NASA Ramps Up Space Launch System Sound Suppression Testing


Space Launch System acoustics testing at NASA's Marshall Space Flight Center
in Huntsville, Ala.

The first round of acoustic tests on a scale model of NASA's Space Launch
System (SLS) is underway. The tests will allow engineers to verify the design
of the sound suppression system being developed for the agency's new deep
space rocket.

The testing, which began Jan. 16 at NASA's Marshall Space Flight Center in
Huntsville, Ala., will focus on how low- and high-frequency sound waves
affect the rocket on the launch pad. This testing will provide critical data
about how the powerful noise generated by the engines and boosters may affect
the rocket and crew, especially during liftoff.

"We can verify the launch environments the SLS vehicle was designed around
and determine the effectiveness of the sound suppression systems," said Doug
Counter, technical lead for the acoustic testing. "Scale model testing on the
space shuttle was very

A 5-percent scale model of the Space Launch System (SLS) is ignited for five
seconds to measure the affects acoustic noise and pressure have on the
vehicle at liftoff. The green flame is a result of the ignition fluid that is
burned along with the propellant during this short-duration test.

Image Credit: NASA/MSFC/David Olive

comparable to what actually happened to the vehicle at liftoff. That's why
we do the scale test."
During the tests, a 5-percent scale model of the SLS is ignited for five
seconds at a time while microphones, located on the vehicle and similarly
scaled mobile launcher, tower and exhaust duct, collect acoustic data. A
thrust plate, side restraints and cables keep the model secure.

Engineers are running many of the evaluations with a system known as
rainbirds, huge water nozzles on the mobile launcher at NASA's Kennedy Space
Center in Florida. During launch, 450,000 gallons of water will be released
from five rainbirds just seconds before booster ignition. Water is the main
component of the sound suppression system because it helps protect the launch
vehicle and its payload from damage caused by acoustical energy. SLS with
NASA's new Orion spacecraft on top will be launched from Kennedy on deep
space missions to destinations such as an asteroid and Mars.

A series of acoustics tests also is taking place at the University of Texas
at Austin. Engineers are evaluating the strong sounds and vibrations that
occur during the ignition process for the RS-25 engines that will power SLS.

First to be tested is the rocket's core stage, which houses many of the
launch vehicle's critical pieces including the flight computer and avionics.
The test of the fully assembled vehicle, which will include the solid rocket
motors, will be conducted later this year.

The SLS core stage model has four liquid oxygen-hydrogen thrusters that
simulate the four RS-25 engines built by Aerojet Rocketdyne of Canoga Park,
Calif. Two Alliant Techsystems Inc. (ATK) Rocket Assisted Take-Off (RATO)
motors represent the five-segment solid rocket motors on SLS. ATK, based in
Promontory, Utah, is building the boosters. The motors burn similarly to how
a solid motor would burn for the initial SLS vehicle configuration.

The first flight test of the SLS in 2017 will be configured for a
70-metric-ton (77-ton) lift capacity and carry an uncrewed Orion spacecraft
beyond low-Earth orbit to test the performance of the integrated system. As
the SLS is evolved, it will the most powerful rocket ever built and provide
an unprecedented lift capability of 130 metric tons (143 tons) to enable
missions even farther into our solar system.

For video of the scale model acoustics testing and more information on SLS,
visit:

http://www.nasa.gov/sls