Why a multistage rocket is needed to get a spacecraft off the Earth and into the space?

The concept for multistage rockets goes back to the early 1900s when a Russian high school teacher named Konstantin Tsiolkovsky first idealized the principle of achieving a successful flight in space. The idea suggested by the teacher is simple: a tremendous amount of power is needed to lift an object up towards the atmosphere, and this power will push through against the pull of gravity and give it efficient speed to send the spacecraft into orbit. The rockets that were invented back then are inadequate for the task, as they lack the power required for them to go up to space without being pulled by the Earth’s gravitational force. What must be done is to utilize a combination of rockets that are linked together and are on top of each other. The bottom rocket will give the others at the top a “piggyback ride” towards the atmosphere and gets them moving fast before the other rockets’ engines are engaged. In this way, the top rocket will be able to conserve its energy and fuel that can allow it to travel fast enough to enter orbit. This rocket combination is called a multistage rocket.

Origins of Multistage Rockets

There are several records in history that show where the concept for multistage rockets came from besides Konstantin Tsiolkovsky’s design, and most of these origin stories are dated in periods before the Russian teacher even created the idea.

According to Chinese history, the multistage rocket was illustrated and described by Jiao Yu and Liu Bowen in the 14th-century book “Houlonging.” In the text, the multistage rocket is designed as a weapon that is used by the Chinese Navy. This rocket is said to be the ancestor to the YingJi-62 ASCM, a multistage anti-ship cruise missile. In the Korean records, it is stated that ChoeMuseon, a scientist and engineer, proposed the idea of using multistage rockets for war. After Museon’s proposal, the multistage missiles were then developed by the Korean Firearms Bureau in the 14th century.

Despite all of these speculated origins of multistage rockets, the only ones that are considered to be related to space flight were developed or invented by Konstantin Tsiolkovsky, Robert Goddard, Hermann Oberth, and KazimierasSimonavičius. However, all of these mentioned scientists and engineers have created their concepts independently, but their ideas were mashed together to form the fully-functioning multistage space rocket that we know today.

Multistage Rocket’s Flight

The multistage rocket is able to achieve great speeds because it lightens its weight by dropping the bottom rockets that it uses as a propellant. Moreover, each stage begins its ascent at higher initial velocity, having been boosted by the jettisoned lower stage. Because of its energy and fuel capacity, a three-stage rocket can reach about three times the speed of a single-stage rocket.

Most spacecraft utilized today are launched into space on top of a three-stage rocket. The first stage of the rocket is called the booster, which is the biggest part because it has to lift itself, the other rockets, and the spacecraft at the top through the densest part of the atmosphere. The booster fires for only one or two minutes before its fuel supply is completely exhausted. Then, the booster separates from the rest of the vehicle and falls back on Earth. The second stage ignites for a few minutes and thrusts the entire rocket higher and faster. When its fuel is exhausted, the second rocket is discarded, and the third stage then utilizes its fuel to boost the spacecraft into orbit. In less than 15 minutes, the spacecraft will be able to accelerate from rest at a speed of 28,000 kilometers per hour.

Multistage Rocket Assembly

Of course, building a multistage rocket is a hard task not only because of its size but also for the complexity of each stage. The stages of the rocket are built separately but simultaneously in only one manufacturing site so that the inspectors will be able to monitor the building progress easier. If the multistage rocket is large, it usually goes through a process called “vehicle assembly, ” wherein all the builders and engineers will put together all the stages of the rocket as well as the spacecraft at the top of it in the manufacturing site. If the multistage rocket is relatively small in size, the builder will be able to assemble directly into the launch pad by lifting each stage of the rocket vertically.

Rockets as Space Debris

Because of the many space missions launched by NASA and other agencies found in different countries around the world, the discarded rocket stages or parts are often left in the “outskirts” of Earth, where they will remain floating for years and most of the time even forever. The space debris would orbit around the Earth at varying speeds, and their numbers have begun to increase after more and more space flights are performed. As of 2019, it is reported that there are more than 20,000 floating objects that are orbiting Earth, and most of the space debris would hit rockets or spacecraft and cause minor to severe damages. There have been multiple missions organized by space agencies to remove debris orbiting the Earth, although most of them are considered failures since they weren’t able to collect as much debris as they can using either robots or ships. These collection or removal missions are still being studied to be more effective.