Final answer:
Astronauts use headphones and microphones to communicate during spacewalks because sound cannot travel in the vacuum of space. Radio communication is the alternative used, enabling astronauts to send and receive messages through the vacuum. Deep-space missions require autonomy and powerful radio transmitters because of the delays in communication due to vast distances.
Step-by-step explanation:
Communication of Astronauts During Spacewalks
During spacewalks, astronauts use headphones and microphones to communicate because sound cannot travel in space. Space is a vacuum, which means there is no medium (like air or water) through which sound waves can travel. Thus, when astronauts are outside of a spacecraft, they cannot talk to each other the way they would on Earth.
Radio communication is the primary mode used by astronauts to overcome this challenge. The radio signals can travel through the vacuum of space, allowing astronauts to communicate with each other and with mission control. For example, if astronauts are in a spaceship orbiting the moon and witness an explosion on the lunar surface, they will not hear it because of the absence of an atmosphere to carry the sound. However, they can still discuss the event through radio communication.
Moreover, deep-space exploration presents unique communication challenges where messages take hours to pass between Earth and spacecraft. This is due to the vast distances, exemplified by outer solar system missions, and underscores the need for spacecraft to be highly autonomous and carry powerful radio transmitters.
The echo during conversations with astronauts on lunar walks is another testament to the importance of radio communication. The echo was used to estimate the distance to the Moon. As the astronauts aboard the Space Shuttle experience weightlessness, they too rely on radio communication to mitigate the challenges posed by the vacuum of space and absence of sound transmission.
In conclusion, radio waves, rather than sound, are essential for astronauts to exchange messages and operate efficiently in the unique environment of space.