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National Aeronautics and Space Administration (view source)
Revision as of 01:29, July 2, 2008
, 01:29, July 2, 2008Galileo
*The '''Surveyor probes''' (1966 - 1968) were the first U.S. spacecraft to land safely on the Moon. The main objectives of the Surveyors were to obtain close-up images of the lunar surface and to determine if the terrain was safe for manned landings. Each Surveyor was equipped with a television camera. In addition, Surveyors 3 and 7 each carried a soil mechanics surface sampler scoop which dug trenches and was used for soil mechanics tests and Surveyors 5, 6, and 7 had magnets attached to the footpads and an alpha scattering instrument for chemical analysis of the lunar material. <ref> http://nssdc.gsfc.nasa.gov/planetary/lunar/surveyor.html </ref>
*The '''Surveyor probes''' (1966 - 1968) were the first U.S. spacecraft to land safely on the Moon. The main objectives of the Surveyors were to obtain close-up images of the lunar surface and to determine if the terrain was safe for manned landings. Each Surveyor was equipped with a television camera. In addition, Surveyors 3 and 7 each carried a soil mechanics surface sampler scoop which dug trenches and was used for soil mechanics tests and Surveyors 5, 6, and 7 had magnets attached to the footpads and an alpha scattering instrument for chemical analysis of the lunar material. <ref> http://nssdc.gsfc.nasa.gov/planetary/lunar/surveyor.html </ref>
*'''Galileo''' was launched from the cargo bay of Space Shuttle Atlantis in 1989. The exciting list of discoveries started even before Galileo got a glimpse of Jupiter. As it crossed the asteroid belt in October 1991, Galileo snapped images of Gaspra, returning the first ever close-up image of an asteroid. In 1994 the spacecraft made the only direct observation of a comet impacting a planet-- comet Shoemaker-Levy 9's collision with Jupiter.
:Galileo's descent probe made the first in-place studies of the planet's clouds and winds, and it furthered scientists' understanding of how Jupiter evolved. The probe also made composition measurements designed to assess the degree of evolution of Jupiter compared to the Sun.
:Galileo extensively investigated the geologic diversity of Jupiter's four largest moons: Ganymede, Callisto, Io and Europa. Galileo found that Io's extensive volcanic activity is 100 times greater than that found on Earth. The moon Europa, Galileo unveiled, could be hiding a salty ocean up to 100 kilometers (62 miles) deep underneath its frozen surface containing about twice as much water as all the Earth's oceans. Data also showed Ganymede and Callisto may have a liquid-saltwater layer. The biggest discovery surrounding Ganymede was the presence of a magnetic field. No other moon of any planet is known to have one.
:The prime mission ended six years ago, after two years of orbiting Jupiter. NASA extended the mission three times to continue taking advantage of Galileo's unique capabilities for accomplishing valuable science. <ref> http://www2.jpl.nasa.gov/galileo/news/release/press030921.html </ref>