How do space probes communicate from billions of kilometers away?

Deep-space communication relies on radio waves sent through large dish antennas on spacecraft and received by giant antennas on Earth. NASA’s Deep Space Network, with stations in California, Spain, and Australia, keeps contact with spacecraft nearly around the clock as Earth rotates. Because the signal spreads out enormously over distance, probes often transmit at very low bitrates, sometimes just bits or a few kilobits per second. Missions like Voyager 1 and New Horizons show how carefully engineered the system must be to receive faint signals across interplanetary distances.