Satellite NASA has more than a dozen Earth science satellites in orbit. They help NASA study the oceans, land and atmosphere. Credits: NASA The Jason-2 satellite orbits Earth. It carries tools and sensors to help scientists study the oceans. Credits: NASA The Sputnik satellite was about the size of a basketball and weighed 183 pounds. Credits: NASA A satellite is a moon, planet or machine that orbits a planet or star. For example, Earth is a satellite because it orbits the sun. Likewise, the moon is a satellite because it orbits Earth. Usually, the word "satellite" refers to a machine that is launched into space and moves around Earth or another body in space. Earth and the moon are examples of natural satellites. Thousands of artificial, or man-made, satellites orbit Earth. Some take pictures of the planet that help meteorologists predict weather and track hurricanes. Some take pictures of other planets, the sun, black holes, da