The Magellan spacecraft, also referred to as the Venus Radar Mapper, was a 1,035-kilogram robotic space probe launched by NASA on May 4, 1989, to map the surface of Venus using Synthetic Aperture Radar and measure the planetary gravity. It was the first interplanetary mission to be launched from the Space Shuttle, the first to use an inertial upper stage booster and was the first spacecraft to test aerobraking as a method for circularizing an orbit. Magellan was the fourth successful, NASA funded mission to Venus and ended an eleven year U.S. interplanetary exploration hiatus.
Beginning in the late 1970s, scientists pushed for a radar mapping mission to Venus. First seeking to construct a spacecraft titled, Venus Orbiter Imaging Radar, it became obvious the mission would be outside the limits of the budgetary constraints during the following years and was subsequently canceled in 1982. Recommended by the Solar System Exploration Committee, a stripped down mission proposal was resubmitted and accepted as the Venus Radar Mapper in 1983. The proposal included a limited focus and a single primary scientific instrument. In 1985, the mission was renamed Magellan, after the sixteenth-century Portuguese explorer Ferdinand Magellan, for his exploration, mapping and circumnavigation of the Earth, a goal this mission would have for Venus.
Chroma key compositing, or chroma keying, is a special effects / post-production technique for compositing (layering) two images or video streams together, used heavily in many fields to remove a background from the subject of a photo or video - particularly the newscasting, motion picture and videogame industries. A color range in the top layer is made transparent, revealing another image behind. The chroma keying technique is commonly used in video production and post-production. This technique is also referred to as color keying, colour-separation overlay (CSO; primarily by the BBC), or by various terms for specific color-related variants such as green screen, and blue screen - chroma keying can be done with backgrounds of any color that are uniform and distinct, but green and blue backgrounds are more commonly used because they differ most distinctly in hue from most human skin colors and no part of the subject being filmed or photographed may duplicate a color used in the background. It is commonly used for weather forecast broadcasts, wherein the news presenter appears to be standing in front of a large map during live television newscasts, though in actuality it is a large blue or green background. When using a blue screen, different weather maps are added on the parts of the image where the color is blue. If the news presenter wears blue clothes, his clothes will also be replaced with the background video. A complementary system is used for green screens. Chroma keying is also used in the entertainment industry for special effects in movies and videogames. The advanced state of the technology and much commercially available computer software, such as Pinnacle Studio, Adobe Premiere, and dozens of other computer programs, makes it possible and relatively easy for the average home computer user to create videos using the "chromakey" function and easily affordable greenscreen or bluescreen kits.