Today on Galileo
Monday, May 3, 1999
Today, Galileo continues with day two of the ninth encounter of the Galileo Europa Mission. On today's observation schedule the Near-Infrared Mapping Spectrometer, Photopolarimeter Radiometer, and Fields and Particles instruments focus their attention completely on Jupiter. The spacecraft flies past Europa today at about 5:37 am PDT [see note 1] at a distance of 908,000 kilometers (564,000 miles). Closest approach to Jupiter also occurs today at about 10:00 am PDT at a distance of 9.4 Jupiter radii (672,000 kilometers or 418,000 miles) from Jupiter's center.
The Near-Infrared Mapping Spectrometer takes the first observations of the day. In a series of three observations, the spectrometer takes a look at a turbulent region in the wake of the Great Red Spot. One of the observations is made while the Great Red Spot is in darkness, the other two while it's in daylight. The Near-Infrared Mapping Spectrometer observes a hotspot region. Hot spots are particularly interesting because they are known to be nearly cloud-free regions, and are believed to be associated with violent downdrafts in Jupiter's atmosphere. Again, one of these observations is taken at night, and another during daylight. These observations will allow an increased understanding of local meteorology, regional dynamics, and cloud particle size, distribution and composition.
As it did yesterday, the Photopolarimeter Radiometer takes another look Jupiter's clouds, searching for small variations in temperature within a given cloud band. The Near-Infrared Mapping Spectrometer will also observe Jupiter's clouds, hoping to detect long-term global variations in the composition and temperature.
During the Perijove Reduction Campaign (the next four encounters), the Fields and Particles instruments will perform a series of recordings to measure plasma and magnetic and electric fields as Galileo passes through the Io torus. The torus is a region of intense plasma and radiation activity, in which there are strong magnetic and electric fields. Constantly replenished by the volcanic activity on Io, it is a vital part of the Jovian magnetosphere. Recordings in this region provide important information on the dynamics of Jupiter's magnetosphere. This orbit's recording is centered at closest approach to Jupiter and is performed for two hours.
Note 1. All times listed correspond to the Pacific Time zone (currently daylight time) and spacecraft event time. Radio signals indicating that an event has occurred on the spacecraft reach the Earth 33 to 50 minutes later, depending on the time of year. Currently, Pacific Daylight Time (PDT) is 7 hours behind Greenwich Meridian Time (GMT), and it takes radio signals 49 minutes to travel between the spacecraft and Earth.
For more information on the Galileo spacecraft and its mission to Jupiter, please visit the Galileo home page.
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