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.

DCSS (Delta Cryogenic Second Stage)

The DCSS has been selected as the interim upper stage for the first two flights of the Space Launch System (SLS), according to a justification on NASA procurement website.

Based on the responses to that sources sought synopsis, NASA determined that the DCSS is the only means available to support the immediate in-space propulsion needs of the SLS within the SLS manifest schedule constraints," says the agency, “the DCSS is the only known in-space stage requiring relatively minor modifications to enable full compliance with the requirements of the early SLS manifest."

The DCSS is powered by a single Pratt & Whitney Rocketdyne RL-10B engine, fueled by liquid hydrogen, like this one:

The rocket has divided the political and space communities, with supporters trumpeting its unprecedented capabilities and detractors blaming the program for taking precious dollars from NASA. In any case, NASA is now legally required to build SLS, earning it the derisive name 'Senate launch system' in some corners.    

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.

Orbital Maneuvering System- Israel Olvera

Orbital Maneuvering System

The Orbital Maneuvering System (OMS) is basically an hypergolic propellant powered engines that are used by the shuttle during three phases: The ascent, the orbit and the deorbit.

During the initial launch, the engines sometimes may be used after main engine cutoff in order to power up or boost the shuttle to the predetermined elliptical orbit. This is called the OMS-1 burn. But it may not be required based on the payload and mission.

Now, the Orbital Maneuvering System-2 burn is used to circularize the elliptical orbit that the shuttle first enters after launch. These engines may be used to change the shuttle’s orbital characteristics during the mission.

The Orbital Maneuvering System engines are used to deorbit the shuttle so it may reenter Earth’s atmosphere.

The OMS provides enough power for orbit insertion, orbit circularization, orbit transfer, rendezvous, deorbit, abort to orbit, and abort once around. It offers more than 1000 pounds of propellant to the aft reaction control system.

Aft Reaction Control System

 The Aft Reaction Control System is a spacecraft which uses thrusters to provide altitude control or even translation. It uses diverted engine thrust to provide stable altitude control of a short/vertical takeoff and landing aircraft.

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Spacecraft reaction control systems are often used for altitude control while reentering the Earth’s surface, station keeping in orbit and control orientation.

The OMS is stored in 2 independent pods located on each side of the orbiter’s aft fuselage. The pods also house the aft RCS (Reaction Control System) and are referred to as the OMS/RCS pods.

Each one of these pods contains one OMS engine and the hardware that is needed to pressurize, store and distribute the propellants to perform the velocity maneuvers. The vehicle velocity required for orbital adjustments is approximately 2ft per second for each nautical mile of altitude change.

During the first OMS thrusting phase, both engines are used to raise the orbiter to a predetermined elliptical orbit. Next, during the thrusting phase, vehicle attitude is maintained by supporting the OMS engines. The Reaction Control System usually does not come into operation with the OMS thrusting period. However, if during an OMS thrusting period the OMS supporting (or gimbal) rate or gimbal period exceeds their own limits, RCS attitude is required. In case that just one OMS engine is used during the thrusting period, but RCS control is also required.

Attitude Control:

It is the exercise of control over the orientation of an object respecting the inertial frame of reference or any other entity such as certain fields, nearby objects, etc.

During the OMS-1 thrusting period, the liquid oxygen and liquid hydrogen that are trapped in the main propulsion system ducts are dumped. The liquid oxygen is dumped out through the space shuttle main engines’ combustion chambers and the liquid hydrogen is dumped through the starboard side, which is the right side. This velocity was pre-computed in conjunction with the OMS-1 thrusting period.

Once the OMS-1 thrusting period is completed, the RCS is now used to null any residual velocities (just in case it is required). The flight crew operates by using a rotational hand controller or the translational hand controller to command the applicable RCS thrusters to null the residual velocities.

The second OMS thrusting period using both OMS engines occurs near the apogee of the orbit established by the OMS-1 thrusting period and is used to circularize the predetermined orbit for that mission. The targeting data for the OMS-2 thrusting period is selected before launch; however, the target data in the onboard GPCs can be modified by the flight crew via the CRT keyboard, if necessary, before the OMS thrusting period.

Upon completion of the OMS-2 thrusting period, the RCS is used to null any residual velocities, if required, in the same manner as during OMS-1. The RCS is then used to provide attitude hold and minor translation maneuvers as required for on-orbit operations. The flight crew can select primary or vernier RCS thrusters for attitude control on orbit. Normally, the vernier RCS thrusters are selected for on-orbit attitude hold.

Bibliography:

“HSF-The Shuttle.” HSF-The Shuttle. N.p., n.d. Web, 6 Feb. 2014

http://spaceflight.nasa.gov/shuttle/reference/shutref/orbiter/oms/helium.html

“Orbital Maneuvering System.” Orbital Maneuvering System. N.p., n.d. Web, 6 Feb. 2014

http://science.ksc.nasa.gov/shuttle/technology/sts-newsref/sts-oms.html

Hydrogen and Oxygen Fuel

What it is:

Well, in my words and what i undersrand Oxygen fuel is like technology that burns pure oxygen with gaseous fuel. For me is a mix of pure air and gasoline.

The Hydrogen fuel is a zero-emission fuel which uses uses electrochemical cells. It is combustion in internal engines. It is used to power vehicles.

How they use it on the SLS:

They use the Oxygen Fuel and the Hydrogen Fuel to feel the OV's (Orbiter Vehicle) tank, because like I have said it, they are like GASOLINE.

Why do they use it on the SLS?

They use it because it is a liquid-fuel cryogenic rocket engine that was used on NASA's Space Shuttle and is planned to be used on its successor, the Space Launch System.

How it works in general:

Well in case of the Oxigen Fuel they use it to welding and cutting. Welding: a welding torch is used to weld metals. Cutting: a torch is used to heat metal to its kindling temperature.

In case of the Hydrogen fuel, it operates similar to a battery.

Bibliography:

www.nasa.gov/.../sls

en.wikipedia.org/wiki/Oxy-fuel

en.wikipedia.org/wiki/Hydrogen-fuel

inventors.about.com/od/.../ss/Physics_Illustr_2.htm