Venus. Venus was badly known until the beginning of space age. Venus, like Mercury, is an inferior planet, that is a planet which is located between Earth and the Sun. This configuration yields that such planets are seen like evening, or morning, stars only. Although Venus is venturing more far away from the horizon than Mercury, another hindrance was that it was covered by a thick blanket of clouds. Such a fact was rendering vain any speculation about Venus' surface or any good assessment of the planet axis tilt and rotation. Venus, since, have been targeted by several missions, of them some former-USSR ones which managed to land at the planet's surface between 1975 and 1981. The last and most comprehensive mission to Venus dates back to 1990 when NASA's Magellan reached the planet and spent 4 years in orbit, mapping the surface in the radar range. This view of Venus was taken by NASA's Mariner 10' mission by 1974 as it was to its way to Mercury and using the bright planet like a gravity-assisted flyby and a direction change. It's a classical aspect of Venus, with its thick cloud blanket. Venus is similar in size to our 7,926-mile wide Earth (12,756 km), with a diameter of 7,521 mi (12,104 km). picture re-worked by site 'Amateur Astronomy', based on a picture courtesy JPL