Spacecraft --- Space Shuttle --- Basic Structure and Launching

A space shuttle weighs about 2.05 million kg, and is consisted of the following major components:
- two solid rocket boosters (SRB) - which is critical for the launch
- an external fuel tank (ET) - which carries fuel for the launch
- an orbiter - which carries astronauts and payload

As a space shuttle is an extremely massive object, a large amount of force is needed to lift it to the space.
Let's discuss the following components which is used in launching.
- two solid rocket boosters (SRB)
- three main engines of the orbiter
- the external fuel tank (ET)
- orbital maneuvering system (OMS) on the orbiter

Solid rocket boosters (SRBs)
The SRBs are solid rockets that provide most of the main force (about 71 percent) which is required to lift the space shuttle off the launch pad. Moreover, the SRBs support the whole weight of the space shuttle orbiter and fuel tank on the launch pad.
Each SRB has the following dimensions, parameters and parts:
Dimensions and parameters:
Height - approximately 46 m
Diameter - 3.7 m
Weight: empty - 87,090 kg full - 589,670 kg
Thrust - 11.7 million N
Parts:
solid rocket motor - case, propellant, igniter, nozzle
solid propellant
- fuel - atomized aluminum (16 percent)
- oxidizers - ammonium perchlorate (70 percent)
- catalyst - iron oxide powder (0.2 percent)
- binder - polybutadiene acrylic acid acrylonite (12 percent)
- curing agent - epoxy resin (2 percent)
jointed structure
synthetic rubber o-rings between joints
flight instruments
recovery systems
- parachutes (drogue, main)
- floatation devices
- signaling devices
explosive charges for separation
thrust control systems
self-destruct mechanism
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Main Engines
The orbiter has three main engines located in the aft (back) fuselage (body of the spacecraft).
Each engine has the following dimensions:
Length - 4.3 m
Diameter - 2.3 m (at its widest point - the nozzle)
Weight - 3039 kg
The main engines provide the remaining force (about 29 percent) to lift the shuttle off the pad and into orbit.
The engines burn liquid hydrogen and liquid oxygen, which are stored in the external fuel tank (ET), at a ratio of 6:1. The fuel is partially burned in a pre-chamber to produce high pressure, hot gases that drive the fuel pumps (turbopumps). The fuel is then fully burned in the main combustion chamber and the exhaust gases (water vapor) leave the nozzle at approximately 10,000 km/h.
Each engine can generate between 748,000 N to 937,200 N of thrust; the rate of thrust can be controlled from 65 percent to 109 percent maximum thrust. The engines are mounted on gimbals (round bearings) that control the direction of the exhaust, which controls the forward direction of the rocket.
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External Fuel Tank (ET)
As mentioned above, the fuel for the main engines is stored in the ET.
The ET has the following dimensions:
Length - 48 m
Diameter - 8.4 m
Weight - 35, 425 kg when empty
The ET is made of aluminum and aluminum composite materials.
Two separate tanks can be found inside it, the forward tank for oxygen and the aft tank for hydrogen, which is separated by an intertank region. Each tank has baffles to dampen the motion of fluid inside. Fluid flows from each tank through a 17 in. (43 cm) diameter feed line out of the ET through an umbilical line into the shuttle's main engines.
Through these lines, oxygen can flow at a maximum rate of 66,600 l/min and hydrogen can flow at a maximum rate of 179,000 l/min.
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Orbital Maneuvering System
The two orbital maneuvering systems' (OMS) engines are located in pods on the aft section of the orbiter, one on either side of the tail.
These engines are used to place the shuttle into final orbit, to change the shuttle's position from one orbit to another, and to slow the shuttle down for re-entry.
The OMS engines burn monomethyl hydrazine fuel (CH₃NHNH₂) and nitrogen tetroxide oxidizer (N₂O₄). Interestingly, when these two substances come in contact, they ignite and burn automatically (no spark required) in the absence of oxygen. Each OMS engine can produce 26,400 N of thrust.
The OMS engines together can accelerate the shuttle by 0.6 m/s². This acceleration can change the shuttle's velocity by as much as 305 m/s.
To place into orbit or to de-orbit takes about 31-153 m/s change in velocity. Orbital adjustments take about 0.61 m/s change in velocity.
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Basic Structure and Launching Position and Orbit Communication Navigation Power Computer Returning to Earth