Radar Astronomy

The nature of a radar experiment varies dramatically from target to target. For example, one usually transmits continuously for a duration equal to the two-way light travel time to the target (that is, until the first echoes are about to return) and then receives for a similar length of time. A complete transmit/receive cycle would take more than four hours for observations of Titan, but as little as 12 minutes for Mars less than one minute for an asteroid ten lunar distances from Earth.