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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Galileo has completed the long awaited Io flybys of the Galileo Europa Mission and the Galileo Millennium Mission, and is now pumping up its apojove in each succeeding orbit in preparation for the chance to perform a dual spacecraft observation of the Jupiter System.
Galileo has completed the Europa leg of the Galileo Europa Mission, and is now pumping down the apojove in each succeeding orbit in preparation for the Io phase.
Analysis of data from darkside and eclipse observations of Io by the NIMS and SSI instruments show that the South Volund hot spot is a manifestation of high temperature active silicate volcanism. The NIMS data are fitted with a two temperature model (developed from modelling terrestrial lavas) which yields a better fit to the data than a single temperature fit.
Jupiter observations in 1963 and 1964 from Clark Lake Radio Observatory in California confirming Io influence on mother planet emissions
Effect of Io on Jupiter radio emission
Stimulation of Jupiter radio emission by Io
Effect of satellite Io on decametric radio emission of Jupiter discussed in terms of co-rotation of magnetospheres with planets
Electrodynamic effects of Jupiters satellite Io
Natural satellite Io effect on Jovian decametric radio emission and albedo
Jovian magnetic field geometry and Io modulated decametric radio emission
Jupiter magnetic field geometry related to Io modulated Jovian decametric radio emission
Four eclipse reappearances observations of Jovian satellite Io by area scanning photometer, considering anomalous brightening
Io brightness anomaly after eclipse by Jupiter
Simultaneous two-color photoelectric photometry of Io and Europa performed during their eclipse by Jupiter on the night of April 5/6, 1971, is reported and discussed. The results are compared with satellite radii obtained using other observational techniques. It is concluded that the eclipse technique can be used to infer satellite radii accurate to plus or minus 10 per cent. In principle the eclipse technique can also be applied to the satellites of Saturn, Uranus, and Neptune for early objective determinations of their radii.
The May 14, 1971, occultation of beta Scorpii C by Io was successfully observed in ultraviolet light near Kingston, Jamaica. Within the limits established by time resolution and the signal-to-noise ratio, both the disappearance and reappearance were found to be instantaneous. Upper limits for the surface pressure for N2, CH4, and H2 atmospheres are 0.09, 0.13, and 44. microbar, respectively. The corresponding number densities are 6.2 x 10 to the 12th power, 9.4 x 10 to the 12th power, and 3.2 x 10 to the 15th power per cu cm. An isothermal atmosphere at a temperature of 100 K was assumed.
Observation of an apparent posteclipse brightening of the Galilean satellite Io from two different observatories on June 25, 1971, employing the technique of area scanning in the ultraviolet. An apparent brightening was observed which amounted to about 0.2 mag at 3500 A and 0.15 mag at 4000 A. It is suggested that the brightening was a transient partial covering of high-albedo material where the contrast is by far greatest in the ultraviolet.
It is argued that the sweeping of trapped energetic MeV protons by Io can result in induced emissions. The instability is caused by the density gradient occurring at the edge of the cavity. It is shown that the azimuthal Larmor drift of the energetic protons which is transverse to both the local magnetic field and the density gradient can excite extraordinary waves with frequencies slightly above the local electron cyclotron frequency. It is found that the emission coefficient is proportional to the square root of (n sub p/n sub t), where n sub p and n sub t denote the density of the energetic protons and the density of the thermal electrons, respectively. The theory also predicts a lower frequency cutoff. This cutoff frequency depends upon the density of thermal electrons in the source region.
A number of anomalous or discordant observations of Io can be explained if this Jovian satellite has an atmosphere containing ammonia. Such an atmosphere will be frozen at the unilluminated pole during the solstices, but will evaporate at the equinoctial seasons. The ammonia atmosphere will explain (1) the posteclipse brightenings and their observed times of occurrence and nonoccurrence; (2) the observed departure from a two-layer model heating curve upon emergency from the eclipse; (3) the discordant temperatures obtained at 10 and 20 micrometers; and (4) discordant temperatures obtained at 10 and 20 micrometers during the total phase of an eclipse by Jupiter.