Search results

Syncom (for "synchronous communication satellite") started as a 1961 NASA program for active geosynchronous communication satellites, all of which were...

Birkhoff is a giant lunar walled plain that is located on the far side of the Moon, in the northern hemisphere. This formation is an ancient impact site...

Ex-meridian is a celestial navigation method of calculating an observer's position on Earth. The method gives the observer a position line on which the...

Weber is a lunar impact crater on the far side of the Moon, and it cannot be viewed directly from the Earth's surface. This crater is attached to the northwest...