Sound cannot travel through the vacuum of space, but visible light and other forms of electromagnetic radiation can. One of these forms is commonly called radio.

The astronauts have devices in their helmets which transfer the sound waves from their voices into radio waves and transmit it to the ground (or other astronauts in space).

The Exact Form Of Electromagnetic Radiation That Provides Communication In Space

They make use of radio waves. Radio waves signal are sent their headsets that in turn translates the signal in the form of sound.

astronaut communicating with people on earth

While communicating with people on Earth – the radio waves are transmitted which in turn are transformed to sound wave by a radio set.

Radio waves comes from the light spectrum called Electromagnetic Spectrum and thus they are light waves.

Unlike sound, light waves doesn’t need a medium to travel and it is for this reason that the sun ray travels through space to the Earth! Isn’t it amazing?

This is exactly the same as how your radio at home works.

Radio waves are often thought of as a form of sound because of their use in this way, but radio waves are NOT sound waves – they are a form of electromagnetic radiation analogous to visible light, and therefore can propagate through a vacuum.

Credit:

https://timesofindia.indiatimes.com/How-do-astronauts-communicate-in-space/articleshow/1401019.cms

How do astronauts communicate in space