Some scientific instruments on the Galileo spacecraft
observe from a distance while others measure fields and particles directly. The Galileo probe
was dropped right into Jupiter's cloudtops to collect data about the atmosphere.
At launch, the spacecraft and probe together had a mass of almost six-thousand pounds,
about as much as two sport utility vehicles. Galileo is over twenty feet tall.
The spacecraft is a "dual-spin" design --- a controlled spin keeps Galileo stable. One section
of the spacecraft rotates at 3rpm. On this section, six instruments rapidly gather data from
many different directions. The other section of the spacecraft holds steady for the four
instruments that must point accurately while Galileo is flying through space.
The 700-pound probe measured about four feet across. Inside the heat shield, the scientific
instruments were protected from ferocious heat during entry. The probe had to withstand
extreme heat and pressure on its high-speed journey at one-hundred-six-thousand miles per
The Jet Propulsion Laboratory
built the Galileo Spacecraft and manages the Galileo mission for NASA. Germany supplied the
propulsion module. NASA's Ames Research Center
managed the probe, which was built by Hughes Aircraft Company.
Click on the image to view a detailed drawing of the Galileo Spacecraft
Next: Spacecraft Basics