Federal officials said Starfire's antisatellite work had grown out of one of the site's other military responsibilities: observing foreign satellites and assessing their potential threat to the United States.

The early photography formed a foundation for Landsat and other Earth observing satellites (Lowman 1999).

Monitor-E is the first Russian satellite of a fleet of newly designed, small Earth observing satellites.

NASA's Earth observing satellites gather data including ocean surface temperature, surface winds, sea level, circulation, and marine life.

Struve also observed satellites of Uranus (Ariel and Umbriel, in 1851) and of Neptune.

Advanced Tests Are Planned The first flights are to observe stars and satellites, according to the Strategic Defense Command.

Most commercial earth observing satellites use retrograde orbit, and almost all communication satellites use prograde orbits.

To observe satellites to the (slightly drifting) Sagnac line, one measures the frequency distribution of the satellite pattern with the Sagnac line as a frequency reference.

For nearly 40 years, Landsat and other Earth observing satellites have been silently orbiting the globe collecting high quality images that document the condition of our changing planet.

The web site is dedicated to helping people to observe and track satellites orbiting the Earth without the need for optical equipment such as binoculars or telescopes.