Exploration of Jupiter disadvantages for colonization because of the severe radiation conditions prevailing in Jupiter's magnetosphere and the planet's particularly deep gravitational well. Jupiter would deliver about 36 Sv (3600 rem) per day to unshielded colonists at Io and about 5.4 Sv (540 rems) per day to unshielded colonists at Europa, which is a decisive aspect due to the fact that already an exposure to about 0.75 Sv over a period of a few days is enough to cause radiation poisoning, and about 5 Sv over a few days is fatal. Ganymede is the Solar System's largest moon and the Solar System's only
Gravity of Mars modifications of gravity model include taking other non-conservative forces acting on spacecraft into account, including atmospheric drag, solar radiation pressure, Mars reflected solar radiation pressure, Mars thermal emission, and spacecraft thrusting which despins or desaturates the angular moment wheels. In addition, Martian precession and third body attraction due to the Sun, Moon and planets, which could affect the spacecraft orbit, as well as relavistic effects on the measurements should also be corrected. These factors could lead to offset of the true gravity field. Accurate modeling is thus required to eliminate the offset. Such work is still ongoing. Many researchers have