Engineers at NASA's Marshall Space Flight Center in Alabama are making progress on the agency's new rocket by listening closely to the roar of four thrusters. The agency is developing the new rocket, called the Space Launch System, or SLS, at Marshall. This vehicle will enable space exploration beyond low-Earth orbit and take astronauts farther into space than ever before.

Marshall engineers recently assembled and ignited a sub-scale collection of thrusters to verify safe operation of an integrated system before creating a full model mockup of the SLS propulsion elements. The combined sub-scale elements, scheduled for testing this fall, will help simulate the intense conditions of the SLS propulsion system, including the noise the engines and boosters make coming off the launch pad.

Test conductors will listen for low- and high-frequency sound waves, as they can both potentially harm the rocket during ascent if not addressed. Low frequency pressure waves can physically impact the vehicle and affect the health of the crew. High frequencies could hurt the smaller, more complex components within the vehicle. Studying these sound waves help engineers redesign the suppression system for a safe launch.

This new round of scale model testing is verifying the operation of the liquid engine models before they are assembled into the full mockup model of the vehicle, liquid engines, and solid rocket motors.

Microphones scattered around the test stand will collect acoustic data and provide valuable information to help redesign Kennedy's sound suppression system at the launch pad to accommodate the SLS, which will be the largest and most powerful launch vehicle ever constructed.