For the first time in more than 3 1/2 years, a space shuttle main engine roared to life on Friday (Jan. 9) in support of NASA's new heavy-lift rocket.

The space shuttle main engine (SSME), now renamed the RS-25D, fired for 500 seconds atop the A-1 test stand at NASA's Stennis Space Center in Mississippi. The first fire of a former SSME since the final shuttle launch in July 2011, Friday's test was the first RS-25D hot fire since the end of shuttle engine testing in 2009.

Four RS-25 engines are planned to power the first stage of NASA's Space Launch System (SLS) megarocket on future missions, including sending astronauts to an asteroid and ultimately to Mars. The first uncrewed SLS test flight is targeted for 2018. [Video: Watch the RS-25 Engine Test Fire]

"The RS-25 is the most efficient engine of its type in the world," said Steve Wofford, the manager of the SLS liquid engines office at NASA's Marshall Space Flight Center in Huntsville, Ala., where the SLS program is managed. "It's got a remarkable history of success and great experience base that make it a great choice for NASA's next era of exploration."

Three RS-25 engines were mounted to the rear of each shuttle orbiter to power the vehicle through its ascent and initial entry into orbit. On the space shuttle, each of the engines routinely operated at 491,000 pounds of thrust. On SLS, they will need to each operate at 512,000 pounds of thrust (on at least the first four flights) and handle colder liquid oxygen propellant and engine compartment temperatures.

"We have made modifications to the RS-25 to meet SLS specifications," Wofford said, "and will analyze and test a variety of conditions during the hot fire series."

In addition to increased thrust and temperatures, the RS-25 engines used on the SLS will encounter greater inlet pressure due to the taller core stage liquid oxygen tank and higher vehicle acceleration, as well as more nozzle heating due to the engine configuration and their position in-plane with the SLS booster exhaust nozzles, Wofford said.

Friday's test fire collected data on the engine's controller unit and inlet pressure conditions.

The engine controller unit, the "brain" of the engine, relays commands to the engine and transmits data back to the launch vehicle. The controller also manages the engine by regulating the thrust and fuel mixture ratio while monitoring the engine's health and status.

The RS-25's new controller will use updated hardware and software configured to operate with the new SLS avionics architecture.

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NASA Conducts 1st Test Fire of Shuttle-Era Engine for New Rocket