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: Space of human space exploration (Mercury, Gemini, Apollo, the space shuttle program and two crew members aboard the International Space Station). The attraction was built on the former site of Horizons, a dark ride that offered optimistic visions of what life might be like in the future. Horizons closed permanently in 1999 after a few years of sporadic operation; construction began on Mission: Space shortly thereafter. Industry estimates put the cost of developing the new attraction at US$100 million. The pavilion, like others at Epcot, features a VIP lounge for HP employees called The Red Planet Room. Initially it was sponsored