You are right, if one were to shout in space, he cannot be heard.
Sound does not travel through vacuum, empty space. I learned that in our Science laboratory, when we were researching the sound energy and its properties.
Yeap, in space no one can hear you due to the Vac , plus there is no friction, sound does need friction as well, since the wave cause a vibration effecting the molecules, which causes a chain reaction and traveling through the space on Earth.
So since there is no friction and a constant state of vac , no air (particals), no sound.
Malaysian government has just sent an astronaut opp…actually a space tourist into space recently, he wanted to do “teh tarik” pulled tea in space but our Prime Minister said cannot. He was angry so I called him and ask him what will he do, he said “Switch off the camera laa……you can do what ever you want maa…..the stupid PM cannot see what? “