Terra (satellite) Terra (satellite) Terra (EOS AM-1) is a multi-national NASA scientific research satellite in a Sun-synchronous orbit around the Earth. It is the flagship of the Earth Observing System (EOS). The name "Terra" comes from the Latin word for Earth. A naming contest was held by NASA among U.S. high school students. The winning essay was submitted by Sasha Jones of Brentwood, Missouri. The identifier "AM-1" refers to its orbit, passing over the equator in the morning. The satellite was launched from Vandenberg Air Force Base on December 18, 1999, aboard an Atlas IIAS vehicle and began collecting data on February
Planet solar wind around itself called the magnetosphere, which the wind cannot penetrate. The magnetosphere can be much larger than the planet itself. In contrast, non-magnetized planets have only small magnetospheres induced by interaction of the ionosphere with the solar wind, which cannot effectively protect the planet. Of the eight planets in the Solar System, only Venus and Mars lack such a magnetic field. In addition, the moon of Jupiter Ganymede also has one. Of the magnetized planets the magnetic field of Mercury is the weakest, and is barely able to deflect the solar wind. Ganymede's magnetic field is several times