead to more focused, fundamental science questions about our solar system: How did the Sun's family of planets, satellites, and minor bodies originate and evolve? What are the characteristics of the solar system that lead to habitable environments? How and where could life begin and evolve in the solar system? What are the characteristics of small bodies and planetary environments and what potential hazards or resources do they hold? To address these science questions, NASA relies on various flight missions, research and analysis (R&A) and technology development. There are seven programs within the Planetary Science Theme: R&A, Lunar Quest, Discovery, New Frontiers, Mars Exploration, Outer Planets, and Technology. R&A supports two operating missions with international partners (Rosetta and Hayabusa), as well as sample curation, data archiving, dissemination and analysis, and Near Earth Object Observations. The Lunar Quest Program consists of small robotic spacecraft missions, Missions of Opportunity, Lunar Science Institute, and R&A. Discovery has two spacecraft in prime mission operations (MESSENGER and Dawn), an instrument operating on an ESA Mars Express mission (ASPERA-3), a mission in its development phase (GRAIL), three Missions of Opportunities (M3, Strofio, and LaRa), and three investigations using re-purposed spacecraft: EPOCh and DIXI hosted on the Deep Impact spacecraft and NExT hosted on the Stardust spacecraft.
    [Show full text]
  • Dynamics of the J Avian Magnetosphere
    25 Dynamics of the J avian Magnetosphere N. Krupp, V. M. Vasyliunas, J. Woch, A. Lagg Max-Planck-Institut fur Sonnensystemforschung, Katlenburg-Lindau K. K. Khurana, M. G. Kivelson IGPP and Dept. Earth & Space Sciences, University of California, Los Angeles B. H. Mauk, E. C. Roelof, D. J. Williams, S. M. Krimigis The Johns Hopkins University Applied Physics Laboratory W. S. Kurth, L. A. Frank, W. R. Paterson Dept. of Physics & As.tronomy, University of Iowa 25.1 INTRODUCTION around Jupiter for almost 8 years (1995-2003), Galileo has collected in situ data of the jovian system over an extended Understanding the dynamic processes in the largest magne­ duration and has for the first time made possible the study tosphere of our solar system is one of the outstanding goals of Jupiter on timescales of weeks, months, and even years, of magnetospheric physics. These processes are associated using the same instrumentation. New regions of the jovian with temporal and/ or spatial variations of the global config­ magnetosphere have been explored, especially the jovian uration. Their timescales range from several tens of minutes magnetotail which was not visited by any of the previous to sizeable fractions of the planetary rotation period to long­ spacecraft (except, to a very minor extent, by Voyager 2). term variations which take several days to develop. They oc­ Additional inputs have become available from ground-based cur on both local and global spatial scales, out to dimensions and Earth-orbit-based measurements and from advanced representing a large fraction of the magnetosphere. global magneto hydrodynamic (MHD) simulations of the jo­ Early indications of a "living", varying jovian magneto­ vian magnetosphere.
    [Show full text]
  • Juno Observations of Large-Scale Compressions of Jupiter's Dawnside
    PUBLICATIONS Geophysical Research Letters RESEARCH LETTER Juno observations of large-scale compressions 10.1002/2017GL073132 of Jupiter’s dawnside magnetopause Special Section: Daniel J. Gershman1,2 , Gina A. DiBraccio2,3 , John E. P. Connerney2,4 , George Hospodarsky5 , Early Results: Juno at Jupiter William S. Kurth5 , Robert W. Ebert6 , Jamey R. Szalay6 , Robert J. Wilson7 , Frederic Allegrini6,7 , Phil Valek6,7 , David J. McComas6,8,9 , Fran Bagenal10 , Key Points: Steve Levin11 , and Scott J. Bolton6 • Jupiter’s dawnside magnetosphere is highly compressible and subject to 1Department of Astronomy, University of Maryland, College Park, College Park, Maryland, USA, 2NASA Goddard Spaceflight strong Alfvén-magnetosonic mode Center, Greenbelt, Maryland, USA, 3Universities Space Research Association, Columbia, Maryland, USA, 