February 1, 1995
In January, Galileo completed its playback of the comet Shoemaker-Levy 9 observations, including the rest of the time- lapsed pictures of the fragment W impact, which appeared to last about 26 seconds. The science teams have also collected and begun to analyze data on fragment R's impact from the photopolarimeter radiometer, infrared and ultraviolet instruments.
Starting January 30 and continuing into March, the Galileo flight team is installing new flight software on the spacecraft in preparation for arrival at Jupiter. Like the operating system of a personal computer, the flight software translates commands from the ground and from a stored flight sequence into the actions of the spacecraft.
The new flight software will operate onboard the spacecraft through the rest of this year and into early 1996. Some critical maneuvers will take place during this time, including deployment of the atmospheric probe, Galileo's approach to Jupiter and its observations of Io and other satellites during approach, receiving and storing the probe's transmitted data and going into orbit around Jupiter on December 7, 1995. The flight software will provide backup storage for probe data and increased options for attitude control and communications, some of which will be used before the spacecraft arrives at Jupiter. Once in orbit the same software will operate the initial data playbacks and orbital operations until March 1996, when even more enhanced flight software will be installed to conduct orbital operations and data return.
The spacecraft continues to operate normally, spinning at
about three revolutions per minute and transmitting data at 10
bits per second to the NASA/JPL Deep Space Network. Currently the
spacecraft's signals take almost 47 minutes to reach Earth and
commands take the same time to be uplinked. The spacecraft is 845
million kilometers (525 million miles) from Earth and 157 million
kilometers (97.6 million miles) from Jupiter.