  We have studied the fascinating dynamics of the nearby Vela pulsar's nebula
in a campaign comprising eleven 40ks observations with Chandra X-ray
Observatory (CXO). The deepest yet images revealed the shape, structure, and
motion of the 2-arcminute-long pulsar jet. We find that the jet's shape and
dynamics are remarkably consistent with that of a steadily turning helix
projected on the sky. We discuss possible implications of our results,
including free precession of the neutron star and MHD instability scenarios.
