Venus is named after the Roman goddess of love and beauty. The planet probably received its name because it is the brightest of the planets known to the ancients. It is the brightest object in the sky except for the Sun and the Moon, and has been known since prehistoric times. Like Mercury, it was often thought to consist of two separate bodies: Eosphorus as the morning star and Hesperus as the evening star, but the Greek astronomers knew better than this.
Since Venus is an inferior planet, it shows phases when you look at it through a telescope from the Earth. Galileo's observation of the phases of venus was valuable evidence in support of Copernicus's heliocentric theory of the solar system.
The first spacecraft reaching Venus was Mariner 2 in 1962. It was later visited by many others (more than 20 in total so far), including Pioneer Venus and the Soviet Venera 7 the first spacecraft to land on another planet, and Venera 9 which brought the first photographs of the surface. Most recently, the orbiting US spacecraft Magellan created detailed maps of Venus' surface using radar.
The first spacecraft to visit Venus was Mariner 2 in 1962. It was subsequently visited by many others (more than 20 in all so far), including Pioneer Venus and the Soviet Venera 7 the first spacecraft to land on another planet, and Venera 9 which returned the first photographs of the surface (left). Most recently, the orbiting US spacecraft Magellan produced detailed maps of Venus' surface using radar (above).
The interplanetary space probe Magellan left Earth in 1989 and fell into orbit around Venus August 10, 1990. Since then, it has sent back spectacular radar images for a new, more-detailed map of Earth's cloud-shrouded sister planet.
NASA had trouble holding a steady radio contact with the spacecraft for a time as it whirled around Venus. Even so, spectacular images of rugged terrain were received.
Magellan completed one complete mapping of 90 percent of the surface of Venus with radar able to peer through the blanket of thick clouds which block visible light for optical cameras, then went into a second mapping cycle.
Noodle Picutres. Magellan's Venus pictures reminded geologists of California earthquake faults, Hawaiian volcanoes, the rift valleys of East Africa and Europe's Rhine Valley. The strips of photos covering territory 1,000 miles long by 15 miles wide, called "noodle" pictures, depicted a violent Venus-scape sculpted with long, parallel valleys and ridgesãlike those between the Rocky Mountains and the Sierra Nevada rangeãas well as deep impact craters, jagged quake faults and expansive lava flows similar to those on Hawaii and in the Snake River plains of Idaho.
Overlapping lava flows six to ten miles wide, of different ages, were bright and dark splotches in the photos. Many Venus-quake faults and fractures suggested movement of the planet's crust had shaped the landscape. Parallel sets of elongated valleys and ridges looked like the basin-and-range area of the intermountain region of Utah and Nevada, or the Great Rift Valley in eastern Africa.
Apparently, part of Venus' crust had been stretched apart. Zigzag lines across the surface were tinsel fractures caused by pulling the crust apart, like the the rift valleys in East Africa or the Salt Trough earthquake fault under California. A pit crater about a mile wide in the photo, like depressions on the slopes of Hawaiian volcano Mauna Lea, may have been volcanic in origin, not the result of a meteor impact. The Devana Chasm, a giant valley, had fault patterns like those in the Rhine Graven region of Germany.
NASA's Pioneer-Venus probe is a small satellite still orbiting Venus. The U.S. sent two interplanetary Pioneer probes to Venus in May and August 1978, one to orbit the planet and the other to deliver four smaller probes to Venus.
Pioneer 12, also known as Pioneer-Venus 1, went into orbit around the planet December 4, 1978. Its highly-elliptical path around Venus brought it to within 100 miles of the surface to do radar mapping, cloud studies and magnetometer readings.
Solar Wind. Pioneer-Venus 1 still is in orbit around Venus, using radar to map the planet surface and send back data about the solar wind. The spacecraft intercepts particles in the solar wind as they pass Venus, flying out from the Sun during the 11-year sunspot cycle. Pioneer-Venus 1 reportedly has less than five lbs. of fuel left but that amount should keep it in proper orbit around Venus until at least 1992.
Radar maps suggested plateaus, volcanoes, and valleys on Venus larger than similar features found on Earth. Previous radar pictures made from Earth, and from Soviet spacecraft at Venus in 1983, displayed lava flows, volcanic craters and craters from meteorite impacts.
Pioneer 13, or Pioneer-Venus 2, was one big probe carrying four smaller probes to be dropped into the atmosphere of Venus. The mothership fired one large 160-lb. probe toward the surface of the planet November 15, 1978. Later, on November 19, it sent three smaller 50-lb. probes.
The probes penetrated the atmosphere of Venus at different locations on December 9, 1978, gathering data and relaying it back to Earth as they descended and hit the planet. One small sounder probe actually survived the hard landing and transmitted data for 68 minutes from the surface. The main Pioneer-Venus 2 mothership also arrived at Venus December 9, entering the upper atmosphere as a probe. It burned in the atmosphere.
The U.S. space agency is considering exploring Venus again. Known as Venus Environmental Satellite (VESAT), the mission would be part of the Discovery program of low-cost, highly-focused science spacecraft. The interplanetary probe would study the atmosphere of Venus.
Venus Environmental Satellite would fly from Earth to Venus where it would go into orbit around that planet. VESAT would examine the atmospheric chemistry and meteorology of our cloud-covered neighbor using an imager, near-infrared spectrograph, a temperature mapper and an X-band radar.
