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Let me take you back to the year 1975. Gerald Ford had just become president after pardoning the disgraced Richard Nixon. One of the first personal computers, the Altair 8800, was the cutting edge of technology. For a tidy $397 you could have yourself a whopping 1 kilobyte of memory. This was also the same year that NASA developed the Space Shuttle Main Engine, which would be the best rocket technology developed by the space agency for 35 years, until now.
In Huntsville, Alabama at the NASA Marshall Space Flight Center the J-2X rocket is currently being built. NASA's partner in this endeavor, Pratt & Whitney Rocketdyne, also developed the liquid rocket engines for both the Apollo Program and the Space Shuttle Program. The J-2X represents the next step in rocket technology, and will be responsible for the future of America's manned and unmanned spaceflight.
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Setting the Stage for J-2X
The history of rocket technology in America can seem a little overwhelming, but you really only need to look at three different rockets to understand where the J-2X comes from. Its predecessor the J-2 rocket was used during the Apollo Mission, in the Saturn V rocket, starting in 1964. The enormous Saturn V rocket remains the biggest and most powerful rocket ever made, and was able to transport people to the Moon because of a peculiar property of the J-2 rocket. This rocket was able to burn twice, with the first burn placing the rocket into orbit, and the second one giving it the escape velocity necessary to reach the Moon and beyond.
The next step in American rocketry was the Space Shuttle Main Engine, which could not launch a payload as far as the J-2, but was instead designed to make several launches into low-Earth orbit before needing to be replaced. The SSME was a very expensive piece of equipment, pulling in at around $50 million each. The next most recent rocket technology to be made in America was the RS-68 rocket engine, built in the 1990s. This juggernaut was designed for the commercial Delta IV rocket, rather than for NASA. It produces an astounding 758,000 pounds of force, which is about 1.5 times the thrust created by the SSME, while costing about $35 million less. This engine is used almost exclusively to put satellites into orbit because it is not human rated, meaning that it was not designed to safely carry a crew of humans.
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J-2X: The Next Step
Developed from the successes and failures of past rocket engines, the J-2X is based mostly on the J-2 rocket. It will keep the J-2's ability to have two burns, meaning that the J-2X will also be able to reach escape velocity. Like its predecessors, it will be fueled by a mixture of liquid oxygen and hydrogen. It will be designed to be used only once, unlike the SSME, allowing it to be more cost effective. The J-2X will not have the sheer thrust of the RS-68, but it will be human rated. Building upon previous rocket engine designs, the J-2X will allow manned space flight to the Moon and beyond.
The J-2X engine was originally planned to be incorporated into NASA's Constellation Program, which would have been comparable to the Apollo Program. With the retirement of the Shuttle Program, NASA could once again start to push the frontier of manned space flight with the use of the J-2X rocket. However, in 2010 the President, due to budgetary concerns, removed the Constellation Program from the 2011 fiscal year budget. Luckily for the people working at the Marshall Space Flight Center, the J-2X engine is still under development. So when NASA eventually does turn again to a serious attempt at manned space flight, the J-2X will be ready.
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Vacuum Thrust: 1,310.000 kN (294,490 lbf)
Propellants: liquid oxygen & liquid hydrogen
Diameter: 3.05 m (10 ft)
Length: 4.7 m (15.4 ft)
Specific Impulse: 448 sec.
Burn Time: 465 sec.
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J-2 Engine: NASA http://history.msfc.nasa.gov/saturn_apollo/documents/J-2_Engine.pdf