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
Mission: Earth, Voyage to the Home Planet and Jones later produced another collaborative work, "Scholastic Encyclopedia of the United States at War", which was published in 1998. Jones wrote another book about his experiences in space, "Sky Walking: An Astronaut's Memoir", which was published in 2006. In "Mission: Earth, Voyage to the Home Planet", astronaut Thomas David Jones recounts his experiences studying the Earth during his first mission with the United States space agency NASA. Jones' space mission lasted eleven days. Jones was a member of the crew of the Space Shuttle "Endeavour", which left Earth in April 1994. The mission was intended to provide the Space