Eli5.. how did they blast off from the moon to get back to earth?
In: 1639
The Saturn V rocket had multiple stages, each with its own engine and fuel load. The benefit of staging is that once you’ve depleted a fuel tank, you can get rid of any extra dead weight and use a different engine which makes it much more efficient.
The amount of energy needed to get into orbit, usually expressed in Δv (meaning the difference in speed you can generate with a given engine and fuel load) is much smaller on the Moon due to the absence of an atmosphere and the much lower gravity. This means that while the rocket that takes off from the Earth needs to be huge and powerful in order to make it into orbit, the rocket that you need to get in orbit around the Moon can be much smaller and less powerful.
The Saturn V had 5 stages. The first two were used to get the rocket to Low Earth Orbit. The third stage was used to do the “Trans-Lunar injection”, which is to set the course for encounter with the Moon. The last two stages were the Command Module (CM) and the Lunar Module (LM). When in space the nacelles protecting the LM would be jettisoned and the LM would be reorientated and docked with the CM. Once over the Moon the CM would use its engine and fuel load to establish a stable orbit around the Moon. Then, two crew members would enter the LM and one would stay on the CM in orbit. When it was time for the crew to leave, the LM would lift off from the Moon’s surface, separating from its landing gear and any extra weight it didn’t need any longer, and meet up with the CM in orbit. Once the crew had transferred inside the CM, they would separate from the LM and return to Earth. With this method they minimised the weight they had to carry around at any point to the possible minimum.
Latest Answers