How do space probes transmit data back to Earth across vast distances?
In: Planetary Science
Imagine you and your friend were on opposite sides of a valley and wanted to communicate in Morse code, which consists of patterns of long and short beeps to indicate letters. Since you’re so far away, you probably will miss most of the beeps and will likely miss most of the message. Instead of using short and long beeps, you decide to play 1 minute of Beethoven’s 9th for 1 minute to mean a short beep and 1 minute of Death Metal to mean a long beep. If the receiver is knows when to start listening, they will likely be able to tell which type of music is playing at least once per minute. Thus they will be able to receive the message, just much much slower.
This technique is known as forward-error correction and is one of the simplest methods to reduce data transfer errors over a noisy channel. There are many many other methods, founded in math, to detect and compensate for errors that are all collectively known as Error Correction techniques.
Latest Answers