Loretta Hidalgo Whitesides - Wired
Since last fall NASA has been faced with the news that vibrations up to 0.5 G inherent in the design of its solid rocket boosters will make the new Ares I a rough ride.
The Space Shuttle is not sensitive to the vibrations of its boosters -- the white rockets strapped to the orange tank, presumably because it is not sitting directly on top of them. But the new Orion crew capsule will sit directly atop the Ares I rocket, and vibrations from the five-segment rocket are expected to be worse than with the four-segment Shuttle booster.
Initially, engineers were worried that the sensitive cryogenics or electronics on board would not do well under that much vibration, but that concern has eased and the team has turned its focus to how vibrations will affect the crew.
The ideal solution would eliminate the vibration at its source in the solid rocket design itself. New configurations of the spacing between segments and other motor design changes have been proposed to smooth out the rocky burn. But that will take time, and NASA wants a short-term option as well. So, in the mean time, they have come up with a suite of systems that will dampen the vibrations after they have started.
Passive vibration control systems (think “shock absorbers”) could be placed between the first two stages to cut down on the highest vibrations (above 0.25 Gs) that are a threat to the health and safety of the crew.