SPACE ENVIRONMENT: VIBRATION AND SHOCK


If you already tried riding an airplane, probably the most unforgettable moments of the ride would be the take-off and landing. During such times, you normally experience uncomfortable movements. It's not a perfect analogy, but basically, your satellite also experiences such uncomfortable movements during launch -- vibration and shock

Vibration are relatively long-duration movements that occur during launch. There are several types of vibration that are attributed to various phenomena:

Quasi-Static Acceleration attributed to:
- Acceleration of the launch vehicle during launch
- Low frequency vibrations due to staging effects

Sinusoidal Vibration attributed to:
- Structural response of the launch vehicle

Random Vibration attributed to:
- Aerodynamic events
- Combustion phenomena

Shock are short duration but high impact movements that occur due to the following:
- Separation of fairing
- Separation of other satellites on launcher
- Separation of the satellite itself
- Release of deployment mechanisms

Vibration and shock levels are known and are usually provided by the launcher. Because of this, tests can be conducted to verify if the satellite can survive the launch environment. The structure should be designed to keep the satellite together under these conditions, and not amplify the vibration to the internal components. Further, there are components like relays, crystals, optical elements, etc... that are sensitive to shock and therefore should be considered in the design.

Launch providers are very strict with ensuring that satellites will not break during launch. Any detached components or unwanted activities such as unintended deployment of mechanisms can compromise the entire launch. As such, vibration tests and safety documents are required before a satellite is accepted for launch. 

Kyushu Institute of Technology
Spacecraft Systems Engineering, 3rd edition
Understanding Space: An Introduction to Astronautics, 2nd edition, Jerry Jon Sellers, McGraw Hill, USA 2004
Space Mission Analysis and Design, 3rd Edition, Wertz & Larson, Microcosm Inc., USA 2005

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