 Teams from the Marshall Space Flight Center ( MSFC ) went to work on the problems . Of primary concern was the pogo oscillation , which would not only hamper engine performance , but could exert significant g @-@ forces on a crew . A task force of contractors , NASA agency representatives , and MSFC researchers concluded that the engines vibrated at a frequency similar to the frequency at which the spacecraft itself vibrated , causing a resonance effect that induced oscillations in the rocket . A system using helium gas to absorb some of these vibrations was installed . 
