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
Breakaway (Space: 1999) built by the nations of Earth as a centre for space research and exploration. Gerald Simmonds, chief executive of the World Space Commission, calls to impress upon Koenig that nothing must delay his first assignment: the launch of the manned deep-space probe to the planet Meta. A viral infection plaguing the Meta Probe astronauts and other operatives on the Moon must not be an obstacle. After Simmonds signs off, Koenig's ship passes the , a space station in lunar orbit; as he watches, the Meta probe ship docks with the station. Meta is a rogue planet currently passing through the