How did NASA solve the Pogo problem?

The Working Group organized a rigorous investigation, which determined the key to mitigating the pogo effect included ‘de-tuning’ the rocket’s engine to change the frequency of the vibration it produced by filling the prevalve cavities on the liquid oxygen (LOX) feed lines with helium gas.

What is pogo suppression?

In this case, the engine shut down before the oscillations could cause damage to the vehicle. Modern vibration analysis methods can account for the pogo oscillation to ensure that it is far away from the vehicle’s resonant frequencies. Suppression methods include damping mechanisms or bellows in propellant lines.

How little vibrations break big rockets?

The engine vibrates up and down with the direction of the rocket’s travel, and if these vibrations match the resonant frequency of the rocket’s structure, which varies as the tanks empty, the whole vehicle will “bounce.” And this bouncing motion can not only damage hardware, it translates to alternating positive and …

What is Pogo stability?

POGO is the longitudinal instability of liquid propellant launch vehicles due to the interaction of structural dynamics with the propulsion system. This interaction may give rise to the initiation of vibrations of large magnitudes when the propulsion and structural frequencies are nearer.

Why do rockets vibrate?

The vibration that is produced by the burning of the solid rocket propellant in the first stage booster is called thrust oscillation. These vibrations – or oscillations – come in the form of waves, which travel up and down the length of the rocket like a musical note through an organ pipe.

What is thrust oscillation?

Also called “resonant burning,” thrust oscillation is a phenomenon in all solid propellant rockets forcing vibrations through the entire structure, in the case of Ares I, that includes the Orion crew module.

What is a Pogo accumulator?

The 3-D printed part tested, called the pogo accumulator, is a beachball-sized piece of hardware that acts as a shock absorber by regulating liquid oxygen movement in the engine to prevent the vibrations that can destabilize a rocket’s flight.

Why do rockets shake?

What is rocket Pogo?

Space launch vehicles can exhibit self-excited longitudinal oscillations, also known as “Pogo” — so named because the phenomenon vibrates the rocket up and down in a manner similar to bouncing on a pogo stick. A key factor in the occurrence of Pogo is how the pumps respond to pressure oscillations in the feed lines.

How does an astronaut feel during take off?

Some astronauts feel dizzy and have an upset stomach during the first few days of a space flight as they get used to zero gravity. This feeling usually goes away after three or four days. After a few days almost everyone is used to zero gravity and feels great.

What does space feel like?

Absence of gravity is known as weightlessness. It is like floating, the feeling you get when a roller coaster suddenly goes down. Astronauts on the International Space Station are in free fall all the time. The astronauts inside it experience weightlessness, floating around in no particular direction.