Search

The Juno Microwave Radiometer (MWR) is a six-frequency scientific instrument designed and built to investigate the deep atmosphere of Jupiter. It is one of a suite of instruments on NASA's New Frontiers Mission Juno launched to Jupiter on August 5, 2011. The focus of this paper is the description of the scientific objectives of the MWR investigation along with the experimental design, observational approach, and calibration that will achieve these objectives, based on the Juno mission plan up to Jupiter orbit insertion on July 4, 2016. With frequencies distributed approximately by octave from 600 MHz to 22 GHz, the MWR will sample the atmospheric thermal radiation from depths extending from the ammonia cloud region at around 1 bar to pressure levels as deep as 1000 bars. The primary scientific objectives of the MWR investigation are to determine the presently unknown dynamical properties of Jupiter's subcloud atmosphere and to determine the global abundance of oxygen and nitrogen, present in the atmosphere as water and ammonia deep below their respective cloud decks. The MWR experiment is designed to measure both the thermal radiation from Jupiter and its emission-angle dependence at each frequency relative to the atmospheric local normal with high accuracy. The antennas at the four highest frequencies (21.9, 10.0, 5.2, and 2.6 GHz) have ∼12° beamwidths and will achieve a spatial resolution approaching 600 km near perijove. The antennas at the lowest frequencies (0.6 and 1.25 GHz) are constrained by physical size limitations and have 20° beamwidths, enabling a spatial resolution of as high as 1000 km to be obtained. The MWR will obtain Jupiter's brightness temperature and its emission-angle dependence at each point along the subspacecraft track, over angles up to 60° from the normal over most latitudes, during at least six perijove passes after orbit insertion. The emission-angle dependence will be obtained for all frequencies to an accuracy of better than one part in $10^{3}$ , sufficient to detect small variations in atmospheric temperature and absorber concentration profiles that distinguish dynamical and compositional properties of the deep Jovian atmosphere. [ABSTRACT FROM AUTHOR]

The European Space Agency (ESA) Rosetta Spacecraft, launched on March 2, 2004 toward Comet 67P/Churyumov-Gerasimenko (C-G), carries a complementary set of instruments on both the orbiter and lander (Philae) portions of the spacecraft, to measure the composition of the Comet C-G. The primary composition measuring instruments on the Orbiter are Alice, COSIMA, ICA, MIRO, OSIRIS, ROSINA and VIRTIS. These instruments collectively are capable of providing compositional information, including temporal and spatial distributions of important atomic, molecular, and ionic species, minerals, and ices in the coma and nucleus. The instruments utilize a variety of techniques and wavelength ranges to accomplish their objectives. This paper provides an overview of composition measurements that will be possible using the suite of orbiter composition measuring instruments. A table is provided that lists important species detectable (depending on abundances) with each instrument. [ABSTRACT FROM AUTHOR]

The European Space Agency Rosetta Spacecraft, launched on March 2, 2004 toward Comet 67P/Churyumov-Gerasimenko, carries a relatively small and lightweight millimeter-submillimeter spectrometer instrument, the first of its kind launched into deep space. The instrument will be used to study the evolution of outgassing water and other molecules from the target comet as a function of heliocentric distance. During flybys of the asteroids (2867) Steins and (21) Lutetia in 2008 and 2010 respectively, the instrument will measure thermal emission and search for water vapor in the vicinity of these asteroids. The instrument, named MIRO (Microwave Instrument for the Rosetta Orbiter), consists of a 30-cm diameter, offset parabolic reflector telescope followed by two heterodyne receivers. Center-band operating frequencies of the receivers are near 190 GHz (1.6 mm) and 562 GHz (0.5 mm). Broadband continuum channels are implemented in both frequency bands for the measurement of near surface temperatures and temperature gradients in Comet 67P/Churyumov-Gerasimenko and the asteroids (2867) Steins and (21) Lutetia. A 4096 channel CTS (Chirp Transform Spectrometer) spectrometer having 180 MHz total bandwidth and 44 kHz resolution is, in addition to the continuum channel, connected to the submillimeter receiver. The submillimeter radiometer/spectrometer is fixed tuned to measure four volatile species – CO, CH3OH, NH3 and three, oxygen-related isotopologues of water, H2 16O, H2 17O and H2 18O. The basic quantities measured with the MIRO instrument are surface temperature, gas production rates and relative abundances, and velocity and excitation temperature of each species, along with their spatial and temporal variability. This paper provides a short discussion of the scientific objectives of the investigation, and a detailed discussion of the MIRO instrument system. [ABSTRACT FROM AUTHOR]

Examines the ultra-relativistic electrons present on the radiation belts of Jupiter. Types of microwave radio emission present in Jupiter; Existence of high-energy electron-radiation belts; Context of the adiabatic diffusion theory.

The use of long-wavelength radio measurements of brightness temperature to remotely measure the thermal structure of the atmospheres of the major planets at great depths (>10 atm.) is discussed. Data are presented which show that the gross features of Jupiter's and Saturn's microwave spectra, as determined from ground based observations, can be explained in terms of thermal emission from ammonia in deep convective atmospheres of He and H. [ABSTRACT FROM AUTHOR]

A survey of current knowledge about Jupiter, Saturn, Uranus, Neptune, Pluto, and their satellites is presented. The best available numerical values are given for physical parameters, including orbital and body properties, atmospheric composition and structure, and photometric parameters. The more acceptable current theories of these bodies are outlined with thorough referencing offering access to the details. The survey attempts to cover the literature through May 1, 1972. [ABSTRACT FROM AUTHOR]