When the space shuttle launched from Kennedy Space Center, its roar was unbelievable. Even spectators from miles away should hold onto their seats and lean back. That sound wave can almost penetrate the body and shake the bones.
USATODAY website reported that not long ago, country singer Clint Black made an announcement on the NASA (National Aeronautics and Space Administration) website. According to Black, the events of some recent satellite launches have made him think of himself.
”You know what, my guitar is like a rocket,” he said.
Is this an exaggeration of show business? no. This is a scientific fact. Blake’s guitar is like a rocket. “Both of them resonate,” explains aerospace engineer Rodney Rocha of NASA’s Johnson Space Center (JSC) in Houston. “When you pick up a guitar,” Black demonstrates, “the first thing you notice is the amp on the bottom half of it. And the resonance amp, it’s shaped to match the sound of the guitar strings.” He Flick the guitar’s E string to send out its unique “sweet” E frequency.
”We call it resonance, and any great guitar needs to have that predominant condition,” says Black.
While the resonance might be great for a guitar, “it can be catastrophic for a spaceship,” Rocha cautions, “when the space shuttle lifts off the ground, the roar of the main engine is so loud that it gets close to the launch pad base. people died – not scorched by the heat from its bottom, but by the sound of its engines, which were ‘playing’ the spaceship with tremendous force. The rumble of sound ran through the ship. Spaceships and payloads (space shuttles or satellites) are constantly seeking, probing, shaking.”
”We can’t let these sounds find and set off those moving resonances,” Rocha said. “Otherwise, The sound will be amplified, the vibration will increase, the bolts may be shaken loose, the cover may be lifted, the joints may be loosened.” Even the tragedy of the space shuttle’s lift-off explosion.
”It does make your mission wobbly,” Black said with a laugh.
These engines are not the only source of sound. There is also a huge tearing sound as the rocket lifts off, through the atmosphere and into space. Going fast through the air causes a loud aerodynamic noise that rattles the entire spacecraft. “During the drive, if you roll down the window a little bit, you can hear similar aerodynamic noises,” Rocha said.
Even in space, these noises don’t stop. When a spacecraft is about to connect to another spacecraft, or when it is about to fire its thrusters away; every time a thruster stops or fires, it feels like it’s being played again.
The engineers’ goal, Rocha said, was to make sure those vibrations decayed quickly before they hit the road. In the language of the musicians, “Rocket designers must avoid ‘reverberations'”.
When Blake strums his guitar, the sound lingers for a while. This is due to the construction of the guitar itself, Blake said: “Note that the guitar is made of light, soft wood, which is easy to vibrate.”
Rockets are made of stiff, heavy materials. Yes, this will reduce resonance and aftertaste. But that’s not the only trick used by spacecraft designers. Sometimes they also modify the shape of the rocket, add supports, or fill in gaps. The purpose is to reduce the vibration caused by the rocket itself.
It’s not easy to tune a rocket because it’s more complicated than a guitar.
Think about it, a guitar is made up of many parts, including the pegs, the tuners, the neck, the capo, the top of the amp, and the six strings on the sides. These six strings emit six fundamental frequencies: 82 Hz, 110 Hz, 147 Hz, 196 Hz, 247 Hz, 330 Hz; the corresponding open chord symbols are E2, A2, D3, G3, B3 and E4.
However, a typical rocket is made up of thousands of parts. The famous space shuttle has more than one million parts. All of these parts vibrate together to produce sound waves of various frequencies, from the bass waves that an elephant can hear, to the high-frequency screeching that resembles running the tip of a fingernail across a blackboard.
But which frequencies do the most harm? Which part is most susceptible to resonance? How are you going to tune this complex device?
To answer these questions, NASA engineers have developed a “sound technology room” for the spacecraft. In these large rooms we have the parts we took from the rockets, exposing them to a lot of noise. “It’s loud enough. One of our 165-decibel horns at the JSC can make a noise like the space shuttle’s main engine,” the engineer said.
By observing how the “object under test” responds to sound, engineers can spot resonances and work to improve them. “Most of the most vulnerable parts are lightweight and high surface area—like a guitar,” he cautions.
The “auditory test” has been a routine item in rocket design since the Apollo program 40 years ago. Rocha said: “At that time, NASA engineers were in some special laboratories, using very loud sounds to test certain parts of the rocket that carried the spacecraft, and the test of the space shuttle followed the same. practice.”
Currently, NASA is preparing to build a new spacecraft, called the Astronaut Exploration Vehicle (CEV), which will be used to send astronauts to the moon and Mars. “I’m sure the CEV will also be tested in this sound test room,” Rocha said.
Who would have guessed? “Controlling the sound is as important to a rocket scientist as it is to a musician,” Blake said, fiddling with his guitar. If you listen carefully, you can hear the launch of the lunar probe in the lingering sound.
By the way, what the heck is sound in space? All of the above refers to human flight in space. Spaceships have air inside that transmits sound waves and can hear conversations in the ears. However, there is no air inside the robotic spaceship and no human noise, but it will vibrate and resonate. They are also like guitars.