4Space Research coupling 5 • Magnetospheric compressions may Corporation, Annapolis, Maryland, USA, Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa, USA, 6 7 enhance reconnection rates and Southwest Research Institute, San Antonio, Texas, USA, Department of Physics and Astronomy, University of Texas at San increase mass transport across the Antonio, San Antonio, Texas, USA, 8Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey, USA, magnetopause 9Office of the VP for the Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey, USA, • Total pressure increases inside the 10Laboratory for Atmospheric and Space Physics, University of Colorado
    [Show full text]
  • EPSC2017-151-1, 2017 European Planetary Science Congress 2017 Eeuropeapn Planetarsy Science Ccongress C Author(S) 2017
    EPSC Abstracts Vol. 11, EPSC2017-151-1, 2017 European Planetary Science Congress 2017 EEuropeaPn PlanetarSy Science CCongress c Author(s) 2017 Properties and circulation of Jupiter's circumpolar cyclones as measured by JunoCam G. S. Orton (1), G. Eichstädt (2), J. H. Rogers (3), C. J. Hansen (4), M. Caplinger (5), T. Momary (1), F. Tabataba-Vakili (1), A. P. Ingersoll (6) (1) Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California USA ([email protected]), (2) Independent scholar, Stuttgart, Germany. (3) British Astronomical Association, London, UK, (4) Planetary Science Institute, Tucson, Arizona, USA, (5) Malin Space Science Systems, San Diego, California, USA, (6) California Institute of Technology, Pasadena, California, USA. Abstract 2. Data JunoCam has taken the first high-resolution visible JunoCam is rigidly mounted on the spinning images of Jupiter’s poles, which show that each pole spacecraft. That way, it can take a full panorama has a cluster of circumpolar cyclones (CPCs), each within about 30 seconds consisting of up to 82 narrow one separated in longitude by roughly equal spacing exposures. Usually, it takes partial panoramas of the [1]. There are five at the south pole and eight at the target of interest. The camera has a horizontal field of north pole. These configurations, including their view of about 58°, and Kodak KAI-2020 CCD sensor asymmetries and the characteristics of individual with four filter stripes, a red, a green, a blue and a cyclones, have remained stable over 7 months from narrow-band 890-nm infrared filter attached on the perijove 1 to perijove 5 as of this writing.
    [Show full text]
  • EGU2018-10209, 2018 EGU General Assembly 2018 © Author(S) 2018
    Geophysical Research Abstracts Vol. 20, EGU2018-10209, 2018 EGU General Assembly 2018 © Author(s) 2018. CC Attribution 4.0 license. Jupiter’s auroras in radio and ultraviolet wavelengths as seen from Juno Masafumi Imai (1), G. Randall Gladstone (2), William S. Kurth (1), Thomas K. Greathouse (2), George B. Hospodarsky (1), Scott J. Bolton (2), John E. P. Connerney (3), and Steven M. Levin (4) (1) University of Iowa, Iowa City, Iowa, United States ([email protected]), (2) Southwest Research Institute, San Antonio, Texas, United States, (3) NASA Goddard Space Flight Center, Greenbelt, Maryland, United States, (4) Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, United States Jupiter is the strongest auroral radio source in our solar system, producing low-frequency radio emissions in a broad frequency range from 10 kHz to 40 MHz from both north and south polar regions of the planet. These sporadic nonthermal bursts and ultraviolet (UV) auroras have been monitored with the radio and plasma wave instrument (Waves) and the ultraviolet spectrograph instrument (Juno-UVS) aboard the spinning Juno spacecraft in polar orbit about Jupiter since July 5, 2016. Waves is capable of recording the electric fields of waves from 50 Hz to 41 MHz with one electric dipole antenna and the magnetic fields of waves from 50 Hz to 20 kHz with one magnetic search coil sensor. Juno-UVS is designed to image and obtain spectra in a wavelength range from 70 to 205 nm with a 4 cm by 4 cm aperture. The Juno spacecraft rotates with a period of 30 s, which modulates the Waves spectral intensity sensed with the dipole antenna.
