August 1, 1994
The Galileo spacecraft captured an extensive range of data on the impacts of the fragments of Comet Shoemaker-Levy 9 on Jupiter July 16 through 22. Because of its position 240 million kilometers (150 million miles) from Jupiter and in the direction of the impact sites on the planet's night side, Galileo was able to make unique direct observations of the impact events which were not visible from Earth.
The data from Galileo's science instruments were stored on the spacecraft's onboard tape recorder. Science teams are now carefully evaluating data stored on tape to select portions to be transmitted to Earth starting in August.
The spacecraft's photopolarimeter-radiometer has already obtained and transmitted light-intensity readings from the impacts of comet fragments H, L and Q on Jupiter's far side. The B impact did not produce a significant indication; data from fragment P was recorded on tape for later playback.
Engineering telemetry indicated that Galileo's computer directed the imaging system, the near-infrared spectrometer, the ultraviolet spectrometer and plasma wave instrument to observe the impacts as planned. The camera observed the fragment D, E, K, N, V and W events, the infrared instrument the C, F, G and R impacts. Their observations are stored on tape, intended for gradual transmission to Earth beginning this month and continuing through January 1995.
The spacecraft continues to operate normally, spinning at
about 3 rpm and transmitting at 10 bits per second to ground
stations of the NASA/JPL Deep Space Network. Galileo is about
640 million kilometers (400 million miles) from Earth, so that a
command takes 36 minutes to reach Galileo, and the response
another 36 minutes to return. The spacecraft will reach Jupiter
on December 7, 1995, when its probe will descend into the Jovian
atmosphere and the orbiter spacecraft will begin two years of
observation and measurement of the planet, its moons and