Yes it does. You can record for 30 seconds if your going to send it, or you can set it to available memory.
Sound is made up of vibrations in the air, and because there is almost no air in the vacuum of space, there is no sound either. What you are hearing in these recordings are electromagnetic radiation...
Yes
Voyager 1 is traveling at a speed of approximately 38,030 mph, 17 km/s, or 11 miles a second.