Final answer:
A duplexer is the radar component allowing a single antenna to act as both a transmitter and receiver, critical for applications like those in NASA's Deep Space Network.
Step-by-step explanation:
The component in radar systems that allows a single antenna to both transmit and receive signals is called a duplexer. The duplexer serves as a switch that alternately connects the antenna to the transmitter or the receiver, so that the antenna can send out a pulse and then, almost immediately, receive the returning echoes that provide information about the location, speed, and characteristics of objects in the radar's range.
This function is particularly critical in radar applications where the same antenna must perform both roles nearly simultaneously. For example, in the case of the NASA Deep Space Network, large dish-shaped antennas are used to both send and receive radar waves to and from distant planetary bodies, satellites, and asteroids, allowing measurement of distances and collection of other valuable data.
Radar systems, such as those at the Kennedy Space Center in Florida and the Arecibo Observatory in Puerto Rico, have been instrumental in exploring space and tracking various objects. The Mars antenna in California's Mojave Desert and the Five-hundred-meter Aperture Spherical Telescope (FAST) in China are notable examples of how radar technology is used in astronomy.