The vibration environment in space operations covers a wide range of amplitudes and frequencies. Vibration due to space module booster and control rockets, aerodynamic loading, cabin machinery, and equipment is considered as [[Space Health Hazards]] Other environmental variables such as weightlessness, linear acceleration, etc., can be expected to interact with vibration either to reduce or to increase the debilitating effects ## Vibration Protection # Body Posture [[Body Posture for Space Design]] The semi-supine position is generally considered best for severe vibration in x, y, or z-axis, especially under high G-bias loads; i.e., launch, reentry, etc. The seated position is worse for z-axis vibration. The standing position is worse for x, y-axis vibration. # Crewmember Supports [[Space Living]] The resonant frequency of crewmember supports should be one-half of the lowest vibration frequency of significance. Supports that can offer vibration protection are: 1. Contoured seats. 2. Contoured and adjustable couches. 3. Elastic seat cushions. 4. Suspension seats. 5. Body restraints. 6. Rigid or semirigid body enclosures. 7. Head restraints. 8. Vibration absorbent hand/foot pads. **Positioning crewmember stations on structure nodal points can alleviate demands on crewmember body support systems** The control of vibration involves three interdependent elements: 1) Vibration control at the source 2) Interruption or absorption along the transmission path 3) Protection at the receiver. Solutions to look at ##### Gas or fluid flow vibrations Reduce flow rate, Use less pressure, Use quieter valve, Modify impeller, Smooth pipe or duct, Lagging of pipe or duct, Use flow turning vanes at bends ##### Gear vibrations Use proper lubrication, Reduce speed, Balance gear, Replace worn/damaged gears, Use higher quality gear, Use different material gear ##### Rotate vibrations Balance rotor/coupling, Modify force or speed, Alter rotor bearings, Add damping, Reduce mass of moving elements ##### Bearing vibrations Lubricate properly, Adjust bearing alignment or mounting, Reduce speed, Replace worn or damage bearings, Different bearing type ##### Magnetic vibration Use quieter motor, choke or transformer, Isolate or enclose, Relocate ##### Belt/chain vibration Adjust tension, Adjust alignment, Lubricate properly, Reduce speed, Change material or type ##### Pump noise Reduce speed, Reduce pressure, Alter pressure cycle, Isolate ##### Combustion noise Correctly adjust burner, Use lower pressure barrier ##### Impact vibration Avoid it, Cushion it, Apply damping ##### Vibrating wall, floor and frames Reduce area, Add mass, Change stiffness, Detune resonances, Add damping material ##### Source/receiver locations Position source or receiver at vibration nodes, Change position of source or receiver or both, Increase distance between source and receiver #Kareena