About 10 minutes after launch the rocket will release barium vapor, which NASA said is harmless, over the Atlantic Ocean north of Bermuda.

"The ionized portion of the cloud becomes tied to the magnetic field lines and diffuses parallel to the field lines but not perpendicular to it.

Because the motion of the neutral portion of the clouds is not constrained by the magnetic field lines, they spread out more quickly and become too thin to see with the naked eye much sooner than the ionized component.".