Space shuttle external fuel tank

Oxygen, in the form of LOX, is widely used as the oxidizing agent in many kinds of rockets and missiles. As an example, the huge external fuel tank required to lift the space shnttle into space holds 145,000 gal (550,000 1) of liquid oxygen and 390,000 gal (1,500,000 1) hydrogen. When these two elements react in the shuttle s main engines, they provide a maximum thrust of 512,000 lb (232,000 kg). 

Space Shuttle PropeUants At liftojf, the arbiter and an external fuel tank carry 3,164,445 L of the liquid propellants hydrogen, oxygen, hydrazine, monomethylhydrazine, and dinitrogen tetroxide. Their total mass is 727,233 kg. Data for the propellants carried at liftoff are given in Table 10.6. 

Facts On January 28, 1986, at 11 38 a.m. EST, the US Space Shuttle Challenger took off from Kennedy Space Center in Florida on Mission 51L. Seventy-three seconds after takeoff, a fire that had broken out on the right solid rocket booster led to an explosion of the adjacent external fuel tank. The shuttle system disintegrated and the orbiter plummeted into the Atlantic Ocean. All seven crew members (Figure 4.6) perished. 

January 28,1986, Cape Canaveral, FL. The 0-ring seal in the booster rocket eroded and blow-by burned a hole in the external fuel tank. Suddenly, mission 51 -L exploded before a world-wide audience on live television. The screens in the control room went blank only a white S remained at the top of each mission control monitor screen. Seventy seconds after launch the Challenger space shuttle fell in pieces from 50,000 ft to the ocean below. ... 

Left bipod ramp.This foam ramp insulates one of the forward connections anchoring the external fuel tank to the space shuttle. It was this foam that broke off after launch. 

A further and key decision was made in that SIAT, in light of the problems uncovered, had recommended additional external reviews of the space shuttle main engine (SSME), the solid rocket boosters (SRB) and the external fuel tank (ET), mentioned earlier. The SIAT team members felt they did not have the required expertise or time to perform these reviews The need to end the SIAT investigation arose simply because we had exceeded the time commitments of the team members. Of the recommended external reviews only the review of the SSME was performed. It was argued that the shuttle program had been reviewed to death and the recommended reviews would be performed in due course by the ASAP. 

The Commission questioned employees of the Marshall Space Flight Center in Huntsville, Alabama, who were responsible for the shuttle s entire propulsion system, including the orbiter main engine, external fuel tank, and SRBs (solid rocket boosters), and also Morton Thiokol, the contractor that had the contract on the SRMs. After the 0-ring problems were discovered through internal documents leaked to the press, the Commission s stance toward NASA shifted from one of cooperative oversight to one of confrontation. 

To understand the technical root cause. Figure 7.8 shows the shuttle system, including the two SRBs, external fuel tank, and shuttle main orbiter vehicle. The SRBs con-tribnte 80% of thrnst at liftoff. They bum for two minutes when, with fuel exhausted, they separate from the orbiter 24 miles downrange and drop by parachute to the sea. The SRBs are made up of a nose forward section, a shroud aft section that covers the nozzle, and a solid-propellant rocket motor (SRM). The SRM consists of four sections, each of which were cast with propellant in the Morton Thiokol factory in Utah and shipped to the Kennedy Space Flight Center in Florida for assembly. 

During the launch of the space shuttle Challenger on January 28,1986, the reaction became imcontroUed. One minute and 13 seconds after takeoff, the external tank and shuttle exploded, killing the shuttle s seven crew members. The accident was caused by defects in the design of O-rings that joined sections of the solid-fuel booster engines, which are attached to the sides of the shuttle. 

The Space Shuttle s main liquid hydrogen-oxygen tank is the largest of the three external tanks. The two smaller boosters use a solid aluminum based fuel. 

As a fuel for the space shuttle, almost 100 tons (400,000 gallons) are stored in the shuttle s external tank. To prepare for a shuttle launch re-... 

Also for the Space Shuttle main engine, an LH2-LOX fuel system was selected which is installed in the External Tank. The LOX tank has a volume of 550 m, the LH2 tank has a volume of 1575 m both consisting of aluminum with a 2.5 m foam insulation [80]. The three high-pressure engines for the Space Shuttle reach a thrust of 2.1 MN each [84]. 

The Space Transportation System (STS) - the space shuttle - consists of an airplanelike orbiter, two solid rocket boosters (SRBs) on either side, and a large cylindrical external tank that holds ciyogenic fuel for the orbiter s main engines. The SRBs detach from the orbiter 2.5 minutes after launch, fall into the ocean, and are recovered for reuse. The external tank is not reused. It is jettisoned as the orbiter reaches Earth orbit, and disintegrates as it falls into the Indian Ocean (Smith, 2003). 

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