On land, you can think of the geoid as the level that ocean water would have if you were to dig a canal from the ocean's shore to any point on land. But the Earth is not in deep space -- it is in the middle of a chaotic solar system. There are all sorts of things changing ...
This straight-line inertial path of a satellite, however, is balanced by a strong gravitational attraction directed toward the center of the planet. Sometimes, a satellite's orbit looks like an ellipse, a squashed circle that moves around two points known as foci. The same basic laws of ...
Assuming that proper radiation shielding is provided, the predominant environmental factor of spaceflight is microgravity—also known as weightlessness. Once settled on a new planetary body such as the Moon or Mars, these will have a gravitational regime different from the one on Earth (1 g). All...
This straight-line inertial path of a satellite, however, is balanced by a strong gravitational attraction directed toward the center of the planet. Sometimes, a satellite's orbit looks like an ellipse, a squashed circle that moves around two points known as foci. The same basic laws of ...
This antenna is how the Voyagers receive commands from Earth and send the data they gather back. No matter where a Voyager spacecraft flies, the high-gain antenna always points toward Earth. One of the booms extending off of the main bus carries Voyager’s radioisotope thermoelectric power ...