Magnetosphere of Jupiter By 1973 the magnetic moment was known within a factor of two, whereas the tilt was correctly estimated at about 10°. The modulation of Jupiter's DAM by Io (the so-called Io-DAM) was discovered in 1964, and allowed Jupiter's rotation period to be precisely determined. The definitive discovery of the Jovian magnetic field occurred in December 1973, when the Pioneer 10 spacecraft flew near the planet. As of 2009 a total of eight spacecraft have flown around Jupiter and all have contributed to the present knowledge of the Jovian magnetosphere. The first space probe to reach Jupiter was Pioneer 10 in
Galileo Probe Galileo Probe The "Galileo" Probe was an atmospheric-entry probe carried by the main "Galileo" spacecraft to Jupiter, where it directly entered a hot spot and returned data from the planet. The probe was built by Hughes Aircraft Company at its El Segundo, California plant, measured about across. Inside the probe's heat shield, the scientific instruments were protected from extreme heat and pressure during its high-speed journey into the Jovian atmosphere, entering at per second. It entered Jupiter on December 7 1995, 22:04 UTC and stopped functioning 23:01 UTC, 57 minutes and 36 seconds later. The probe was released from the