    [Show full text]
  • Radiation: Lessons Learned
    Radiation:Radiation: LessonsLessons LearnedLearned Scott Bolton Southwest Research Institute Insoo Jun Jet Propulsion Laboratory This document has been reviewed for export control and it does NOT contain controlled technical data. Juno Science Objectives • Origin – Determine O/H ratio (water abundance) and constrain core mass to decide among alternative theories of origin. • Interior – Understand Jupiter's interior structure and dynamical properties by mapping its gravitational and magnetic fields. • Atmosphere – Map variations in atmospheric composition, temperature, cloud opacity and dynamics to depths greater than 100 bars. • Polar Magnetosphere – Explore the three-dimensional structure of Jupiter's polar magnetosphere and aurorae. Juno Juno Payload Gravity Science (JPL/Italy) Magnetometer— MAG (GSFC) Microwave Radiometer— MWR (JPL) Energetic Particles —JEDI (APL) Plasma ions and electrons — JADE (SwRI) Plasma waves/radio — Waves (U of Iowa) Ultra Violet Imager — UVS (SwRI) Visible Camera – Juno Cam (Malin) InfraRed Imager – JIRAM (Italy) Radiation Lessons Learned 3 Juno Juno Mission Design Launch: August 2011 5 year cruise Baseline mission: 32 polar orbits Perijove ~5000 km 11 day period Spinner Solar-powered Orbit is designed to avoid radiation from the inner belts of Jupiter. Dips inside inner belt at perijove and goes above belts (Juno is in polar orbit). Radiation Lessons Learned 4 Juno Orbit 4: Juno Gravity Science 5 days 4 days 6-hour Jupiter science pass 3 days 2 days 1 day Opportunities for 0 communication 11 with Earth 10
    [Show full text]
  • Modeling the Stability of Polygonal Patterns of Vortices at the Poles of Jupiter As Revealed by the Juno Spacecraft
    Modeling the stability of polygonal patterns of vortices at the poles of Jupiter as revealed by the Juno spacecraft Cheng Lia,1, Andrew P. Ingersollb, Alexandra P. Klipfelb, and Harriet Brettleb aAstronomy Department, University of California, Berkeley, CA 94720; and bDivision of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 Edited by Neta A. Bahcall, Princeton University, Princeton, NJ, and approved August 3, 2020 (received for review April 30, 2020) From its pole-to-pole orbit, the Juno spacecraft discovered arrays falls off faster than the 1/r dependence of a vortex patch sur- of cyclonic vortices in polygonal patterns around the poles of Ju- rounded by a region with zero vorticity—suggesting anticyclonic piter. In the north, there are eight vortices around a central vortex, vorticity surrounding the cyclones. In other words, the cyclonic and in the south there are five. The patterns and the individual vortices are “shielded.” Shielding may explain the slow rotation vortices that define them have been stable since August 2016. The (1.5° westward) of the structure as a whole during the 53 d of one azimuthal velocity profile vs. radius has been measured, but ver- orbit (5). tical structure is unknown. Here, we ask, what repulsive mechanism On Earth, cyclones drift poleward (6, 7), but they dissipate prevents the vortices from merging, given that cyclones drift pole- over land and cold ocean. Jupiter has neither land nor ocean, so ward in atmospheres of rotating planets like Earth? What atmo- the question is, why do cyclones neither accumulate at the poles spheric properties distinguish Jupiter from Saturn, which has only nor merge? Saturn has only one cyclone, and it is surrounded by one cyclone at each pole? We model the vortices using the shallow a sea of smaller anticyclones (8).
    [Show full text]
  • Juno Mission to Jupiter
    National Aeronautics and Space Administration Juno Mission to Jupiter unknown how deeply rooted Jupiter’s colorful, banded clouds and planet-sized spots are. And scientists yearn to understand what powers the auroras — Jupiter’s northern and southern lights. These mysteries make it clear that although Jupiter’s colorful clouds get most of the attention, some of the most enticing mysteries are hiding deep inside the planet. A Five-Year Journey Juno’s trip to Jupiter will take about five years. Though the journey may seem long, this flight plan allows the mission to use Earth’s gravity to speed the craft on its way. The spacecraft first loops around the inner solar system and then swings past Earth two years after launch to get a boost that will propel it onward to its With the exception of the sun, Jupiter is the most destination. dominant object in the solar system. Because of its enormous size and the fact that it was likely the first In July 2016, Juno will fire its main engine and slip of the planets to form, it has profoundly influenced the into orbit around the giant planet to begin its scientific formation and evolution of the other bodies that orbit mission. our star. NASA’s Juno mission will allow us to examine this gas giant planet from its innermost core to the outer A Solar-Powered, Spinning Spacecraft reaches of its enormous magnetic force field. Jupiter’s orbit is five times farther from the sun than Earth’s location, so the giant planet receives about During its mission, Juno will map Jupiter’s gravity 25 times less sunlight than Earth.
    [Show full text]