Flyby missions

Flyby Mission procedure in which a spacecraft on its way to another destination examines a planet as it flies past that planet. 

The American craft Mariner 4, launched on November 28, 1964, completed the first successful flyby of Mars. Mariner 4 s television pictures of tbe Martian surface were the first images of another planet sent back from deep space and changed the way the scientific community viewed the possibility of life on Mars. Mariner 6 and Mariner 7, in 1969, were similarly successful flyby missions, making closer ap>-proaches and providing more photographic and other data to that already compiled by Mariner 4. 

The composition of the Phobos and Deimos surfaces are of interest to astronomers at least partly because they provide additional information about the nature of the solar system. Some individuals go further and anticipate that the information may someday have some important practical application. Those who are thinking about human travel to Mars suggest that the two moons may contain materials that can be converted into fuels for space travel and thus play an important role in future trips back and forth between Earth and Mars. The practicality of this suggestion is at question, however, since no missions to or flybys of the moons are currently scheduled. 

Apart from its most general features, the physical and chemical characteristics of Uranus were largely unknown to astronomers prior to the Voyager 2 flyby in 1981. That mission, however, provided a host of new data about the planet, its ring system, and its moons. For example, Voyager reported that the temperature of the planet at both poles is approximately the same, about 58 K (—215°C), in spite of the fact that one pole always points toward the Sun and the other pole... 

The era of space travel has provided astronomers with a valuable new tool for the study of comet structure, composition, and behavior. During the two-year period 1985-86, no fewer than six spacecraft made flybys of comets. The first of these was NASA s ISEE-3 (International Sun-Earth. Explorer 3), which after completing its primary mission of studying the Sun was targeted to pass through the tail of Comet Giacobini-Zinner in September of 1985. At that point, it was renamed the International Comet E q)lorer (ICE). ICE also observed Comet Halley from a distance of 17 million miles (28 million km) in March 1986. 

A second successful U.S. comet mission was Deep Space 1, launched from Cape Canaveral on October 24, 1998. Its principal goal was to test a variety of new space technologies. It completed this primary mission in Septemher 1999. The spacecraft s mission was then extended to include a flyby of Comet Borrelly, which it accomplished on Septemher 22, 2001. Deep Space 1 sent hack black and white photographs of the comet, infrared spectrometer readings, ion and electron data, and measurements of the magnetic held and plasma waves in the vicinity of the comet. 

The Galileo mission to Jupiter and beyond obtained nearly 5 of the required 9 kilometers per second delta-v from one flyby of Venus and two flybys of Earth. This is only slighdy higher than the delta-v required to reach lunar orbit. 

MESSENGER (Mercury Surface, Space, ENvironment, GEochemistry, and Ran-gin) is a very ambitious mission to Mercury. The spacecraft was launched on August 4, 2004 and performed two Venus flybys in 2006 and 2007 and made its first Mercury flyby on Jan 14, 2008. Mercury orbit insertion is planned in 2011. Head et al., 2009 [160] reported on widespread nature of volcanism, the presence of pyroclastic deposits, and the volcanic filling of impact craters and basins on Mercury. 

The Deep Impact mission revealed many details of the properties of comet Tern-pel 1. The spacecraft arrived at comet Tempel 1 on July 4, 2005 to impact it with a 370 kg mass. The spacecraft was launched from Earth in January, 2004. The im-pactor was a battery powered spacecraft that operated only for one day. Images from the comet were obtained till few seconds before the collision. The closest approach of the main spacecraft to the comet was 500 km. The flyby spacecraft monitored the impact. 

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