Final answer:
An astronaut on a spacewalk would see the flash of light from the explosion of a satellite in space, but would not hear the explosion because sound cannot travel through the vacuum of space.
Step-by-step explanation:
When a satellite is launched into space and explodes after exiting the Earth's atmosphere, an astronaut on a spacewalk outside the International Space Station (ISS) would experience this event differently than we would on Earth. The key reasons for this are the absence of air in space and the properties of light and sound.
During the explosion, the astronaut sees a flash of light because light can travel through the vacuum of space. However, the astronaut would not hear the explosion since sound cannot travel through a vacuum; there is no medium like air in space for sound waves to travel through. Consequently, option (a) is correct - The astronaut would see a flash of light.
No shockwave would be observed by the astronaut, as shockwaves are a result of displacing air and require a medium to propagate, which does not exist in the vacuum of space. Additionally, experiencing weightlessness is a constant state for astronauts on a spacewalk outside the ISS and is not specific to the event of the explosion.