The Command and Service Module (CSM) was a crucial component of NASA's Apollo program, designed to transport astronauts to the Moon and back. The CSM consisted of two main parts: the Command Module (CM), where astronauts lived and worked, and the Service Module (SM), which housed essential systems like propulsion and power. The CSM was launched atop a Saturn V rocket and played a vital role in missions such as Apollo 11, the first manned Moon landing. After completing its mission, the Command Module re-entered Earth's atmosphere, while the Service Module was jettisoned before re-entry.