The Stennis Space Center marked the passing of an era, an end of one long story in the U.S. space program and anticipation of a new chapter.

At the largest U.S. rocket engine test complex, engineers conducted the final space shuttle main engine test on its A-1 Test Stand, ending tests at that facility for the Space Shuttle Program. The A-1 Test Stand was the site of the first test on a shuttle main engine in 1975.

Tests will continue, however, at the A-2 Test Stand until the shuttle program ends in 2010.

This doesn’t mean that the A-1 Test Stand is retired, however. Far from it. The stand soon will test the rocket that will carry America’s next generation human spacecraft, Orion.

The A-1 stand begins a new chapter in its operational history in October. It will be temporarily decommissioned to convert it for testing the J-2X engine, which will power the upper stage of NASA’s new crew launch vehicle, the Ares I.

That J-2X engine also will power the Earth departure stage of the Ares V new cargo launch vehicle. The Ares I and V vehicles will provide the thrust, while the Orion crew capsule will be future astronauts’ home in space.

The J-2X is a modification of the Apollo Program’s J-2 engine, which helped send the first Americans to the moon. The original J-2s also were tested at Stennis.