RS-25

The RS-25 engines are the most powerful engines in the world. Also they will be the first reusable engines in history. They were used 30 years ago on another mission, but now they know that they are the right ones to carry with this mission. These engines are 200 feet long and have a diameter of 275.6 feet of diameter. They will be the main engines powering the SLS. They will also be the only ones to function on all of the missions while the astronauts are in space.

The RS-25 will function with hydrogen and liquid oxygen fuel. These engines are already in Florida for trials and they are installing new technology like new hardware and a new battery.

Each engine will be equipped with a Main Engine Controller, an integrated computer that controls all of the engine's functions and monitors its performance.

These engines are very sophisticated because they have 50,000 parts. The engines produce a specific impulse for 453 seconds in a vacuum, or 363 seconds at sea level, consuming 1,340 L of propellant per second. They have a mass of approximately 3.5 tones and are capable of throttling between 67% and 111% of its rated power level in one percent increments. The RS-25 operates at extreme temperatures, with the liquid hydrogen fuel being stored at 250 °C while the temperature in the combustion chamber reaches 3,315 °C     

After 135 missions and more than 280 hours of trials, 100% of missions succeeded. So before using this huge engine, that is referred to with the nickname of “Clark Kent”, they will make further trials to show this is not only the best engine in history but also the right one for the mission. So these engines will allow  the SLS to push 73 times faster than an Indi-500 race car.

Here are some examples that NASA gives us on their official page to know how powerful these engines are:

The fuel turbine that is on the RS-25 is so powerful that if it were spinning an electrical generator instead of a pump, it could power 11 locomotives; 1,315 Toyota Prius cars; 1,231,519 iPads; lighting for 430 Major League baseball stadiums; or 9,844 miles of residential street lights -- all the street lights in Chicago, Los Angeles or New York City.

Pressure in the RS-25 is equivalent to the pressure of submarine experiences three miles beneath the ocean.

The RS-25 engines will be starting their final  trials after they finish testing the J-2X, at the end of November 2014.

The SLS is a mission made by NASA; this would help us to create, new technologies, ad to investigate with more details, our solar system. Also they would send 4 astronauts, to the orbit of the earth, so they would live there, and go on missions. They would also investigate the moon, mars and some asteroids, that are around the earth. The SLS would be launched on 2017, on its first mission, but the second mission would be send with the astronauts, on 2021. So this would be one of the most important missions that the NASA are making, also the SLS, would be the biggest rocket, being even bigger than Saturn V.  This project would also use very advance technology that would help the rocket be on orbit, they would use very powerful engines and boosters, to make of this mission one of the most important on human history.