Edited by Michelle Ho
Robert H. Goddard was an American physicist, regarded as the father of modern rocket propulsion, he successfully tested and launched the first liquid-fueled rocket on March 16th 1926. This was a monumental achievement at the time, as it was a first in the history of rocket propulsion research, and to this day, liquid-fueled rockets are the most commonly used type of rocket propulsion to be used in space missions (NASA, 2017).
Rockets work by taking advantage of momentum; or how much power a moving object is; they expel hot exhaust, and even though the exhaust’s gas molecules don’t weigh much individually, they exit the rocket’s nozzle very quickly, giving them a massive amount of momentum. As a result, the rocket moves in the opposite direction of the exhaust with the same amount of energy. Since rockets are designed to be used in space, they need to have their own oxidizers, which is the substance that plays the role of oxygen in burning fuel, these oxidizers are called propellents (National Geographic, 2019).
There are a couple of different types of rocket propellents, but the main two are solid and liquid propellents, and both types of propellents have their own advantages and disadvantages. Solid fuel rockets are simple and reliable, but once it is ignited, it can’t be stopped, they will keep burning until it runs out. Solid fuel rockets also can’t be throttled to control thrust. Solid fuel typically consists of a solid oxidizer in a polymer binder mixed with energetic compounds, metallic additives, plasticizers, stabilizers, and burn rate modifiers (Masterclass, 2021).
Liquid fuel rockets provide less raw thrust compared to solid-fuel rockets, but they can be controlled, which allows astronauts to regulate the speed of the rocketship. These types of rockets can also be turned on and off by either opening or closing the propellent valves. Examples of liquid fuel include liquid oxygen, liquid hydrogen, or Dinitrogen tetroxide combined with hydrazine (N2H4), MMH, or UDMH (Masterclass, 2021).
References
American rocketry pioneer Robert H. Goddard and his first liquid-fueled rocket
[Photograph]. (2017, August 4). NASA.
https://www.nasa.gov/centers/goddard/about/history/dr_goddard.html
Masterclass. (2021, September 29). Retrieved March 9, 2022, from
https://www.masterclass.com/articles/what-are-the-different-types-of-rocket-fuel-learn-
about-solid-and-liquid-rocket-fuel-and-how-rocket-fuel-has-changed-over-time#what-
else-do-rockets-need-besides-fuel
NASA. (2017, August 4). Retrieved March 9, 2022, from
https://www.nasa.gov/centers/goddard/about/history/dr_goddard.html
National Geographic. (2019, January 4). Retrieved March 9, 2022, from
https://www.nationalgeographic.com/science/article/rockets-and-rocket-launches-
explained
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