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Aeronautical Engineering/Space Shuttle Main Engine Rocket Questions


Hello, my name is Lauren Colella, I am 16, and am a sophomore at Brewster High School in New York. I am currently enrolled in a Pre-AP Chemistry class and as our final project we are required to receive information from an expert in order to complete a lab report about rockets and why/how they work. My particular rocket happens to be the Space Shuttle Main Engine. I was wondering if you would be willing to answer some of my questions. Thank you for your time. Lauren Colella
1)In a Space Shuttle Main Engine rocket, why is a liquid fuel source used instead of a solid or a gas?
2) Does the size of the rocket depend on what is inside of it/ what it is made out of? Does the size alter the results?
3) What makes this specific rocket able to lift off of the ground?
4) Does the exhaust from the rocket hurt the environment? Is it dangerous to be released?
5) What is special about this rocket, compared to others?

Hi Lauren,

Solid rockets are difficult to control and once lit, they "run" until all the fuel is used up...
Liquid rockets are more controllable and can be throttled (made to produce a varying level of thrust)...
Certainly the size of the rocket depends on the payload.  It takes a lot of energy (coming from the fuel) to put objects in orbit and/or escape the Earth's gravitational pull, so you don't want the rocket to be any larger than necessary to lift a specific payload.
Each of the Space Shuttle Main engines can lift around 400,000+ lbs at liftoff and there are three of them...  the main thrust source at liftoff for the Shuttle though was the solid rocket boosters...
Because the shuttle's main engines used hydrogen and oxygen, the exhaust was simply water...and there is nothing wrong with that... :)
The main thing that was so special about the shuttle's main engines is that they produced a tremendous amount of thrust (yet only weighed around 8,000 lbs, equivalent to a couple of cars) and they are reusable... after each flight the engines were checked refurbished and tested for another flight...  most rocket engines only have to work once...

Thank you and I hope this helps,

Aeronautical Engineering

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