The National Graphic website offers updated satellite imagery as does the ArcGIS.com and EarthExplorer, which is presented on the U.S. Geological Survey website. Digital Globe also offers satellite imagery on its site. The company provides satellite mapping for military and industry use, including oil and gas exploration.
NASA's Goddard Space Flight Center explains the basic process of transmitting satellite data to the ground. According to its website, a satellite gathers data and conveys the information to one of several receiving stations. The data is then transmitted to a science center. Therefore, three stages are involved then in getting information from the communications device to the ground.
To accumulate satellite data, telescopes are used, which collect huge quantities of information. Two kinds of data are gathered. Housekeeping data overviews a satellite's details, such as where the device is pointing, its status information and what parts are working. The housekeeping information then is used by ground crew workers to make sure everything is operating as it should.
Science data is included on the instruments inside the satellite. Information in the form of measurements and images is transmitted back to Earth. Therefore, researchers use the housekeeping information to assess the operation of the instruments while they gather data from on board the satellite. As instruments record their observations, the data is transmitted back to the crew.