According to NASA, the J-2X rocket engine, a critical component of the planned heavy lift launcher and hence hopes form exploration beyond low Earth orbit is about to be tested at the Stennis Space Center in Mississippi.
The J-2X is a modern version of the venerable J-2 engine that was used in the second and third stages of the Saturn V, which launched American astronauts to the moon. There were five J-2s in the second stage and one in the third stage. The J-2 in the third stage was restarted to blast the Apollo space craft out of low Earth orbit and send them to the moon.
The J-2X would serve a similar role for deep space missions. The performance of the J-2X is far in advance of its venerable predecessor. It will be capable of generating 294,000 pounds of thrust at sea level for the launch portion of the mission and 242,000 pounds of thrust to blast a space craft into a trajectory to the moon, an Earth approaching asteroid, or some other deep space destination.
The J-2X will be tested on the A-2 test stand at Stennis, which was used to test Apollo era engines in the 1960s, was modified to test the space shuttle main engine in the 1970s, and has now been modified to test the J-2X.
The Space Launch System, which uses hardware from both the space shuttle system and the now canceled Ares family of launchers, would consist of two stages in its final form. The exact design of the planned heavy lift vehicle is still in flux as of this writing. But what seems to be evolving in a two stage vehicle, the first stage powered by a combination of solid rocket boosters and a version of the space shuttle main engines, with the second stage powered by the J-2X, according to NASA Space Flight. It will be capable in its final form of launching 130 tons into low Earth orbit.
The idea of building a heavy lift launcher is the result of a tug of war between the Congress and the White House. When the Obama administration originally cancelled the Constellation program, it deferred the development of a heavy lift launcher in favor of a development program that would create "game changing technologies" for space exploration that would, it was alleged, make space flight beyond low Earth orbit easier and cheaper.
Congress, not trusting the Obama administration to keep any commitments concerning space exploration, balked at this plan. Congress mandated that a deep space craft, based on the old Orion design, and a heavy lift launcher be built within five years. NASA is, more or less, attempting to fulfill this mandate, though many within the space agency and the White House still do not see the need for a heavy lifter at this time.
Nevertheless, building a heavy lift launcher is a matter of law as well as public policy. As part of that, the first engine designed to take human beings beyond low Earth orbit is about to be tested by NASA.
Mark R. Whittington is the author of Children of Apollo and The Last Moonwalker. He has written on space subjects for a variety of periodicals, including The Houston Chronicle, The Washington Post, USA Today, the L.A. Times, and The Weekly Standard.
